As farmers were preparing to plant their first cotton seeds for the 2004 crop, John Norman reminded them to watch out for their old nemesis.
“In the Rio Grande Valley we deal with the boll weevil every year, and throughout the year, not just in the spring and fall,” he said during the recent Pre-Planting Seminar in Weslaco, Texas.
“You either get rid of the weevil, or get out of the cotton business,” Norman said. Experts estimate that boll weevils cost Texas cotton growers $20 million annually in lost yields.
“And there's more to weevil control than spraying cotton,” said Norman. He stressed the importance of a uniform planting date. In the Rio Grande Valley that means planting should take place from about the 20th of February to the 15th of March. By planting within that time frame, insecticide sprays will be more effective.
Before or after that date, yields go down. It's not a good practice to get a head start by jumping the season since “weevils like early cotton.” These early-season applications can cut down the weevil population only if the majority of cotton farmers go after the pests at about the same time, as opposed to some growers making their first treatment at one time and others treating two months later.
In areas where early boll weevils are common, it is important to use pre-emptive sprays for over-wintering weevils — one to two applications no and others treating two months later.
In areas where early boll weevils are common, it is important to use pre-emptive sprays for over-wintering weevils — one to two applications no more than five days apart, starting at pinhead square. “Your neighbor's field has an impact,” said Norman, so the more people involved in this, the more over-all success. It is important for cotton farmers to monitor early season infestations in all fields, especially around the edges, as well as cotton near any known over-wintering sites. Finding squares on the ground is a clue that to early boll weevil activity. Then it's time to get busy.
Norman warned against abandoning fields. “I know it costs money (to treat the weevil), but you have to think about the long-term benefit.” When it comes time to make defoliant decisions, Norman advised adding insecticide to the mix. “The more people who do this in an area, the better off you all are.” He warned, though, about being careful to use a weevil control that won't heat up the herbicide.
If a farmer is going into conservation tillage, as many are, every time the cotton is treated, insecticide should be added to the herbicide. Mixing insecticides with herbicide to kill the stubble adds pressure on the weevil population. “You're going across your field anyway.”
Norman said the key to weevil control is destruction of live cotton stalks with total destruction of all fruiting forms. “The quicker you can get to them after harvesting, the better,” said Norman. “Don't wait three to four weeks.” Shred the stalks and add herbicide as soon as possible since it only takes a couple of weeks for shredded cotton to start squaring and about five weeks or less for seedling cotton to start squaring. It is important to make sure that volunteer cotton from sprouting seed is killed.
Cotton stalks must not only be eliminated from the farmer's field, but also from ditches, pastures, gin yards, etc.
Since the Rio Grande Valley has benefited from timely rains and the cotton market is encouraging, growers express a lot of optimism. But in order to have a successful crop, all producers have to control the weevil.