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Summary of Thrips! responses

Grant R. Cramer cramer at med.unr.edu
Tue Nov 28 21:11:18 EST 2000

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<TITLE>Summary of Thrips! responses</TITLE>
As many of you requested, I have included the multiple responses 
about thrips below.<BR>
In addition, I did a little internet investigating on my own. An 
excellent site on thrips and their control can be found at:<BR>
My thrips appear to be the western flower thrips, so I used the site 
above. There are other web pages for other kinds of thrips at the 
same ipm.ucdavis.edu URL. There seems to be a number of pesticides 
used, but there also seems to be even more effective biological 
controls including the pirate bug and predatory mites (see the web 
site and comments below). <BR>
I would also add that a technician in another plant lab at our 
University has used pyrethrin-based bombs to fumigate the plants and 
effectively control thrips without injury to the plants.<BR>
Given the sensitivity of Arabidopsis to insecticides, the pesticide 
resistance that western flower thrips have built up and the 
effectiveness of biological controls, I am planning to fumigate to 
reduce initial populations, followed by repeated applications of 
biological controls (one of the predatory mites as they seem to be 
the cheapest) to keep thrip populations at a low level. <BR>
Thanks to all who provided useful information (see below).<BR>
-- <BR>
Grant R. Cramer<BR>
Associate Professor<BR>
Mail Stop 200<BR>
Department of Biochemistry<BR>
University of Nevada<BR>
Reno, NV 89557<BR>
phone: (775) 784-4204<BR>
fax: (775) 784-1650<BR>
email: cramer at unr.edu<BR>
web page: http://www.ag.unr.edu/cramer/<BR>
  &nbsp;&nbsp;&nbsp;Do you or someone there have a pesticide license ? 
&nbsp;A chemical called <BR>
Conserve works great at 5 mil / gal but can only be purchased with a <BR>
license. &nbsp;No thrip and no phytotoxicity.<BR>
  &nbsp;&nbsp;&nbsp;Uplands Farm Manager<BR>
  &nbsp;&nbsp;&nbsp;PO Box 100<BR>
  &nbsp;&nbsp;&nbsp;1 Bungtown Road<BR>
  &nbsp;&nbsp;&nbsp;Cold Spring Harbor Laboratory<BR>
  &nbsp;&nbsp;&nbsp;Cold Spring Harbor New York 11724<BR>
  &nbsp;&nbsp;&nbsp;Voice 516 367 - 8829<BR>
  &nbsp;&nbsp;&nbsp;Fax &nbsp;&nbsp;&nbsp;516 367 - 4031<BR>
  &nbsp;&nbsp;&nbsp;Email <FONT COLOR="#0000FF"><U>mulligan at cshl.org<BR>
</U></FONT>We have tried many things,<BR>
including heating the chambers to 60 degrees overnight with thorough<BR>
bleaching, and those thrips keep returning. &nbsp;It is really 
becoming a problem<BR>
for us!<BR>
Thanks, Judy Brusslan<BR>
1. I have had mild thrip problems several times - I've used Green Cross<BR>
Diazinon garden and fruit tree spray diluted according to package 
It doesn't kill the plants, but it causes brown spots when sprayed; it is<BR>
useful to keep thrips at bay in an emergency (to harvest siliques) but I<BR>
wouldn't use it as a long-term solution - besides it is probably too 
toxic to<BR>
use safely indoors on a continuous basis.<BR>
2. &nbsp;This summer I tested for the first time the thrip predator 
mite Amblyseius<BR>
cucumeris purchased from a local seed company. &nbsp;It eats small 
thrips and<BR>
spider mite eggs. It needs 3-4 weeks to get established, so it's 
added before<BR>
thrips are a problem. &nbsp;It certainly had no effect on the plants 
nor did I<BR>
acquire any thrip infestation, as happened in previous summers. 
&nbsp;I'm planning<BR>
to get some more and spread them about the plants.<BR>
3. &nbsp;Our greenhouse tech says that keeping plants several storeys 
up should<BR>
prevent airborne thrip contamination from outside (via windows); she also<BR>
recommended sterilizing ALL seed before planting it, as a 
preventative in case<BR>
thrip eggs get into collected seed and propagate that way.<BR>
Hope this is helpful. &nbsp;I'm interested in solutions to thrips. 
&nbsp;Maybe if<BR>
someone has a sure-fire cure you could post it.<BR>
Moira E. Galway,<BR>
Department of Biology, St. Francis Xavier University,<BR>
PO Box 5000, Antigonish, Nova Scotia,<BR>
B2G 2W5, Canada.<BR>
We've also experienced thrip infestations and got rid of them by <BR>
treating the plants with a pesticide called &quot;Merit&quot; 
(imidacloprid) <BR>
which is commercially available. &nbsp;&nbsp;&nbsp;We purchase ours 
locally in San <BR>
Diego at Target Specialty Products (phone 858-586-1933). &nbsp;We pay <BR>
$81.70 for two 8 ounce bottles of the wettable powder. &nbsp;The cost <BR>
seems high, but it lasts a long time. &nbsp;I believe it is most effective <BR>
when used to water the plants. &nbsp;Our 10X stock solution is made at a <BR>
concentration of &nbsp;370 mg/Liter. &nbsp;A single application 
should take <BR>
care of the problem. &nbsp;We have used it for aphid problems and find <BR>
that spraying works well to control the aphids.<BR>
Here is a website about the pesticide, which is also the active <BR>
ingredient in some popular flea control products for pets:<BR>
Good luck<BR>
Dear Grant:<BR>
For thrip control on Arabidopsis, we use a predatory mite with excellent<BR>
results in growth chambers and growth rooms. &nbsp;We are using Amblyseius<BR>
cucumeris. &nbsp;You don't have to worry about spraying or phytotoxicity!<BR>
These mites can be purchased from the Green Spot company (Phone<BR>
603-942-8925). &nbsp;The slow-release packets work very well, and they are<BR>
pretty economical, about $5 per packet, which treats 100 square feet.<BR>
These packets remain effective for about 8 weeks.<BR>
We have also tried the thrip predatory mites Hypoaspis miles and Iphiseius<BR>
degenerans, and they have also worked well, although they were more<BR>
Good luck!<BR>
Tim McNellis<BR>
Penn State University<BR>
Hi Grant, <BR>
I use a product called Marathon (i'm &nbsp;in an odd lab transition 
just now,<BR>
so I can't run and look at the bottle, but I can find out the company if<BR>
no one else tells you) It works pretty well mixed in with the soil, at<BR>
about 1mL powder per liter soil. &nbsp;For bad infestations, I sprinkle<BR>
additional pesticide directly onto the soil. &nbsp;We haven't seen any<BR>
ill-effects on the plants, but I don't think Thrips are completely<BR>
controlled, either. &nbsp;<BR>
I'd love to know what other responses you get. &nbsp;If you want me to find<BR>
out more about Marathon, let me know and I'll make the effort. <BR>
Hi Grant. &nbsp;Don't know about thrips, though in general I find 
very sensitive to pesticides.<BR>
Grant, You should try a pesticide called Conserve by DowAgroSciences. <BR>
It is extremely effective, no problems with phytotoxicity, and has a <BR>
12 hour REI.<BR>
It is important to use a wetting agent along with the Conserve. &nbsp;I <BR>
use M-Pede at 3-4 tbs/gallon. &nbsp;M-Pede is also sold as Safer's Soap.<BR>


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