Agricultural News
2012 Caddo County Cotton Crop Off to a Good Start
Fri, 15 Jun 2012 11:36:14 CDT
A mild winter, early spring and timely rain have given Caddo County cotton farmers' crop a good start.
Jeannie Hileman, manager of the Farmers Coop gin here explained the 2012 crop has an early start, even if there have been attacks from cotton aphids on the young plants.
"We have a really good start for a crop this year," she said. "Much of the cotton is already at the pinhead square level of growth, just before beginning to form new bolls on the bottom branches of the plant. We have seen a lot of thrips in some fields. Seed treatments helped in the early stages of growth, but several producers have had to spray for the pest."
Dr. Randy Boman, Oklahoma State University Research Director and Cotton Extension Program Leader, accompanied by staffers Jerry Goodson and Shane Osborne, outlined how the 2012 cotton crop is shaping up to a group of Caddo County producers here this week.
Goodson reported on the continuing problem of thrips in young cotton this year. "Thrips are not generally a serious pest of Oklahoma cotton, except in years when unfavorable growing conditions limit early season growth. Heavy thrips infestations can occur if plants have emerged before wheat or other small grains mature. Mature thrips often move into stands of succulent cotton seedlings, causing curled and misshapen leaves which inhibits growth and may cause maturity delay. Thrips infestations vary from field to field and from year to year and should be handled accordingly.
"Thrips are small, approximately one-sixteenth inch in length. The color varies according to species. It may be similar to the color of wheat straw, yellow, black or light brown. The adults have two pairs of long, narrow fringed wings which enable them to fly from one crop to another. The life cycle contains several stages: egg, larva, pupa and adult. Larvae and adults will over winter in debris and trash near the field. In the spring, the adult females lay eggs by inserting them into the plant tissue. The creamy white eggs hatch into small larvae which begin to feed on the plant. After a short time, they burrow into the soil and transform into a non-feeding stage called the pupae. They emerge as adults and continue to feed on the plant.
"Thrips damage cotton by using their rasping-sucking mouthparts to feed on the plant surface. Ruptured cells release plant fluids which are sucked up by the insects. Injury first appears as dark brown spots which assume a silvery appearance several days later. Feeding occurs on the lower side of the leaf and may injure the terminal bud so that new leaves fail to develop and growth is retarded. Leaves will be crinkled and cupped. Economically damaging infestations occur when plants average three thrips per plant at the three leaf stage. Plants with fewer leaves can tolerate fewer thrips per plant whereas larger plants can tolerate slightly higher populations. For questions concerning this, call the Altus Center."
"Weekly scouting is the only way to monitor a treatment's performance. Expect damaging populations of thrips to materialize first in fields where no at-planting insecticide was used. Windy conditions will impact a producer's ability to accurately assess thrips numbers. In-field detection becomes nearly impossible as the wind picks up. Take a composite sample pulling at least 30 plants across the field placing them in a plastic bag or bucket. Waiting to examine plants until you return to your vehicle will take longer, but it will be a lot more accurate.
"Besides looking on the underside of cotyledons and true leaves, be sure to examine the terminal bud. Both adults and immature thrips feed and lounge there and are easily overlooked unless you carefully inspect this region. Also, don't forget to count and record the numbers of dislodged thrips running around on the inside of the baggie.
"Crop demographics play a large role of thrips pressure. Wheat is widely known as an early season habitat for thrips. However, alfalfa is another thrips nursery that can produce large numbers of the insects. With each cutting, thrips migrate from the field in search of a food source. Cotton fields in close proximity to alfalfa meadows may experience a huge influx of thrips overnight that might rival the exodus from nearby wheat fields.
Also, with the amount of spring rainfall we have had, a lot of other alternate hosts have provided considerable habitat for thrips to buildup.
"Finding adult thrips in protected fields is normal and is expected as long as the thrips migratiion continues. Remember thrips blown in from adjacent fields may not feed immediately and feeding is required for the insect to pick up a lethal dose of a systemic insecticide. Historically, Temik (aldicarb) has been a product of choice, however, with the loss of this product in 2011, farmers have come to rely more on seed treatments such as Gaucho (imidacloprid) or Cruiser (thiamethoxam) for early control. Other seed treatment products containing these products are also being sold."
Over the top sprays can be used in fields planted to glyphosate-tolerant (Roundup Ready Flex and GlyTol) varieties. This strategy of tank mixing an insecticide with glyphosate is cost effective. Acephate (Orthene) has been a standard foliar thrips treatment for many years. Application rates can be found in the Cotton Comments edition described in this article.
This information was taken from Cotton Comments, a periodical online production of the OSU Southwest Research and Extension Center staff which you can find by clicking here..
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