Back to the other Hotline tapes

This is Jack Bacheler at NCSU with the Wednesday Cotton Insect Update. Unlike last week, this a hot, dry Wednesday, June 24.

Like last week, the cotton areas that we’ve worked in this week have been on the quiet side, insect-wise.

With our recent and upcoming weather predicted to be on the dry side, this would a good time to be sure that spider mites are on your scouting checklist. Although 2007 and 2008 should have been ideal for spider mite buildups after our dry starts and heavy thrips spraying, mites just never materialized on more than a few acres. Let’s hope for a repeat. However, when mites do become established in cotton at economic levels, they can be a real treatment headache, often requiring a high rate of an expensive material with less than satisfactory results. Look initially for the yellowish leaf stippling followed by a bronzing or reddening of leaves. A hand lens focused on the undersides of symptomatic leaves can more accurately reveal the presence of living mites and their eggs. Field edges along ditch banks and mowed rights of way can be good starting points, but whole field assessments can also reveal mites in field interiors, particularly in reduced till situations.

We continue to receive reports from consultants and growers of seeing more adult plant bugs than in recent years, so be sure that at least weekly retention counts of upper squares are being made. The higher priority cotton fields for potential plants bug damage are earlier squaring, lusher fields.

So far, cotton aphids appear to be at low levels throughout most of the state. But this species has explosive reproductive potential and can seem to appear out of nowhere overnight. In years past, we have received of our cotton aphid calls during the first three weeks in July. Fortunately, we have effective materials to control cotton aphids in the Southeast, and biocontrol actually comes through here in a high percentage of the cases in the form of aphid mummies and the parasitic fungus.

Although serious scouting for stink bug damage to quarter-sized bolls does not to begin in earnest until the second week of bloom, it would appear that stink bug levels are relatively high at this time. The degree to which stink bugs will likely become an economic problem on cotton will largely be determined by July and early August rainfall. The more rain, the more likely we will have higher stink bugs levels. Although a droughty July would likely result in cotton plants less attractive to stink bugs (as was strikingly the case in 2007), the unfortunate tradeoff would be lower yields. Most of us would take the stink bugs.

Well, that’s it for this week. We’ll provide the next insect report next Wednesday on June 29. See you then.