Thrips and aphids have been reported in new cotton in southwestern Oklahoma, according to Terry Pitts, Oklahoma State University Extension integrated pest management specialist.
Pitts reports heavy thrips migrations are currently occurring as bordering crops and weeds dry down and mature.
Prolonged migration can occur for fields next to pastures and weedy areas, Pitts says. He suggests producers keep a careful watch on these cotton fields.
"Fields that still fit these criteria and were treated with an at-plant systemic or seed-treated insecticide have already shown signs the residual effect of the insecticide is wearing off," he says.
These fields need to be monitored closely as heavy infestations may destroy terminal buds resulting in stunted cotton plants.
Treatment, Pitts says, is advised when the number of thrips averages one or more per true-leaf present. So far, thrips in cotton have been highly variable. However, as a word of caution, Pitts says to be very careful to watch fields where young cotton plants are struggling.
He says Orthene is a good to use on thrips and it will work well as a tank mixture with glyphosate. Pitts also indicates producers should be careful when scouting for the insects not to confuse thrips damage with wind damage.
"The effects are very similar for both conditions," he says. He also asks producers to remember insecticidal control is rarely justified once cotton plants reach the five to seven true-leaf stage, or when plants have begun to square.
Aphids are appearing in cotton fields early this year, Pitts says. These are small, slow moving, highly prolific insects that feed primarily on the underside of cotton leaves.
The two black tail-pipe like structures protruding from the back of the abdomen of cotton aphids are known as cornicles and are useful in identifying aphids, he says.
Cupped leaves, Pitts says, can result when high numbers of aphids feed on young, developing cotton leaves. Heavy, prolonged infestations of this insect can cause severe stunting of young cotton plants. Aphids excrete honeydew, which, under arid late season conditions, can result in a condition known as "sticky cotton" that causes problems when cotton is milled.
Pitts says Bidrin or any other product registered for thrips control is effective for aphids.
Pitts is stationed at the OSU Southwest Research and Extension Center, 16721, South US HW 283, located south of Altus, Okla., in Jackson County. He can be reached at 580-482-8880. His cell number is 580-318-3121. Pitts' email address is firstname.lastname@example.org.
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