RESUMO
California pistachios are threatened by several stink bug species (Hemiptera: Pentatomidae), including the native Thyanta pallidovirens (Stål) and Chlorochroa uhleri (Stål), as well as the invasive Nezara viridula (L.). In pistachio, control tactics often target specific life stages, which makes knowledge about life histories fundamental to successful IPM programs. For that purpose, life history parameters of these stink bug species were assessed. Nymphal development and survivorship at seven constant temperatures, upper and lower development thresholds, thermal constants, adult longevity and fecundity, and life table parameters were evaluated. No species completed development at 15°C or 35°C. For N. viridula, egg to adult development was fastest at 30°C, whereas for T. pallidovirens there was no significant difference between 27.5 and 30°C and C. uhleri development was similar between 25 and 30°C. Egg to adult survival was highest at 22.5°C and 27.5°C. The thermal requirements as degree-days (DD) to complete immature development were estimated to be 714.3, 370.4, and 434.8 for C. uhleri, T. pallidovirens, and N. viridula, respectively. For C. uhleri, life table calculations produced a value of 56.7 d for mean generation time (To), 24.89 for net reproductive rate (Ro) and 0.057 for the intrinsic rate of increase (r). Thyanta pallidovirens had a To of 39.9 d, a Ro of 81.10 and a r of 0.11. The results are discussed with respect to the improvement of IPM in California pistachios, and the information presented may contribute to the control of these pest species in other ecosystems.
Assuntos
Ecossistema , Heterópteros , Animais , Ninfa , Reprodução , TemperaturaRESUMO
Life history parameters were established under controlled laboratory conditions for the green stink bug, Chinavia hilaris (Say) (= Acrosternum hilare), to improve pest control in pistachios in California. Parameters measured and calculated included survival and development at seven constant temperatures (ranging from 15 to 35 degrees C), development time, upper and lower development thresholds, thermal constants, fecundity, generation time, net reproductive rate, and intrinsic rate of increase. C. hilaris did not complete development at 15 and 35 degrees C. Within the range of 20-27.5 degrees C, development time decreased linearly with temperature; it increased again at 30 degrees C. The lower threshold was calculated by linear methods to be 12.3 degrees C, and the thermal constant was calculated to be 588 degree days. Fastest development was recorded at 27.5 degrees C, whereas greatest survival was observed at 22.5 degrees C. At 27.5 degrees C, mean fecundity was 53.5 eggs per female, mean generation time was 74.4 d, net reproductive rate was 20.09, and intrinsic rate of increase was 0.04. Use of a nonlinear model yielded estimates of 13.2, 28.4, and 33.4 degrees C, for the lower threshold, optimum temperature, and upper threshold, respectively. Results were compared with similar studies and interpreted in the light of pest management needs in pistachio. Increased emphasis on monitoring and management ofoverwintering sites and early-season migration are recommended.
