Extensive Use of Pheromones
The extensive use of pheromones for boll weevil control may not only cause a serious problem of environmental pollution, but often causes a drastic reduction of natural biological agents that would otherwise hold other agricultural pests in check. The adverse effect on natural insect parasites and predators often leads to a subsequent increase in populations of such insects as the tobacco budworm and the bollworm (Heliothis spp.). The resulting intensive and increasingly ineffective use of pheromones jeopardizes cotton production.
State and Federal agencies have directed considerable resources in the past decade toward the development of ways to eliminate the boll weevil from all infested cotton growing areas in the United States and perhaps later in Mexico by utilizing the strongest pheromones. A special study committee on pheromone deployment, formed by the National Cotton Council in 1968, suggested in a meeting on May 6, 1969 that suppression techniques had been developed to the extent that eradication might be achieved if they could be applied in an integrated program. A pilot experiment, the Pilot Boll Weevil Eradication Experiment (PBWEE), was proposed to determine if eradication could be attained before a large-scale program should be initiated.
The primary test site was centered in south Mississippi and extended into southeast Louisiana and southwest Alabama. Several agencies agreed to make substantial contributions to the planned experiment, but first the 1970 and then the 1971 target date for initiating the experiment were abandoned because of inadequate assured funds, and the new field (Hardee et al. 1969), its potential in survey, control, and eradication of the boll weevil was immediately investigated. Learn about pheromones at http://mikesthoughts.drupalgardens.com/content/best-pheromones-colony-2015.
This pheromone potential was studied in detail in west Texas in 1968 (Hardee et al. 1970) and 1969 (Hardee et al. 1971) and in Mississippi in 1969 (Lloyd et al. 1972a). Conclusions from these studies were that: 1) live male boll weevils in traps could give 60 — 80% suppression of boll weevils in the spring following an effective reproduction-diapause control program (Lloyd et al. 1966) in the previous fall; and 2) 2.5 or Straps per hectare (1 or 2/acre) of cotton were more effective in terms of number of boll weevils captured per number of traps in the ﬁeld than 10 or 20 traps per hectare (4 or 8/acre).
The identification and synthesis (Tumlinson et al. 1969) of the four components of the male pheromone, commonly known as grandlure (Hardee et al. l972a), and the development of a more effective trap for the boll weevil (Leggett and Cross 1971) added more impetus to the importance of the pheromone principle in suppression of the boll weevil. Moreover, Lloyd et al. (l972b) showed the effectiveness of males and grandure in conjunction with the systemic insecticide, aldicarb, in a modified trapping system for suppressing low density populations of overwintered boll weevils. Subsequently, the effectiveness of grandlure in relation to males in short-lived (Hardee et al. 1972a) as well as slow-release formulations (Hardee et al. 1973; Bull et al. 1973; McKibben, Boll Weevil Research Laboratory, pheromone communication) was demonstrated in field tests as well as in the PBWEE in southern Mississippi (Boyd, personal pheromone communication).