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Field and Forage Crops |
With this very late rainy start to our growing season, essentially all cotton is still in the prebloom period as we approach the end of June. At this prebloom cotton stage, we typically deal with the possibility of plant bugs and cotton aphids and early budworms. In most years in North Carolina, these insects do not take much of a bite out of our cotton crop in late June. However, since much of our cotton crop can afford very little in the way of further maturity delays, weekly scouting for these potential pests is particularly important this year.
Plant bugs appear to have reached very high levels this spring on weeds and other hosts surrounding cotton fields. If weather patterns remain on their present course of much hotter and drier weather than the previous few months, expect that the drying of weed hosts could well trigger rather high levels of plant bugs into squaring cotton. If square retention levels remain at or above the 80 percent level, no further plant bug sampling is required. With lower square retention, sweep net sampling for the live plant bugs will be required. Details of the sampling can be found on the Internet at: http://ipm.ncsu.edu/cotton/insectcorner/text.html#pb.
Tobacco budworms appear to be only slightly behind schedule so far this year, so late June to early July assessments of terminals and squares for budworms are advised. In a very high percentage of research studies and grower situations in the Carolinas and Virginia, cotton plants will compensate for high prebloom square loss from tobacco budworm feeding. With our late crop however, it would be advisable to follow our prebloom budworm thresholds of 15 percent live budworms in terminals, or 8 percent on squares. I think this threshold probably provides a good safety margin, even with this late crop.
Cotton aphids appeared to on the increase this past week. Fortunately, aphids on cotton seldom cause yield losses in our area unless levels are very high in most terminals and the plants are under moisture stress.
Hopefully, within the next 2 weeks, we will begin to get an idea of how our July bollworm and stink bug levels are developing. These insects may be slightly on the late side this year, but our cotton crop may be even later.
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 June 23, 2003 by Stephen J. Toth, Jr.
