Interaction of Beauveria bassiana Bals Vuill with Leptocorisa oratorius FabHemiptera Alydidae with special reference to chitinase

Abstract

Rice earhead bug, Leptocorisa oratorius Fab. and Leptocorisa acuta Thun. newline(Hemiptera: Alydidae) are the most important sucking pests of rice. The insect cause newlinesignificant yield losses to the rice crop in the field condition. Therefore, the present newlineinvestigation was carried out with a view to study the seasonal incidence of L. oratorius newlinein relation to the meteorological parameters, their damage potential, biology, newlinepathogenicity of Beauveria bassiana (Bals.) Vuill. against different stages of newlineL. oratorius and to characterize the B. bassiana-chitinase that secreted during insect newlinefungus interaction. newlineTo study the seasonal incidence of L. oratorius, an experiment was conducted at newlineInstructional Cum Research (ICR) Farm, Assam Agricultural University, Jorhat during newlineAhu, 2018 and 2019 and Sali (Kharif), 2018 and 2019. During Ahu, 2018 and 2019, the newlinepopulation of L. oratorius was first appeared on 2nd week of May i.e. 20th standard newlinemeteorological week (SMW) with an average of 0.33 and 0.30 adult per hill, newlinerespectively. The population was gradually increased with a peak of 2.66 and 1.56 adult newlineper hill on 24th SMW (2nd and 3rd week of June), respectively. During Sali (Kharif) 2018 newlineand 2019, the population of L. oratorius was first appeared on 41st standard (SMW) with newlinean average of 0.30 and 0.36 adult per hill, respectively. The population was found to be newlinehighest at 1st week of November i.e. 44th SMW with an average of 1.20 and 1.13 adult newlineper hill, respectively. The correlation studies between incidences of L. oratorius with newlinemeteorological parameters showed non significant correlation with all the newlinemeteorological parameters during Ahu, 2018 and Sali (Kharif), 2018 and 2019. newlineHowever, during Ahu 2019, it showed significant positive correlation with maximum (r newline= 0.802) and minimum (r = 0.711) temperature and BSSH (r = 0.631) whereas, significant newlinenegative correlation with morning (r = -0.849) and evening (r = -0.750) relative humidity newlineand non significant negative correlation with rainfall (r = -0.255). Multiple regression newlineanalysis during Ahu...