EFFECTIVENESS OF Pauesia juniperorum IN CONTROLLING POPULATION OF CYPRESS APHIDS IN MALAWI

The cypress aphid, Cinara cupressivora is a significant pest of Cupressaceae species and has caused serious damage to naturally regenerating and planted forests in Africa, Europe, Latin America and the Caribbean and the Near East. This study was conducted to determine the effectiveness of biological control of Cypress Aphids (Cinara cupressivora) using Pauesia juniperorum in Cupressus lusitanica clonal seed orchard in Dedza, Malawi. The data was extracted from monthly reports (1994 to 2002) of the Forestry Research Institute of Malawi. A statistically significant (X2=57.62, P<0.001) association was found between the presence of P. juniperorum and presence of C. Cupressivora. The reduction on the percentage presence of C. cupressivora was 23 times (Odds ratio = 22.9) more likely to occur in the presence of P. juniperorum than in its absence. The study further revealed that there was a statistically significant (X2=3573.06, P<0.001) association between the presence of P. juniperorum and damage of C. lusitanica. The damage on the C. lusitanica was 65 times (odds ratio 65.3) more likely to get reduced in the presence of P. juniperorum than in their absence. There was also a significant (P<0.001) difference in the mean number of cypress aphids per tree branch per month before (5.56±0.75) and after (2.69±0.51) the release of P. juniperorum. The study therefore confirms effectiveness of P. juniperorum as a sustainable biological control agent for Cypress Aphids.