Grasshoppers in Crops 8-21-15

Grasshoppers in Crops 8-21-15

Grasshoppers in Crops

Grasshoppers
Figure 1. See those bits of yellow throughout the photo? Grasshoppers have been reported moving into crops in some eastern Nebraska fields. (Photo by Gary Zoubek)

Aug. 21, 2015

We are getting reports of grasshoppers feeding on crops in eastern Nebraska.  As grasshoppers get larger they are more difficult to control with insecticides.  Make sure the insecticide you choose is labeled for the target crop(s) you need to protect.  Also be aware of preharvest intervals (the required interval between application and harvest); they vary between insecticides.  See July 10 Crop Watch article, Scout Field Borders for Grasshoppers, for more details on suggested insecticides.

The following guidelines can be used to help make a decision to treat on crop and non-crop areas.

Bob Wright
Extension Entomologist

Table 1. Treatment guidelines based on number of grasshoppers (nymphs and adults) per square yard.
Grasshopper Population Within Fields Field Borders Treatment Necessary?
Non-economic 0-2 5-10 No
Light 3-7 11-20 Uncertain — depends on size, species, type of crop
Moderate 8-14 20-40 Probably
Abundant 15 or more 41 or more Yes