Farm Progress is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Cold winter may have left insect relief

Wet, cold winters make folks shiver and pine for spring, but west Texas cotton farmers are thankful for this year's miserable weather. Thanks to snow, ice and nasty cold snaps, they may get by with fewer insecticide sprays this season.

Jim Leser, entomologist with the Texas A&M Research and Extension Center at Lubbock, says protecting cotton early is always important but adds that growers will be forced to economize where possible with prices stagnant and expenses higher.

He hopes they can save a few dollars on insect control costs.

“Predicting insect infestations is difficult,” says Leser, “but we're off to a good start.”

Emerging boll weevil numbers, for instance, likely will be significantly lower because of a cold, wet winter. He also expects beet armyworm and looper infestations to be insignificant for the 2001 season. Back-to-back years with heavy beet armyworm problems, he says, are rare. Wet, cold winters also appear to limit their number.

Weather, however, seems to have no impact on thrips, and Leser says cotton farmers should prepare to treat these damaging pests.

‘We always have thrips around. A major factor in thrips infestations is wheat that dries down as cotton enters a growth stage that attracts them.

“We have significant wheat acreage in all our cotton production areas,” Leser says. “The Blacklands (in central Texas) and the High Plains normally have significant thrips problems because cotton develops vegetation just as wheat dries down. Thrips move into the cotton because it's often the best game in town.”

Fleahoppers and plant bugs (lygus) numbers also may increase when winter and early spring months are wet.

“Early moisture favors wild weed hosts for these pests,” Leser says. “Entomologists in California use weed hosts to predict fleahopper and lygus infestations.

Leser says wild hosts that dry down as cotton begins squaring may set the crop up for damaging infestations. “Weeds have to mature and dry down before cotton blooms to be a factor,” he says. “After blooming, cotton is not as vulnerable to damage since the plant fruits enough to offset most insect injury.”

The lygus is more complex. “Other crops, such as potatoes, alfalfa and peanuts serve as good hosts for lygus,” Leser says. “What happens to these crops in fields adjacent to cotton may influence lygus infestations.”

Leser is concerned that fleahoppers and lygus could cause serious problems for cotton this year.

Aphids, he says, also pose prediction problems. “They often come in early. They overwinter in the High Plains as nymphs and adults, but farmers can limit opportunity for aphids developing into an economic pest.”

He says the Boll Weevil Eradication Program may help with aphid, fleahopper and lygus control. Overwinter weevil treatments may not include the ideal insecticides to control the pests but may suppress and keep them from developing to damaging levels.

“Eradication zones in other states have seen some benefits with plant bug suppression,” he says.

Leser doesn't anticipate a boll weevil year. “Eradication and a cold winter have knocked numbers down to the lowest level since they moved into the area.

“But, with a good growing season, even a small number of surviving weevils can build to high numbers by late season. But, with any luck, the combination of low numbers early and an early crop will come together to keep farmers from having to spray for weevils.

“The pieces are falling into place for low cost weevil control. That's good news for cotton growers.”

Leser says caterpillars also could pose few problems. “It does not look like a beet armyworm or looper year and that's another major savings for farmers, especially when farmers need to economize.”

He says budworms pose little concern for High Plains growers most years. “They come in late, from acreage down south. It's a rare year that we have significant problems with budworms in the northern range of the Texas cotton belt.”

He says Bt cotton helps as well.

“The bollworm is tougher, and we have two sources of infestation: our own worms that overwinter and fly-ins. In our worst years, bollworms migrate from the south. It's impossible to predict what migration will be since they have to develop farther south and then get conditions favorable for migration into our area.”

Leser says bollworm infestations caused little trouble for the past few years. “Low numbers last year means we had fewer to overwinter. The indigenous population should be relatively low. Bt corn also helps keep numbers down. Also, if corn acreage drops, so does potential for bollworm infestation.”

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.