EFFECTS OF RAPE GROWN IN SO2‐ENRICHED ATMOSPHERES ON PERFORMANCE OF THE APHID, MYZUS PERSICAE (SULZER) *

Abstract Performances of the aphid, Myzus persicae, were monitored during feeding on leaves of the rape, Brassica chinensis, previously fumigated with SO2 in a range of concentrations between 20 and 160 nl/1 at 25°C. Response of the aphids depended on dose of the air pollutant. Moderate dose of SO2 treatment on the rape greatly enhanced the aphids' performances while high level of the pollutant heavily suppressed their growth and reproduction. They performed best at about 80 nl/l SO2, where nymphal mean relative growth rate (MRGR), adult fecundity and intrinsic increase rate(rm) of the population increased by 31.5%, 89.8% and 42. 7% over those of control aphids, respectively. Determination of the plant chemistry suggests that the altered relative content of methionine induced by So, exposure might be responsible for this response of dosage dependence.