Field assessment of Mustard aphid, Lipaphis erysimi (Kalt.) on cultivars of Indian mustard (Brassica juncea L.)

The incidence of Lipaphis erysimi appeared on mustard commenced from 2^nd S.W. and gradually reached its peak 207.22, 262.89 aphid /10 cm central twig in 5^th standard week, thereafter population started to decline significantly and reached its lowest 2.56, 0.44 in 6^th S.W. during 2007–2008 and 2008–2009 crop seasons, respectively. The highest population of L. erysimi was observed in 4^th and 5^th S.W. from PRKS-14 (126.11 aphid) and PR-2006-14 (207.22 aphid), respectively during 2007–2008 with lowest zero from PBC-2005-3. Whereas during 2008–2009 crop season, it was highest as on Ashirvad (174.00 aphid), Ashirvad (360.56 aphid) and lowest as on PRKS-28 (1.11 aphid), PRKS-28 (4.11aphid) in 4^th and 5^th S.W., respectively. After 5^th S.W. the population of L. erysimi gradually declined due to increase in temperature.