Cotton Insect Newsletter Vol. 21, No. 10, July 23, 2003 Call 1-877-629-1474 for Cotton Insect Hotline

Cotton Situation:  Nearly 50% of the crop is setting bolls this week.  There is a considerable acreage of cotton that has just begun squaring freely.  In most of the fields that I have checked, there are still high percentages of squares being set.  Up to this point, I have seen very little loss of squares or small bolls.   Moisture continues to be abundant.  We expect to receive another 1-2 inches of rain throughout the cotton-growing regions of the state today and Thursday, with some locally heavy thunderstorm activity.  What a contrast this year has been when compared to the previous two years.  Last year, we couldn't buy a drop of rain, and this year, I don't think I have set foot in a field that didn't have all the moisture it needed and then some. Insect Situations:  This bollworm flight is on.  Eggs are being reported from the Savannah River to the North Carolina line.  I talked briefly on Tuesday with Al Averitt, a cotton consultant in the southeastern part of North Carolina.  He said they still had not seen any evidence of moth activity being on the increase in that part of the world.  Down around the Georgia line, it was a different story.   Last Thursday, Tom Smith found that egg counts had increased up to 30-50/100 plants in the Blackville-Springfield area.  Tommy Walker called on Monday and reported they were seeing an increase in neonate (newly emerged)  worms in purple blooms.  They had seen counts in the worst fields ranging from 30-100 small worms per 100 plants.  In Bt cotton, the threshold for an insecticide treatment would be 30 small worms, since you have to assume that perhaps 20% will avoid being killed by the toxin.  He also stated that they were somewhat surprised at the high numbers of small worms in fields where egg counts were relatively light.  This would lead us to assume that a high percentage of eggs were being deposited further down the stalk.  If you are only looking at terminals, you will probably miss the boat.  Scouts should be routinely looking in pink or purple blooms for small worms.  Examine the colored blooms that are still erect.  After the blooms have softened and folded over each other, scouts will have a tough time separating them to check for worms.     Early this morning, I looked at some test plots here at the station.  The air was still, cool and damp.  Female bollworm moths were abundant and readily visible resting on the tops of leaves.  The egg count was 50/100 plants in terminals plus 20-30 more in the lower parts of the plants.  Eggs laid further down on the plant were deposited on stems and old leaves primarily.  Although I didn't see any this morning, it's likely that some eggs were deposited directly on squares, white or colored blooms and on dried bloom tags.  My search for larvae in purple blooms came up empty.    Although the bollworm flight is on in earnest, there are still fields that are apparently receiving fairly low egg deposits.  Seemingly, these fields would be attractive to the moths, but the eggs just aren't showing up.  Well, maybe some of the eggs are being consumed by predators.  Where aphids infested fields for two or three weeks,  a strong cadre of predators moved in, reproduced and stayed around after the fungus knocked out most of the aphids.  Big eyed bugs, minute pirate bugs, green lacewing larvae, fire ants and other predators can be found in these fields. According to He/ID tests conducted by Candy Roach, egg samples from cotton fields have been running from 50 to 80% bollworms.  Tobacco budworm eggs have comprised 30% or more of the samples from Darlington and Marlboro Counties.  This is a higher percentage of budworm that we would normally expect to see.  Budworm moths have been scarce in both fields and pheromone traps, however.  In fact, we are catching very few bollworm moths in traps in both the Savannah Valley and the Pee Dee areas.        The main insect to worry about besides the bollworm this week is the ubiquitous stink bug.  No, that's not a new species--just one of Webster’s words that means being everywhere.  Being everywhere, that is, except where you want them.  Our stink-bug test is still not attracting many, but hopefully, by the time the plants have produced quarter-sized bolls, the ubiquitous stink bug will show up.   Elsewhere, there have been numerous reports of green stink bugs, and this week, more greens and southern green stink bugs are being found in the lower part of the state.    Boll Weevil Traps:  As I mentioned in a previous newsletter, there have been some problems with placing pheromone traps this year.  I called Randy Lynch this morning to report some fields that were not being trapped in Darlington County.   He said a few farmers had called him after we alerted them last week about the problems they had getting intended acres for cotton in four counties: Darlington, Dillon, Florence and Williamsburg.  Let's all continue to keep a sharp eye out for those fields that haven't been trapped, and when you find them, report to Randal Lynch or Wyman Taylor at 800/269-9928.   Mitchell Roof  Extension Entomologist

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