 |
Field and Forage Crops |
This is shaping up to be one of those years of widely varying cotton planting dates. Expected maturity differences in the cotton crop may significantly impact the attractiveness and susceptibility of various cotton fields to insects. Overall, cotton insect management in most cases would be helped by good moisture patterns for the remainder of the growing season.
In dry weather, thrips levels and damage are typically more troublesome. On one hand, wild and cultivated hosts such as wheat dry down earlier, resulting in an earlier, more complete exodus from these hosts into succulent young seedlings (like peanut and cotton) resulting in higher thrips levels. Dry weather can also result in greater cotton seedling susceptibility to thrips via more limited uptake of both seed and granular at-planting insecticide treatments. A change to wet weather patterns would help the thrips situation through both renewed insecticide uptake and quicker seedling growoff.
If three weeks have elapsed since planting or when the first true leaf begins to appear, be aware of a high probably of having to make a foliar spray behind both Gaucho and Cruiser seed treatments, especially if our dry weather continues. Because we often experience especially high levels of thrips in Virginia and in the Carolinas, higher-labeled rates of insecticides are generally suggested. Fields should be checked every 4 or 5 days. Because seed treatments have about a 3-week residual (even with good moisture levels), moderate to high levels of thrips can become established rapidly under these conditions. So far, Temik 15G at the 5 pound or greater rate has held well where moisture has been adequate, but be sure to inspect cotton fields in which the 3 to 4 pound rate was used, and in dry fields where uptake may be compromised.
In late planted cotton (after about May 15-20), although a seed treatment alone or a lower 3.0 to 3.5 rate of Temik is suggested and may get one through the thrips susceptibility period, these late-planted fields should nevertheless be watched carefully. If thrips damage is present, the lack of treating a late-planted cotton field can result in ill-afforded maturity delays.
At least based on telephone calls, cutworm problems have been minimal, so far. However, many cotton fields are just now approaching the expanded cotyledon to two to three true leaf stage where cutworms seem to magically come out of hiding. In reduced tillage situations, stand inspections for seedling clipping from night-feeding cutworms along with routine assessments for thrips and their damage is recommended, especially where the weed or cover crop burn down preceded the planting date by less than about three weeks.
The initial 2004 cotton scouting school for Robeson, Scotland and Hoke counties is scheduled for 9:30 a.m. on June 22 in the Extension Conference Room (Suite 800), County Government Center, 231 E. Cronly Street, in downtown Laurinburg. Contact David Morrison (telephone: 910-277-2422; e-mail: david_morrison@nusu.edu), Georgia Love (telephone: 910-671-3276; e-mail: georgia_love@ncsu.edu) or Keith Walters (telephone: 910-671-3276; e-mail: keith_walters@ncsu.edu) for details. Producers, summer scouts, industry personnel and consultants are invited to attend the school.
The warm, dry weather in many areas of North Carolina may have a significant impact on thrips injury, tomato spotted wilt virus, and thrips control. If weather conditions remain somewhat dry over the next few weeks, then control from the at-plant, in-furrow insecticides (such as Temik or Thimet) may not be as strong as one would like to see. Watch the crop over the next few weeks and be ready to respond with a foliar insecticide treatment if the at-plant insecticide products do not seem to be performing well. The warm, dry weather is quickly forcing thrips out of field borders and weeds and into crops such as peanuts. This means that thrips injury and the risk from tomato spotted wilt virus may be higher than normal, especially in early-planted peanuts. Remember that multiple foliar sprays for thrips do not appear to provide any additional benefits.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on May 17, 2004 by Stephen J. Toth, Jr.