Impact of Climate Variables on Occurrence of Rice Earhead Bug, Leptocorisa oratorius (F.) (Hemiptera: Alydidae)

Rice earhead bug, Leptocorisa oratorius (F.) (Hemiptera: Alydidae) is one of the major sucking pests of rice, causing significant yield losses worldwide. The population fluctuation and infestation of earhead bug is influenced by different meteorological parameters. A field experiment was conducted at the ICR (Instructional Cum Research) Farm, Assam Agricultural University, Jorhat with a view to study the occurrence of L. oratorius on rice crop during Ahu (Autumn rice) season, 2018 and 2019. The population of L. oratorius was first observed in the field during the month of May and attained its peak population (2.66 and 1.56 adult per hill) on second and third week of June in 2018 and 2019, respectively. The occurrence of L. oratorius was also correlated with the different climate variables viz., temperature, relative humidity, rainfall and bright sunshine hour (BSSH). The correlation analysis revealed no significant impact of climatic variables on the occurrence of L. oratorius population during 2018, while all the variables except rainfall showed significant correlation with the occurrence of L. oratorius population during 2019. In 2019, a significant best fit multiple regression model was developed for L. oratorius to predict their seasonal occurrence under agro-climatic condition of Jorhat, Assam. The per cent grain infestation was also recorded during 2018 and 2019, which was found to be 39.34 and 37.11 per cent, respectively.