Update on Insecticides and Miticides for the Ornamental Market

November 5, 2002 - 13:01

Find out what's on the horizon, what's losing registration and what's been updated in the insecticides and miticides category.

I've been kidding around at some of the recent conferences
by polling the audience to determine its makeup. First, I ask how many in the
audience work in greenhouses, then how many work in nurseries or both since
many nurseries have associated greenhouses. Lastly, I jest that what's left of
the audience must be the chem-reps. It seems like at every conference of late,
most of the representatives of the chemical companies are there to give a
little speech about the latest products they have on the market for
ornamentals.

Mostly they concentrate on the fungicides, but occasionally they have a new or developing insecticide or miticide. Relatively few insecticides have been in development over the last few years, but there is hope on the horizon. I'm becoming aware of more compounds that are somewhat secret in nature, and if I told you about them I'd have to eliminate you. Well. . .they might eliminate me. However, that should provide you with some hope for the future. It is very important that the ornamental industry be provided with more alternatives for pest control. Resistance management begs for it.

Although you can see more reps at every conference, you
might not hear the same story every time. The companies themselves and labels
have been changing very rapidly. It's easy to discuss what's available here in
California, but that will leave out a number of pesticides that are first
registered everywhere else. I particularly like Ann Chase's description of a
list of fungicides she provided last year in her column. She said, "The
majority of the products included are currently labeled somewhere in the United
States, though you should check the label to see if they are registered for use
in your area." I completely agree, and that's the approach I will take in
this discussion.

Miticides

As you are probably already aware, there has been a flurry
of new miticides in development over the past few years. Some of them are
already on the market. The following is a review of the most recent changes.

EPA registration for Tetrasan 5WDG (etoxazole) from Valent
USA and Ultiflora (milbemectin) from Gowan are expected this fall, hopefully by
the time this article is published. Tetrasan is a 5-percent WDG (water
dispersible granule) that can be used at 8-16 ounces 100 per gallon. It's a new
class of miticide with a mode of action much like an insect growth regulator.
Mites are not insects, but they still have to shed their skin to grow. Like
insect growth regulators, they don't kill adults, but are active on eggs and
nymphs, and may sterilize adult females. Residual activity lasts between 21-28
days. Ultiflora is a naturally derived, broad-spectrum miticide with
translaminar activity. Like Avid (abamectin), Ultiflora also has activity
against leafminers. Residual control is 21-28 days.

Floramite SC (bifenazate) has been around for awhile now as
a wettable powder, but Uniroyal has developed an SC formulation. It already has
a federal label and some state labels. It has a better wetting agent in the SC
formulation, and Uniroyal has been demonstrating better activity with the SC
than with the comparable WP. We've had similar results here at UCR against
Lewis mite on poinsettia.

Akari 5SC (fenproximate) miticide from SePRO now has an
interiorscape label, formerly greenhouse-only for spider mites. Outdoor
registration is expected next year and SePRO is expanding the label to include
eriophyid and tarsonemid mites.

Insecticides

I won't belabor the fact that
the broad-spectrum pesticides of the past are dwindling at an ever-increasing
rate. Last year, Dr. Dick Lindquist mentioned fenoxycarb and bendiocarb in this report. This year (2002),
greenhouse use of Knoxout GH (diazinon) and Fulex Dithio Smoke/Plantfume 103
(sulfotepp) were lost, and Nemacur (fenamiphos) will be phased out over the
next few years. Diazinon sales must stop by the end of this year. Sulfotepp
production and sale were to have been terminated by September 30 this year, and
use must stop September 30, 2004. In spite of the bad news, the outlook is
still promising because a number of new insecticides have been under
development in the last few years and some are now available. The only downside
is that they have a somewhat narrower spectrum of activity.

IGRs

Pedistal 10 SC (novaluron) is a
new product from Uniroyal. It is considered a benzopheny urea much like diflubenzuron.
It acts the same way too, as an IGR or a chitin synthesis inhibitor. It is
expected to reduce the reliance on OPs, has low mammalian toxicity, and is
considered to be a low risk to the environment and non-target organisms. It has
activity against thrips, whitefly, lepidoptera and leafminer. An earlier
version called Rimon 10EC received the federal and state labels first but was
submitted for greenhouse use only. Uniroyal resubmitted for greenhouse,
nursery, landscape, Á interiorscape and shadehouse use, and the SC
formulation should be available sometime this fall.

Another IGR making its way into
the market is Talus Insect Growth Regulator (buprofezin 70%) from SePRO Corp.
It is a new insecticide for control of immature stages of whitefly, scale, mealybug
and leafhoppers. It is also a chitin synthesis inhibitor, so it affects the
insect as it molts. The initial registration will be for outdoor use.

Chloronicotinyls

Flagship 25 WG (thiamethoxam) is
another insecticide of the chloronicotinyl class that's under development by
Syngenta. It has excellent activity against aphids, whiteflies and mealybugs on
ornamentals as well as grubs, billbugs and chinch bugs in turf. This product
has flexibility of application including drench, irrigation and foliar. Registration
is pending.

Here's another merger you should
be aware of. Bayer Corporation is now known as Bayer Crop Science to merge the
two company names of Bayer Corporation and Aventis Crop Science. They are
divesting a new product called Tristar 70 WP (acetamiprid), which has great
promise for the greenhouse, nursery and landscape industries. Like Flagship
mentioned above, it is a new chloronicotinyl class insecticide. Its fate is not
yet known, but it is sure to become a usable product for the future. It received
reduced-risk status from the EPA, and it is expected to be available this year.
Bayer Crop Science is also developing another chloronicotinyl called
thiacloprid 480 SC. It is softer on non-target organisms, but the spectrum is
broader to include some microlepidoptera (small moths), which are very small
moths for the non-entomologist. Registration is not going to happen for awhile.

New Chemistry

FMC is developing a new product
from ISK Biosciences called Flonicamid. It will be registered for greenhouse use on ornamentals. Flonicamid 50 WG is
considered an OP replacement and received reduced-risk status, which usually
streamlines the registration process. Flonicamid is systemic and suppresses the
feeding of sucking insects. At the moment, the mode of action of this chemical
is unknown; however, it appears to be unique. We look forward to testing this
new compound here at the university.

An Old Standby

For those of you folks in
California, Mesurol 75W from the Gowan Company is now registered indoors and
outdoors as a sprayable insecticide and molluscicide. It has a broad spectrum
of activity, especially against western flower thrips, snails and slugs. Gowan
is also introducing Mesurol Pro, which is a new bait formulation of the product
for use indoors and outdoors against snails, slugs, sowbugs and millipedes.
Both products can be used in ornamental production and landscape areas.

Finally

One trend that's picking up
momentum is testing the compatibility of the newer, narrow-spectrum pesticides
with biological control agents. Biological control was much more difficult in
the past because of the consistent use of broad-spectrum insecticides and
miticides. However, there are more and more examples of successful biological
control of ornamental pests when used in an integrated pest management program.
With the narrower spectrum of activity of the pesticides and the pest
management restrictions on the label, many in the industry want to know the
toxicity of their products against the more common biological control organisms
sold commercially. The use of alternatives like biological control and IGRs
early in a cropping cycle for some ornamentals will also prolong the efficacy
of these newer pesticides.

I know that pesticide rotation
may be a confusing issue to some. To start with, pesticide rotation should
occur by chemical class, and there's plenty of published information now on
pesticide chemical classes, but not much yet on what to start with and which to
rotate to. A proper rotation scheme will most likely have to be designed
specifically for each pest and host. As a simple example, there are not many
pesticides to rotate amongst when trying to control the leafminer on
chrysanthemums. Using an IGR like Citation early, possibly in combination with
a parasitoid, will delay any chance of resistance buildup in the greenhouse.
IGRs are compatible with many beneficials because they are usually deployed as
adults, which are not susceptible. Following the IGR, a rotation to a more
conventional pesticide like a pyrethroid or OP followed by Avid in the last
stages of the crop is a good rotation scheme. More to come.

There. . .now I'm going to go
out and see if I can find some nice, early, pest-free, Thanksgiving Day
poinsettias. Happy holidays!

About The Author

James A. Bethke is a research associate in the Department of Entomology at the University of California Riverside. He can be reached by phone at (909) 787-4733 or E-mail at bethke@citrus.ucr.edu.

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