Influence of environmental factors on seasonal incidence of lepidopteran pests of rice

Abstract

Rice is one of the most important cereal crops grown throughout the world. Despite of using improved agronomic practices, we cannot get optimum production and productivity. Several factors are responsible for low productivity in rice. A wide range of insect pests are reported to attack rice plant at different stages of life cycle. Among several insect pests, lepidopteran pests such as yellow stem borer, rice leaf folder are considered as most destructive and responsible for severe yield losses. The incidence pattern of lepidopteran pests at different standard weeks was studied. Then effect of various environmental factors like rainfall, morning RH, evening RH, maximum temperature, minimum temperature, average temperature was established by calculating correlation coefficients. It provides as a reference for selecting suitable management practices for reducing pest population.

Seasonal Incidence of Rice Gundhi Bug, Leptocorisaoratorius F. (Hemiptera: Alydidae) in Three Different rice Growing Seasons of Assam

“…The correlation studies revealed that gundhi bug population had a significant negative correlation with maximum temperature (r = -0.652), minimum temperature (r = -0.760), evening relative humidity (r = -0.765) whereas positive significant correlation was found with morning relative humidity (r = 0.734) and BSSH (r = 0.661) (Table 4). Similar findings were documented by Mohanta et al [9] who reported a significant negative correlation of maximum temperature, minimum temperature, evening relative humidity and positive correlation with morning relative humidity with rice gundhi bug. Kalita et al [11] also confirmed that the occurrence of gundhi bug revealed significant negative correlation with maximum temperature, minimum temperature, and rainfall while significant positive correlation with morning relative humidity.…”

“…) was observed on 46 th SMW (3 rd week of November) when the crop was at hard dough stage. Mohanta et al [9] from Varanasi, Uttar Pradesh also recorded peak population of rice gundhi bugs on 46 th SMW. Kalita et al [10] from Sikkim also reported that Gundhi bug started to appear from 42 nd SMW onwards and reached peak during 45 th SMW.…”