To quantify year to year pest fluctuations and longer-term pest status trends of a number of North Carolina's cotton insect pests, several large scale surveys were undertaken. The surveys consisted of treatment and pest information received from licensed independent crop consultants, county agents and producers (1993 to present), and from direct damaged boll assessments (1985 to present) (Bacheler and Mott, 1995).

With this past year's finding of potential shifts in the tolerance of bollworms, Helicoverpa zea (Boddie), and tobacco budworms, Heliothis virescens (F.), to pyrethroids (J.W. Van Duyn and J.R. Bradley, Jr., pers. comm.) via adult vial testing, it is essential to have accurate baseline data on the status, damage and acreage treated for both our major and presently-minor cotton insect pests on Bollgard and conventional cotton, so the inevitable shifts in pest abundance and damage can be more quickly and reliably recognized.

Plant bugs, Lygus lineolaris (Palisot de Beauvois), appear to be increasing in general, and, for the first time in 1998 (except for previous observations of plant bugs in selected cotton fields adjacent or near Irish potato fields in several northeastern North Carolina cotton fields) as a late season post-bloom pest of Bollgard cotton. Tobacco budworm levels have fluctuated significantly, but the percent of North Carolina's acres treated for second generation budworms has averaged approximately 5% for the past 5 years, with beneficial insects, high levels of plant compensation, and few insecticide treatments resulting in very little insecticide pressure for resistance development in this generation. European corn borers, (Ostrinia nubilalis) (Hubner), have shown a steady decline from 6.6% damaged bolls across the state in 1985, compared with a low of 0.12% in 1998. Boll damage from bollworms, fall armyworms, (Spodoptera frugiperda) (J.E. Smith), and stink bugs, primarily Acrosternum hilare (Say) and Euschistus servus (Say), and overall late season boll damage has fluctuated from year to year, but no trend or change in overall or individual pest status is evident. Cotton aphids, Aphis gossypii Glover, show some yearly variability in acreage treated, but natural factors, primarily 2 species of mummifying wasp parasites and the fungus, Neozygites fresenii, routinely hold damage to very low, sub-economic levels. In 4 of the past 5 years, less than 1% of North Carolina's cotton acreage has been treated with insecticides for cotton aphids. Beet armyworms, Spidoptera exigua (Hubner), can inflict very heavy localized damage to cotton; however, these migrating pests have only been present at economic levels in 1977, 1995 and 1998 in North Carolina. Overall applications of late season insects have varied between 2.0 (1997) and 3.8 (1994) in the 1985 to 1998 time period, with no apparent trend toward a greater or lesser application frequency.