Pest & Crop

Purdue Cooperative Extension Service
August 18, 2006

Pest & Crop Newsletter, Entomology Extension, Purdue University

In This Issue Insects, Mites, and Nematodes

Soybean Aphid Numbers Back Down Again – (Christian Krupke)

After a spike in aphid numbers about 10 days ago, we are back down to single digits aphids/plant in most areas. At this point it is highly unlikely that aphids will make a 2006 “run” and build the populations sufficient to necessitate treatment. It is useful to note that although we had aphid numbers in the low to mid 100’s/plant in some fields, followed by favorable “aphid weather” (temperatures in the 80’s, low relative humidity) we did not have any of these fields reach threshold. This is an example of the importance of scouting when it comes to these pests, and of the folly of “spraying early.” Growth curves of soybean aphid populations are difficult, if not impossible, to predict and the best bet is sticking to weekly counts and treating only at threshold. We will have another update on soybean aphid numbers later this month.  

back to top

divider

Harvest Restrictions for Soybean Insecticides - (John Obermeyer and Christian Krupke)

Severe woollybear caterpillar feeding

Severe woollybear caterpillar feeding.

Fortunately soybean aphid has not developed as much of a threat this year. However, defoliating insects such as bean leaf beetle, woollybear caterpillars, or grasshopper may be on the rise in some fields. The following listing includes some of the many insecticides registered for soybean insect control, including rate per acre and harvest restrictions. Refer to the label for insects controlled and specific rates and application information.

 

 



Product
Rate and Formulation
Days Before Harvest
carbaryl (Sevin)
2/3 lb. 80WSP
1-2 pt. 4F, XLR+
21
21
chlorpyrifos (Lorsban)*
1pt. 4E
28
cyfluthrin (Baythroid 2)*
1.6-2.8 oz. 2EC
45
deltamethrin (Delta Gold)*
1.5-1.9 fl. oz. 1.5EC
21
dimethoate (Dimethoate)
1 pt. 400, 4EC
21
esfenvalerate (Asana XL)*
5.8-9.6 oz. 0.66EC
21
gamma-cyhlothrin (Proaxis)*
1.9-3.2 oz. 0.5EC
45
lambda-cyhalothrin (Warrior)*
1.9-3.2 oz. 1CS
30
permethrin (Ambush)*
                  (Pounce)*
3.2-6.4 oz. 2EC
2-4 oz. 3.2EC
60
60
zeta-cypermethrin (Mustang Max)*
2.8-4.0 oz. 1.5EW
21
*Restricted Use Pesticide

back to top

divider

Click for Table.
Black Light Catch Report.

back to top

divider

Weather Update

Temperatures as of August 16, 2006

back to top

divider