Cotton IPM Update – 5/26/2017

Cotton maturity across the Mid-Coast ranges from half-grown square to near cutout. Pest insects to be aware of include cotton fleahopper, bollworms, stink bugs and verde plant bugs.

Continue to monitor young cotton for cotton fleahoppers until the first week of bloom.  If you have a decent fruit set at bloom of at least 70% retention, the cotton fleahopper should not be a pest after first bloom.

By bloom, the cotton plant should have 80% or more of the harvestable fruit.  Since the fleahopper is not able to cause square loss to squares larger than a pinhead, fleahoppers will no longer pose an economic threat to the crop.

The cotton fleahopper is rather easy to control when using proper rates of any of a number of insecticides.  Below is the results of an insecticide trial conducted a few weeks ago to a population of adult cotton fleahoppers. All of the insecticides worked as expected controlling the emerging nymphs for 7 days after application. As expected, none of the treatments maintained control at 10 days after application.Once the crop is blooming, inspect plants for cotton bollworms, verde plant bugs and stink bugs. The method of checking plants I use to inspect the squares and bolls beginning at the top of the plant. I am primarily looking for worms and plant bugs and fruit damage. When damaged squares are found, try to track the damage to the worm. While most worms will be controlled by Bt cotton varieties do not assume the Bt cotton will prevent economic losses from occurring. Use an economic threshold of 5-10,000 worms per acre.  More information on Bt Cotton HERE.

We begin to check for Stink Bugs in the second week of bloom.  At this time, pull bolls that are 1-inch in diameter, pop them open and check the insides for stained seed cotton and wart growth on the inside boll wall.

When choosing to apply plant growth regulators, be sure to check the field for total nodes and nodes above white flower. Avoid using PGRs after the first or second week of bloom. This is generally too late to have a beneficial effect on plant height and could have a negative impact on yield, especially to stressed cotton.

Crop tour dates are as follows:
Victoria County Crops Tour –  June 13

Refugio County Crops Tours – June 14

Calhoun County Crops Tour – June 15

Comments are closed.