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Field and Forage Crops |
One thing about the wet spring is now that we are able to get back into cotton fields to continue planting, in most areas we should have plenty of moisture for rapid stand emergence and good cotton seedling grow-off conditions, assuming the warm weather continues.
With May 10 to 15 and later plantings, improved cotton grow-off conditions often translate into less time that young cotton seedlings are vulnerable to thrips damage. In practical terms, a 3.5-pound rate of Temik might provide about the same degree of protection as our standard 5.0-pound rate on cotton planted in April. Seed treatments Gaucho and Cruiser may also come closer to providing enough thrips protection to avoid an automatic foliar treatment on this late-planted cotton.
On the other hand, producers must try to avoid further maturity delays from thrips damage to late-planted cotton. Therefore, late cotton planted with less Temik or with a seed treatment must be monitored carefully for both the small immature thrips and for the beginning of young, curly possum-eared leaves and/ or stunted buds beginning at the expanded cotyledon to first true leaf stage.
These checks can be done rather quickly, but the small seedlings must be inspected carefully. A hand lens can be a big help in locating these small thrips.
If one can find an average of about one immature thrips per true leaf per plant, or any immature thrips are present in addition to curly leaf or stunting damage, a foliar insecticide treatment is probably needed.
Remember that the earlier wet conditions presently have provided plenty of food for thrips on other wild and cultivated hosts, and a return to warm, dry weather can result in major thrips flights in the last half of May. Be aware that even rapidly growing cotton may be subject to high thrips levels, even if it is for a shorter period of time.
We have received a small number of telephone calls about grasshoppers and cutworms on cotton so far this year. Other pests like cotton aphids, spider mites and plant bugs could start showing up in the next few weeks. On many farms, the above pests more often than not do not occur in economically important or treatable numbers.
The initial cotton scouting school is scheduled for the Robeson/Scotland/Hoke county area in mid-June. Detailed information on the scouting school will be provided in next week's issue of the North Carolina Pest News.
We have received reports of cutworm problems on tobacco from the northern Piedmont. Fields that have been prepared just a few days prior to transplanting and still have undecayed plant material in them are the ideal spot to see cutworm problems. Growers should check their fields carefully for cutworm problems by counting plants (damaged versus undamaged) in several locations. The threshold for rescue treatments is 5 percent of plants cut or damaged. We have never been able to measure yield reduction with 5 percent early stand loss, so this is a conservative threshold. Rescue treatments could include Orthene or the newly-registered Warrior. Treat in late afternoon with a significant volume of water (10+ gallons per acre) in a band over the row. Wait at least a couple of days before judging the degree of control or resetting plants.
After seeing a significant problem with tobacco splitworms (potato tuberworms) in 2002, we have been placing pheromone traps in selected counties. These traps are just now going out in most locations. Doug Bullard in Cumberland County reports that he has found moths in one of two locations. None of the other traps have been in place long enough to generate reports. We have not yet seen damage in tobacco. Based on this one trap location, growers in the upper Coastal Plain should be alert for tunneling in tobacco leaves.
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 12, 2003 by Stephen J. Toth, Jr.