Santee, South Carolina, USA
February 4, 2016
Jeremy Greene, Clemson entomologist, explains some steps producers can take to help control thrips in cotton crops. Best management practices for managing thrips was one of several topics addressed during the 2016 South Carolina Cotton Growers’ annual meeting. Image Credit: A. Denise Attaway
Developing insect management programs and selecting top varieties to plant can help South Carolina cotton producers grow more profitable crops in 2016.
Among the topics covered during the South Carolina Cotton Growers’ Annual Meeting, held Jan. 26. Clemson University Cooperative Extension and Research specialists shared best management practices for managing thrips, stinkbugs and bollworms, as well as how to choose the cotton variety best suited for a plot of land.
Thrips is a main pest of South Carolina cotton. Proper scouting is one essential step in controlling thrips in a cotton field, said Jeremy Greene, Clemson entomologist.
Thrips can be detected by shaking seedlings in a large cup or over paper or cloth to dislodge the insects for counting. Significant feeding injury to new leaves is another indication thrips are present and causing damage. The threshold for thrips is two per plant, with the presence of immatures as a clear indicator that efficacy of an at-plant treatment has diminished.
Thrips can delay or reduce crop yields and are predictable pests that should be managed every year with insecticides at planting.
“You can be assured thrips will be present every year in South Carolina cotton crops,” Greene said.
Some management tips for thrips Greene gave include: planting cover crops and utilizing heavy residue in a reduced tillage system, using starter fertilizer with irrigation, avoiding herbicide stress (proper calibration/delivery), apply foliar applications early (first leaf bud is best), as well as using at-plant insecticides (seed/hopper box treatments, in-furrow granular materials such as Temik (if you still have some – label good until 2018) or Thimet, or in-furrow liquid sprays such as imidacloprid or acephate, or a combination of these mentioned.
Planting date also plays an important role in the susceptibility of seedling cotton to feeding injury from thrips. Historically, early-planted cotton experienced more problems with thrips than cotton planted later in the planting window. However, it is more common recently to experience maximum pressure from thrips during the middle of the planting season, around May. A new model will be available to producers soon to help them predict periods of heightened risk to thrips in cotton.
In addition to thrips, stink bugs are another important group of insect pests in cotton. Stink bugs can cause major losses in yield and problems with fiber quality. The peak blooming period (weeks 3-5) is the most critical time for protection against stink bugs, Greene said. Fiber quality is preserved when stink bugs are managed to protect yield.
“It is important to pay attention to field edges, borders and adjacent landscapes,” Greene said. “The interface of cotton with peanuts is a great example of an adjacent crop that can be an attractive location for stink bugs. Woodland margins with wild hosts for stink bugs can also be a hot zone for the insects in cotton. Scout these areas first when making decisions about using insecticides for stink bugs.”
Greene warned producers of a new stink bug already established in portions of South Carolina. This stink bug is the brown marmorated stink bug.
Bollworms were another insect pest Greene addressed during the meeting. According to Greene, bollworms can be controlled primarily by using Bt cotton, although the technology does not provide 100 percent control of the species. Growers still need to scout for and manage bollworms, as needed, Greene cautioned.
To aid cotton producers in their fight against insect pests, the Clemson Cooperative Extension Service has two mobile apps. Found at http://www.clemson.edu/extension/mobile-apps/, the first app is the Calibrate My Sprayer App for iOS and Android devices. This free mobile app aids in the proper calibration of spraying equipment. The second app, found on the same page, is the Mix My Sprayer app, also for iOS and Android devices. The My Sprayer app is a free app that aids users with quick, accurate calculations of product mixes to be applied with spraying equipment. Custom lists of favorite products by category can be created.
In addition to learning how to control for insect pests, attendees of the Cotton Growers’ Meeting also learned the importance of proper variety selection. Mike Jones, state cotton specialist, said cotton quality is based on four characteristics: strength, length, micronaire and color.
“Genetics and the environment play an important role in the quality of cotton,” Jones said. “It is important producers do their homework and determine which variety will work best for their area of the state. What works best for other regions of the Cotton Belt may not work best for the Pee Dee Region and so on.”
Jones gave a recap of the 2015 cotton crop which showed 235,000 acres were planted compared to 280,000 acres planted in 2014. Of these planted acres, 124,000 acres were harvested at 581 pounds per acre. The total for 2014 was 912 pounds per acre. South Carolina cotton produced 150,000 bales in 2015 compared to 520,000 bales in 2014.
Issues that affected the 2015 cotton crop included weather that was hot and dry in the early season and too much rain that came late in the season, leading to delayed planting, poor stands and delayed crop development, poor fruit set, low seed numbers and poor defoliation. Other issues included record rainfall and flooding in most areas from remnants of Hurricane Joaquin; seed-sprouting; hardlock bolls; fields too wet for harvest (47 percent of crop went unharvested); and more than 45 percent of the crop was planted in new, untested cotton varieties. Cotton producers also faced low prices coupled with poor yields and grades.
For more information about these and other agriculture-related topics, go to www.clemson.edu/extension/
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