We’ll talk more about sampling for plant bugs after bloom initiation with ground cloths in the coming weeks. The key with much of our insect management advice is to get out there and look at cotton fields regularly and to use suggested thresholds for treatment decisions.

Stink bugs also big in 2012?

We appear to have huge populations of brown stink bugs in the state so far this year (links to previous posts on management in corn and the future of insecticide management), with many recently coming off of mature and even harvested wheat, weed hosts and other plants.

In the case of field corn, some infestations in the zone of newly-developing corn ears already appear to be significant. In the case of cotton, about all we can say is that we have the potential for very high levels at this point.

On the plus side, we typically do not find significant stink bug damage to bolls until after about the second week of bloom. If the weather turns dry between now and the first or second week of bloom and negatively impacts cotton growth, potential damage to cotton bolls could drop significantly.

However, at this point, 2012 reminds me of our Year of the Stink Bug in North Carolina 2004, when we averaged just under 15 percent boll damage from stink bugs averaged across the state, as opposed to our longer term average of 3 to 4 percent boll damage under grower conditions.

Remember, however, that percent damaged boll figures for stink bugs do not equate to as high a level of yield loss as with bollworms. Unlike bollworms, which more often than not damage the whole boll, stink bugs damage a variable number of boll locks, ranging from complete boll damage to no boll damage. We’ll have much more on stink bugs in the coming weeks as the season unfolds.

Cotton aphids

 In North Carolina, we also often seem to have more reports of cotton aphid infestations during wetter weather. However, in tests conducted here and elsewhere in the Southeast, we have very few cases of yield losses resulting from cotton aphid infestations if adequate or excessive moisture levels exist.

Yield losses from cotton aphids primarily result from large populations throughout fields that then become economic infestations when cotton dries down quickly and the subsequent moisture stress adds to the similar stress caused by aphid feeding. 

And, more often than not here, aphid mummy parasitoids and a parasitic fungus come to the rescue.