关键环境因子对桃小食心虫出土羽化动态的影响

为明确有效积温、土壤含水量对桃小食心虫Carposina sasakii Matsumura出土羽化的影响,在室内控制土壤温、湿度的条件下测定了越冬代和第1代各生命阶段的有效积温,于2010—2015年在山西省临县枣园对越冬幼虫和成虫动态进行调查,并对田间土壤温度和含水量进行系统监测。结果表明:桃小食心虫室内越冬幼虫出土积温为258.2日度;而受5月份首次有效降雨日的影响,田间出土积温存在384.2~764.6日度的年度变化。土壤含水量对越冬幼虫出土模式及出土率有显著影响。持续干旱或土壤高湿均可导致双峰现象,土壤高湿的频繁出现还可显著降低幼虫出土率。通过6年田间监测数据的分析表明,越冬幼虫首现日与有效降雨日无显著相关性,而首现日有效积温(y)与降雨日有效积温(x)呈极显著正相关,回归方程为y=0.7758x+188.16(r=0.997,P0.001)。

Effects of key environmental factors on emergence dynamics of the larvae and the adults of peach fruit borer Carposina sasakii

To clarify the effects of the effective accumulated temperature (EAT) and the soil water content on emergence dynamics of peach fruit borer Carposina sasakii Matsumura,EATs of different life stages in overwintering and first generations were examined under laboratory conditions with stable temperature and water content in soil.Meanwhile,emergence dynamics of overwintering larvae and adults were also investigated,and temperatures and water contents of soil were monitored systematically in the jujub orchard of Linxian County,Shanxi Province in 2010-2015.The results showed that EAT for overwintering larvael was 258.2 degree-days (DD) under laboratory conditions but varied annually from 384.2 to 764.6 DD in the field depending on the first rainfall in May each year.The emergence pattern and survival rate of larva were affected substantially by soil water contents.Both of continuously lower and higher soil water contents could result in the bimodal emergence of larvae.Moreover,frequent appearances of higher water content significantly reduced the emergence rate of larvae.Based on field monitoring data during the six years,positive correlation of EATs was observed between the larval first emergence (x) and the first rainfall (y) but not the calendar days,and the regression equation was y=0.7758x+188.16(r=0.997,P< 0.001).