Tham khảo tài liệu 'insecticides pest engineering part 16', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The Conundrum of Chemical Boll Weevil Control in Subtropical Regions 439 Weevil Eradication Foundation 2011 . Eradication involves three techniques over a 4-5year period pheromone trap detection reduction of boll weevil food supply and malathion treatments USDA-APHIS 2007 . The process starts with a series often seven of fall malathion applications that were once and probably erroneously Showler 2010 termed diapause sprays McKibben et al. 2001 . The aim is to reduce late season populations that will be further and dramatically reduced during cold temperate winters when food is unavailable and temperatures can be lethal Showler 2009b c 2010 . Pheromone traps are then deployed around all cotton fields during the following spring planting and spraying of each field begins 5-6 weeks later based on trap captures the process is repeated annually until the boll weevil is no longer found USDA-APHIS 2007 . Still there are 262 000 ha of cotton in east and subtropical south Texas where eradication has not been achieved Texas Boll Weevil Eradication Foundation 2011 . While the chance of boll weevil dispersal from infested areas on wind and in hurricane systems exists Texas Boll Weevil Eradication Foundation 2011 particularly from nearby Mexico where eradication efforts are not underway there are other overriding factors contributing to the pest s persistence in the subtropics Showler 2007 2009b . Misconceptions relating to boll weevil ecology and biology Showler 2009c while immaterial in cold temperate areas appear to underlie the challenges to eradication efforts under subtropical conditions Showler 2009b 2010 . 2. Misunderstandings There have been misconceptions pertaining to fundamental aspects of boll weevil survival outside its native Mesoamerican region that involve dietary habits overwintering and diapause all of which interrelate Showler 2007 2009b c 2010 presenting obstacles to temperate eradication approaches when used in the subtropics. Ultimately the problem .
