What is in this article?:
- Insect pest management in corn and sorghum
- Monitor populations
- Little insect activity reported in Gulf coast corn.
- Consider height of sorghum, leaf damage in determining treatments.
- Monitor insect populations.
If the populations and infestations continue to increase, treatment most likely would be warranted. Dimethoate 4E (8 to12 ounces per acre) applied with hollow cone nozzles has provided control where volume rates of 7 to10 gallons per acre were utilized. It is critical to use hollow cone spray nozzles.
We are likely to seecorn leaf aphid in the whorls of sorghum. Plants can sustain much greater numbers of this aphid since it does not inject a toxin as do greenbug and yellow sugarcane aphid. In fact, even under very heavy corn leaf aphid numbers with abundant honeydew and seemingly a lot of damage I have not been able to show a yield increase through insecticidal control.
It would also be advisable to watch for increasing numbers of greenbug as plants increase in size. This aphid also has a toxin which affects the leaves. The aphid can cause economic damage up to hard dough. Consult B-1220, Managing Insect and Mite Pests of Texas Sorghum dated May 2007 for a thorough discussion.