POTENTIAL FOR BOLL WEEVIL TRANSPORT TO GINS ON MODULES

摘要

threat of reintroduction and reinfestation is always of concern. As several eradication zones in Texas approach functionaleradication, there has been growing unease at the prospect that gins serving customers in neighboring infested zones mayserve as sites for reintroduction of weevils. We began a series of experiments in three regions of Texas designed todetermine the potential for boll weevil transport on or in cotton modules to the gin yard. Surveys indicated that there weresurprising numbers of adult weevils present in defoliated cotton just prior to harvest, especially if green bolls were stillpresent on the plants. Live weevils were recovered in samples of harvested cotton taken from module builders, and averagesof calculated weevils per module in the three different areas of Texas ranged from 203 to 3,750, and weevils calculated to beon the surface ranged from 3 to 52. The latter represent weevils that could disperse from the module during or after transportto the gin. We released marked weevils on the top (under a tarp) and sides (not under a tarp) of stationary modules andestimated the percentage of weevils that dispersed within 10-24 hr. In another experiment, marked weevils were released onthe top, side, and end of a module which was then transported 6 or 30 miles. Our results indicate that most weevils dispersefrom the release sites if temperatures are warm enough -- by flight if not under a tarp, by walking and burrowing if under atarp on top of the module. Most weevils died under the tarp when temperatures were high, but some were unaccounted forand may have escaped lethal temperatures by burrowing into the loose cotton on top of the module. Overall, our resultsindicate that one can expect at least a small number of weevils to make it to the gin alive inside a module depending on thestarting population of weevils in the defoliated cotton. The percentage of weevils remaining on the surface of a module fromthe time of its construction can be expected to decrease the longer the module remains in the field, especially with high(>80oF) temperatures, because of the observed high propensity of weevils to disperse from modules by flight.