Fungal Pathogens for Biocontrol of Thrips in Greenhouses 1991 Proposal
PROJECT SUMMARY
Western flower thrips (WFT) pose a major economic threat to the floriculture
industry. WFT control using conventional chemical techniques is difficult,
often ineffective and complicated with the development of insecticide resistance.
Novel approaches to WFT management are needed. Our proposal objectives
aim to investigate the role of insect pathogenic fungi for incorporation
into existing greenhouse IPM strategies.
We have already shown that a number of fungal pathogens are toxic to
WFT and with further tests will select the most lethal and versatile ones
for evaluation in small-scale trials. We aim to study the performance of
these pathogens against WFT larvae infesting flowers and against prepupae
and pupae in the soil. This will enable us to identify strains which are
efficacious and the insect stage and environment which can most effectively
be targeted for control. Finally, we will determine the persistence of
fungal inocula in soils to ascertain how often treatments should be applied
and whether a stable fungal population will develop in the soil to provide
a long-term reservoir of infective material.
These objectives will provide essential preliminary information for
the development of these fungi as biocontrol agents of WFT. Furthermore,
we believe these pathogens have tremendous potential for the control of
other serious pests such as aphids and whiteflies, providing a practical,
effective, environmentally safe and economically viable component for pest
management in the floriculture industry.
INTRODUCTION
The greenhouse is an ideal environment for crop production, providing
proper temperatures, nutrients and water to plants while protecting them
from the extremes of weather. Such conditions, unfortunately, favor insect
development and reproduction. Insect pests, and the cost of their control,
are major problems facing growers. These problems are compounded by the
development of insecticide resistance by pests, phytotoxicity, the hazards
to pesticide applicators, stringent regulations for insecticide use and
the astronomical costs of development, registration and use. These factors
coupled with the public’s negative perception of agricultural chemicals
strongly points out the need for development of alternative management
strategies. Biological methods of pest control are, therefore, very attractive
providing safe, often self- perpetuating short- and long-term control.
Pest management strategies must be systematically developed with a strong
biological component, including an understanding of the interactions between
the target pest and its natural enemy complex. Initially the efficacy of
the bio- control agent against the pest must be experimentally demonstrated.
Then an assessment should be made of their performance in an actual greenhouse
situation. The compatibility of the strategy with other management techniques,
presently in use, can then be determined.
In our current research on the biological control of pear thrips, Taeniothrips
inconsequens, a new pest of sugar maple, we discovered a fungal pathogen,
Verticillium lecanii, causing significant mortality to this insect. Of
particular interest to the floricultural industry is that during the course
of our investigations we have found that our strains of V. lecanii isolated
from pear thrips are highly toxic to the western flower thrips, Frankliniella
occidentalis, (WFT). In fact, they are significantly more pathogenic than
other V. lecanii strains, including those presently produced commercially
and sold for greenhouse pest management in Europe (material from A. Gillespie,
Chr. Hansen’s biosystems, Denmark). These isolates have been obtained from
forest environments in Vermont, Wisconsin, Massachusetts, Pennsylvania,
Connecticut and New York, where exploration for WFT pathogens has not been
done previously. In addition, they appear to possess a number of unique
characteristics which favor their development (R. Humber, USDA-ARS, pers.
comm.).
WFT is a major pest of chrysanthemums and many of the bedding plants.
It is also a vector of the devastating tomato spotted wilt virus which
has a wide range of greenhouse hosts. Research proposed herein is designed
to investigate the potential of these fungal pathogens for the management
of WFT, and other pests of greenhouse crops. As evidenced by our credentials,
our experience with thrips biocontrol has centered on the forest environment.
We do not pretend to present ourselves as greenhouse IPM experts, but sincerely
believe we have unique isolates of several fungal pathogens which have
tremendous potential for use in the floriculture industry. As applied entomologists
we want to expand our research to include the evaluation of entomopathogens
for biocontrol of thrips and aphids in greenhouses. This is the logical
next step for us. We have in place a team of scientists with many years
of experience in entomology and insect pathology. The Vermont team has
taken the lead in the United States to develop biocontrol strategies for
thrips in forests and this exciting, productive research program will facilitate
success of the objectives outlined herein.
Floricultural crops are an excellent example of crops which cannot tolerate
WFT damage (Parrella & Jones 1987). This research will involve selection,
through bioassay, of those pathogens showing the highest toxicity to WFT.
Following screening experiments, the ability of these pathogens to control
WFT in small scale trials will be determined. This series of experiments
will provide essential base-line data on the efficacy of these fungi as
biocontrol agents and will form the foundation for further development
of entornopathogens in greenhouses.
In future experiments these strains must be screened for activity against
other major pest species, including aphids and whiteflies. It is highly
probable that one or more of these fungi will also be pathogenic to these
greenhouse pests, so that potentially, one fungal strain could be used
to control a range of insects. This has obvious economic advantages. In
brief we propose the following objectives: 1. Select fungal strains for
pathogenicity to WFT among isolates of Verticillium lecanii, Beauveria
bassiana and Metarhizium anisopliae, considering toxicity to the pest and
performance according to temperature. 2. Conduct small-scale efficacy trials
on thrips-infested chrysanthemums and soil using promising fungal strains.
3. Monitor the survival and maintenance of an effective level of inoculum
in soil treated with fungal pathogens. Current and Related Research Entomologists
at the University of Vermont responded to public concern over widespread
defoliation caused by pear thrips in 1988. It must be understood that this
pest damaged over 2 million acres of sugar maple trees in the Northeast
and people everywhere demanded immediate action. An intensive research
and management effort was started with funds allocated from the Emergency
Board of the State of Vermont. Research was designed to address the major
concerns of growers and managers. Basic questions, such as “How many thrips
are there in my sugarbush?”; “Will we have similar damage in 1989?” and
“What can we do about this insect?”, were asked.
These concerns formed the basis of a truly applied research program.
Because this was a new pest in a new ecosystem we were forced to develop
a series of protocols to initiate survey and detection procedures to facilitate
the process of predicting future damage (Parker et al. 1990, Skinner &
Parker 1990). This was done through development of an efficient extraction
method for determining thrips populations in different soil types (Parker
& Grehan 1991).
In the course of our state-wide surveys, which were done in over 110
forests, we discovered thrips populations that were infected with a fungal
pathogen (Fig. 1). At the same time we were actively involved in a foreign
exploration project to learn what the natural enemies of pear thrips were
in eastern Europe, their region of origin. This research clearly demonstrated
that fungal pathogens had the greatest potential for management (Carl et
al. 1989).
In the next year our research emphasis was directed towards understanding
the basic biology of the insect and developing fungal pathogens for management.
Rearing, handling and bioassay techniques for pear thrips and other thrips
species (WFT and onion thrips) were developed.
Funds were secured from a variety of sources including IBM, The Windham
Foundation, and the USDA Competitive Grants Program. Basic pathogenicity
studies coupled with investigations of the growth of fungal pathogens are
now underway. We quickly found that WFT and onion thrips responded to our
isolates in a similar fashion as pear thrips. WFT are much easier to rear
and therefore many of the bioassays were done with this species. Fungal
isolates were obtained from many different areas and interestingly we discovered
that our isolates from pear thrips were highly pathogenic WFT. This information
was passed to greenhouse growers in Vermont and thus we were urged to become
involved in management of WFT. As stated previously, we are neophytes in
the IPM of greenhouse pests. However, we have an impressive scientific
team that has extensive expertise in entomological methodologies and insect
pathology. This team is supported by the leading scientists in the world
who deal with thrips and fungal pathogens. The fact that we have not been
involved in greenhouse management is therefore not a major disadvantage.
We believe we have a unique collection of fungal isolates that should and
will be used in the greenhouse industry for biocontrol of thrips. We request
this funding to facilitate our introduction into the industry and to demonstrate
that our material has tremendous potential for use. The experience we have
gained from working with other We are also assessing the incidence and
distribution of other entomopathogenic fungi, such as B. bassiana and M.
anisopliae, in forest soils throughout the eastern U.S. Soil subsamples
have been taken from all sites in our pear thrips regional survey to determine
the incidence and distribution of these entomopathogens, using media selective
for the isolation of V. lecanii (Leslie & Parbery 1972), B. bassiana
and M. anisopliae (Chase et al. 1986, Gaugler et al. 1989). Isolates are
sub- cultured, identified and screened for pathogenicity. This work is
funded through a grant from the USDA.
To date, our detection of fungus- infected thrips is based solely on
extraction of mummified specimens by Rotation. However some entomopathogens
do not cause mummification of the insect body, but cause the insect body
to disintegrate and mortality caused by these pathogens would go undetected.
Therefore, soil will be baited with thrips larvae (Zimmermann 1986, Carl
et al. 1989), and after incubation at 20′C, thrips will be removed by hand
sorting, and cultured. Fungal isolates obtained in this manner will be
tested to confirm pathogenicity to thrips. If these isolates show promise
for thrips control they may be considered for development in the future.
Rationale and Significance Biological control of insect pests is often
the preferred management strategy because of its reduced risk to environmental
quality. It is a long-term strategy requiring research and development
to assure success. Our work development of entomopathogens for pear thrips
management offers hope for control of other agricultural soil-inhabiting
insects as well. The strains of entomopathogenic fungi isolated from thrips
in Vermont soils may be well adapted to other agricultural situations,
such as greenhouses. As pear thrips and WFT both have vulnerable soil stages,
fungi from forest soils may work successfully against both pest species
(R. Hall & A. T. Gillespie, pers. comm.). Our results will produce
new knowledge relating to the principles of plant pest science, particularly
the factors that may limit the effectiveness of a fungal biocontrol. agent
of this type in the soil compared to the aerial environment. our proposed
research is unique in the selection of thrips-pathogenic V. lecanii strains,
and for the appraisal of these strains in a greenhouse environment. The
pathogenicity of V. lecanii isolates to thrips larvae has been demonstrated
in laboratory assays. There is a need to further select and develop these
strains for greenhouse use. Commercial formulations of V. lecanii are currently
available specifically for use in greenhouse conditions. However they are
less pathogenic than our strains to WFT, and are not currently registered
for commercial use in the U.S. Research has shown that pathogenicity varies
among V. lecanii strains, probably in response to environmental conditions
(Jackson et al. 1985). Therefore, careful screening of local fungal isolates
for pathogenicity is essential for development of this biological control
agent for WFT (Zimmermann 1983, Heale et al. 1989).
FUTURE RESEARCH DIRECTIONS LONG-TERM PLAN FOR DEVELOPMENT OF ENTOMOPATHOGENS
FOR BIOCONTROL OF WFT - Determine the effect of relative humidity on spore
germination and production. - Determine the most suitable inoculum (conidia,
blastospores, or hyphae) for WFT infection and develop formulations of
entomopathogens for use in greenhouse situations. - Conduct small-scale
pilot tests in greenhouses for efficacy and proper timing of application.
- Determine the effect of select formulations on non-target organisms,
such as beneficial insects commonly used for pest management in greenhouses,
and mammals. - Determine the longevity of select formulations in the greenhouse.
- Conduct an operational greenhouse trial. - Evaluate compatibility of
select entomopathogens with other pesticides used in greenhouses. - Assist
in the government registration process for greenhouse use. - Integrate
the biological control strategy into a total pest management plan.
REVIEW OF SIGNIFICANT LITERATURE Thrips - Pests of Garden, Greenhouse,
Field and Forest For many years thrips have been known as worldwide plant
pests, attacking a broad range of hosts (Lewis 1973). In the last ten years
many species have surfaced or resurfaced as serious pests. For example,
pear thrips, introduced into California in 1902 where it caused damage
in orchards until 1960, recently reappeared in the East, though this time
inflicting severe and widespread injury to sugar maple (Parker et al. 1988).
Western flower thrips (WFT), a native of the United States, was for years
considered only a minor pest. However, in the past 10 years this thrips
has also gained prominence, and currently ranks as one of the most serious
pests in the greenhouse industry (Robb 1989). Though the specific reasons
for this general thrips resurgence is unknown, climatic changes and extensive
pesticide usage leading to resistance may partly explain these shifts in
insect pest problems.
In contrast with many other thrips species, the damage of WFT is not
limited to injury resulting from foliar or flower feeding. WFT is the principle
vector of tomato spotted wilt virus (TSWV), which intensifies the damage
potential of this pest to greenhouse crops. Like WFT, TSWV has a broad
host range, thereby infecting weeds outside the greenhouse which act as
a reservoir for repeated infection (Zitter et al. 1989). Management of
Western Flower Thrips The ever changing status of insect pests requires
continual reevaluation of existing management strategies and development
of new approaches. In the past growers have commonly relied upon chemical
pesticides for insect control. However, several aspects of WFT biology
make its control with chemicals very difficult. First, WFT are thigmotactic,
tending to hide in tight crevices and feed within deep folds of plant leaves
and flowers, which makes good contact between pest and pesticide difficult
to achieve. Secondly, widespread resistance of WFT to commonly used pesticides
has now been reported, limiting growers choices for effective materials
(Georghiou 1981, Robb 1989). Finally, because WFT is abundant both in and
outside the greenhouse, reinfestation of treated areas occurs continually,
often requiring repeated pesticide applications.
These problems illustrate the great need for development of effective
integrated pest management strategies for the greenhouse industry. Cultural
controls and utilization of natural enemies that are compatible with existing
chemical insecticide practices need to be incorporated. The following characteristics
are sought for the ideal biocontrol agent: 1. High level of field efficacy
and cost effective,
2. Ease of production and application,
3. Compatibility with other control strategies,
4. Non-toxic to mammals,
5. Minimal potential for development of pest resistance. Entomopathogens
meet many of these qualifications and offer great potential for long-term
management of WFT in greenhouses. However research and development of this
strategy lags far behind that of chemical control. Only now with the increased
incidence of insecticide resistance is the reality of the need for biological
control methods being realized. Thrips Biological Control - A Viable Alternative
Biological control in a greenhouse environment offers great opportunities
as well as some drawbacks. Because it is a controlled environment, manipulation
of conditions within the greenhouse can be accomplished to the advantage
of the biological control agent. This is particularly advantageous in terms
of fungal pathogens which in some cases require high humidity to be effective
(Hall & Papicrok 1982, Samson & Rombach 1985).
Numerous natural enemies have been found controlling greenhouse pests,
including hymenopterous parasites, predatory mites and fungal pathogens.
Though parasites and predators may often be independently effective, in
cases of high pest populations and continual reinfestation of greenhouses
from the outside, these organisms are unable to maintain pest populations
below acceptable levels (M. Parrella, pers. comm.).
In addition, rearing large numbers of natural enemies and maintaining
their populations in the absence of the host may be difficult. Ideally,
integration of multiple and compatible control methods is required. Fungal
pathogens show great potential in this regard because many are not toxic
to natural enemies but maintain efficacy in conjunction with chemical pesticides.
In addition, fungi are unique among insect pathogens because they are able
to penetrate the host directly, making ingestion of the fungal material
unnecessary (Hall & Papierok 1982).
In many respects development of fungal pathogens for thrips control
is in its infancy. Though a formulation of V. lecanii is currently in use
in Europe, at present there are no commercially available fungal pathogens
for control of thrips in greenhouses in the U.S. Research by L. Osborne
and M. Parrella on a Paecilomyces sp. shows great promise (M. Parrella
& L. Osborne, pers. comm.). However, development of other fungal organisms
is badly needed to expand the arsenal available to growers. Fungal Pathogens
for Thrips Control Verticillium lecanii.
This entomopathogen was first discovered in 1939 infecting scale insects
(Samson & Rombach 1985). Since then it has been found attacking a wide
range of insects, including aphids, beetles, moths and flies to name only
a few (See Appendix 1). Though the host range of V. lecanii is relatively
broad, research has focused on its efficacy as a biocontrol agent of aphids,
whitefly and thrips in greenhouses. Studies have shown repeatedly that
these pests can be maintained below economic injury levels (Hall 1981,
Binns et al. 1982, Khalil et al. 1985, Gillespie 1987). Because of this
success, commercial formulations are currently available in Europe for
use in greenhouses. This fungus is somewhat unique among entomopathogenic
fungi in that it is also a saprophyte, surviving on decaying organic matter,
and a hyperparasite attacking various fungi, i.e., rusts (Sainson &
Rombach 1985). This aspect of its biology lends itself to persistence in
the environment because even without suitable insect hosts, the fungus
can survive on dead plant material. This fungus is particularly well suited
for commercial manufacture because it will grow on all conventional mycological
media, making laboratory culture relatively simple (Hall 1981) and large-scale
production methods have been developed and standardized (Samsinakova &
Kalalova 1976).
In 1988 we first discovered pear thrips larvae infected with V. lecanii
in a survey of thrips distribution in forest soils (Skinner et al. 1991).
These infected specimens were easy to detect because of their unique pink
coloration (Fig. 1). We found incidence of this fungal infection throughout
Vermont, sometimes at levels exceeding 20% (Skinner et al. 1991), which
led us to investigate its occurrence in other eastern states, where we
again found the fungus. The natural widespread distribution of this fungus
indicates its potential tolerance for a range of environmental conditions.
In addition because of its ubiquitous occurrence in the East, future registration
of this material would be easier than introduction of a foreign organism.
Variability in pathogenicity among strains has been reported (Hall 1984,
Kanagaratnam et al. 1982). Therefore, evaluation of V. lecanii strains
isolated from pear thrips will be a valuable addition to existing information
on this pathogen.
Many characteristics of V. lecanii suggest its unique potential as a
suitable candidate for use in an integrated pest management program for
greenhouses. Firstly, as stated above, this fungus has saprophytic capabilities,
therefore it is able to survive despite low or absent host populations.
Secondly, research has shown that with proper timing it can be used effectively
in conjunction with other natural enemies (Ekbom 1979, Harper & Huang
1986) and chemical pesticides (Olmert & Kenneth 1974, Gardner et al.
1984). Finally entomopathogenic V. lecanii strains have been found to be
non-toxic to plants (Samson & Rombach 1985) and humans (Burges 198
1, Samson & Rombach 1985, Eaton et al. 1986).
Metarhizium anisopliae and Beauveria bassiana. Though much of the past
research on thrips control in greenhouses has focused on V. lecanii, these
two entomopathogens also show promise as effective biocontrol agents for
WFT, and warrant evaluation. Both have been shown to be compatible with
many commonly used pesticides (Vanninen & Hokkanen 1988), and studies
show they are not toxic to humans (Burges 1981). M. anisopliae is a soil-borne
fungus that has been shown to infect over 200 hosts, indicating the strong
need to evaluate compatibility with non-target natural enemies. Research
indicates that it has potential for use against the soil phase of the peach
fruit moth (Yaginuma & Takagi 1987), the black vine weevil in greenhouses
(Gillespie & Claydon 1989) and field populations of the pasture cockchafer
(Gillespie & Claydon 1989).
Though efficacy as a foliar material may be limited, B. bassiana has
been shown to persist in soil, a characteristic favoring its effectiveness
against the pupae of WFT (Storey & Gardner 1988). It has been used
successfully in field trials against numerous insect pests, including the
colorado potato beetle, the corn borer and the codling moth (Gillespie
& Claydon 1989). OBJECTIVES Objective 1. Select Fungal Strains. Select
fungal strains for pathogenicity to WFT among isolates of V. lecanii, B.
bassiana and M. anisopliae, considering toxicity to the pest and performance
according to temperature.
The toxicity of the fungi will be determined by laboratory bioassay
against second instar WFT. Strains of V. lecanii, B. bassiana and M. anisopliae
which have already been shown to be pathogenic to this insect in screening
assays will be used. It is important that a range of fungal pathogens be
included, provided they exhibit comparative pathogenicity, as different
species will show different traits which might predispose them to use in
a greenhouse environment. The ability of the pathogens to infect the insect
over a range of temperatures is also desirable, and them influence of temperature
on infection is being addressed in a current research project. Objective
2. Conduct Small-Scale Trials. Conduct small-scale efficacy trials on WFT-
infested chrysanthemums and soil using promising fungal strains.
As WFT inhabits two distinct environments in its life cycle, on plants
and in the soil, we aim to evaluate the performance of pathogens selected
in Obj. 1 against the insect stages found in these environments. This will
provide essential information on the ability of these fungi to control
the pest in a truer simulation of the insect’s habitat, enable us to identify
which strains might realistically be used, and the insect stage and environment
which can most effectively be targeted for control. Objective 3. Determine
Persistence in Soils. Monitor the survival and maintenance of an effective
level of inoculum in soil treated with fungal pathogens. This is an important
consideration for determining the persistence of viable fungal inoculum
in soil and the carry-over potential of entomopathogens for thrips control.
MATERIALS AND METHODS Objective 1. Select Fungal Strains. in our screening
assays, the toxicity of numerous fungal pathogens has been demonstrated.
These include 11 V. lecanii strains, all isolated from pear thrips; two
strains of B. bassiana; and one strain of M. anisopliae. We are currently
screening additional strains which may be included in the bioassay tests.
Five strains will be selected for further evaluation.
One of the prime considerations for selection will be the calculated
toxicity of each strain following bloassay against second- instar WFT.
A. Fungal Culture. All fungal isolates will be cultured on spread plates
of quarter strength Sabouraud dextrose agar supplemented with 0.25% w/v
yeast extract and incubated at 20 +/- 0.5 C for 10 to 14 days. Conidiospores
will be harvested from the plates by washing with 0.05% Tween 80. Spore
concentration will be determined using a hemocytometer and viable spore
counts will be conducted 24 h prior to the assay (Hall 1976). Spore batches
with > 95% viability will be used. For the dose-mortality tests spore concentrations
from 10^4 to 10^6/ml in sterile distilled water will be used. B. Bioassay.
Conidia will be applied to two 7-cm diam. sterile filter papers (650ul/paper)
and 10 WFT placed on one of the papers (Fig. 4A). The second paper is then
placed over the top of the thrips and the paper-\ \ thrips-paper “sandwich”
is clamped into a type of modified Munger cell (Robb 1989) (Fig 413). This
arrangement does not damage the thrips which are maintained in close contact
with the spore-treated papers. The cells are then placed in plastic bags
to prevent drying and held at 20 +/- 0.5 C. Control assays will be similarly
conducted using sterile distilled water only. Mortality will be assessed
after 5 days. Dead larvae will be surface-sterilized with 1% Clorox, placed
on sterile glass slides and incubated under conditions of high humidity.
These preparations will be examined by phase contrast microscopy after
5 days to confirm infection of the insect with the test fungus. Five replicates
(20 larvae/concentration per fungal strain) will be performed.
C. Expected Results. From the bioassay, we expect variation in the calculated
LC50 and LC90 values (conidial concentrations causing 50% and 90% mortality,
respectively) for the different fungal strains tested. These values will
be used as indicators of the relative potencies of the strains. D. Data
Analysis. Mortality rates among treatments will be adjusted for control
mortality using Abbott’s formula (Abbott 1925). LC50 and LC90 values can
then be calculated by probit analysis (Finney 1962). Values will be compared
using analysis of variance (ANOVA). E. Other Considerations for Strain
Selection. We feel that it is desirable to select different fungal species,
provided they exhibit comparable pathogenicities, for the small-scale trials
planned in the next stage of the investigation. This is because we plan
to target WFT at different developmental stages and in two distinct environments,
i.e. an aerial environment (larval and adult feeding stage); and a soil
environment (prepupal and pupal quiescent stage). It is likely that some
of the fungal species will perform better in one environment than the other,
so that chances of selecting the best type of fungal pathogen for control
of WFT will be enhanced. Furthermore, greenhouse conditions vary in terms
of temperature and humidity. Having a broad base of strain types, we will
be able to ultimately identify the best and most practical strains for
control purposes. Some of these factors are already being addressed by
our work on the influence of temperature on germination, growth and sporulation
in the different fungal strains.
Objective 2. Conduct Small-scale Trials. As WFT inhabits two distinct
environments in its life cycle, i.e. on plants and in soil, we aim to evaluate
the performance of the selected pathogens against the insect stages found
in these environments. This will provide valuable information on the potential
of the fungi to control the pest and the environment which can most effectively
be targeted for control purposes. 2.1 Plant Treatment. A. Preparation of
Inoculum. Fungal inocula will be prepared as outlined in Obj. 1. B. On-Flower
Assays. Thirty potted chrysanthemums bearing approximately three flowers
each will be placed in a large thrips- proof cage, the design of which
has been developed in previous pear thrips work (Parker et al. 1990). The
plants will be maintained at 20′C in an isolated greenhouse. On day 0,
the cage will then be flooded with 200 adult thrips (5 days old) which
will be allowed to move freely onto the flowers to oviposit. WFT have a
pre- oviposition period of approximately 2 days when reared at 20′ (Robb
1989). By collecting adults 5 days after eclosion from a culture maintained
at 20′C in the Entomology Lab, the females will have mated and be ready
to oviposit on suitable material. As the sex ratio of WFT is approximately
1:1 (Robb 1989), by introducing large numbers of adults taken from a healthy
population approximately half of the individuals introduced into each cage
are expected to be females. There will be sufficiently high numbers to
induce a heavy and relatively homogenous floral infestation for each experiment.
Four days after introduction of the adults (day 4), the plants will
be individually removed from infestation cages and the adults dislodged
from the flowers by firm tapping. The adults are easily dislodged in this
fashion, and as the eggs take approximately 6 days from laying to hatching
at 20′C (Robb 1989), there should be no larvae present on the flowers at
this stage. The “clean” plants will then be placed in a second cage free
of adult thrips.
The plants will be maintained at 20′C for a further 6 days to allow
the bulk of the eggs to hatch and develop through to second instars. At
this time (day 10) plants will be randomly selected and placed in batches
of five for treatment. Conidial suspensions prepared in 0.05% Tween will
be applied using a Potters spray tower. A range of conidial concentrations
will be used, equivalent to the LC90, 2 x LC90, and 4 x LC90, values. For
the controls, a 0.05% Tween solution only will be sprayed onto the plants.
The plants will be placed into cages (five per cage), according to treatment
directly after application, and maintained at 20′C for a further 5 days
(until day 15). For the duration of the experiment, plants will be examined
on a daily basis after treatment for evidence of damage symptoms developing
as a result of thrips feeding. On day 15, the infested plants will be taken
to a cold room and larval population counts made on each of the flowers,
dislodging larvae onto a dark surface. At counting, thrips larvae will
be transferred to vials using a fine camel’s-hair brush. Any dead thrips
recovered will be recorded separately and infection confirmed using methods
described in Obj. 1. By doing the counts in a cold room, larval movement
will be slowed down so that accurate counts can be made. This will also
prevent thrips from migrating to other cages. Three replicates per concentration
per fungal strain will be done.
C. Expected Results. Comparisons between populations on control and
treated plants will indicate whether the fungal treatment has been effective
in suppressing the pest. The influence of spore concentration on mortality
will also be investigated. All thrips should remain in the on-plant larval
stage for the duration of the experiment, facilitating full evaluation
of the treatment effect. We acknowledge that our calculations on life cycle
times are based on the observations of Robb (1989). Conditions in our lab
and the WFT culture may differ and refinements to the timing of the experiments
may be required. However, these will be straightforward and the results
will enable us to generate essential preliminary information on which future
experimental work can be based. D. Data Analysis. Differences in larval
populations according to treatment will be compared using suitable statistical
procedures defined by the University of Vermont Experiment Station Statistician.
2.2 Soil Treatment. A. Preparation of Inoculum. Soil inocula will be prepared
as outlined in Obj. 1. B. Soil Assays. Chrysanthemum plants will be infested
with adult WFT as described above. The thrips will be allowed to oviposit
for 4 days before their removal from the plant. The time taken for WFT
to develop from egg to prepupae is approximately 19 days at 20′C (Robb
1989) but the late second instar larvae begin to enter the soil to pupate
approximately 17-18 days after egg hatch.
We intend to leave the flowers for 18 days after removal of the adults
before cutting them off at ground level. Most of the thrips in the soil
at this time will be second instars or prepupae. Pots will be randomly
selected in batches of five, and the soil will be inoculated with appropriate
suspensions of fungal conidia in 0.05% Tween using a Potters Tower. A range
of conidial concentrations equivalent to the calculated LC90, 2 x LC90,
and 4 x LC90, will be applied. For the controls, 0.05% Tween only will
be applied. Water-Tween suspended conidia should move adequately through
the soil profile (Storey et al. 1987) to enable inoculum to reach the pupating
thrips. Inactivation of the inoculum by sunlight is not of real concern
at this stage as the pots will be protected from any harmful rays. Furthermore,
as moist soils will be used, deactivation of the fungal material by desiccation
will not be a problem. After soil treatment, sticky lids coated with Tanglefoot
will be placed over the pots and the adult emergence rate monitored over
time. Batches of five treated pots, one replicate, will be maintained at
20′C in separate thrips- proof cages for 10 days. After this time, all
viable thrips will have emerged and an estimate of the population remaining
in the soil carried out by soil extraction using the methods of Parker
& Grehan (1991). The soil count will provide an estimate of the number
of thrips killed by each treatment. Three replicates per fungal strain
per concentration will be performed.
C. Expected Results. Differences in the numbers of adult thrips emerging
from the soils according to the treatment applied will be observed. Variations
are expected between emergence numbers depending on the fungal strain and
the conidial concentration used. As with the flower assays, methods for
the soil assays may have to be modified depending on the thrips developmental
rate. However, these experiments should enable us to identify fungal strains
which could be used against WFT in soil.
D. Data Analysis. All data generated will be analyzed by the Experiment
Station Statistician to reveal differences in the relative efficacies of
the different treatment regimes applied.
Objective 3. Determine Persistence in Soils. Entomogenous fungi such
as M. anisopliae have been shown to survive and potentially multiply in
the soil over time (Yaginuma & Takagi 1987). Information on the survival
of fungal inocula is essential to ascertain how often treatments should
be applied and whether a stable fungal population is present to provide
a long-term reservoir of infective material. From information generated
in Obj. 2, we will be able to select fungal strains (max 3) which show
good activity in soil assays. The survival of these in soils will be evaluated
by selecting one conidial concentration, which caused high thrips mortality
in the soil assays, for initial soil treatment. A. Prepamtion of Inoculum.
Conidia will be produced as outlined in Obj. 1. B. Soil Inoculation. One-hundred
gram samples of potting soil (fine sandy loam) will be weighed. For each
fungal strain, a batch of 36 x 100 g samples will be sterilized by autoclaving.
When cool, these will be transferred to small plastic pots and inoculated
with 10 ml of the respective conidial suspension. A second batch of 36
non-sterile soil samples will also each be inoculated with 10 ml of the
conidial suspension. The pots will be placed inside plastic bags to prevent
soil drying and transferred to an incubator at 20′C. Batches of sterile
and non-sterile soil win be similarly prepared for the control treatments,
and inoculated with sterile distilled water only. Three pots per treatment
will be removed from the incubator 0, 5, 10, 15, 20 and 25 days after inoculation
for introduction of thrips. A 1 g soil sample, taken to a depth of 1 cm,
will be removed immediately after inoculation to estimate the conidial
concentration at the start of the experiment, and following incubation
for the proscribed period.
C. Soil Assay. Chrysanthemum flowers will be infested with thrips adults
and larval populations allowed to develop as described in Obj. 2.2.B. Flowers
will be cut 12 days after adult removal so that the bulk of the larval
population will still be in the flowers as late-second instars. Flowers
will be placed in small vials over the treated soils, one flower per pot,
the pots will be enclosed to prevent drying and incubated at 20′C. This
will allow the larvae to complete their development on the flower and drop
naturally onto and enter the soil to pupate. Flowers will be removed after
6 days (22 days after initial adult infestation) and the pots covered with
sticky lids. Adult emergence will be monitored for 10 days (day 32), after
which the soils will be extracted using the methods of Parker & Grehan
(1991) to determine numbers of non- emergent thrips. Symptomatic larvae
recovered in the extraction process will be treated as in Obj. 1 to confirm
fungal infection. A third 1 g soil sample will be taken just prior to extraction
to monitor fungal populations at the end of the experimental period.
D. Estimation of Conidial Concentration in the Soil. Estimates will
be made using the methodologies of Chase et al. (1986) and Gaugler et al.
(1988), plating the soil suspensions onto media selective for V. lecanii
(M. Brownbridge & L. de Murguia, unpubl. data), M. anisopliae (Sneh
1991) or B. bassiana (Chase et al. 1986). E. Expected Results. The experiments
will indicate the persistence of the respective fungal strains in soils
over time. This will be monitored in terms of the size of the fungal load
in the soil, and on the infectivity of the soil for thrips entering it
to pupate. The influence of other soil organisms on survival and multiplication
will be partially addressed by using sterile and non-sterile soils. Rather
than seeding the soils with prepupae or pupae, the methods proposed are
simpler and simulate a more natural process, with the larvae moving through
the soil to pupate. This movement may enhance their chances of picking
up a lethal dose of fungal inoculum. These data will provide further information
on the relative merits of different fungal strains for thrips control.
It might also be envisaged that survival and multiplication of the fungus
in the soil would be enhanced if thrips entered the soil and became infected
there. This would result in the production of inoculum in and on the cadavers
of the insect and provide a further source of infective material. This
specific question is not being directly addressed in this series of experiments,
but would be a logical next step in future investigations.
F. Data Analysis. Statistical analyses will be carried out on the data
to determine the significance of the respective soil treatments and time
on fungal survival and multiplication, and on the maintenance of infectivity
for thrips.
RESEARCH TEAM
University of Vermont Personnel: Bruce L. Parker will administrate
and direct all research activities of this project. Est. time: 5 % Michael
Brownbridge will be responsible for conducting all pathological research.
Est. time: 30%
Donald L. McLean will be responsible for conducting all entomological
research. Est. time: 30 %
Margaret Skinner will help with collection and rearing of insects and
other technical aspects of the project. Est. time: 50%
John Aleong, Agricultural Experiment Station Statistician, will assist
in the development of sampling, experimental design and supervise analyses
and interpretation of results. Est. time: <5%
Unassigned part-time technicians will assist seasonally with laboratory
and greenhouse research as required.
Collaborators David Marshall, Mailloux Greenhouses, Ferrisburgh, VT,
will provide technical consultation on applied commercial aspects of fungal
control technology. Est. time: <5%
Raymond Carruthers and Richard A. Humber, USDA-ARS, Ithaca, NY will
provide technical assistance in methods, fungal identification and storage
of pathogenic material. Est. time: <5%
Trevor Lewis, Institute of Arable Crops Research, UK, will provide technical
assistance, advise on all matters relevant to thrips bioecology. Est. time:
2%
Adrian Gillespie, ar Hansen’s BioSystenu, will assist with mass culture
and formulating V. lecanii, and consult relevant to field use of entomopathogens.
Est. time: 2%
FACILITIES AND EQUIPMENT
Entomology Research Laboratory: 115 m2, includes 6 offices, computer
room, 2 wet labs, rearing room, and lab space. Greenhouses: 30 m2 temp.-controlled
glass greenhouse, 65 m2 temp.-controlled plastic greenhouse. Equipment:
2 15-m2 mobile labs -with hoods, air conditioning and rearing chambers;
4 low-temp.-controlled environmental chambers; 15-m2 walk-in cooler; 3
refrigerators; 10-m2 walk-in freezer; 2 chest and 2 upright freezers; 4
chemical fume hoods; oven; dishwasher; autoclave; Torsion electronic precision
balance; and fully equipped workshop with engineering staff. Insect Pathology
Laboratory: 125 m2, with 5 pathology labs, 3 temp.- controlled insect rearing
rooms and 2 offices. Equipment: Labconco microbiological hood, Market Forge
Sterilmatic autoclave, VWR temp.-controlled incubator, 2 environmental
chambers, Precision Scientific water bath, Ohaus electronic balance, pH
meter, magnetic stirrer, water still, Beckman J-6 centrifuge, 1 refrigerator,
1 freezer. Outbuildings: Garages for 3 vehicles and 2 secure storage buildings.
Microscope Equipment: BH-2 Olympus research microscope with phase contrast
and camera system; Olympus VMZ stereo microscope with zoom lens and ring
light; 10 Bausch & Lomb dissecting microscopes and light tables; ACMI
Boroscope with fiber optic light system and video equipment. Computer Equipment:
2 Zenith portable computers; 4 Zietec dataloggers wt soil temperature and
weather monitoring equipment; 9 AT&T 6300 personal computers; 4 IBM
printers; Laser printer; Hewlett-Packard plotter; NEC printer; on- line
access to mainframe computer Campus Support Facilities: Digital DEC System-20
with complete array of statistical and graphical programs and statistical
support services; Scanning electron microscope; Transmission Electron Nficroscope.
Vehicles: 5 pick-up trucks, 2 4-wheel drive vehicles, van, 2-door automobile
APPENDICES
APPENDIX 1
REPORTED INSECT HOSTS OF VERTICILLIUM LECANII
Homoptera:
Aphidae:
Macrosiphoniella sanborni, Macrosiphum avenae,
Aphis fabae, Apis gossypii, Myzus persicae,
Brachycaudus sp., Brevicoryne brassicae
Scales:
Trialeurodes vaporariorum
Lecanium coffeae, L. virdide, L. hemisphaericum,
L. nigrum, Coccus hesperidum,
Hemiptera:
Nabis alternatus
Coleoptera:
Leptinotarsa decemlineata, Colorado beetle
Scolytus scolytus, large elm bark beetle
Scolytus multistriatus, small elm bark beetle
Oulema gallaeciana, cereal leaf beetle
Thysanoptera:
Thrips tabaci, onion dirips
Frankliniella occidentalis, western flower thrips
Taeniothrips inconsequens, pear thrips
Lepidoptera:
Pyrausta nubilalis, European corn borer
Cydia pomonella, codling moth
Lymantria dispar, gypsy moth
Orthoptera:
Melanoplus bivittatus, M. packardii, M. sanguinipes
Diptera:
Aedes triseriatus
Rhabdophaga rosaria
Hymenoptera:
Encarsia formosa
Nematus pavidus
Pristiphora abietina
Collembolla
RESUMES
BRUCE LAWRENCE PARKER
Personal History
Title: Entomologist and Professor of Entomology
Affiliation: Department of Plant & Soil Science
The University of Vermont, Burlington, Vermont, USA 05405
Mailing Address: Entomology Research Laboratory
655B Spear Street
Tel. 902-658-4453
South Burlington, VT 05403
Fax. 802-656-0285
Education:
Thayer Academy, Braintree, MA. 1949 - 1951
University of Maine, Orono, ME. 1951 - 1955 B.A.
Cornell University, Ithaca, N.Y. 1958 - 1962 M.S.
Cornell University, Ithaca, N.Y. 1962 - 1965 Ph.D.
Military Service: United States Marine Corps 1955
- 1957 Sgt.
Employment Record:
Title: Experimentalist
1957 - 1965
Employer: Cornell University
Supervisor: Dr. James E. Dewey, Entomologist
Description: Research - bioassay of insecticides
Title: Professor of Entomology 1965 - present
Employer: University of Vermont
Supervisor: Dr. Lawrence Forcier, Dean
Description: Research (70%) and teaching (30%)
Employment Assignments
Sabbatical - December 1972 - March 1974
University of Malaya, Kuala Lumpur
Description: Research and teaching.
World Bank Consultant - August 1977 - February 1978
Agricultural Development M.A.R.D.I., Serdang, Malaysia.
Agricultural Consultant. February 1979 - April 1979
Government of Malaysia, Plant Protection Division, M.A.R.D.I., Serdang,
Malaysia.
Sabbatical - June, 1980 - July, 1981
International Potato Center, Lima, Peru
Supervisor: Dr. Richard L. Sawyer, Director General
Description: Management of pests in rustic stores.
Agricultural Consultant - August 1982 - September 1982
U.S.A.I.D. Contract with Government of Honduras
Escuela Nacional de Agricultura, Catacamas, Olancho, Honduras.
Agricultural Consultant - March, 1983 - April 1983
U.S.D.A. Asuncion, Paraguay
Description: Presentation of workshop on insect and disease problems in
stored grains.
Agricultural Consultant - August 1983
El Centro Universitario Regional del Litoral Atlantico and
Vermont Partners Project, Honduras.
Description: Negotiations on personnel exchange; data collection at Comayagua
Fish
Sta.; consulting on IPM vegetable crops.
Invited Participant - June 1984
International Potato Center, Lima, Peru. 27th Planning Conference on IPM.
Description: IPM review and member of final committee for preparation of
5-year
world-wide potato IPM research plan.
Regional Entomologist- January 1987 - January 1988.
International Potato Center, Nairobi, Kenya
Description: Developed capabilities in potato IPM in Ethiopia, Kenya, Rwanda,
Burundi,
and Zaire. Acting Regional Director July 27-September 7.
Regional Entomologist - August - September 1988.
International Potato Center, Nairobi, Kenya
Description: Strengthened capabilities in potato and sweet potato IPM in
Ethiopia and
Kenya. Acting Regional Director September 12-26, September - October 1989,
September - October 1990.
Certification:
Registered Agricultural Entomologist No.0346
Commercial Pesticide Applicator No. 2-KKK
RECENT PUBLICATIONS
Grant, J. A., B. L. Parker & H. Suharto. 1990. Controlled-release insecticides
for stored-grain
pest control in Indonesia. I. Laboratory tests. ASEAN Food J. 5(l):34-42.
Grant, J. A., B. L. Parker & D. S. Damardjati. 1990. Controlled release
insecticides for
stored-grain pest control in Indonesia II. Warehouse trial. ASEAN Food
J. 5(2):71-78.
Grehan, J. R., B. L. Parker, D. L. Wagner, J. Rosovsky & J. Aleong.
In press. Root damage
by conifer swift moth: A potential factor in high elevation red spruce
decline. Forest Sci.
Leonard, J. G., D. R. Tobi & B. L. Parker. In press. Spatial and temporal
distribution of
Korscheltellus gracilis in the Green Mountains, Vermont. Environ. Entomol.
Parker, B. L. & E. N. Doane. 1991. The 1990 conference on Thysanoptera.
Abstracts: So.
Burlington, VT, Oct. 23-24. Vt. Agr. Exp. Sta. Bull. 698. Univ. Vt., Burlington.
68
PP.
Parker, B. L., M. Skinner & T. Lewis. 1991. Towards understanding Thysanoptera.
1989
February 21-23; Burlington, Gen. Tech.Rep. NE-147. Radnor, PA. USDA, Forest
Ser.,
NE Forest Exp. Sta.
Parker, B. L., M. Skinner, S. H. Wilmot & D. Souto. 1990. Proceedings,
regional meeting:
Future plans and methods for pear thrips research. Burlington, VT, Nov.
15-16, 1989.
Univ. VT, Ag. Exp. Sta. Bull. 697. 151 pp.
Parker B. L. & G. Hunt. 1989. Phthorimaea operculella (Zell.): New
locality records for East
Africa. Am. Potato J. 66: 583-586.
Parker, B. L., K. E. McGrath, S. Moulton & H. B. Teillon. 1989. History
of the major forest
insects in Vermont. A joint VT Agr. Exp. Sta. and State of VT publication.
Res. Rep.
57. Univ. VT, Burlington. 32 pp.
Parker, B. L., G. W. LaBar & K. E. McGrath. 1988. Chronic effects of
pesticides on
freshwater fish: a review of the literature. Agr. Exp. Sta. Res. Rep. 55.
Univ. of VT,
Burlington. 70 pp.
Parker, B. L., M. Skinner & H. B. Teillon. 1988. Proceedings, regional
meeting: The 1988
thrips infestation of sugar maple. Bennington, VT June 23. VT Agr. Exp.
Sta. Bull.
696. 113 pp.
Skinner, M., B. L. Parker & D. R. Bergdahl. In press. Verticillium
lecanii isolated from larvae
of pear thrips, Taeniothrips inconsequens in Vermont. J. Invertebr. Pathol.
Skinner, M., B. L. Parker, T. M. ODell & W. E. Wallner. In review.
Distribution of gypsy
moth parasitoids in low-level host densities in different forest physiographic
zones.
Envir. Entomol.
Skinner, M. & B. L. Parker. 1988. Groundwater monitoring for agricultural
chemicals: a
review of existing practices. Vt. Agr. Exp. Sta. Res. Rep. 54. Univ. Vt.,
Burlington.
57 pp.
Tobi, D., W. E. Wallner & B. L. Parker. 1989. The conifer swift moth,
Hepialis gracilis,
and spruce-fir decline. In Proceedings of the US-FGR Symposium: Effects
of
atmospheric pollutants on the spruce-fir forests of the eastern United
States and Federal
Republic of Germany. Gen. Tech. Rpt. USDA, Forest Service, Broomall, PA
361-
363.
Wagner, D. L., D. R. Tobi, W. E. Wallner & B. L. Parker. In press.
Korscheltellus gracilis
(Grote): A pest of red spruce and balsam fir roots. Can. Entomol.
Wagner, D. L., D. R. Tobi, B. L. Parker & W. E. Wallner. In press.
The conifer swift moth,
a pest of red spruce and balsam fir. Envir. Entomol.
Wagner, D. L., D. R. Tobi, B. L. Parker, W. E. Wallner & J. G. Leonard.
1989. Immature
stages and natural enemies of Korscheltellus gracilis. Ann. Ent. Soc. Am.
82(6):717-
724.
Wagner, D. L., D. R. Tobi, B. L. Parker, W. E. Wallner & J. G. Leonard.
1989. Immature
stages and natural enemies of Korscheltellus gracillis. ESA Annals 82(6)
998-1010.
Wagner, D. L., B. L. Parker & W. E. Wallner. 1987. Are swift moths
the culprits? Vermont
Science 11:1-4.
Curriculum Vitae
MICHAEL BROWNBRIDGE
Address: The University of Vermont
Nationality: British
Entomology Research Lab
655B Spear Street
South Burlington, VT 05403
Graduate Education:
October 1976-June 1979. Department of Agricultural Biology,
The University of Newcastle Upon Tyne, Newcastle Upon Tyne, England.
BSc (Hons) Degree in Agricultural Zoology. June 1979
Honours Research Project: Effects of the Entomopathogenic Fungus Verticillium
lecanii
on the Aphid Myzus persicae.
Post-Graduate Education:
January 1980-December 1983. Department of Agricultural Biology
The University of Newcastle Upon Tyne, Newcastle Upon Tyne, England.
Thesis submitted April 1985.
Degree awarded June 1985.
Thesis Title: Evaluation of Bacteria as Control Agents of Pasture Leatherjackets
(Tipula
spp.: Tipulidae).
Content: Survey of pathogens and parasites of tipulid larvae; evaluation
of pathogenic
bacteria recovered from tipulid larvae.
Professional Experience:
April 1984-December 1986. Post Doctoral Research Fellow, Department of
Biology,
Ben Gurion University, Beer Sheva, Israel.
Research: isolation and evaluation of mosquito pathogenic bacteria; mode
of action of
B. t. i.; formulation of bacterial pathogens for mosquito control; effects
of environmental
factors on persistence and toxicity of mosquito pathogens.
April 1987-March 1990. Post Doctoral Research Fellow, The International
Centre of
Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi, Kenya.
Research: Isolation and evaluation of B.t. for the control of Lepidopteran
pest species
in sorghum and maize; formulation and field testing of selected Bt. isolates
for control
of cereal stem borer larvae, and the African armyworm.
April 1990-November 1990. Research Scientist, ICIPE, Kenya.
Research: Formulation and field testing of Ba. for the control of cereal
stem borer\
\
larvae in multi-locational and multi-varietal trials; investigations on
the molecular mode
of action of B. t.
November 1990-to date. Assistant Research Professor, The University of
Vermont,
Entomology Lab., South Burlington, VT.
Research: Evaluation of entomopathogenic fungi for the control of pear
thrips,
Taeniothrips inconsequens, and western flower thrips, Frankliniella occidentalis.
Teaching/Supervisory Experience:
1987. ICIPE Regional Training Course in Insect Pathology.
1987-1990. Insect pathology course given to post-graduate students in the
African
Regional Post-Graduate Programme in Insect Science (ARPPIS) at ICIPE.
2 C1987-1990. Supervisor for 5 students taking M.Phil degrees in biological
control.
Supervision of one student for a PhD degree in insect pathology.
Awards:
1980. Ministry of Agriculture Fisheries and Food (UK) studentship, for
post-graduate
studies (3 years).
1990. Japan Society for Promotion of Science (JSPS) Research Fellowship
(not
appropriated).
Society Membership:
Society for Invertebrate Pathology
American Mosquito Control Association
Association of Applied Biologists
Institute of Biology
Languages Other Than English:
French, Hebrew, Swahili.
SELECTED PUBLICATIONS
Brownbridge, M. & L Margalit. 1986. New Bacillus thuringiensis strains
isolated in Israel are
highly toxic to mosquito larvae. J. Invertebr. Pathol. 48:216-222.
Brownbridge, M. & J. Margalit. 1987. Mosquito-active strains of Bacillus
sphaeficus isolated
from soil and mud samples collected in Israel. J. Invertebr. Pathol. 50:106-112.
Brownbridge, M. & J. Margalit. 1987. Identification of Bacillus thulingiensis
strains, toxic to
mosquitoes, recently isolated in Israel.
Brownbridge, M. & B. I. Selman. 1989. Improvements in rearing lab cultures
of leatherjackets
(Tipula spp.) (Diptera, Tipulidae). Entomologist’s Mon. Mag. 125:123-127.
Brownbridge, M. In press. Isolation of new entomopathogenic strains of
Bacillus thuringiensis
and Bacillus sphaericus. Israel J. Entomol.
Brownbridge, M. In press. The role of bacteria in the management of Chilo
spp. Insect Sci.
Applic.
Brownbridge, M. & T. Onyango. In press. Screening of exotic and locally
isolated Bacillus
thuringiensis (Berliner) strains in Kenya for toxicity to the spotted stem
borer, Chilo
partellus (Swinhoe). Trop. Pest Management.
Brownbridge, M. & T. Onyango. In press. Laboratory evaluation of four
commercial
preparations of Bacillus thuringiensis (Berliner) against the spotted stem
borer, Chilo
partellus (Swinhoe) (Lepidoptera: Pyralidae). J. Appl. Entomol.
Hamal, M., M. Brownbridge, M. Broza & B. Sneh. In press. Screening
for highly effective
isolates of Bacillus thuringiensis Berliner against Spodoptera exenipta
Walk. and S.
littoralis Boisd. (Lepidoptera: Noctuidae). Phytoparasitica.
Broza, M., M. Brownbridge & B. Stich. In press. Monitoring secondary
outbreaks of the
African armyworm using pheromone traps and scouting for egg masses, to
determine
the optimal timing for application of Bacillus thuringiensis. Ecol. Entoniol.
Broza, M., M. Brownbridge, M. Hanial & B. Sneh. In press. Control of
the African armyworm
Spodoptera exempta Walker (Lepidoptera: Noctuidae) in Kenyan fields with
highly
effective strains of Bacillus thuringiensis Berliner. Phytoparasitica.
DONALD LEWIS MCLEAN
Personal History
Title: Entomologist and Professor of Entomology
Affiliation: Department of Plant & Soil Science
The University of Vermont, Burlington, Vermont, USA 05405
Mailing Address: Entomology Research Laboratory
655B Spear Street
Tel. 802-658-4453
South Burlington, VT 05403
Fax. 802-656-0285
Education:
Tufts University,
1953 B.S.
University of Massachusetts
1955 M.S.
University of California, Berkeley
1958 Ph.D.
Employment Record:
Title: Junior Entomologist
1958 - 1959
Employer: University of California, Davis, CA
Title: Assistant Entomologist
1959 - 1965
Employer: University of California, Davis, CA
Title: Associate Professor of Entomology 1965 - 1972
Employer: University of California, Davis, CA
Title: Professor of Entomology
1972 - 1987
Employer: University of California, Davis, CA
Title: Professor Plant and Soil Science 1987 - Present
Employer: University of Vermont
Employment Assignments
Chair, Department of Entomology - 1974 - 1979
University of California, Davis, California
Acting Associate Dean, College of Agricultural and Environment Sciences
- 1978 - 1979
University of California, Davis, California
Dean, Division of Biological Sciences - 1979 - 1985
University of California, Davis, California
Dean and Director, College of Agriculture and Life Sciences - 1987 - 1991
University of Vermont, Burlington, Vermont
Research Associate, Department of Plant & Soil Science - 1991 - Present
Entomology Research Laboratory, University of Vermont
Research
Summary of Research
Laboratory and Field Biology, Physiology, Behavior and Ecology of Some
aphid and
Leafhopper Vectors of Plant Pathogens (Univ. of California, Davis).
Design and Implementation of Electronic Measurement Systems to Study Aphid
and
Leafhopper Probing and Feeding Behavior (Univ. of California, Davis).
Biochemical, Physiological and Morphological Investigations of the Primary
Symbiont
of the Pea Aphid (Univ. of California, Davis).
Management of aphids and thrips in greenhouses (Univ. of Vermont).
Administrative Advisory Committees
1976 - 1979 Member, Agricultural Pest Control (Advisory to Director, California
Department of Food and Agriculture, Sacrament).
1976 - 1985 Administrative Advisor, Western Regional Coordinating
Committee 24,
Pests and Diseases of Grapes.
Professional Society Affiliations
American Association for the Advancement of Science
American Institute of Biological Sciences
Entomological Society of America
Sigma Xi
Elected and Appointed National Offices, Entomological Society of America
1966 - 1968 Secretary, Vice-Chair, Chair, Subsection Cc, Insect Vectors
in Relation
to Plant Diseases
1984 President, Entomological
Society of America
PERTINENT PUBLICATIONS
McLean, D. L. 1962. Transmission of lettuce mosaic virus by a new vector,
Pemphigus
bursatius. J. Econ. Entom. 55(5):580-583.
McLean, D. L. and M. G. Kinsey. 1963. Transmission studies of a highly
virulent variant of
lettuce mosaic virus. Plant Disease Reporter 47(6):474-476.
McLean, D. L. 1964. An attempt to relate depth of stylet penetration to
the transmission
efficiency of two aphid vectors. J. Econ. Entom. 56(6):955-957.
Hodges, L. R. and D. L. McLean. 1969. Correlation of the transmission of
bean yellow mosaic
virus with salivation activity of Acyrhtosiphon pisum (Homoptera: Aphididae).
Ann. Ent.
Soc. Amer. 62(6):1398-1401.
Houk, E. J. and D. L. McLean. 1974. Isolation of the primary intracellular
symbiote of the pea
aphid, Acyrthosiphon pisum. J. Invert. Path. 23:237-241.
Bacon, O. G., V. E. Burton, D. L. McLean, R. H. James, W. D. Riley, K.
G. Baghott and
M. G. Kinsey. 1976. Control of the green peach aphid and its effect on
the incidence
of potato leaf roll virus. J. Econ. Entom. 69(3):410-414.
Hemmati, K. and D. L. McLean. 1977. Gamete-seed transmission of alfalfa
mosaic virus and
its effect on seed germination and yield in alfalfa plants. Phytopathology
67(5):576-
579.
Purcell, A. H.@ A. H. Finley and D. L. McLean. 1979. Pierce’s disease bacterium:
Mechanism of transmission by leafhopper vectors. Science 206:839-841.
Hemmati, K. and D. L. McLean. 1980. Ultrastructure and morphological characteristics
of
mycoplasma-like organisms associated with Tulelake aster yellows. Phytopath.
Z.
99:146-154.
Ullman, D. E. and D. L. McLean. 1988. The feeding behavior of the summer-form
pear psylla.
Ent. Exp. and Appl. (In Press).
Ullman, D. E. and D. L. McLean. 1988. The feeding behavior of the winter-form
pear psylla
on reproductive and transitory host plants. Ann. Ent. Soc. Amer. (In Press).
Ullman, D. E., C. O. Qualset and D. L. McLean. 1988. The role of Rhopalosiphwn
padi
(Homoptera:Aphidae) probing activities in barley resistance to barley yellow
dwarf virus.
Environ. Ent. (Submitted).
MARGARET SKINNER
Personal History
Title: Research Technician
Affiliation: Department of Plant & Soil Science, The University of
Vermont
Entomology Research Laboratory, 655B Spear Str., So. Burlington, VT 05403
Education:
University of Vermont Ph.D.
1987 - present Major: Entomology
M.S.
1984 - 1987
Major: Entomology
Ohio Wesleyan University B.A.
1968 - 1972
American Univ. of Beirut, Beirut, Lebanon
1971
Work Experience:
Entomological Experience:
1984 - now Research Technician - Univ. of Vermont
Entomology Research Laboratory
1988 - now Coordinate research on pear thrips bioecology
in a forests. Design,
conduct and oversee research on pear thrips biology and management;
compile, analyze and interpret data; and publish and present findings.
1984 - 1987 Coordinated field work for USDA-funded research
on biological control
of the gypsy moth. Supervised field technicians in data collection and
entry; prepared written reports and oral reports.
1985 & 1986 Teaching assistant in Forest Entomology.
1986 -1987 Designed state-wide groundwater survey
program to monitor contamination
by agricultural pesticides for VT Dept. of Agriculture. Developed program
protocols and quality assurance plan; providing recommendations for
monitoring well design and construction, and sampling methods.
Human Services Experience:
1979 - 1988 Coordinator - Supervised Apartment Program
at Burlington-based mental
health agency. Designed training plans for mentally handicapped adults
living independently in apartments, supervised 8 - 10 staff.
1978 Residential
manager - Community for mentally handicapped adults in
Glouchester, UK. Managed household of handicapped adults; providing
counseling and clinical interventions.
1974 -1978 Orchard Manager in community for mentally
handicapped adults in No.
Ireland. Supervised orchard maintenance with residents, and coordinated
harvest and marketing of annual 2-ton fruit crop.
1972 -1974 Professional potter and pottery teacher.
Memberships and Certificates:
- Certified Pesticide Applicator, License #001586, Dept. of Agriculture,
State of Vermont.
- Governor’s Task Force on Pear Thrips - Member 1988 - present.
- Entomological Society of America - Graduate Student Committee. - Student
Advisory
Committee to the Graduate College
- Graduate representative to Plant & Soil Science Dept. - Univ. of
Vermont - 1988 - present.
Selected Publications:
Parker, B. L., M. Skinner & H. B. Teillon. 1988. The 1988 thrips infestation
of sugar
maple. Univ. VT Agric. Exp. Stn. Bull. 696. 113 pp.
Parker, B. L., M. Skinner, S. H. Wilmot & D. Souto. 1990. Proceedings,
regional meeting:
Future plans and methods for pear thrips research. Burlington, VT. Nov.
15-16, 1989.
Univ. Vt. Ag. Exp. Sta. Bull. 697. 151 pp.
Parker, B. L., M. Skinner & T. Lewis. 1991. Towards Understanding Thysanoptera.
Gen.
Tech. Rep. NE-147. USDA, For. Ser., NE For. Exp. Sta. Radnor, PA.
Skinner, M. & B. L. Parker. 1988. Groundwater monitoring for agricultural
chemicals: A
review of existing practices. Univ. VT Agric. Exp. Stn. Res. Rpt. 54. 57
pp.
Skinner, M. & B. L. Parker. 1991. Bioecology of pear thrips: distribution
in forest soils, pp.
193 - 212. In B. L. Parker, M. Skinner & T. Lewis, [eds.], Towards
Understanding
Thysanoptera. Gen. Tech. Rep. NE-147. USDA, For. Ser., NE For. Exp. Sta.
Radnor,
PA.
Skinner, M., B. L. Parker & S. H. Wilmot. 1991. The life cycle of pear
thrips, Taeniothrips
inconsequens (Uzel) in Vermont, pp. 435 - 444. In B. L. Parker, M. Skinner
& T.
Lewis, [eds.], Towards Understanding Thysanoptera. Gen. Tech. Rep. NE-147.
USDA,
For. Ser., NE For. Exp. Sta. Radnor, PA.
Skinner, M., B. L. Parker, W. E. Wallner & T. M. ODell. 1991. Distribution
of gypsy moth
(Lepidoptera: Lymantriidae) parasitoids in low-level host densities in
different forest
physiographic zones. Envir. Entom. In review.
Skinner, M., B. L. Parker & D. R. Bergdahl. 1991. Verticillium lecanii,
a fungal pathogen
of pear thrips, Taeniothrips inconsequens (Uzel) in Vermont. J. Invert.
Path. 58:000-
000.
Parker, B. L., M. Skinner & J. Grehan. 1989. A mechanized soil extraction
system for
determining population densities of pear thrips in sugarbushes. Univ. VT.
Entomol.
Res. Lab. Final Rpt. to the North American Maple Syrup Council. 25 pp.
Skinner, M. & B. L. Parker. 1989. Vermont soil survey for pear thrips:
Protocol for
regional sampling program. Univ. VT. Entomol. Res. Lab. Rep. 7 pp.
Project Leader Qualifications
The Project Leader, Bruce L. Parker, has an M.S. and Ph.D. in entomology
from
Cornell University. He is a Professor of Entomology at the University of
Vermont where he
has been continually employed for 26 years with major responsibilities
in Integrated Pest
Management. He directs all research activities at the Entomology Laboratory.
The following
projects related to thrips research and management have recently been funded
and are directed
by him:
Fungal Pathogens for Biocontrol of Pear Thrips
USDA, Competitive Grants
$120,000
Foreign Explorationfor Thrips Entomopathogens
USDA,ARS
$16,500
The Biological Control of Pear Thrips with Fungi
USDA, ARS
$50,000
The Fungal Infection Process in Pear Thrips
NAMSC
$10,500
Towards Understanding Thysanoptera
USDA, Forest Service
$10,000
At the Entomology Research Laboratory Dr. Parker directs a research team
that is
comprised of 3 Ph.D research associates, 3 Ph.D. and 4 M.S. graduate students,
3
undergraduate work-study students, 2 high school research apprentice students
and 5 technicians.
An important component of the research activities is the education of young
people. Emphasis
is placed on practical aspects of research and developing individuals to
effectively work in
agricultural situations in the future. Dr. Parker has 88 research publications
to his credit.
It should be stressed that the strength of this proposal is found in the
total team
interdisciplinary effort. The Project Leader is important but the scientists
doing the research
are each highly qualified individuals and will ensure success. Dr. Brownbridge,
the Insect
Pathologist, has years of experience with fungi and biological control
mechanisms. Dr.
McLean, Past President of the Entomological Society of America, is a scientist
with vast
experience, particularly with insect vectors of disease, and is known world-wide
for his
expertise. Ms. Skinner, will soon complete all requirements for her PhD
and has done her
thesis research on the Bioecology of pear thrips. Couple this team with
an impressive list of
cooperators and the total qualifications should speak for themselves.
BUDGET
Project Start Date: January 1, 1992
End Date: December 31, 1992
CONTRIBUTING AGENCY
American Floral Plant & Soil
Univ. of
Direct Costs
Endowment
Department
Vt.
Personnel
Salary & Wages
B. L. Parker
0
0
0
M. Brownbridge
$6,500
0
0
D. McLean
0
22,838
0
M. Skinner
5,500
0
0
Total Salaries
12,000
22,838
0
Total Fringe Benefits (36%)
4,320
8,222
0
Other Expenses
Statistical Services
1,750
0
0
Supplies
5,500
0
0
Travel and Milage
1,250
0
0
Total Other Expenses
8,500
0
0
Total Direct Costs
24,820
31,060
0
Total Indirect Costs
0
0
13,523
TOTAL PROJECT COST:
$69,403
American Floral Endowment Contribution
$24,820
University of Vermont Contribution
$44,583
MAILLOUX’S VT. COUNTRY FARM MARKET
RTE.7 FERRISBURGM, VT. 05456 (802) 8177-3396
AUG. 01, 1991
The American Floral Endowment
Dear Fellow Growers,
I am writing you, to both indicate our support, and encourage
your support for the study of fungal pathogens for bio-
control of thrips in Greenhouses, being carried out at the
University of Vermont-
As growers, we are constantly combatting thrips in both
our greenhouses and in our field crops with ever decreasing
resul ts .
We feel that the University of Vermont’s staff,
facilities, and experience in this area of bio-control places
them on the leading edge of this rapidly expanding segment of
our industry. As such we have indicated our willingness to
assist them in any way possible, including the use of our
greenhouse range to further their work.
I sincerely hope you will give this matter the
consideration it deserves.
Thank-you in advance.
Pest Control Coordinator
STATE OF VERMONT
DEPARTMENT OF AGRICULTURE, FOOD & MARKETS
OFFICE OF THE COMMISSIONER
DIVISION OF AGRICULTURALDEVELOPMENT
DIVISION OF ANIMAL & DAIRY INDUSTRIES
DIVISION OF PLANT INDUSTRY, LABORATORIES & CONSUMER ASSURANCE
Au-ust 2, 1991
Ms Betty Abrahams
American Floral Endowment
37 Camelot Drive
Edwardsville, IL 62025
Dear Ms Abrahams:
As you are well aware, Western Flower Thrips, Frankliniella occidentalis.
is a major pest of
greenhouses in most of the U.S. The damage caused by this and other thrips
has inflicted severe
economic hardships on several growers in Vermont as in other states. Western
Flower Thrips is
also a vector of Tomato Spotted Wilt Virus for which there is no control
once the disease in
introduced into the plant. With this in mind, we would like to strongly
support Dr. Bruce Parker
and his exceptional research team at the University of Vermont with their
proposal– “Fungal
Pathogens for Biological Control of Thrips in Greenhouses”.
Current control measures, including the use of organophosphates such as
Chlorpyrifos, are not
always reliable. Control efforts are long overdue using fungal pathogens.
We feel the use of
fungal pathogens needs more research and should prove to be an effective
and efficient means to
control thrips. Once these pathogens are identified and efficacy data is
obtained, their use will be
welcomed by the greenhouse industry.
We have had the pleasure of working with Dr. Bruce Parker and his research
team on several
projects over the past 14 years. His expertise, professionalism and reliability
are second to none.
Over the past +/- five years, Dr. Parker and his team have been working
with pear thrips on sugar
maple. Their research also includes the use of fungal pathogens. They have
consulted with world-
renowned thrips experts such as Dr. Lewis,Trevor and have an excellent
working relationship with
these authorities. Vermont is fortunate to have this professional staff
working for them.
We would be happy to speak with you about Dr. Parker and his research proposal
if you
would like. Our telephone number is (802) 828-2431. Please consider Dr.
Parker’s research
proposal for funding.
Sincerely,
-CECIL f @@q
4oon P. Turmel
Scott Pfister
State Entomologist
State Plant Pathologist
116 STATE STREET, MONTPELIER, VERMONT 05620
MAILING ADDRESS: 120 STATE STREET, MONTPELIER, VERMONT 05620
(802) 828-2500 FAX: (802) 828-2361
