Doug Johnson, Extension Entomologist
There are some unusually large populations of green cloverworms on soybeans scattered around the state. This is a very common insect in soybeans which always has the potential for economic damage, but very rarely causes economic damage. The populations I have seen thus far are not at the economic threshold, but were much larger than I am used to seeing. It makes sense to look at your soybeans, especially late planted or slow developing beans.
|Green cloverworm caterpillar on soybean stem.|
These pests are foliage feeders. They will strip the leaf tissue from between the veins leaving the veins, petioles and stems behind like a skeleton.
It takes a great many of these caterpillars to cause an economic problem. Economic threshold (ET) depends not only upon the number of green cloverworms, but also on the stage of the plants, the value of the beans, and the cost of treatments. ETs may be found in:
IPM-3, KY IPM Manual for Soybeans at: http://www.uky.edu/Ag/IPM/manuals.htm and
ENT- 13, Insecticide Recommendations for Soybeans at: http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html
These insects are not very hard to kill. It is most important to detect them before they reach threshold and determine if control is needed. If you find them only after the damage has been done, you can kill them, but you can’t put the foliage back on the plants!