Effect of water stress on performance of Lipaphis erysimi (Kalt.) and its body size in brassica

บทคัดย่อ

The effect of three water regiems on biological parameters of Lipaphis erysimi was studied on twocultivars of oilseed brassica, namely Bulbul-98 and UCD 310/3 under complete rendamized design (CRD) havingtwo factors, cultivars and water stress, replicated 15 times. The moisture levels significantly affected theseparameters, influencing the performance of L. erysimi. Its developmental time increased with the severity of waterdeficit on both hosts with a trend of the shortest to the longest period from 100 % field capacity to 50 % field capacity.Its fecundity, being highest at field capacity, was decreased with a decrease in water supply. The intrinsic rate ofincrease (rm) was inversely proportionate to water regimes and aphid’s development. They were small sized inBrassica carinata at 75 % field capacity and at 100 % field capacity in B. napus. An indirect proportion between thebody size of aphid and moisture levels was observed. Bulbul-98 at field capacity was most favourable whereas UCD310/3 at the same moisture level was the most detrimental for L. erysimi.