The Development of Integrated Pest Management in Floriculture Progress Report — June 1998
Date 6/1/98
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 7/97 to 7/98
Anticipated Date of Project Completion/Final Report - 6/30/99
Individual(s) Conducting Project:
(List Project Leader First)
Michael P. Parrella - Title Professor and Chairman
Telephone Number (916) 752-0492
Project Title: Development of Integrated Pest Management
Strategies for the Floriculture Industry
Control of insect and mite pests on floriculture
crops continues to be a major concern for flower growers across the country.
As we enter the era of ‘reduced risk’ pesticides, growers must have the
knowledge to use these products effectively. This mandates a more
thorough understanding of many pest species’ biology. In addition,
many of these reduced risk pesticides will not be able to stand alone –
they will need assistance (such as biological control) to work effectively.
Therefore more practical information on biological control and the compatibility
of reduced risk pesticides with commercially available natural enemies
are needed. This AFE funded project has focused on developing data
on reduced risk pesticides to facilitate their registration. In addition
biological information is being developed for selected pests which can
be used to enhance the effective use of reduced risk pesticides.
Finally we have been investigating practical aspects of biological control
and compatibility of natural enemies with selected reduced risk pesticides.
The major focus of research over the past few years has been the western
flower thrips, but work has also addressed whiteflies, aphids, spider mites,
and worms.
Research with Western Flower Thrips
Identification
A grower friendly key to the thrips attacking floriculture crops in.
North America is nearing completion. I presented an overview of this
key at the Roses Inc. Spring meeting (Minneapolis, MN., May 27) and
got some good feedback. Large color photographs are an integral part
of this key, and we anticipate that growers, PCAS, etc., will be able to
separate common thrips species that may occur in the greenhouse.
There are many species of thrips which can migrate into the greenhouse
and pose no threat to the crop. If these are captured on sticky cards,
a grower may be tempted to spray because of the large numbers on the cards.
With this key, the grower should be able to distinguish pest from non-pest
thrips, and therefore reduce unnecessary pesticide applications.
Biology
Studies have been completed on the distribution of thrips in roses and
chrysanthemums. We have examined both within and between plant distribution.
Such information is essential to effectively target pesticide sprays and
to develop statistically accurate sampling plans for this pest. Thrips
have a tendency to prefer developing buds, and appear aggregated on this
part of the rose plant. The data are less definitive for chrysanthemums.
Data for roses suggests that if growers direct sprays to the developing
buds (and in the process use less water and pesticide than conventional
spraying) good thrips control will result. We tested this idea with
a cooperating grower and were able to use 35% less water (and pesticide)
when directing sprays to the buds when contrasted to a full volume wet
spray.
Based on our understanding of the spatial distribution of thrips in
roses, taking 15 - 20 rose buds per range will provide for a statistically
valid sample regardless of cultivars present. Contrasting trap catches
on blue and yellow cards in a rose greenhouse, we found that blue usually
caught more thrips than yellow. Therefore blue may be the color of
choice if growers are interested in knowing whether thrips are present
in the greenhouse. However, when using cards to predict the number
of thrips in rose buds, the two colors were about equal. Based on
an examination of the spatial distribution of thrips caught on traps, 8
10 blue or yellow sticky cards are required in a greenhouse to accurately
estimate thrips populations.
Work on damage caused by thrips in rose buds suggests that growers can
tolerate 1-2 thrips per flower. This information, coupled with the
fact that blue or yellow cards are useful in predicting these low number
of thrips (I - 2) per rose flower, enhances the utility of sticky cards
as predictive sampling tools.
Research with Western Flower Thrips, Aphids, Whiteflies, Spider Mites
and Their Natural Enemies
Reduced Risk Pesticides
We have worked with a number of insecticides this past year most of
which are classified as ,reduced risk products; some are already registered
and some have registration pending. Materials in our trials included:
Sucrose Octanoate, Cinnacure, Floramite, CGA215944 (Relay), Alpha Hexyl,
Triad, and Spinosad, Beauveria bassiana (BotaniGard) and Adept.. We evaluated
many of these products for their ability to control aphids, western flower
thrips, spider mites, and whiteflies in direct contact and residual bioassays.
In some situations we combined materials (such as the insect growth regulator
Adept and the entomopathogenic fungus Beauveria bassiana) and tested for
synergism. In addition, many of these materials were evaluated for
their compatibility with commercially available natural enemies including
green lacewing larvae and aphid and whitefly parasitoids. As expected,
the ability to control the pests in these trials varied considerably from
product to product. For example, Cinnacure was very effective against
the eggs and adults of spider mites, while Triad was ineffective against
mites. Enormous variability was found when contrasting the various
products and their compatibility with natural enemies. For example,
Floramite proved to be very compatible with green lacewing larvae and aphid
parasitoids, while Cinnacure was highly toxic to these biological control
agents. However, the ultimate test of compatibility may be in the
commercial greenhouse. For example, although Beauveria bassiana was
lethal to natural enemies in our laboratory bioassays, it appeared to be
compatible with both whitefly and aphid parasitoids in commercial poinsettia
and Asiatic lily greenhouses, respectively.
Future Plans
The coming year marks the final one for this project. However,
this proposal was made part of a ‘team’ proposal and may be absorbed into
a much larger project spanning 3-4 years. In essence, the work will
continue on reduced risk pesticides, biological control, and biology with
a major focus on western flower thrips.
Publications in Trade Journals
1997. Parrella, M. P. Do biocontrols have a future in greenhouse
production. Greenhouse Product News. 7: 22-24. (copy included)
1997. Murphy, B. C., Tunyalee Morisawa, and Michael P. Parrella.
Insect killing fungi, floriculture’s IPM future? GrowerTalks.
Dec. (copy included)
1998. Parrella, M. P. Insect Growth Regulators: their limitations
and advantages. GrowerTalks. (in press)
1998. Parrella, M. P. Thrips palmi on Ficus in the Netherlands:
Separating fact from fiction. Planned for publication in both GrowerTalks
and Floriculture International (in press).
1998. Parrella, M. P. Unequal pricing of pesticides: is it justified?
Greenhouse Product News. (in press)
1998. Parrella, M. P. Pesticide use and retail florist.
Floral Management. Society of American Florists (in press).
