The Development of Integrated Pest Management in Floriculture Progress Report — August 1995
Date August 30, 1995
Title of Project The Development and Implementation of Integrated Pest Management Strategies in
Floriculture
Institution where work is being conducted Department of Entomology
University of California, Davis, CA 95616-8584
Amount of Endowment Grant $40,000
Covering Period 1/1/95 to 12/31/95
Anticipated Date of Project Completion/Final Report – Indefinite
Individual(s) Conducting Project:
(List Project Leader First)
Michael P. Parrella – Title Professor and Chairman
Telephone Number (916) 752-0492
Chuck LeGault – Staff Research Associate
Brook Murphy – Title Postdoctoral Researcher
Judy Nelson, Mark Hanzlik, Roger Sher – Title Graduate Students
The Development and Implementation of Integrated Pest Management Strategies in Floriculture
Michael P. Parrella
University of California – Davis
- Project Objectives:
- 1) a. Evaluate the potential of new and commercially available biological control agents of the westernflower thrips. Explore the basic biology of natural enemies of the western flower thrips and examine combinations
of natural enemies for control of this pest, b. Continue the evaluation of natural enemies, on a
comparative basis, for biological control of other pests in greenhouses;
2) Continue the basic biology and identification of thrips in an
effort to understand feeding, oviposition, and pupation behavior in selected floriculture crops;
3) Continue the
search for new pesticides which have potential for use in floriculture and maintain contact with chemical
manufacturers to assure that the ornamental’s industry is not overlooked for potential registrations. Assist in
labeling materials for ornamentals and help fill in data gaps for materials undergoing reregistration. Evaluate new
and old pesticides for compatibility with selected natural enemies in culture at UC Davis. Continue monitoring for
insecticide resistance in the western flower thrips and develop alternative strategies for controlling these arthropods
and for managing the development of resistance.
- Major New Advancements Over the Preceding Twelve Months:
- The western flower thrips continues to be a major floriculture pest throughout the United States. In manycases it is the key pest and the success or failure of an IPM program for a particular crop often depends on the ability
of the grower to get a handle on the western flower thrips population. If insecticides are used, repeated applications
are usually required and the toxicity of effective materials are inconsistent with the basic tenets of IPM. In a two-part
article published in GrowerTalks (2, 3) I discussed the latest information available on the biology, control and
identification of thrips in the greenhouse.
- Effective biological control of this pest in floricultural crops is not possible with the available slate ofnatural enemies. Research done with regular releases of the predaceous mite, Amblyseius cucumeris, and the
predaceous bug, Orius tristicolor, failed to produce a high quality crop of chrysanthemums. This past summer/fall,
we have been evaluating the combinations of these natural enemies as well as another predaceous mite (Iphesius
degenerans) and an entomopathogenic fungus (Beauveria bassiana). The work with the ftingus is in cooperation
with the Vermont group (Brownbridge, Parker, and Skinner); they are examining the utility of this fungus (and
others) for biological control in greenhouses. This research is ongoing and only preliminary results are available,
but the most promising combinations appear to be the fungus plus predaceous mites. Initially we were excited about
the discovery of a thrips parasite in California (Ceranisus spp.) and a parasitic nematode (Thripinema aptini).
Unfortunately, these proved very difficult to mass-rear for greenhouse biological control evaluations. We were able
to generate some basic biological data on these natural enemies, and still plan to work with them as biological
control agents. We sent the parasitoid to the Netherlands as our contribution to a program where the Dutch are
surveying the world trying to find a good biological control agent for the western flower thrips. They completed
some detailed biological studies on our species (and others) and concluded that its utility as a biological control
agent (via heavy releases into commercial greenhouses) was limited (Loomans et al. 1995).
- We are in the final stages of developing protocols for biological control of the silverleaf whitefly attackingpoinsettias. This project was the first to report that the commercially available parasitoid, Encarsia formosa, was
ineffective against the silverleaf whitefly on poinsettia. (Despite this, many growers and researchers still continue to
work with this species.) In addition, this project was one of the first to report on the utility of Encarsia
luteola/formosa “Beltsville Strain” for whitefly control on poinsettias and we have gotten good results with this
parasitoid when used together with the predatory lady beetle, Delphastus pusillus. One student has just completed
his Master’s degree working with D. pusillus for whitefly control and he has just accepted a position as Entomology
Farm Advisor in Bakersfield, CA. There are no commodities directly tied to this position-he may initiate some
work on greenhouse crops. A Ph.D. student will finish in Sept. and she has focused on the interaction and
compatibility of the predator (D. pusillus) with several parasitoid species.
- The importance of this whitefly biological control research has diminished somewhat with the advent of thenational registration of Marathon by Bayer. Although this product is extremely effective, it is not immune to the
development of resistance. We are trying to develop a system where natural enemies are used early in the crop and
Marathon towards the end. In this way a clean crop is produced without total reliance on a pesticide. This puts less
pressure on the insecticide and will dramatically slow the development of resistance.
- Things started off slowly for the registration of new pesticides as we moved into the 1990’s. It seemed asthough the agrochemical industry had reached the end of its creative period with respect to developing new
chemistry and novel control compounds. Obviously this was not true and things have changed dramatically over the
past year. There is more activity with new chemistry and with the potential registration of novel materials over the
past 12 months than during the entire decade of the 1980s. This is exciting, because many of the products fit the
profile of a reduced risk pesticide which means that the EPA will put these products on a fast track for registration.
A listing of these products is too long for this progress report, and a separate trade magazine article will appear
shortly (1). We are working closely with many of these manufacturers to assure 1) their continued interest in
labeling for floriculture and 2) to assist them in developing a functional greenhouse label. Some products evaluated
this past year possess novel modes of action that provide excellent activity against the target pest, fit the positive
profile of a biorational material, and afford good compatibility with natural enemies. Such products can potentially
fit into IPM programs for floriculture crops that are being developed around the country.
- Future Plans Covered by the Endowment Grant:
- As work continues with biological control of the western flower thrips, we realize that proper thripsidentification (at the grower level) is critical to successful control with natural enemies or pesticides. We are
developing a key to the thrips attacking floriculture crops. This was briefly covered in recent trade publication (3),
but a more complete key will be finished shortly. This key should help growers and the extension/scientific
community with the problem of proper thrips identification. Research with IGRs and other biorational materials
suggest that while many of these appear perfect for IPM programs and afford compatibility with natural enemies,
they must be properly used in order to be effective. In that regard, we are developing protocols (based on computer
simulations) that will allow the intelligent scheduling of applications of these products to maximize their
performance and fit within an IPM program.
- In order to effectively manage western flower thrips, growers need to have an idea of how to effectivelymonitor populations and what thresholds trigger some remedial action. In addition, the relationship between thrips
caught on yellow/blue cards and thrips numbers on the actual plant and damage caused are unknown. We hope to
begin to answer these questions this year with research continuing into 1996.
- Anticipated Benefits for Floral Industry:
- This AFE project is designed to provide flower growers with components of an IPM program which can beapplied in their operations for the purpose of maintaining quality of production while reducing pesticide use. This is
accomplished at two levels: 1) some data generated by the project is of immediate use to growers (pesticide
efficacy, information on basic biology in relation to pesticide efficacy, how to estimate pest populations in the
greenhouse, evaluation of commercially available natural enemies, etc.) and can be applied to production facilities
without delay, and 2) other data is being compiled which focuses on the development of a more complete system
where biological control is a major component of an IPM program. In some cases, for example, some of the natural
enemies used to control western flower thrips are not yet available commercially. However, we are building the
knowledge base for a fully integrated pest control program that can be adopted by growers in years to come.
- References Cited:
- Loomans, A. J. M., J. C. van Lenteren, M. G. Tommasini, S. Maini, and J. Ruidavets. 1995. Biological control ofdirips pests. Wageningen Agricultural University Papers 95.1: 201pp.
- Publications Appearing in 1995 as a Result of AFE Support:
- 1. Parrella, M. P. 1995. New greenhouse pesticides are fact not fantasy. GrowerTalks (Oct. or Nov. – in press).
- 2. Parrella, M. P. 1995. Thrips management guide. Part I: Prevention and control. GrowerTalks (April) 58(1 1):30 – 39.
- 3. Parrella, M. P. 1995. Thrips management guide. Part II: Proper identification. GrowerTalks (July) 59(4):82-94.
- 4. Kabashima, J., D. Ken Giles, and M. P. Parrella. 1995. Electrostatic sprayers improve pesticide efficacy ingreenhouses. California Agriculture (July-August) 49(4): 31-35.
- 5. Murphy, B., C. LeGault, and M. P. Parrella. Insect growth regulators: Their proper use in the greenhouse tomaximize their inclusion in IPM programs. GrowerTalks (in press, scheduled for late 1995 or early 1996).
- 6. Parrella, M. P. 1995. Managing the silverleaf whitefly, pp. 131-150. In A. Bishop, M. Hausbeck, and R.Lindquist (eds.), Proceedings for the Eleventh Conference on Insect and Disease Management on Ornamentals.
Society of American Florists, Alexandria Virginia.
- 7. Greene, I. D. and M. P. Parrella. 1995. Two new natural enemies of western flower thrips in California, pp.277-279. In B. L. Parker, M. Skinner and T. Lewis (eds.), Thrips Biology and Management. NATO ASI
Series. Series A: Life Science Vol. 276. Plenum Press, New York.
- 8. Robb, K. L., J. Newman, J. K. Virzi and M. P. Parrella. 1995. Insecticide resistance in western flower thrips,pp. 341-346. In B. L. Parker, M. Skinner and T. Lewis (eds.), Thrips Biology and Management. NATO ASI
Series. Series A: Life Science Vol. 276. Plenum Press, New York.
- 9. Parrella, M. P. 1995. IPM – Approaches and prospects, pp. 357-363. In B. L. Parker, M. Skinner and T. Lewis(eds.), Thrips Biology and Management. NATO ASI Series. Series A: Life Science Vol. 276. Plenum Press,
New York.
- 10. Robb, K. L. and M. P. Parrella. 1995. IPM of western flower thrips, pp. 365-370. In B. L. Parker, M. Skinnerand T. Lewis (eds.), Thrips Biology and Management. NATO ASI Series. Series A: Life Science Vol. 276.
Plenum Press, New York.
