Development and Implementation of Integrated Pest Management Strategies for Poinsettias Progress Report — December 1994
Date December 31, 1994
Title of Project Development and Implementation of IPM Strategies for Poinsettias
Institution where work is being conducted Cornell University
Amount of Endowment Grant $ 15,000
Covering Period 1/94 to 12/94
Anticipated Date of Project Completion/Final Report Spring 1997
Individual(s) Conducting Project:
(List Project Leader First)
John P. Sanderson - Title Assoc. Prof. Entomolgy
Telephone Number 607-255-5419
Rod Ferrentino - Title IPM Coordinator
Development and Implementation of IPM Strategies for Poinsettias
John P. Sanderson
Cornell University
- A. Project Objectives:
- Applied Research:
- I. Whitefly management
- A. Evaluate and implement whitefly sampling plans for use in stock plant
production and the finished crop.
Poinsettia IPM program. Develop training materials and procedures.
MA (with MA funds) this past fall. The results, including cost estimates, are currently under
analysis.
to develop a computer model for whitefly population development that can be used for making
control decisions. She returned to Holland in December, but will continue to collaborate on the
model, using our data. She has used our data sets of whitefly cohort fates, daily temperatures, and
crop canopy growth to determine stage-specific survivorship and developmental times (on a degree-day
basis) through the growth of the crop. These results are needed for the model. We have also
made initial decisions on the information from model output that would be most useful to growers,
and she is currently in the process of writing the first version of the model. Additional data sets of
whitefly levels, cohort fates, temperatures, and crop canopy growth, that are needed for model
validation, have now been collected for three poinsettia crops.
on poinsettia in replicated greenhouse trials at Cornell. Tests with the “Beltsville strain” of Encarsia
formosa were completed in Fall, 1994. Though the data are still under analysis (the tests were
completed in mid-December), this species/strain is very promising. Commercially-acceptable
whitefly levels were obtained with releases of 1 wasp/plant/week, and particularly good control was
achieved with 3 wasps/plant/week. Plans are underway to make this parasite available commercially
in the future. In our Spring 1994 tests, Eretmocerus nr. californicus (Arizona strain) also appears
to be a promising parasitoid for silverleaf whitefly control, and is now commercially-available on a
limited basis.
various parasitoids on 1994 poinsettias among extension professionals/researchers in the Northeast
(who have independent funding). Trials were planned in 8 commercial greenhouses in New York
(A.F.E.-funded), as well as in CT, MA, NH, and Ontario, Canada. Unfortunately, the insectaries
that were to supply the wasps for the trials had severe production problems throughout August and
September. As a result, all tests outside of New York were canceled, and only five were continued
in New York. Of the five, we could not obtain enough parasites at the start of the crop at three
locations to finish the crop without the need for insecticides, though the season-long number of
sprays was reduced. However, the natural enemy supply was sufficient in two locations to produce
high quality poinsettias without any insecticide applications. Our results demonstrated that
regardless of the parasite species, parasites cannot be used “too little, too late”, but that the timing
and numbers of releases are critical to achieve adequate control. Unfortunately, we were not able to
replicate the studies at enough sites to provide a robust evaluation of the various parasitoid species
under commercial conditions. We have subsequently provided additional insectaries with some of
our parasitoid species, so that in the future, back-up supplies can be obtained if it becomes
necessary.
greenhouses at Cornell in Fall, 1994. Four applications at 5-day intervals of Back-Off, a
formulation of Metarhizium anisopliae strain ESC-1, reduced whitefly levels from a severe
infestation to well below control levels, but not quite to commercially-acceptable levels. In
cooperation with the University of Vermont (M. Brownbridge), we tested two formulations of their
Beaveria bassiana strain. After four applications at 5-day intervals, the oil formulation reduced
whitefly levels ten times lower than the control treatment. Both of these whitefly pathogens look
promising for whitefly control, particularly if they are integrated with other natural enemies.
been reduced in scope.
and adults caught on sticky cards, are being gathered in commercial greenhouses.
greenhouses, comparing Gnatrol (B.t.i.), Exhibit (nematode: S. carpocapsae) and a predaceous mite
(Hypoaspis miles). Gnatrol appeared to be effective in one of the sites, while Hypoaspis was
effective in the other. The inconsistent results, coupled with differences in growing conditions,
suggest that factors such as type of irrigation system, growing media, or other factors may influence
the effectiveness of the various natural enemies.
which served as demonstrations for several poinsettia educational tours for local growers. We have
also participated in several national grower conferences. I convened a Northeastern U.S.
Greenhouse IPM Workshop for researchers and extension professionals to foster information
exchange and to identify and coordinate implementation strategies across the region. In July 1994,
30 IPM specialists from ME, NH, VT, MA, PA, MD, CT, NY, and Ontario, Canada, met at Cornell
for a very productive 2-day meeting. Cooperative efforts among northeastern states in applied
research and implementation were arranged for whitefly sampling, various biological control trials,
and the start of an economic analysis of selected pest management strategies. The group will meet
again at Cornell in July, 1995. Cornell will host a Greenhouse IPM Conference in Fall, 1995, in
which the results of these AFE-supported studies will be provided to growers and extension
specialists. Results will be incorporated into a new edition of Cornell’s IPM Manual.
mention work from two separate research laboratories that have recently documented resistance in
certain silverleaf whitefly populations to the newly-registered insecticide, Marathon 1G
(imidacloprid). One of these labs has also documented high levels of resistance to Applaud
(buprofezin) in silverleaf whiteflies from Dutch floriculture greenhouses (although Applaud is not yet
registered in the U.S., a registration package has been submitted to the E.P.A.). Many U.S.
greenhouse growers have high hopes that Marathon or other insecticides will continue to be “magic
bullets” for control of whiteflies and other sucking insect pests. These recent results suggest that
resistance to Marathon may develop sooner than later if the insecticide is not used carefully (i.e.,
within an IPM context). It would be extremely short-sighted for the industry to rely on new
insecticides for pest control and suspend efforts to develop and implement IPM programs for these
pests. We must continue the development of cost-effective control strategies to which the pests
cannot become resistant, such as biological control.
suggest refinements in release strategies (e.g., species to use, timing releases, numbers to release).
These refinements will then be evaluated in commercial greenhouses on spring stock plants and fall
Christmas crop. Back-up plans are now in place to avoid the parasite supply problems that were
encountered in 1994. The predictions generated by the initial version of the computer model will be
compared with our validation data sets to identify necessary improvements. Eventually the model
will be evaluated under commercial conditions, both for grower-friendliness and for predictive
accuracy. The research on fungus gnat damage levels will be begun during Spring, 1995, and
further studies on fungus gnat monitoring and biological control will be done. The Northeastern
U.S. Greenhouse IPM Workshop for researchers and extension professionals will meet again in
July, 1995. The purpose of the workshop is to foster information exchange and to identify and
coordinate implementation strategies across the region. Our AFE-funded research results will thus
be provided to workshop participants, particularly those who expressed interest in our work. This
network is intended to speed up implementation goals across a wide region. For example, four
states plan to cooperate in whitefly biological control trials in-1995, using standardized procedures
developed at Cornell. Thus in one year we can accomplish applied research, educate local extension
personnel, and make use of demonstration sites in many states at once. Cornell will also host a
Greenhouse IPM Conference in Fall, 1995, in which the results of these AFE-supported studies will
be provided to growers and extension specialists. Results will be incorporated into a new edition of
Cornell’s IPM Manual.
program for all phases of commercial poinsettia production that emphasizes biological control and
other alternative control strategies. Results of the applied research will be incorporated into the major
effort to demonstrate and implement current IPM practices in commercial greenhouses, and develop
training information that can be used to implement IPM programs in other states.
