UC IPM Online UC ANR home page UC IPM home page


SKIP navigation


Research and IPM

Grants Programs: Projects Database

Project description

Biological Control of the Leafminer, Liriomyza trifolii (Burgess) on Commercially Grown Chrysanthemums. (87SA010)
Program UC IPM competitive research grants program
M.P. Parrella, Entomology, UC Riverside
K.M. Heinz, Entomology, UC Riverside
Host/habitat Greenhouse Crops; Flowers; Chrysanthemums
Pest Leafminer Liriomyza trifolii
Discipline Entomology
Diglyphus intermedius
Systems Applications
Start year (duration)  1987 (Three Years)
Objectives Develop a predictive model for the rational use of inoculative releases of the parasitic wasp on floricultural crops.

Conduct laboratory studies on the biology of the pest and parasite to refine the model.

Conduct field trials in chrysanthemum and marigold production greenhouses to test the model and evaluate parasite release rates.

Distribute information to growers, PCAs, and commercial insectaries.

Final report Inundative/inoculative releases of natural enemies have long been considered as a viable strategy for the control of insect pests of greenhouse crops. However, implementation of inundative biological control is fraught with problems due to the inability to answer fundamental questions regarding the release of natural enemies such as how often, how many, how and where should the natural enemies be released. To facilitate the use of biological control in greenhouse crops, a predictive model has been developed over the last three years with UC IPM funding. The model has been remarkably successful in predicting releases of the parasitoid, Diglyphus begini, to achieve biological control of the leafminer, Liriomyza trifolii, infesting greenhouse chrysanthemums. The model is extremely user friendly and has been written for use on an IBM XT, AT, or compatible personal computer. To initiate the model, the user must input four values: 1) the average number of mines per leaf; 2) the average number of L. trifolii, the number of parasitoids to be released per week for the duration of the crop, increases the predictability of biological control and should lead to an increase in the utilization of this management strategy. Following the release rate recommended by the model, L. trifolii, which resulted in the production and harvest of a salable cut chrysanthemum crop in Carpinteria, Santa Barbara County, without the use of any pesticides in 1989.

Top of page

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright 2019 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   web template revised: February 18, 2019 Contact webmaster.