Integrating Control of Botrytis and Powdery Mildew in a Greenhouse Crop 1995 proposal
CROP
been leaf, stem, and bract blight caused by Botrytis cinerea (Strider and
Jones, 1985). However, another foliar fungal disease called powdery mildew
(PM) (Oidium sp.) can be a problem for poinsettia growers, especially those
in the northern United States and Canada. White, talcum-like powdery mildew
colonies up to approximately 1/2″ in diameter occur on either the upper
or lower leaf and/or bract surfaces. In many cases, PM detection is delayed
because colonies may be primarily on underside of lower leaves. Therefore,
growers may not be aware of PM infection until late in production when
the bracts are infected and the losses significant. Customer dissatisfaction
(retail shops and consumers) also occurs when poinsettias develop PM after
leaving the production greenhouse.
Growers who detect PM early in production report successful elimination
of the disease by removing infected leaves and applying fungicides. Similarly,
sanitation and fungicide application have long been integral components
of Botrytis disease management. Unfortunately, fungicides that are commonly
used against B. cinerea do not control PM on poinsettia The fungicides
Ornalin, Chipco 26019, and Exotherm Termil are frequently used to control
Botrytis blight, but none of these materials is currently recommended for
control of PM. At least 20 poinsettia growers responding to a survey on
PM had used Bayleton/Strike, Cleary’s 3336/Domain/Fungo Flo, Zyban, or
Phyton 27 in 1992, with at least 60% of those growers reporting efficacy
(Hall, 1993).
Controlling disease caused by B. cinerea and Oidium sp. by modifying
the greenhouse environment would allow more precise disease management
than traditional control methods provide. However, since the environmental
requirements for these two fungi are different, individual thresholds must
be incorporated to provide control for both Botrytis and PM. B. cinerea
conidia require free moisture in order to germinate. In contrast, free
moisture is not necessary for PM to germinate. In order to produce a cost-effective,
high quality poinsettia, integrated disease management strategies including
sanitation, fungicide application, and enviromnental manipulation must
be established to control Botrytis blight and PM.
LITERATURE REVIEW – Powdery Mildew (PM). The first observation
of PM on poinsettias in the U.S. is reported to have occurred in Pennsylvania
and the Pacific Northwest in 1990. Growers in Mexico reported PM on poinsettia
during 1988 and 1989 and growers in Puerto Rico have also observed PM.
In April 1992, growers from the Midwest, South, and East Coast reported
PM (Daughtrey and Hall, 1992; Daughtrey and Macksel, 1994b). PM was frequently
reported in the fall of 1992 and sporadically in 1993 (M. Hausbeck and
M. Daughtrey, personal observations). Since PM is a relatively new disease
on poinsettia, the specific causal agent is unidentified. Although PM diseases
occur on many hosts, the individual species of PM are very host specific.
Accordingly, the PM that occurs on poinsettia has not been transferred
to other crops (Daughtrey and Hall, 1992).
In general, the occurrence, distribution, and severity of a PM infection
are affected primarily by temperature, relative humidity, light, and wind
(Coyier, 1985). Conidia germinate on the leaf surface and produce germ
tubes, followed by the production of haustoria which penetrate the host’s
epidermis. Maximum genriffiation of conidia of the PM on poinsettia is
72, 61, and 42% at 25, 20, and 15C, respectively, when relative humidity
is 85% (Hausbeck and Kalishek, 1994). Observations in the field on cucurbit
crops indicate that PM has the potential to “explode” once established
at a low level. Incidence of cucurbit leaves infected with PM increased
from 10% to 70% within a week’s time under favorable environmental conditions.
In contrast, the epidemic was halted in the portion of the field where
fungicides were applied when disease was first noted (Hausbeck, unpublished
data).
The following fungicides are labeled for control of powdery mildew and
list poinsettias on their label: Phyton 27, Cleary’s 3336 F/Cleary’s 3336
WP/Domain FI/Fungo Flo, Terraguard 50W, and Zyban. A number of systemic
fungicides effective for PM control on other crops are not available to
poinsettia growers.
Botrytis Blight. Botrytis can is a serious disease of poinsettias.
It causes considerable damage on the stems and foliage during propagation
and throughout the growing season, and, most importantly, may attack bracts
during the critical flowering period. Free moisture and temperature are
of primary importance for B. cinerea conidial germination and subsequent
infection, although conidia can be very tolerant of drying (Good and Zathureczky,
1967). When free moisture is present, conidia of B. cinerea germinate within
60 minutes of inoculation at the optimum temperature of 20C. Four hours
after inoculation, 40% of the conidia have germinated and by 6 hours, 77%
of the conidia have germinated (Hausbeck, unpublished data).
Conidial “showers’ are typically associated with grower activity (Hausbeck
and Pennypacker, 1991). The occurrence of conidial “showers” during and
immediately after harvesting of cuttings is important in disease management.
Cuttings removed from the stock plants may be exposed to large concentrations
of airborne conidia that may influence disease occurrence during propagation.
In order to protect plants, fungicides that are effective against B.
cinerea are used repeatedly. Continuous use of systemic fungicides has
resulted in selection of resistance in greenhouse B. cinerea populations
to benomyl (Benlate) and vinclozolin (Ornalin, Curalan) (Moorman and Lease,
1992). Modification of the environment in a commercial greenhouse has been
a successful in a commercial greenhouse to reduce B. cinerea inoculum and
blight. Environmental modification could be used in conjunction with a
disease prediction system to reduce sole dependency on fungicides (Hausbeck,
1993).
OBJECTIVES AND POTENTIAL BENEFITS – As the greenhouse industry
moves toward the 21st century, growers must face increased regulation and
adopt enviromnentally-sound practices which will result in increased costs
in production and narrow the profit margin. In addition to these challenges,
poinsettia growers are in the unique position of managing a “new” disease
called PM. This disease appears to have the potential to negatively impact
the poinsettia industry through reduction of plant quality and/or increased
fungicide costs. However, in the rush to learn about powdery mildew, the
longtime nemesis of poinsettia (Botrytis blight) must not be forgotten.
Rather, the inclusion of B. cinerea in this project will benefit all greenhouse
floral crops that are infected by Botrytis blight.
Therefore, the following objectives have been defined.
1. Develop a scouting program for management of PM and Botrytis
blight.2. Develop an effective fungicide spray program for PM and Botrytis
blight. a.) Identify fungicides effective against the foliar blights of
poinsettia that may safely be used on foliage and/or bracts. b.) Determine
the appropriate timing of fungicide applications during the disease cycles.
c.) Determine an effective fungicide rotation to prevent occurrence and
build-up of resistance. d.) Provide efficacy and phytotoxicity data necessary
to support a full or special registration of effective fungicides that
are not currently labeled for control of foliar blights on poinsettia.3. Investigate the epidemiology of PM. &) Determine the level and
duration of temperature and RH necessary for conidia of PM to germinate,
infect, and sporulate on poinsettia tissue, b.) Investigate the ability
of the fungus to remain latent in host tissue, c.) Investigate the efficacy
of heat treatments in eliminating active and latent infections, d.) Screen
poinsettia cultivars for resistance to PM.4. Incorporate the known epidemiological data on B. cinerea with that
determined for PM into an integrated disease management system that utilizes
sanitation, fungicide applications, and environmental manipulation to reduce
disease incidence and severity.
MATERIALS AND METHODS -
1. Develop a scouting program and guide for PM and Botrytis blight.
PROGRESS TO DATE - A scouting program was implemented in a commercial
greenhouse range that had just been discovered to have poinsettias infected
with PM. Stock plants and cuttings were scouted weekly. One out of every
30 plants was observed. Plants were selected at random using a zig-zag
pattern between benches. Both the top and bottom surfaces of four older,
mature leaves were observed. If PM was discovered, plants were flagged
and infected leaves were removed and placed in plastic bags to prevent
further spread of the fungus. Typically, on each infected plant, two to
five leaves had PM colonies present. For our research purposes, the cultivars
where PM was detected were scouted again at a 1:10 ratio to better determine
the incidence of disease. Fungicide applications were based on weekly scouting
results. The fungicide used was chosen and applied by the geenhouse staff.
Greenhouse environmental conditions including temperature, relative humidity
and leaf wetness were monitored. On the first observation, 36% of one poinsettia
cultivar was infected with PM. The fungicides chosen and applied by the
grower included an application of Phyton 27 (1.5oz/10 gallons) and an application
of Terraguard 50W a week later. Within six weeks of the initial scouting
date, PM could not be detected and did not reappear during the course of
crop production (Hausbeck, et al., 1994).
2. Develop a safe and effective fungicide spray program for PM and
Botrytis blight. Collect efficacy and phytotoxicity data necessary to support
a full or special registration of needed fungicides.
PROGRESS TO DATE – Fungicide trials in MI and NY clearly indicate
that Domain, Strike, Terraguard, Phyton 27, Sunspray + baking soda combinations,
insecticidal soap, Chipco 26019, and UBI4077 may be of benefit in managing
powdery mildew on poinsettia (Daughtrey and Macksel, 1994a; Hausbeck, 1995
in press).
The 1994 evaluation of the commonly recommended fungicides was recently
completed at Michigan State Univ. (MSU) on poinsettias in full color (NOTE:
Strike 25DF is not registered for use on poinsettias and was included for
comparison only!). Fungicide sprays were initiated soon after the first
appearance of PM colonies on bracts. While growers would certainly want
to avoid a situation where PM has progressed to the bracts as in this study,
this particular system works well in research to determine the ability
of fungicides to control disease. Also, previous fungicide studies conducted
at Cornell University and MSU clearly show that PM can be controlled with
fungicides AFTER the appearance of white colonies if scouting is used to
detect the disease early while colony numbers are low.
In this study, the Chipco 26019 and the Strike treatments were applied
at 14-day intervals (a total of 2 applications), and all other fungicide
treatments were applied at 7-day intervals (a total of 3 applications)
. At the end of the experiment colonies on two randon-dy identified bracts
were counted to determine whether the fungicide treatments had provided
effective control. PM was best controlled by applications of either Chipco
26019 WDG 50 WG (1.0 or 2.0 lb/ I 00 gal) or the higher rates of Terraguard
50W (16-4-4 or 16-9-8 oz/100 gal for the first, second, and third applications)
or Cleary’s 3336 WP 50WP (1.5 lb/100 gal). Since there was no difference
between the Chipco 26019 rates investigated in this study, the lower rate
of 1.0 lb/100 gal could be expected to provide the same level of control
as the higher rate of 2.0 lb/100 gal. Likewise, the lower rates of Terraguard
50W (16-4-4 oz/100 gal) were as effective as the higher rates of Terraguard
50W (16-8-8 oz/100 gal). However lowering the Terraguard 50W rates further
to 8-4-4 oz/100 gal was not equally effective as the higher Terraguard
rates used in this study.
In this experiment, even the best treatments did not remove the colonies
that existed prior to the first fungicide application. This is why PM must
be controlled early in production and removal of infected leaves, if feasible,
is helpful. The fungicides used in this trial were evaluated for their
ability to prevent the further development of PM beyond that existing prior
to the first application of fungicide. Although the best fungicide treatments
evaluated in this trial would be unacceptable in controlling PM on the
bracts, these treatments would be highly effective on poinsettias not in
color especially if the disease was detected early.
A weak link in managing PM on poinsettias has been the inability to
protect bracts in the finishing or postharvest production phase. If systemic
fungicides could provide protection for an extended period of time beyond
application, the vulnerable finishing stages would be covered. To evaluate
the length of time fungicides can provide protection against PM, plants
were maintained for 56 days beyond the last fungicide application in a
greenhouse full of poinsettias that were heavily infected with PM. Fungicides
were evaluated based on their ability to suppress production of conidia
(sporulation) in colonies on bracts and foliage. In this study, 42 days
appeared to be the longest duration of control available beyond the last
application from the fungicides evaluated in this study. None of the PM
colonies were active 42 days after higher rates of Terraguard 50W (16-4-4
oz or 16-8-8 oz/100 gal, a total of 3 sprays) were applied following disease
detection. It was interesting that when healthy plants were treated with
Terraguard 50W (4 or 8 oz/100 gal, a total of 4 applications) prior to
exposure to PM, protection lasted for 42 days. Good control was also obtained
42 days after the last application when Chipco 26019 50WG (1 or 2 lb/100
gal) or the lowerrate of Terraguard 50W (8-4-4 oz) was used after the detection
of PM. When a low rate of Terraguard 50W (2.0 oz/100 gal, a total of 4
sprays) was applied prior to exposure to PM, good control was obtained
for 42 days. Although colonies for all treatments were active 56 days after
the last fungicide treatment, control was still obtained for the “best”
treatments described at 42 days in comparison to the untreated control.
It has not been determined whether multiple applications used in this study
are necessary to provide the duration of PM control observed.
Researchers in MI, NY, and TX will conduct additional studies on fungicide
efficacy and residual in controlling PM on poinsettia, including: Baking
Soda, Bayleton/Strike, Chipco 26019, Cleary’s 3336/Domain/Fungo Flo, Daconil,
Dithane T/0, Eagle, Milban, Oil/Sunspray, Omalin, Phyton 27, Pipron, Protect
T/O, Zyban, Rubigan, Soap (Mycogen’s 1446), Sulfur, Terraguard, Triforine,
and Zineb.
3. Investigate the epidemiology of PM.
a.) Determine the level and duration of temperature and relative humidity
(RH) necessary for conidia of PM to germinate, infect, and sporulate on
poinsettia tissue.
PROGRESS TO DATE – Effects of temperature and relative humidity
(RH) on germination, appressorium formation, and shriveling of conidia
were studied in 15, 20, and 25C growth chambers. Conidia were incubated
in scaled containers for 24 hr on 9-mm-diameter leaf discs cut from mature
leaves of poinsettia ‘Freedom’. The discs were placed on 2.5 x 1.25 cm
pieces of water agar on screening over saturated salt solutions that provided
95, 85, 75, 65, 55, 45, 35% RH. A minimum of 100 conidia, on each of three
leaf discs were observed and each experiment was conducted three times.
Maximum germination of conidia was 72, 61, and 42% at 25, 20, and 15C,
respectively when RH was 85%. Appressorium formation was not significantly
affected by temperature or RH with >89% of the germinated conidia forming
appressoria. Shriveling of conidia was least (6%) at 25 C and 95% RH; greatest
(39%) at 20C and 35% RH (Hausbeck and Kalishek, 1994).
An additional study was conducted at MSU in two research greenhouses
hereafter referred to as GH2g and GH11a (Shaw and Flausbeck, 1995). Multi-stemmed
poinsettias in full color, grown in 13.2 cm plastic pots were obtained
from a commercial greenhouse in Nov. 1994. Several cultivars were used.
Three benches in each of the two greenhouses contained a random assortment
of 35-40 poinsettia spaced at 8-9 pots per m. The date and time of watering
and other significant grower activity were documented by greenhouse personnel.
Plants in GH2g were inoculated on 18 Nov. 1994 by vigorously shaking an
infected poinsettia with sporulating colonies over the healthy poinsettias.
Colonies were observed on all inoculated plants on 28 Nov. 1994. Plants
in GH11a were not intentionally inoculated but colonies were first observed
on 29 Nov. on three poinsettias. On 9 Jan. 1995, 90% of plants in GH11a
were observed to be infected. Temperature (temp.), relative humidity (RH)
and vapor pressure deficit (VPD) were monitored using a Neogen EnviroCaster
(Neogen, Mason MI, 48912)
Atmospheric conidial concentrations (ACCs) were monitored from 5 Dec.
1994 to 1 June 1995 in GH11a and from 5 Dec. 1994 to 17 July 1995 in GH2g.
A Burkard 7-day recording volummetric spore trap operating at a flow rate
of 10L/min was placed in each greenhouse in the center of a bench among
the poinsettias. Under a compound microscope at 100x magnification, conidia
were identified as Oidium sp.. To determine the infectivity of ACCs, 3
healthy poinsettias were placed on each bench in each greenhouse from 7
Jan. to 27 Mar. 1995. Trap plants were exposed to ACCs for 7 days, removed,
and incubated in a greenhouse and exan-dned daily for visible PM colonies.
Peak conidial concentrations (PCCs) were not associated with grower
activity. When averaged over a 179-day period, atmospheric conidial concentrations
(ACCs) were highest in both greenhouses between the hours 1000 and 1700
and appeared to be associated with increases in temp. and VPD. However,
on individual days, PCCs were observed to occur in association with a decrease
in VPD that occasionally occurred following watering.
GH2g had significantly higher ACCs througbout the study than did GH11a.
Although 1OO% of the poinsettias in GH2g were infected with PM 43 days
before a comparable disease incidence in GH11a, it was of interest that
over the duration of this study the ACCs between the two greenhouses were
never comparable. During May, maximum temps in GH11a were >30C on seven
days while temps in GH2g were >30C only once. ACCs in GH11a declined following
the mentioned period of high temps. GH2g reached max temps of >30C in mid-Junc,
after which ACCs also declined.
During 23 Jan. to 6 Mar., trap plants in GH2g developed colonies an
average of 2 days sooner than those in GH11a. This may be due to higher
ACCs increasing chances of successful inoculation or because environmental
conditions which favored higher ACCs also favored successful conidial germination.
In GH2g, after a minimum of 6 days at temps >30C, PM colonies were no longer
observed on trap plants although small numbers of ACCs were still observed.
These data suggest that at high temperatures: (>30C), conidia are not readily
produced and those conidia that are produced during may not be viable.
Future studies should include a measurement of wind speed to compare with
other environmental factors.
Studies of the environmental conditions necessary for sporulation will
be investigated using whole plants that will be inoculated and maintained
under optimum conditions for germination and infection. Following the incubation
period, plants will be moved to a growth chamber set at 15, 20, or 25C
at levels of RH of 60, 70, 80, or 90%. The time to colony appearance will
be noted and leaf discs removed, prepared as described previously, and
the newly-formed conidia counted.
b.) Investigate the ability of the fungus to remain latent in host tissue.
Poinsettias will be inoculated and incubated in a growth chamber under
a regime favorable for germination and infection (as determined by previous
experiments). Following incubation, cuttings will be removed and maintained
in a growth chamber under conditions that are unfavorable for colony development
for 1, 4, and 8 weeks. Plants will then be returned to the environmental
conditions that are known (based on previous studies) to prompt PM development.
The time to colony formation will be noted. Histological studies including
scanning electron microscopy will be pursued if results from the described
study indicate additional information could be obtained through those methods.
c.) Investigate the efficacy of heat treatments in eliminating active
and latent infections. Cuttings will be inoculated and incubated under
conditions favorable for germination and infection. Cuttings will then
be exposed to temperatures of 28, 32, or 40C for 2, 7, or 14 days. Following
the exposure to these temperatures, cuttings will be placed under environmental
conditions favorable for PM.
d.) Screen poinsettia cultivars for resistance to PM.
PROGRESS TO DATE – Multiple-stem poinsettias with mature bracts
representing 12 cultivars were arranged on a greenhouse bench in a completely
randomized design with 4 replications. All plants were inoculated by tapping
PM-infected plants above healthy plants to release conidia. Cultivars with
red bracts (Freedom Red, Red Sails, V-14 GIory, Supjibi Red) had more bracts
infected (>91%) than cultivars with pink (V-14 Pink, Hot Pink)(85%),white(Topwhite,V-14WI@te,
V-17 Angelika White) (53-96%, or variegated bracts (Jingle Bells 3, Pink
Peppermint, V-17 Angelika Marble) (53-79%) (Celio and Hausbeck, 1994).
4. Incorporate the known epidemiological data on B. cinerea with
that determined for PM into an integrated disease management system that
utilizes sanitation, fungicide applications, and environmental manipulation
to reduce disease incidence and severity.
PROGRESS TO DATE - A weather-driven conidial release predictor
developed for use for Botrytis blight on onions in the field was used to
time protectant fungicide sprays for control of Botrytis leaf blight on
a greenhouse crop in a commercial operation. A computerized automated field
weather station (Envirocaster) was used. Plots receiving weekly sprays
of chlorothalonil or predictor-time sprays were not significantly different
based on visual disease ratings although both plots had lowered disease
ratings in comparison to the unsprayed control plots. Since the humidity
was high, an equal number of sprays was applied for plots receiving weekly
or predictor-timed sprays (Hausbeck, 1995).
The influence of DIF on the susceptibility of poinsettia bracts to Botrytis
was investigated using the following day/night temperature regimes: 16/16,
16/19, 16/22, 19/19, 19/16, 19/22, 22/22, 22/16, and 22/19. When poinsettias
were grown under the same average temperature prior to inoculuation, DIF
(16/22, 19/19, 22116) did not impact subsequent disease development. Susceptibility
did appear to be increased by increasing average temperatures from 16 to
22 and is related to plants maturing faster at higher temperatures. Bedding
plants were also included in this study and it was determined that DIF
does not increase plant susceptibility to Botrytis although it was noted
that seed-propagated geraniums are much more susceptible to Botrytis blight
than either petunias or bedding impatiens (Pritchard, 1995).
LITERATURE CITED
Celio, G.J., and M.K. Hausbeck. 1994. Susceptibility of poinsettia
cultivars to Oidium sp. Phytopathology 84:1158.
Coyier, D.L. 1985. Powdery mildews. In: Diseases of Floral Crops – Vol.
1, Praeger Publishers Division, Westport, Connecticut, D.L. Strider, editor.
pp.103-140.
Daughtrey, M., and J. Hall. 1992, Powdery mildew – A new threat to your
poinsettia crop. GrowerTalks, September, pp.23-31.
Daughtrey, M., and M. Macksel. 1994a. Efficacy of fungicides for control
of powdery mildew disease of poinsettia, 1992. Fungicide and Nematicide
Tests 49:373.
Daughtrey, M.L. and M.T. Macksel. 1994b. Occurrence and control of powdery
mildew in U.S. greenhouses. (Abstr.) Phytopath. in press.
Ferrentino, Gerard W. 1992. Pest Monitoring: The basis of any IPM Program.
Proceedings for the 8th Conference of Insect and Disease Management on
Ornamentals, SAF, Alexandria, VA, pp. 37-41.
Good, H.M., and Zathureczky, P.G.M. 1967. Effects of drying on the viability
of germinated spores of Botrytis cinerea. Phytopathology 57:719-722.
Hall, J. 1993. Powdery mildew. 65th International Floriculture Industry
Short Course. Cincinnati, Ohio.
Hausbeck, M.K. 1993. Biological Control and Environmental Manipulation
for Control of Botrytis. Proceedings for the 9th Conference of Insect and
Disease Management on Ornamentals, SAF, Alexandria, VA, pp. 73-79.
Hausbeck, M.K. 1995. Forecasting Diseases. Greenhouse Grower pp.43-
46.
Hausbeck, M.K. 1995. Managing powdery mildew on poinsettia – Getting
the most out of your fungicides. Greenhouse Grower (anticipated publication,
August).
Hausbeck, M.K., and J. Kalishek. 1994. Influence of temperature and
relative humidity on germination of conidia of Oidium spp. on poinsettia.
Phytopathology 84:1085.
Hausbeck, M.K., J. Kalishek, M. Daughtrey, and L. Barnes. 1994. Keep
the colonies at bay (part 1). Greenhouse Grower, August, pp. 45-48.
Hausbeck, M.K., J. Kalishek, M. Daughtrey, and L. Barnes. 1994. Keep
the colonies at bay (part 2). Greenhouse Grower, September, pp. 88-92.
Hausbeck, M.K., and S.P. Pennypacker. 1991. Influence of grower activity
and disease incidence on concentrations of airborne conidia of Botrytis
cinerea among geranium stock plants. Plant Dis. 75:798-803.
Moorman, G., and R. Lease. 1992. Benzimidazole- and Dicarboximide-Resistant
Botrytis cinerea from Pennsylvania Greenhouses. Plant Dis. 76:477-480.
Pritchard, P.M. 1995. Influence of DIF on the susceptibility of floral
crops to Botrytis cinerea. M.S. thesis, Michigan State University, 92 pp.
Shaw, B. and M.K. Hausbeck. 1995. Epidemiology of powdery mildew on
Poinsettia. Phytopathology (in press).
Strider, D.L., and R.K. Jones. 1985. Poinsettias. In: Diseases of Floral
Crops – Vol. II, Praeger Publishers Division, Westport, Connecticut, D.L.
Strider, editor. pp. 351-404.
BUDGET – The following budget is proposed:
Greenhouse Supplies: 1,500
Growth and Dew Chamber Usage and Supplies 1,800 ($50/unit/month x 3
units)
Salaries Graduate Student Stipend (1/2 time) 15,000
Graduate Student Stipend (1/4 time) 7,500
Undergraduate Research Assistant 5,200 ($5.00/hr x: 20 hrs/wk x 52
wks)
* Research Technician (1/4 time) 7,500
TOTAL 38,500
Anticipated funding from Poinsettia Growers Association 7,000
Anticipated funding from various chemical companies 4,000
Amount requested from AFE 27,500
QUALIFICATIONS OF RESEARCHERS
Dr. Mary Hausbeck is an Assistant Professor and Extension Plant
Pathologist at Michigan State University. Her current responsibilities
at MSU include greenhouse crops. She has completed studies on the crown
and root rot of geraniums caused by Pythium ultimum documenting etiology,
symptomatology, fungicide efficacy, and cultivar resistance. She has also
provided information essential to the development of environmental manipulation
of B. cinerea. She has also published research on TSWV/INSV on greenhouse
crops. In addition, she routinely screens fungicides for efficacy against
foliar and root rot pathogens on a wide range of crops.
Ms. Margery Daughtrey is a Senior Extension Associate with the
Department of Plant Pathology, Cornell University and conducts a research
and eversion program on diseases of ornamental plants. She has conducted
numerous powdery mildew control trials on annuals, woody, and herbaceous
perennials and greenhouse poinsettias, testing conventional fungicides
as well as horticultural oil and sodium/potassium bicarbonate formulations.
Ms. Daughtrey has assisted in the development of the NY Greenhouse IPM
program, which has successfully developed and executed improved management
strategies for greenhouse and sweet potato whiteflies on poinsettias.
Dr. Larry Barnes is an Associate Professor and Extension Plant
Pathologist at Texas A & M University. Dr. Barnes received his B.S.
degree in microbiology and his M.S. degree in plant physiology from Texas
Tech University. He received Hs Ph.D. in plant pathology from Texas A &
M University. Dr. Barnes is responsible for supervision and operation of
the Texas Plant Disease Diagnostic Laboratory as well as plant pathology
extension educational programs in greenhouse crops.
