Date 2/28/93

Title of Project The Development and Implementation of Integrated Pest Management Strategies in Floriculture

Institution where work is being conducted University of California, Davis, CA 95616

Amount of Endowment Grant $ 50, 000
Covering Period 9/1/92 to 2/28/93

Anticipated Date of Project Completion/Final Report

Individual(s) Conducting Project:

(List Project Leader First)

Michael P. Parrella - Title Professor

TelephoneNumber (916) 752-0492

The Development and Implementation of Integrated Pest Management Strategies in Floriculture

Michael P. Parrella

University of California-Davis

Progress Report to the American Floral Endowment, 2/28/93

A. Project Objectives:

1) Biological control - evaluate natural enemies of selected floriculture pests to

determine their potential in providing control–focus on whiteflies, aphids, and the western

flower thrips;

2) Implementation of a statewide IPM program for chrysanthemums in California;

3) Biological studies with selected greenhouse pests and their natural enemies–westem flower

thrips and whiteflies are the focus here;

4) Continue research on performance of new and old

pesticides for control of greenhouse pests and determine their compatibility with selected

natural enemies. Included in this objective was development of data on pesticide resistance

which could be used to suggest pesticide rotation patterns which, when employed, would

reduce the development of resistance in the greenhouse; and

5) continue the compilation of

worldwide of literature on pests in the greenhouse.

B. Major New Advancements Over the Preceding Six Months:

As information is generated that has relevance to growers, my project will try to publish

any new data in a timely fashion. We have made major strides in our understanding of the

biology, biological control and insecticide resistance of the western flower thrips. On carnation,

there is a strong preference for feeding and egg laying in the sepals near an opening bud. In

contrast, few eggs, little feeding, and poor survival occurs in other vegetative parts of the

carnation. This has implications for control because now pesticides can be targeted where the

thrips prefer to feed and lay eggs rather than to the entire plant. We currently have in culture

two new natural enemies of the western flower thrips–a parasitoid (Ceranisus sp.) and a

nematode (Thripenema nicklewoodii). Biological studies and statewide surveys are underway to

understand more about their potential to effect control of this major pest. Insecticide

resistance studies have been completed with the western flower thrips; adults appear to be

naturally tolerant of abamecttn while first and second instars are susceptible. Resistance has

been detected in these early instars where abamectin has been used extensively. (See

references #s 1, 2, 3, and 4.)

We have made considerable strides with biological control of the sweetpotato whitefly.

At this time three natural enemies have the most potential for control: the predaceous beetle,

Delphastus pusillus, and two parasitoids, Encarsia luteola and Encarsia tabacivora. We have

shown that the predator and parasitoids are compatible when used together (that is, D. pusillus

does not feed on later developing whiteflies that have been parasitized). Releases of low rates E.

luteola and D. pusillus into a commercial poinsettia range produced a high quality crop of

poinsettias with no insecticide applications. Research with the biology of the sweetpotato

whitefly suggests that the cultivar on which a whitefly develops has a strong influence on its

choice of a cultivar to feed and to lay eggs as an adult. Olfactory cues given off by different

poinsettia cultivars appear to play an important role in host plant selection by adult whiteflies

(see reference # 5).

A statewide IPM demonstration project was conducted in potted chrysanthemums

utilizing biological control as the primary pest control tactic. Three potted plant growers in

three separate growing regions in California participated. Trials consisted of IPM/biological

control treatments vs. grower pest control practices. Primary pests encountered were thrips,

leafminers, and aphids. Beneficial organisms used for control were: Diglyphus begini or D.

isaea (leafminers), Amblyseius cucumeris (thrips) and Chrysoperla rufilabris (aphids); pesticides

were used as a last resort. Results indicate that the biological control treatments had greater

insect damage than the grower treatments but a high quality crop was still produced.

Chrysanthemums grown under the IPM/biological control treatment vs. the grower treatment

did not differ in terms of their salability. We are encouraged by these findings and are planning

to continue the project this coming year. It Is hoped that our results will stimulate growers of

ornamental plants to utilize biological control as part of their pest management strategies. (See

reference #s 6 and 7.)

Research with the melon aphid on potted chrysanthemums has shown that releases of

young instars of Chrysoperla rufilabris may not be the best choice of a natural enemy to use for

aphid control. They were capable of reducing aphid populations, but it required two releases at

the rate of 25 per plant (in controlled experiments) to achieve this. Apparently strong

Interspecific repellency is occurring because we are able to recover only a small percentage of

the Chrysoperla after these heavy releases.

New pesticides continue to be evaluated for control of the major greenhouse pests. We

are concentrating on ‘biorational’ materials that generally fall into two categories: insect

growth regulators (such as phenoxycarb and buprofezin) and botanical materials such as

Margosan (Neem). Results with some of these materials have been very encouraging.

Buprofezin continues to look outstanding for whitefly control and we are currently working

with how best to utilize this material in the field. A more traditional material, the granular

insecticide Merit produced by Miles, also continues to excel in the control of a wide range of

floricultural pests. We are in the process of evaluating many other materials from NorAm,

Dow, American Cyanamid, Rohm and Haas, Whitmire, and Ciba Geigy.

Literature continues to be compiled. I have committed to writing a book for Cornell

University Press which will be an updated version of the classic publication Biological Pest

Control - The Glasshouse Experience (originally by Hussey and Scopes). This book was

published in 1985 and enough has taken place since that time to justify a rewrite. In addition,

I am a co-convener with John Sanderson of the International Organization of Biological

Control, Working Group for Integrated Control in Glasshouses which will be held in California

in April. This meeting is ’sold out’; there are more than 100 participants from 21 countries

around the world.

C. Future Plans Covered by the Endowment Grant:

Large trials are underway with biological/IPM programs in poinsettia where we will be

testing the most effective natural enemies discussed above. This is being done with

cooperating growers as well as in my greenhouses on the Davis campus. We are particularly

Interested in examining the interactions of different natural enemies used simultaneously for

biological control. Detailed studies with many floricultural pests and their natural enemies will

continue–the more data we have the better we are able to formulate control IPM strategies

using either pesticides or natural enemies. The amount to time and effort that goes into

studying biology in this project should not be underestimated because a good portion of the

four graduate students supported by this AFE grant have basic biology as an important

component of their Master’s and Ph.D. work. The statewide implementation project in

chrysanthemums will continue and we hope to repeat this in another crop this year.

Resistance studies will continue and now focuses on spider mites which appear to have

developed resistance to Avid. Considerable research will concentrate on the new natural

enemies of the western flower thrips discovered last year. Research with new ‘biorational’ and

other pesticides will continue in an effort to generate data required for registration.

Compatibility studies with natural enemies will also continue.

D. Anticipated Benefits for Floral Industry:

This AFE project is designed to provide flower growers with components of an IPM

program which can be applied in their operations for the purpose of maintaining quality of

production while reducing the 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.

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 for floricultural crops. While this data is not of

immediate use to growers (for example, some of the natural enemies we are working with for

biological control of the sweetpotato whitefly and western flower thrips are not yet available

commercially) we are building the knowledge base for a fully integrated pest control program

that can be adopted by growers over the next few years.

E. References Cited:

1. Greene, I. & M. P. Parrella. 1992. Get a grip on thrips: an eye on control. Greenhouse

Grower 10(12):54-56.

2. Greene, I. & M. P. Parrella. 1992. Get a grip on thrips: cultural control. Greenhouse

Grower 10(13):62-66.

3. Greene, I. & M. P. Parrella. 1992. Get a grip on thrips: the basics of biocontrol.

Greenhouse Grower 10(14):68-72.

Note: The stand alone publication by Greenhouse Grower magazine entitled Get a Grip

on Thrips will contain a thorough treatment of all insecticides available for control. This

was not included any of our articles published separately in the magazine. Half the

proceeds from the sale of this booklet will be donated to my research project at UC

Davis.

4. Greene, I. & M. P. Parrella. 1993. An entomophilic nematode, Thripenema nicklewoodii

Siddiqui (Tylenchida: Allantonematidae) and an endoparasitic wasp, Ceranisus sp.

(Hymenoptera: Eulophidae) parasitizing Franklinella occidentalis (Pergande)

(Thysanoptera: Thripidae) in California. Proceedings of the IOBC Conference, Working

Group for Integrated Control in Glasshouses. Asilomar, Calif. (in press).

5. Heinz, K. M. & M. P. Parrella. 1993. All poinsettia culitvars do not smell alike: just ask a

sweetpotato whttefly. GrowerTalks (in press).

6. Hesselein, C, K. Robb, J. Newman, R. Evans, and M. P. Parrella. 1993.

Demonstration/integrated pest management program for potted chrysanthemums in

California. pages 5-10. In J. Hall & K. Robb, (eds.), Proceedings of the Society of

American Florist’s Ninth Conference on Insect and Disease Management on

Ornamentals, San Diego, California.

7. Berube, C. & M. P. Parrella. 1993. Predators and parasites; prey for us. GrowerTalks (in

press).

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