  Two years study was carried out during 2006-07 and 2007-08 crop seasons to
study the response of different genotypes of oilseeds Brassica to Lipaphis
erysimi (Kaltenbach) infestation both under field and screen house conditions
and to find out the relationship of various biochemical constituents to aphid
infestation. Among the various genotypes, the population of L. erysimi was
significantly high on Brassica rapa variety brown sarson cv. BSH 1 and B. rapa
var. yellow sarson cv. YST 151 in unprotected set i.e. 53.7 and 52.3 aphids/
plant, respectively. However, it was the lowest on Eruca sativa cv. T 27 (4.7
aphids/plant) followed by B. carinata cv. DLSC 2 (20.9 aphids/ plant) which
suffered the least yield loss i.e. 5.79 and 10.59 per cent, respectively.
Almost similar trend was observed in seedling mortality, which was the maximum
in BSH 1 and YST 151, while no seedling mortality was observed in the case of T
27 during both the years of study. Analysis of various biochemical constituents
revealed that glucosinolates, total phenols and ortho-dihydroxy phenols had
inverse relationship with the aphid infestation. Higher amount of these
biochemical constituents in T 27 and DLSC 2 was responsible for lower aphid
infestation on these genotypes.
