摘要 : The extent to which the western flower thrips pupates on or off the host plant in glasshouse crops determines the effectiveness of ground-based control methods. Glasshouse experiments with water traps, sticky traps and infra-red v... 展开 The extent to which the western flower thrips pupates on or off the host plant in glasshouse crops determines the effectiveness of ground-based control methods. Glasshouse experiments with water traps, sticky traps and infra-red video recording in crops of cucumber and pot chrysanthemum, when average relative humidities were below 80%, showed that large numbers of second-instar larvae dropped to the ground to pupate. The percentage of larvae dropping rather than remaining on the plant was calculated to be 96-99% in cucumber and 92-99% in pot chrysanthemum. Experiments with water traps showed that most larvae dropped during the evening trapping period from 16.00 to 24.00 h for both crops in the glasshouse. The pattern was similar, but less marked, for pot chrysanthemum in a controlled-temperature laboratory at 25 degrees C and 80-95% relative humidity. Continuous infra-red video recording in a heavily infested cucumber crop showed there was a marked peak in dropping during a period of about 1-4 h each evening, with peak rates reaching 4,000 to 8,000 larvae m^-2 h^-1. The time of the peak drop varied between days, suggesting that an environmental cue is involved. Possibilities for exploiting this behaviour for control are discussed.Digital Object Identifier http://dx.doi.org/10.1556/APhyt.47.2012.1.11 收起