Field studies were conducted in India, during the 1999/2000 and 2000/01 rabi seasons, to detemine the impact of intercrops on the incidence of Lipaphis erysimi on Indian mustard. The treatments comprised Indian mustard+wheat (2:3; 3 rows of intercrop and 2 rows of Indian mustard), Indian mustard+barley (2:3), Indian mustard+chickpeas (2:2) and Indian mustard. Aphid populations were recorded from 5 randomly selected plants from each plot at weekly intervals from initial appearance to harvest. Visual counts of aphids were made to record the populations on wheat, barley and chickpeas. Higher aphid numbers were recorded on Indian mustard and Indian mustard+chickpea intercrop. The average number of aphids was higher during the 1999/2000 season and lower during the 2000/01 season. The peak population was observed during the second and fourth weeks of February. The Indian mustard+chickpea intercrop had significantly higher aphid populations (320.35), followed by Indian mustard (234.71) during the 1999/2000 season possibly due to the plant height and the extra nitrogen made available by chickpeas resulting in better succulence of Indian mustard. The range of aphid populations was 153.60-320.35/5 plants during the 1999/2000 season and 118.88-125.81/5 plants during the 2000/01 season.
