Illegal immigrants are getting a lot of attention on the political front these days, but cotton farmers may have some “illegal alien” issues of their own to deal with before another planting season rolls around.
These immigrants are insects that can build up around field borders, in earlier-planted crops and along ditch banks before and during the growing season, says Roger Leonard, research entomologist with Louisiana State University.
“We know that a number of these pests don't spring up in the middle of the field — they have to migrate in,” Leonard told participants in the first-ever Cotton Consultants Conference held on the eve of the National Cotton Council's Beltwide Cotton Conferences in Nashville, Tenn.
“Being able to establish contiguous fields on a farm and actually developing a farmscape plan will help you as a consultant know where to sample in terms of hot spots or migration of the insects from those other areas.”
The new Cotton Consultants Conference was conceived and planned by Bill Robertson, former cotton specialist for Arkansas, who now works as manager of plant physiology for the National Cotton Council, which conducts the Beltwide Cotton Conferences.
“The consultants were the only group that didn't seem to have their own technical conference,” said Leonard, who served as emcee for the event. “We hope this will be the first of many conferences designed specifically to help consultants stay abreast of the latest technology.”
Leonard, an entomologist based at the LSU AgCenter's Macon Ridge Research Station in Winnsboro, La., urged consultants to begin working with producers to develop and coordinate their production plans for 2008 early.
“A lot of insect problems can be stopped before they ever start just by recognizing a few simple points,” he noted. “One of those is planning for pests that will migrate in from other areas.”
Leonard said consultants and growers need to recognize the potential of emigrated pests on field borders “whether it's a levee system that is rarely mowed, ditch banks, borders of fields that are not being planted or will be planted at a later time. All are producing insects that are moving into these fields. “By applying a management strategy — either by mowing, tilling, applying herbicides or just knowing they are there by sampling — gives you a lead on how to best manage those pests in that crop.”
Consultants and growers also need to consider what Leonard refers to as in-field “resident” pests. By proper termination of winter or spring vegetation, growers can eliminate many of those pests since many cannot survive without host plants, he notes.
Most researchers recommend a timely application of herbicides or tillage to allow a three-week window between dead vegetation in the field or complete mortality and planting the crop.
“We also need some residual control so that that vegetation doesn't come back and allow insect pests to re-infest that field,” says Leonard.
Consultants should be involved in variety selection, he said, because the varieties may dictate the sampling methods they use for determining the levels of pest infestations in specific fields.
“With the number of trait combinations that currently exist, it's not an easy system to look at and make a recommendation any longer,” says Leonard. “There are a lot of different varieties with various traits that impact the overall production system and insect pest management in a dangerous way if you're not aware of what's going on.”
Consultants need to evaluate systemic insecticide inputs based on the range of insects to be controlled, including nematodes, mites and thrips, he said. Ideally, the best at-planting systemic pest control input would provide control of thrips, cotton fleahoppers, spider mites and other arthropod pests through the first 40 days of the growing season.
“This is preventive IPM (insect pest management) because we know we are going to have a thrips problem with the majority of this crop as it comes up. This planning also helps you to manage not only insects but also nematodes and diseases.”
Growers have the option of using seed treatments or in-furrow granule or liquids at planting. “The granule insecticide option would be Temik, and we have a number of liquid fungicides that are still available,” Leonard noted.
He also urged growers and consultants to avoid “convenience applications” of pesticides and to use caution with systems that require “automatic” oversprays for thrips and plant bugs.
“Such practices can create pest problems, particularly from cotton aphids and spider mites as the season progresses. Avoid co-applying insecticides with Roundup formulations as a convenience; that is, use them only when insect pest control is needed.”