Throughout the growing season we will try to keep producers, consultants and agents up to date on the “insect conditions” in North Carolina and how to manage situations before and as they arise.
With cotton planting now under way, thrips management decisions will soon follow.
As I have said many times in the past, mid-April to approximately May 10 planted cotton will likely be most at risk for thrips damage, primarily due to typically slower seedling grow-off conditions.
A few observations come to mind:
• Seed treatment residual begins to decline as soon as seed is planted. No more than 2 ½ to 3 weeks of activity can be expected.
• Optimum cotton seed treatment uptake matches optimum cotton seedling growth: moist soils and warm temperatures.
• Foliar application timing for thrips is most effective when cotton is between the expanded cotyledon to first true leaf stage.
• Seedlings with “herbicide burn” stress are more subject to thrips damage (another stress). That does not mean, however, that herbicide-burned seedlings have thrips.
• Tank-mixes to control both weeds and thrips can reduce application costs. However, a tank-mix prioritized for weed control applied after the first or early second true leaf stage may expose the seedlings to significant thrips damage. In this case, we recommend separate trips over the field.
• Producers and scouts should concentrate their attention to live yellow immature thrips in terminals. Older damage can be misleading.
• Once cotton reaches the 5 true leaf stage, even if the seedlings are badly damaged from thrips, additional control is not needed.
Because we don’t expect anything exciting on the cotton insect front for at least the next few weeks, these updates will be on the short side until then.
Between now and then, remember that by Googling our Cotton Insect Corner web site, you can access various kinds of cotton insect information, including images of pests and their damage, insecticide performance comparisons, insect scouting and management guidelines, all of our project’s applied research dating back to 1999 and other tips and advice for managing whatever unfolds in 2013.
Also check out this blog, the NC Field Crops Blog, for updates about field crops (including tobacco) and small fruit IPM.
We’ll try to provide weekly updates at this site, even when things are slow on the cotton insect front.