Rice cultivar selection against Leptocorisa acuta (thunb.) and their economic thresholds based ecological management

Rice cultivar selection against the rice bug, Leptocorisa acuta (Thunb.) (Hemiptera: Alydidae), in relation with phytochemical regime of three selected rice (Oryza sativa L.; Family: Poaceae) cultivars [IR-22 (IET21850), IR-64 (IET-19189) and IR-36 (IET-19969)] were studied. The demographic data of L. acuta like l _x, s_x, T_x, e_x, L_x, K or GM and age specific fecundity parameters like F_x, R₀, r_m, DT₇, λ, λ, PMF and N_twere varied (IR-22 > IR-64 > IR-36) significantly (P<0.05) due to respective nutritional and anti-nutritional quality of the cultivars. The EI and ET of L. acuta were 1.350, 2.246, 3.070 and 1.055, 1.888, 2.717 pests/m² (16 ± 2 hills/m²), respectively for IR-22, IR-64 and IR-36 cultivars. For a single pest per square meter (16 ± 2 hills/m²) the possible time that can be taken to reach EI (Ti days) and ET (Tt days) were 1.216, 4.652, 9.178 and 0.216, 3.652, 8.178 days respectively for IR-22, IR-64 and IR-36 cultivars. The ET based time series of the said pest (L. acuta) will be helpful for time based judicious application of any control measures. Similarly seed yield (SY) and benefit cost ratio (BCR) of IR-22, IR-64 and IR-36 cultivars were 1940.299, 2089.552, 2388.060 (kg/ha) and 0.945, 1.094, 1.393, respectively. The carbon sequestration efficiency (CSE) of IR-22, IR-64 and IR-36 cultivars were 9578.789, 10989.795 and 12949.903 lbs/ha, respectively with significant (P<0.05) variations due to different biomass production. The demography of L. acuta in relation with respective host chemical regime will enable growers to find the most resistant cultivar (IR22 < IR64 < IR36) based on BCR values as well as susceptibility (IR22 > IR64 > IR36) due to host antibiosis mechanism against this pest. Thus, by knowing the host quality of different rice cultivars along with respective ET based time series will help to make sustainable ecological management by climate smart pest management (CSPM) of this pest (L. acuta) or other such rice pests and or other such crops in near future.