The Development of Integrated Pest Management in Floriculture Progress Report –June 1997
Date 5/30/97
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 $58,560
Covering Period 7/96 to 7/97
Anticipated Date of Project Completion/Final Report - Year 2000
Individual(s) Conducting Project:
(List Project Leader First)
Michael P. Parrella - Title Professor and Chairman
Telephone Number (916) 752-0492
Project Title: The Development and Implementation of Integrated
Pest Management Strategies in Floriculture
- A. Project Objectives1. Develop a key to the species of thrips attacking floriculture crops
that can be used by growers, pest control advisors and extensionists
2. Develop a sampling/monitoring program for western flower thrips for
roses and chrysanthemums 3. Determine the relationship between density
of thrips in flowers and damage-in essence estimate the level of thrips
that may be ‘acceptable’ to flower growers.
4. Examine the reasons for the resurgence of leafminers as pests in
floriculture crops and explore the feasibility of biological control using
novel control agents.
The development of a guide to thrips attacking floriculture crops has
been expanded to include both a pictorial guide as a well as an interactive
guide on CD ROM. I published an article for growers on thrips identification
that included many color photographs of thrips species (1995a&b). This
publication is serving as a template for a stand alone publication. The
importance of such a guide for growers is threefold: 1) Many thrips species
that come into greenhouses are not pests. If growers understand this, then
unnecessary pesticide applications can be avoided; 2) Not all thrips are
created equal. That is, the biology of thrips species varies. If growers
identify thrips and can correctly associate that thrips with its biology,
then control strategies can be developed for that species of thrips; and
3) Not all thrips are capable of transmitting viruses. There are less than
ten species with this capability. Growers concerned about the virus will
be able to tell if the species of thrips caught on yellow cards or found
on plants is a potential vector of these viruses.
Sampling plans for thrips on roses and chrysanthemums are nearing completion.
When the within-plant distribution of thrips was examined, it was found
that thrips prefer the developing buds and associated leaves in roses;
no preference was found in chrysanthemum. Therefore, our sampling unit
in roses is the developing bud while leaves, developing buds, or young
flowers can be sampled in chrysanthemum. This has important implications
for pesticide applications. For roses, it is important to get thorough
coverage on developing buds, while for chrysanthemums, the entire plant
needs to be sprayed. We are still in the process of quantifying the between
plant distribution of thrips in roses and chrysanthemum and this will be
finished in the coming year. Such information will give us an idea of the
number of samples to take to be confident of the mean number of thrips
per flower. Roses demonstrated no injury when caged with two thrips as
soon as the buds began to open. This is our ‘acceptable’ level of thrips
per, flower. This data is still being gathered for chrysanthemum. Blue
and yellow sticky cards were found to be good predictors of low levels
of thrips per flower. They can be used not only as general indicators of
population increases and decreases, but also as predictors of damaging
thrips populations in rose flowers. This makes sticky cards important tools
in the management of western flower thrips. It was found the yellow traps
were a better predictor of thrips in flowers than blue traps.
Leafminers continue to increase as pests of both chrysanthemums and
gerbera in California greenhouses. A reduction in susceptibility to the
material Avid is suspected, although resistance has not be documented.
I am functioning as a bridge between DowElanco, and Merck in trying develop
a mutually agreeable framework for the labeling of Conserve (DowElanco’s
product) for leafminer control in greenhouses. Ultimately some sort of
rotation between the two products will be mandated on the label. We continue
to make advances in the use of the parasitoid, Diglyphus and the nematode,
Steinernema carpocapsae for control of leafminers. Large scale field trials
will be conducted this spring. I have published two articles this past
year on leafminer biology and control.
Publications:
- Parrella, M. P. 1995a. Thrips management guide. Part I: Preventionand control. GrowerTalks (April) 58(1 1): 30 - 39.
- Parrella, M. P. 1995b. Thrips management guide. Part II: Properidentification. GrowerTalks (July) 59(4): 82-94.
GrowerTalks 60(7):34,36, 38-39, 40, 43. Also printed in Floriculture International
6(11):18-22, 24.
60(6):54, 57-58, 60-62.
