Biology of the Pea Aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae) on Cool-Season Legumes

Abstract

The biology of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on four legumes (faba bean, field pea, lentil and grass pea) was studied in a greenhouse during the 1999/2000 seasons. There was no significant difference in length of nymphal period and number of moults (instars) among the crop species tested. The aphids generally took 9 to 11 days to reach the adult stage with a maximum of 3 moults. Lifespan was significantly longer on lentils than on other crops. Significantly more aphids survived beyond 15 days on lentil than on other crops. Similarly, the reproductive and post-reproductive period and adult longevity were longer on lentil. The pre-reproductive period was significantly higher on field pea than on the other crops. The net reproductive rate (R0) was highest on lentil (103.56 females/female) and the intrinsic rate of increase (r) was highest on faba bean due to a short generation time (14.27 days). Generally, lifetime fecundity was higher on lentil (115.10/female) due to a higher daily reproduction rate (6.7 nymphs/female/day) on this crop. Nymphal production per aphid was strongly and positively correlated with lifespan, reproductive period and adult longevity but not of the nymphal period. Daily nymph production was significantly correlated with minimum temperature on lentil alone (F = 4.61, P < 0.05). Knowledge of the crop species and varieties susceptible to pea aphid is useful for identifying diets for the mass rearing of aphids for use in resistant variety selection and as diet for artificial natural enemy production. The present experiment indicates that lentil is suitable for both purposes.