The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative ...The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative humidity of 65% and a photoperiod of 14：10 （L： D） hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage, Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃ and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.展开更多
Predicting the population dynamics of insects in natural conditions is es- sential for their management or preservation, and temperature-dependent development models contribute to achieving this. In this research the ...Predicting the population dynamics of insects in natural conditions is es- sential for their management or preservation, and temperature-dependent development models contribute to achieving this. In this research the effects of temperature and soil moisture content on egg development and hatching of Clavipalpus ursinus （Blanchard） were evaluated. The eggs were exposed to seven temperature treatments with averages of 7.2, 13.0, 15.5, 19.7, 20.6, 22.0 and 25.3~C, in combination with three soil moisture contents of 40%, 60% and 80%. A linear and two non-linear （Lactin and Briere） models were evaluated in order to determine the thermal requirements of this developmental stage. Temperature affected significantly the time of development and egg hatching, while no significant effect was observed for moisture content. Thermal requirements were set as： 7.2℃ for lower developmental threshold, 20.6℃ for optimum developmental threshold, 25.3℃ for maximum temperature and 344.83 degree-days for the thermal constant. The linear model described satisfactorily egg development at intermediate temperatures; nev- ertheless, a slightly better fit of the observed data was obtained with the Lactin model. Egg development took place inside a narrow range of temperatures. Consequently, an increment of soil temperature could generate a negative impact on the population size of this species or changes in its biological parameters.展开更多
文摘The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative humidity of 65% and a photoperiod of 14：10 （L： D） hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage, Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃ and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.
文摘Predicting the population dynamics of insects in natural conditions is es- sential for their management or preservation, and temperature-dependent development models contribute to achieving this. In this research the effects of temperature and soil moisture content on egg development and hatching of Clavipalpus ursinus （Blanchard） were evaluated. The eggs were exposed to seven temperature treatments with averages of 7.2, 13.0, 15.5, 19.7, 20.6, 22.0 and 25.3~C, in combination with three soil moisture contents of 40%, 60% and 80%. A linear and two non-linear （Lactin and Briere） models were evaluated in order to determine the thermal requirements of this developmental stage. Temperature affected significantly the time of development and egg hatching, while no significant effect was observed for moisture content. Thermal requirements were set as： 7.2℃ for lower developmental threshold, 20.6℃ for optimum developmental threshold, 25.3℃ for maximum temperature and 344.83 degree-days for the thermal constant. The linear model described satisfactorily egg development at intermediate temperatures; nev- ertheless, a slightly better fit of the observed data was obtained with the Lactin model. Egg development took place inside a narrow range of temperatures. Consequently, an increment of soil temperature could generate a negative impact on the population size of this species or changes in its biological parameters.
