 |
Field and Forage Crops |
It appears that the status of cotton around the state depends on who you are talking to. In the western Piedmont, cotton is still less than 50 percent planted with the recent cool, rainy weather tough on cotton that is up or trying to come up. Elsewhere, most cotton planting is completed and, with decent stands in many areas, cotton is just waiting for a return to warmer weather to go with the very high moisture levels.
Thrips can make life miserable for cotton producers under a couple of weather scenarios. One scenario is hot, dry conditions that can result in poor insecticide uptake and can trigger large migrating flights of adult thrips into cotton. A second scenario is cool, wet weather that often leaves slow-growing seedlings susceptible to thrips for a longer time. We are certainly in the latter situation across much or all of the state. With both weather scenarios, remember that the clock is still running with seed treatments. The general guideline of three weeks from planting until loss of residual activity with seed treatments still holds. Remember that foliar sprays behind seed treatments on cotton planted before about May 15 to 20 is best timed for about the first true leaf stage. One probably does not need to worry about splitting hairs with the size of the first true leaf.
Based on early telephone calls and observations, thrips levels in general appear to be down from the previous three years, especially 2002. Temik at 4 pounds or more so far appears to be holding up. We have seen some instances in the past, however, in which total rainfall in the 5 to 7+ inch range has washed the highly soluble active ingredient of Temik (aldicarb) out of the root zones of cotton plants on some soil types. Sprays following Temik or cotton planted with a seed treatment after mid May should be based on damage to new leaves and/or buds, and the presence of the small yellow-colored, wingless immature thrips. Orthene 97 in the four ounce of product range, or an equivalent insecticide, should be used for foliar sprays to insure adequate residual activity, although do not plan on more than about 7 days thrips control, even under good conditions.
Although migrating winged adult thrips can certainly damage cotton seedlings, the presence or absence of immature thrips is a better indication of present insecticide activity. Magnification can be a big help in seeing these larval thrips.
The return of warm sunny days will help get this thrips season behind growers, with the benefits of faster cotton grow-off probably outweighing the greater thrips flights likely in the drier weather.
Although some spraying of tobacco for budworms has begun, it is probably too early to get an indication on the possible size of this year's budworm populations. Cotton aphid levels appear to be low at this time. Spider mites on cotton can wait until we get a more extended period of warm, dry weather. This would be a good time to check for possible cutworm damage on reduced- tillage cotton.
Budworms are the hot topic for tobacco farmers in the southeastern corner of North Carolina. Growers there have been treating for this pest, with varying degrees of success, for over a week. We will likely see this pest further north in the Coastal Plain in the near future. Look first at the largest tobacco in the area; these fields are most attractive to egg-laying moths (but don't ignore smaller tobacco). Remember that the treatment threshold is 10 percent of plants with a live budworm present. This is a very conservative threshold. Treating earlier will likely cost more than it saves. Early treatment, with some insecticides, will also kill some of the beneficial insects and may lead to even worse pest problems later.
A few aphids have been seen in older tobacco in the southeastern part of the state, but we have had no reports of significant build-up.
A couple of unlucky farmers in Wake County have found infestations of whitefringed beetles. These pests are in the soil as larvae (grubs) and feed on the stem and roots in a fashion similar to wireworms (but worse). If plants are wilting, dying, or just stunted, look at the root system. If the stems are heavily scarred, check the soil around plants for the grubs. These grubs are white or yellow-white in color, about a half inch in length, heavy-bodied, and slightly curved or "C" shaped from the side. They have no legs and the head is reduced (sometimes all you see is the dark brown mandibles). Unfortunately, if you find you have this pest, there is not much to be done except to keep the tobacco growing as well as possible. No insecticides applied to the soil after transplanting will help, and even applications made broadcast before transplanting only suppress the population a bit.
We have not yet seen or heard reports of splitworm (potato tuberworm) damage in tobacco. However, we have caught some moths in a series of pheromone traps. Moths have been confirmed from traps in Robeson and Cumberland counties and reported (but not yet confirmed) from traps in Nash County. Numbers have been low (a maximum of 6 moths in a week). Growers should check their plants carefully for leaf mining. As soon as we work out the considerable problem of identifying these small moths in traps, we will report more detailed trap catches.
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 23, 2003 by Stephen J. Toth, Jr.
