INTERACTIONS BETWEEN TRAP PLACEMENT AND BOLL WEEVIL COLONIZATION OF COTTON

Authors: Spurgeon, Dale; CATTANEO, MANDA - TEXAS AGRIC EXPER STATION

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/3/2006
Publication Date: 6/12/2006
Citation: Spurgeon, D.W., Cattaneo, M. 2006. Interactions between trap placement and boll weevil colonization of cotton. In: Proceedings of the Beltwide Cotton Conferences, January 3-6, 2006, San Antonio, Texas. 2006 CDROM.

Interpretive Summary: Eradication programs rely heavily on pheromone traps, placed in close proximity to cotton fields, for monitoring populations of the boll weevil. It is known that such traps do not capture all responding weevils. Thus, trap placement with respect to field borders may influence weevil colonization patterns in adjacent cotton. In preliminary field studies we found that trap placement with respect to the edge of the field did not influence the ability of weevils to colonize cotton once the plants were producing flower buds. However, before this time a higher probability of cotton infestation was observed when traps were placed immediately adjacent to cotton plots (41%) than when they were separated from cotton by a short (8-9 m) distance (12%). Therefore, trap placement may play an important role in weevil colonization patterns, and eradication programs may benefit from increasing the distance between traps and cotton.

Technical Abstract: Eradication programs rely heavily on pheromone traps, placed in close proximity to cotton (Gossypium hirsutum L.) fields, for monitoring populations of the boll weevil (Anthonomus grandis Boheman). It is known that such traps do not capture all responding weevils. Thus, trap placement with respect to field borders may influence weevil colonization patterns in adjacent cotton. We examined the influence of trap placement on colonization of early-season cotton in the Lower Rio Grande Valley of Texas. Fourteen replications of paired trap placements (0.8 m and approximately 8 – 9 m from the outermost row of cotton) were established on either the northern or western sides of cotton fields. These sides were selected so traps would be downwind from cotton given prevailing wind direction. Each week, two 20-m row sections centered on each trap were sampled using a pneumatic (KISS) sampler. Plant phenology (vegetative, pinhead square, matchhead and larger square) was also monitored in each sampled row. A given sample area was considered infested if a weevil was recovered from either row. The probability of infestation was modeled using trap position and plant phenology as explanatory variables. Preliminary results indicated trap position did not influence weevil colonization during pinhead and later phenological stages. However, for vegetative plant stages the probability of infestation associated with the close trap placement (0.41) was increased compared to the more distant trap placement (0.12). Therefore, trap placement may play an important role in weevil colonization patterns, and eradication programs may benefit from increasing the distance between traps and cotton.