Seasonal Changes in Bollworm (Lepidoptera: Noctuidae) Moth Catches in Pheromone Traps in a Large Area

Abstract

Bollworm, Heliothis zea (Boddie), pheromone traps were spaced 3.2 km apart and were arranged in a 9 × 7 grid pattern covering 492 km2. Traps were operated from early April through late September in 1981, 1982, and 1983. Moth catches in traps were correlated with cropping patterns (land use) and with rainfall. Bollworm moth catches during the spring months were highest in areas planted with wheat. As the wheat matured, more moths were caught in areas planted with cotton, guar, and sorghum. Fewer moths were caught adjacent to fallow fields and rangeland throughout the season. Moth catches during the spring were not correlated with catches during the summer; but beginning in June, moth catches during the summer months maintained a positive, significant correlation with each other. One major shift in moth distribution patterns occurred during June, a time when wheat was harvested and summer crops had emerged after planting. In 2 yr, moth catches during the spring months were positively and significantly correlated, and there were positive, significant correlations between summer months in all 3 yr. These between-year correlations indicate that there was some similarity over time in the patterns of change in moth catches. Catches during late season were not indicative of patterns of catches during early spring the following year. There were some significant, positive correlations between moth catches and rainfall. Rainfall may be an additional factor influencing moth distribution in regions dominated by dry land crop production.