RESUMEN
A field trail Comprising of nine insecticides conducted at farmer’s field in endemic area of pests on cauliflower in Siwan district of Bihar during 2018-19. Data revealed that Indoxacarb 14.5 SC @1.0 ml/L of water was found to be most effective insecticides on major pests of cauliflower i.e. leaf webber (41.06% reduction), tobacco caterpillar (48.91% reduction), Diamond Back Moth (64.40% reduction) and aphid (69.96% reduction) over farmer’s practices (chlorpyriphas 20 EC @ 1.5 ml/L of water) i.e. 24.67% 27.86%, 32.47% and 34.81% reduction of leaf webber, tobacco caterpillar, Diamond Back Moth and aphid, respectively. Similarly, significantly highest yield (144.26 q/ha) produced cauliflower in treatment of Indoxacarb 14.5 SC. However, Cost-benefit analysis revealed that highest cost-benefit ratio of 1:11.15 in treatment of Cartap hydrochloride 50 SP @ 1.0gm/L of water followed by Thiodicarb 75 WP @ 1.0g/L (1:9.39), Indoxacarb 14.5 SC @ 1.0 ml/L (1: 7.96), Emamectin benzoate 5 WSG @ 0.25 gm/L (1:7.22), Novaluran 10 EC @ 1.0 ml/L (1:6.48), Spinosad 45 SC @0.33 ml/L (1:6.34), Avemectin 1.9 EC @ 0.5 ml/L (1:5.57), Azadirachtin 0.15% @ 4 ml/L ( 1:4.10) and farmer’s practices (1:3.10), respectively.
RESUMEN
The objective of this work was to study the selectivity of the insecticides acephate, deltamethrin, dimethoate, methamidophos, methyl parathion, and pirimicarb to first, second, and third instar nymphs and adults of the predator Doru luteipes (Scudder) (Dermaptera: Forficulidae) in comparison with last instar nymphs of the prey Brevicoryne brassicae (L.) (Hemiptera: Aphididae). Pirimicarb and deltamethrin were highly selective to all developmental stages of D. luteipes; the same was observed with acephate except for first instar nymphs to whom it showed median selectivity. Dimethoate showed median selectivity, but methamidophos and methyl parathion were low selective to the predator. Second and third instar nymphs and adults of D. luteipes were more tolerant to acephate, methyl parathion and pirimicarb than first instar nymphs. First and second instar nymphs showed similar tolerance to deltamethrin, dimethoate and methamidophos. Concentration-response curves for dimethoate (to adults and first and second instar nymphs) and methamidophos (to third instar nymphs) showed steeper slopes indicating an homogeneous response of these developmental stages to these insecticides.
Este trabalho teve por objetivo estudar a seletividade dos inseticidas acefato, deltametrina, dimetoato, metamidofós, paratiom metílico e pirimicarbe a ninfas de último estádio de Brevicoryne brassicae (L.) (Hemiptera: Aphididae), em relação a adultos e ninfas de primeiro, segundo e terceiro estádios do predador Doru luteipes (Scudder) (Dermaptera: Forficulidae). Pirimicarbe e deltametrina foram altamente seletivos em favor de todos os estádios de desenvolvimento de D. luteipes, sendo que o mesmo ocorreu para o acefato, com exceção de ninfas de primeiro estádio do predador às quais ele é medianamente seletivo. Dimetoato foi, em geral, medianamente seletivo enquanto metamidofós e paratiom metílico foram pouco seletivos em favor do predador. Adultos e ninfas de segundo e terceiro estádios de D. luteipes foram mais tolerantes ao acefato, paratiom metílico e pirimicarbe do que ninfas de primeiro estádio do predador. Ninfas de primeiro e segundo estádios apresentaram tolerância semelhante a deltametrina, dimetoato e metamidofós. As curvas de concentração-mortalidade do dimetoato (para adultos, ninfas de primeiro e segundo estádios do predador) e metamidofós (para ninfas de terceiro estádio) apresentaram as maiores inclinações, indicando que os estádios estudados apresentam resposta homogênea a esses inseticidas.