The Development of Integrated Pest Management in Floriculture 1995 Proposal
Strategies in Floriculture
1996
This proposal continues research initiated over the past few years which
has emphasized the development and implementation of integrated pest management
strategies in floriculture with a focus on biological control. The project
covers a broad range of arthropod pests attacking the major floricultural
crops in the U.S. A major objective is to formulate practical alternatives
to pesticides in floriculture and still provide the means for a grower
to produce a high quality crop. My continuing proposal for 1996 includes
the following areas: biological control, biological studies of pests and
their natural enemies; pesticide efficacy and compatibility with natural
enemies, development of practical sampling plans for major pests; and continued
compilation of literature in the areas of IPM and biological control related
to production of floriculture crops.
The concept of biological control continues to be supported by most
growers, but few mainstream commercial growers utilize biological control
in their production. There are several reasons for this, but a major limitation
is the inability of commercially available natural enemies to provide the
level of control demanded during the production of an aesthetic value crop.
In addition, concurrent pesticide use or the residues from recently applied
materials are often incompatible with natural enemies. This proposal directly
addresses these limitations by 1) examining the feasibility of utilizing
two or more natural enemies simultaneously to achieve acceptable control,
and 2) screening new biorational pesticides that may offer compatibility
with, rather than eradication of, natural enemies. This work is started
in the laboratory/greenhouse and then transferred to the field where research
is done with cooperating growers. The major pests addressed in this section
include western flower tbrips and mealybugs.
Basic biological studies will continue with the natural enemies of leafminers,
western flower thrips, and whiteflies. Such information will allow for
better utilization of natural enemies biological control programs. Sampling
plans for western flower thrips and mealybugs will be developed to better
aid growers in determining the level of these pests in the greenhouse.
In addition, we will try to develop a relationship between the number of
thrips caught on sticky cards and the presence of thrips on the crop.
DETAILED EXECUTIVE SUMMARY
Biological Control
a. Work will continue where several natural enemies will be examined
for their potential to control western flower thrips. The predaceous bug,
Orius sp., the predatory mite, Amblyseius cucumeris, and the fungus Beauvaria
bassiana will be evaluated singly and in combination-research will be done
on chrysanthemums and roses. Although difficult to rear in sufficient numbers,
the parasitoid Ceranisus sp. will be included in these evaluations.
b. Continue work on the evaluation of natural enemies, on a comparative
basis, for biological control of selected greenhouse pests. The focus will
be on natural enemies of the leafminer, Liriomyza trifolii, and will include
the parasitoid Diglyphus begini and the nematode, Steinernema carpocapsae,
used together for biological control of this pest. This is also being supported
by the BPI Foundation and the Gloeckner Foundation.
c. Examine the practicality of releasing the mealybug destroyer, Cryptolaemus
montrouzieri, and the parasitoid, Leptomastix dactylopii, for biological
control of citrus mealybugs attacking commercial roses.
d. Examine the potential of genetically altered insect viruses to kill
worm pests in floriculture crops. Recombinant viruses overcome the major
limitations of wild viruses-the slow speed of kill and the host range of
worm pests controlled. This work is also being supported by the UC Biotechnology
Research and Education Program.
Biological Studies
a. Continue the basic biology of thrips in an effort to understand
feeding, oviposition, and pupation behavior in selected crops. b. Complete
studies of selected parasitoids of the silverleaf whitefly with emphasis
on Encarsia pergandiella.
Sampling Information
a. Sampling plans will be developed for western flower thrips in chrysanthemums,
roses and carnations, and for citrus mealybug in rose.
Pesticide Efficacy and Compatibility
a. Continue the search of new pesticides which have potential for use
in floriculture. Maintain contact with chemical manufacturers to assure
that the floriculture industry is not overlooked for potential registrations.
Assist in developing labeling for new pesticides for ornamentals.
Literature Review
Data and references are continually compiled which deal with arthropod
pest problems and their control in greenhouses. The major thrust here is
to be aware of the rapidly changing situation regarding biological control-
especially new information coming out of Europe. I am editing (together
with Dr. Kevin Heinz, Texas A&M) a book on Biological Control in Protected
Culture which will have an international slate of chapter authors. The
book will be published by Geo. G. Ball publishing.
Note: Because of the size of my project, the number of people involved,
the amount or work proposed, and the fact that It is a multiple year project,
it is redundant to present detain of the entire proposal each year. Portions
of this proposal that represent new areas of research are biological control
of mealybugs, the development of sampling plans for western flower thrips
and mealybugs and the use of genetically altered viruses for worm control
in floriculture. These sections are expanded more fully and take up most
of the page limit for the 1996 AFE proposal.
1, 2, & 3 Introduction, Literature Review, Objectives, & Anticipated
Benefits Mealybugs
Mealybugs, especially the citrus mealybug (Planococcus citri [Rissol),
are major problems in ornamental production throughout the world. Although
usually a problem associated with foliage plants (Hamlen et a]. 1981),
this mealybug commonly occurs on cut flowers such as chrysanthemum and
rose. The literature associated with mealybugs and biological control of
mealybugs as pests of interiorscape plants was thoroughly reviewed by Parrella
(1981), and much of the information applies to all mealybugs attacking
ornamental plants. With a dense covering of water repellent wax on their
bodies as well as covering their large egg masses, the citrus mealybug
is difficult to control. When effective pesticides can be found, they must
be applied every two weeks for control.
It is typical in rose production ranges to find Streptocarpus growing
between greenhouses or around the perimeter of the rose greenhouse itself.
This plant usually supports heavy populations of the citrus mealybug which
the grower usually ignores because if the high tolerance of Streptocarpus
for mealybugs-even where spectacular populations exist, no damage to the
flowers is evident. Although this mealybug can attack roses, the mealybugs
usually do not move onto the rose crop. Although mealybugs have appeared
as featured pests in the Roses Inc. Bulletin (March 1939, pg. 14 and July
1941, page 5), they have not been much of a problem. However, recently
mealybugs have increased as pests on a wide variety of crops, including
roses. This could be the result of a host switch by P. citri from Steptocarpus
to rose. The citrus mealybug can be difficult to control in roses with
registered pesticides and may be an excellent candidate for biological
control. The mealybug destroyer, a very effective lady beetle which specializes
on feeding on mealybugs, will be used. Important points to consider for
successful biological control of mealybugs with the mealybug destroyer
include: 1) the abundance of mealybugs at the time the predators am released,
2) the environmental conditions at the release site, and 3) suitability
of infested plants for biological control by the predator. All these limiting
factors are met in a rose range infested with mealybugs. Western Flower
Thrips and Mealybugs
There is little information on the development of sampling plans for
thrips or mealybugs in floriculture crops. The general consensus is that
using blue sticky traps is the best method for trapping adult thrips. WFT
are attracted more to this color than to yellow so the presence of thrips
can be detected more quickly (and at lower densities) than with yellow
traps. In addition, we have developed a method to streamline counting thrips
and other pests caught on sticky traps (Heinz et al. 1992). An international
Monitoring Group composed of researchers/extension specialists from more
than 19 countries around the world was formed at the International Biological
Control Meeting held in Asilomar, CA. in the spring of 1993. The intent
is to establish some sort of consistent sampling methods for all greenhouse
pests so that data from country to country and researcher to researcher
can he compared. In addition, the data may be useful in establishing economic
thresholds/tolerance levels for different pests. Ile first pest this monitoring
group is concentrating on is the western flower thrips. It is clear that
various shades of blue will catch different numbers of thrips, but blue
traps are internationally recognized as the color to use. Data on the relative
trapping efficiency and the relationship between thrips caught on traps
and thrips on plants or in flowers have not been determined. This type
of information is critical to establishing threshold levels of thrips in
greenhouses. A threshold level of 20 WFT/trap/week has been tested in a
commercial chrysanthemum operation in Switzerland. Treatments were made
only when this number of thrips were found on traps and damage never exceeded
5% loss of flowers. This threshold is now being tested on roses and other
floral crops in Switzerland.
Little data are available for other species of thrips. To generalize
from WFT to T. palmi (the melon thrips), could be dangerous. Work done
in Japan with different colored traps suggests that white traps, positioned
0.5m above the ground were most effective for melon thrips in vegetable
greenhouses. In addition, another Japanese study set thresholds levels
of thrips at 4.4 adults/sticky trap/day in sweet pepper or 0.015 adults
per flower. It is too early to tell how this work relates to the melon
and other thrips in floriculture greenhouses.
Distributional data and sampling plans have been developed for western
flower thrips on greenhouse cucumbers (Shipp and Zariffa 1991) and sweet
pepper (Steiner 1990) and for field grown tomatoes (Salgureo Navas et al.
1994). There is no information available on sampling thrips in floriculture
crops or on the possible relationship between thrips caught on sticky traps
and thrips actually on the plants.
There is no information on sampling for mealybugs in floriculture crops.
The only data that relates to this is the information available from counts
taken from plants before and after pesticide application (Neal et al. 1982).
Viruses for Control of Worm Pests
Lepidopterous, larvae are among the worst pests in greenhouses all
over the world. A number of different species are involved in causing damage
across a wide range of floriculture and vegetable crops grown under glass.
Worm problems are particularly serious for the outdoor specialty cut flower
grower.
For the lepidoptera, most growers rely on the application of Bacillus
thuringiensis (Bt) which is effective and quite specific. Application of
this product does not disrupt ongoing biological control of other pests
on the same crop. Because of the many positive aspects of using Bt for
worm control, this is the most widely used biological control agent in
glasshouses; estimates are that more than 50% of all the greenhouse acreage
worldwide uses Bt (van Lenteren 1990). While Bt dominates, there are concerns
over the possibility of resistance development, the relatively slow speed
of kill, the lack of epizootics developing in the crop, and its relatively
poor performance against some major glasshouse pests in the genera Heliothis
and Spodoptera. For this reason, there is considerable interest in the
recent registration of baculoviruses for control of Spodoptera on glasshouse
crops Europe (Moed et al. 1990). However, genetically altered baculoviruses
offer improved performance over wild type viruses-increased speed of kill,
wider host range, the safety and compatibility of Bt would make these the
products of choice if available to the glasshouse industry.
The floriculture glasshouse industry in California (with a total crop
value of >$500 million per year) wages a constant battle against worm pests.
Many of these glasshouse operations are situated adjacent to field production
so migration into greenhouses by Heliothis and Spodoptera are very common.
Once in a floriculture greenhouse, breeding can be continuous while crops
are present. Chrysanthemum, Dendranthema grandiflora, is a major floriculture
crop in the state and is commonly attacked by Spodoplera and Heliothis.
This crop will used when the project moves into the field. In addition,
any new baculoviruses will be evaluated for their compatibility with selected
natural enemies (for example, Diglyphus begini) that may be important for
biological control of other pests in chrysanthemum. The protocol for these
evaluations has already been developed (Heinz et al. 1995).
4. Materials and Methods
Mealybugs
A Large rose grower in Salinas has agreed to cooperate with us in this
trial. He currently has a serious mealybug problem and has been unable
to gain control using conventional insecticide applications. Part of our
work with this grower will be to evaluate some of the newer biorational
pesticides, but we are interested in exploring the possibility of using
the mealybug destroyer and a parasitoid for biological control. In a heavily
infested block of Cara Mia, one section from each of two heavily infested
beds will be covered with a woven material to create a ‘tent’ over the
plants. Fans will be located at either end of the tent to promote good
air flow. Into this tent, approximately 1000 mealybug destroyers will be
released. The tent will form a living insectary in this greenhouse. We
anticipated that the predators will feed on the mealybugs and lay eggs.
Additional releases will be made into these tents if they are needed. Weekly
samples will be taken in the tents and in the greenhouse proper. After
3-4 weeks, the tent will be removed allowing the adults and their progeny
to move into the greenhouse itself. An adjacent greenhouse win serve as
a control. We recognize the need to replicate this study, but the infested
area does not lend itself to further replication. This particular study
is both an experiment and a demonstration to the grower. Once the mealybug
problem is reduced to lower levels (in approximately 10-12 weeks) we plan
to release the parasitoid Leptomasix dactylopii which should work effectively
at keeping the mealybugs at low densities.
Western Flower Thrips and Mealybugs
Blue cards will be positioned just over the crop at approximately one
per 400 sq. ft. These will be checked 2x per week; the crops will be roses,
carnations, and chrysanthemums. At the same time, leaves, terminal growth
and flower samples will be taken (this will depend on the stage of the
crop). The plant will be stratified such that the bottom, middle and top
parts will be sampled; samples will be immediately submersed into dilute
alcohol for later counting. At least 30 different sites in the greenhouse
will be sampled. We hope (through regression/correlation analyses) to see
if there is a relationship between thrips on the traps and on the plants.
In addition, information on the distribution of the thrips, within a plant
and greenhouse will be obtained–a research and grower oriented sampling
plan will be developed from these data. In talking with growers who use
yellow or blue traps for monitoring thrips, there have been many occasions
where there have been large numbers of thrips on the traps and none on
the plants (most importantly, no plant damage was evident). This suggests
that both sticky traps and the plant must be sampled before making a decision
regarding whether or not to spray. In this situation it could have been
that thrips were migrating into the greenhouse from another crop and simply
did not find the floriculture crop (or that particular cultivar) to their
liking. This suggests that if thrips are migrating into the greenhouse,
little or no relationship will be found between the traps and the plants.
On the other hand, there may be a good relationship if the thrips are developing
in the crop itself. For this reason, we will have traps outside and at
the vents and doorways to determine when and if migration occurs so this
can be taken into account during the analysis.
For mealybugs in the rose greenhouse discussed earlier, the plants will
be stratified with leaf/shoot samples taken from the lower part and from
the first fully expanded leaf on the new rose break. In this way we will
obtain information on the general mealybug population as well their ability
to cause direct damage to the marketed commodity, the flower and flower
stem itself. Samples will be placed into plastic bags and returned to the
laboratory for processing. Egg masses, immature and adult mealybugs will
be counted. As with western flower thrips, this will provide us with information
on the within plant and within greenhouse populations. These data can be
used to begin developing guidelines on how to effectively sample mealybugs
on roses.
Viruses for Control of Worm Pests
Genetically altered baculovirus will be compared to wild type virus
for control of lepidoptera in commercial chrysanthemum ranges. Cooperating
growers are available in San Diego, Santa Barbara, Salinas and Half Moon
Bay and many of these growers participated in the development and implementation
of our IPM program for chrysanthemums (Hesselein et al. 1993). Through
contact with the farm advisors in these areas, we would be apprised of
infestations and proceed with the evaluations. In greenhouses where this
work will be done, the houses would be screened using material from Green-TekTM
(407 N. Main Street, Edgerton, WI 53534) Insecta 500 insect screen. While
screening is not necessary, it is a precautionary move to allay potential
criticism and concerns over virus infected animals escaping from the trial
greenhouse. Because worm pests tend to be highly clumped in a glasshouse
infestation, we would locate infested plants and mark them with red-flagging
tape. The number and stage of worms would be counted on each plant; this
will be done for at least ten plants in the greenhouse. A drop cloth would
be placed on the soil at the base of the plant (in mums grown for cut flowers)
or under pots (in mums grown as pot plants) to catch and retain larvae
falling off plants after viral infection. These same plants and the areas
around them would be sampled 24, 48 and 72h after application. To avoid
problems with pseudoreplication, each greenhouse would be divided into
three sections using screening material. In this way we would have at least
three replicates of the evaluation of the genetically altered virus per
greenhouse. This may not be possible in all cases and would depend on the
degree and extent of the infestation and the physical layout of the cooperating
greenhouse operation.
5. Literature Cited
Copland, M. J. W., C. C. D. Tingle, M. Saynor, & A. Panis. 1985.
Biology of glasshouse mealybugs and their predators and parasitoids, pp.
83-90.
In Biological Pest Control - The Glasshouse Experience (N. W. Hussey
& N. Scopes, eds.). Comell University Press, Ithaca, New York.
Hamlen, R. A., D. W. Dickson, D. E. Short, & D. E. Stokes. 1981.
Insects, mites, nematodes and other pests, pp. 429-479. In Foliage Plant
Production (J. N. Joiner, ed.). Prentice Hall, Inc., Englewood Cliffs,
New Jersey.
Heinz, K. M., M. P. Parrella, & J. P. Newman. 1992. Time-efficient
use of yellow sticky traps in monitoring insect populations. J. Econ. Entomol.
85:2263-2269.
Heinz, K. M. B. F. McCutchen, R. Herrmann, M. P. Parrella, & B.
D. Hammock. 1995. Direct effects of recombinant nuclear polyhedrosis viruses
on selected nontarget organisms. J. Econ. Entomol. 88:259-264.
Hesselein, C., K. Robb, J. Newman, R. Evans, & M. P. Parrella. 1993.
Demonstration of integrated pest management program for potted chrysanthemums
in California, pp. 5-10.
In: (J. Hall & K. Robb, eds), Proceedings of the Society of American
Florists Ninth Conference on Insect and Disease Management on Ornamentals,
San Diego, California.
Society of American Florists, Alexandria, Virginia. Moed, de G. H.,
W. van der Werf & P. H. Smits. 1990. Modelling the epizootiology of
Spodoptera exigua nuclear polyhedrosis virus in a spatially distributed
population of Spodoptera exigua in greenhouse chrysanthemums. Proc. of
IOBC Conference of the Working Group for Integrated Control in Glasshouses
SROP/WPRS Bull., XII/5:135- 141.
Neal, J. W., Jr., D. R. Pillit, J. E. Koch, & L. W. Douglas. 1982.
Evaluation of chemical products against selected pest of greenhouse and
outdoor ornamental crops, 1977-1982.
USDA, ARS, Production Rept. No. 183, 56 pp.
Parrella, M. P. 1981. Pests of Interior Plants: Mealybugs. Horticulture
Supplements III. H81a. Interior Plantscape Manual of Practice. McGinley
Press, Herndon, Virginia
Salgureo Navas, V. E., J. E. Fundeburk, T. P. Mack, R. J. Beshear, &
S. M. Olson. 1994. Aggregation indices and sample size curves for binomial
sampling of flower-inhibiting Frankliniella species (Thysanoptera: Thripidae)
on tomato. J. Econ. Entomol. 87:1622-1626.
Shipp, J. L. & N. Zariffa. 1991. Spatial patterns of and sampling
methods for western flower thrips (Thysanoptera: Thripidae) on greenhouse
sweet pepper. Can. Entomot. 123:989-1000.
Steiner, M. 1990. Determining population characteristics and sampling
procedures for the western flower dirips (Thysanoptera: Thripidae) and
the predatory mite Amblysieus cucumeris (Acari: Phytoseiidae) on greenhouse
cucumber. Environ. Entomol. 19:1605-1613.
van Lenteren, J. C. 1990. Integrated pest management in protected crops:
the inescapable future. Proc. of IOBC Conference of the Working Group for
Integrated Control in Glasshouses. SROP/WPRS Bull. XII/5:91-99.
6. Budget
2 full time laboratory Assistant II @ $4,880/month x 6 months (includes
benefits) $29,300
Miscellaneous supplies 1000.00
Total Request = $30,300
Note: This funding is requested for individuals already in these positions
based on funding from previous years. They are well-trained workers who
perform the detailed work outlined in this project very well.
7. Leader Qualifications
Dr. Parrella’s responsibilities at Davis are 80% research and
20% teaching in addition to being chairman of the Department. He teaches
Economic Entomology (Entomology 110) and contributes to other courses in
the Departments of Entomology and Environmental Horticulture and in the
Plant Sciences. His research program has concentrated in the area of ornamentals
with a focus on developing pest management systems with a firm reliance
on biological control. Dr. Parrella has worked with many different ornamental
crops and with most of the major pests attacking these crops over the past
15 years. His research involves determination of basic insect biology,
developing monitoring/sampling systems, evaluations of old and new insecticides
for phytotoxicity, efficacy and for compatibility with natural enemies,
evaluation of new pesticide application techniques, and understanding and
managing insecticide resistance. The main emphasis of his research focuses
on the biology/ecology of predators and parasitoids and their potential
use for biological control in greenhouses.
An important part of Dr. Parrella’s research and teaching is directing
graduate students and postgraduate scientists-he currently has 9 (1 postdoctoral
scientist, 5 Ph.D.s, and 3 Masters) working on different pest problems
affecting the ornamental’s industry.
Dr. Parrella publishes regularly in scientific and trade journals and
is the author of more than 200 publications. He is on the editorial board
for the scientific magazines American Entomologist, Entomophaga, and the
Journal of Environmental Horticulture and he is a contributing writer for
the trade magazine GrowerTalks. Dr. Parrella organized the “First Conference
on Insect and Mite Management on Ornamentals” in 1985 sponsored by the
Society of American Florists. This has become an annual event.
In 1986, Dr. Parrella received the Researcher of the Year Award from
the California Association of Nurserymen. In 1987, Dr. Parrella received
the Entomological Society of America (ESA) Recognition Award in Entomology
(sponsored by Ciba). This award, presented annually by the ESA, a professional
society with more than 9,200 members, is intended “to provide additional
recognition to entomologists who have made or are making significant contributions
to agriculture.’ In 1991, Dr. Parrella received the Futura Award from the
Professional Plant Growers Association in recognition of contributions
made to the floriculture industry by building for the future through teaching
and research.
