Managing Cotton Aphids
Cotton aphids have been more prevalent than normal this year in NC. Treatment is only recommended if the following conditions are met:
- Infestation levels are “relatively high”
- Plants do not have adequate moisture
- Mummifying parasites are not present
- Fungal pathogens are not present
Sometimes the use of broad spectrum insecticides can flare aphid populations by killing beneficial insects that control them (ladybird beetles and parasites, for example).
The active ingredients (neonicotinoids) in the chemicals Admire Pro, Centric and Belay have been shown to be resistant in Midsouth aphids. We shipped suspected neonicotinoid-resistant North Carolina aphids to Jeff Gore at MS State in 2012. The population we sent was 7x resistant to imidacloprid than a susceptible control colony. Spray failures can be a result of neonicotinoid resistance here in NC. However, it is important to take other factors into account. It’s hard to kill aphids with anything if you spray before a hard rain, don’t get adequate coverage, etc. Transform is an example of an effective non-neonicotinoid option to manage aphids.