Pheromone was collected from the air surrounding cultured boll weevils,Anthonomus grandisBoheman, as they fed on flower buds from seven cotton genotypes,Gossypium hirsutumL., grown in two field environments. An effluvial method was used to collect the pheromone, and capillary column gas chromatography was used to quantify it. Significantly more pheromone was collected when boll weevils fed on flower buds from some glanded genotypes than when they fed on flower buds from glandless genotypes (i.e., genotypes without epidermal glands containing terpenoid aldehydes). Boll weevils feeding on flower buds of some glanded genotypes produced significantly more pheromone than those boll weevils feeding on flower buds of other glanded genotypes depending upon the environment where the cotton was grown. The amounts and ratios of the four pheromone components also were affected by genotype and the environment where they were grown. These results suggest that boll weevil pheromone quantity and quality is dynamic in time and space depending upon host-plant genotype, environment, and insect age.