Effect of Temperature and Soil Coverage on Pupae Emergence of Ectropis obliqu Prout

Tea looper moths, Ectropis obliqu Prout, is one of the major pests that infest tea bushes, Camellia sinensis, at the plantations. To determine the effect of ambient temperature and soil coverage on the emergence of the moth pupae, 5 temperatures (i.e., 24, 26, 28, 30, and 32℃) and 4 depths of covering soil (i.e., 0, 1, 2, and 4 cm) were applied for the study in the lab. The results showed that, at 24-32℃, the pupae development period was shortened with significantly altered emergence rates. The rate reached a peak of 82.12% at 26℃ followed by a steady decline under further increased temperatures. At high temperatures, the eclosion of the female pupae occurred earlier than that of male pupae, and the female/male ratios in a population were raised as a result. Soil covered over the pupae also exerted a significant effect on eclosion of the moth. The lowest emergence rate of 33.33% was found when the pupae were covered by 4 cm of soil. Therefore, deep plowing could ameliorate the harmful effect on tea plants during the peak pest season. On the other hand, no significant effect of the soil coverage on the time of pupae emergence was observed.