Morphology, population dynamics of Aphis gossypii Glover and reproductive biology of Myzus persicae (Sulzer) on peppers
1990
Samhan, I.J.A.
The population trend of Aphis gossypii Glover (Homoptera: Aphididae) in the Central Jordan Valley from Nov 1987 to the end of Oct 1988, and the reproductive biology of Myzus persicae (Sulzer) (Homoptera: Aphididae) in the laboratory were studied on three hot and three sweet pepper cultivars, namely: Anhime Chilly, Cayenne Long Slim, Pical (F1), Pip, Sonar (F1) and Video (F1). A key was designed for identification of these aphids and Aphis fabae and a key for the different nymphal instars of Aphis gossypii. Results showed that non of the tested cultivars were immune to any of the aphids. However, significant differences in the susceptibility among the cultivars to both aphids were found. The mean number of Aphis gossypii per plant and the percent of the infested plants throughout the season were 107.8; 105.3; 76.8; 71.7; 58.8 and 28.5, and 18.4%; 20.6%; 18.0%; 15.3%; 14.3% and 10.7% for Anhime, Sonar, Pip, Pical, Video and Cayenne, respectively. There were two peaks for population of Aphis gossypii in the field. The first was from Nov 1987 to end of Jan 1988, and the second from Jun to Sep 1988. Fecundity of Myzus persicae was 60.4; 58.4; 50.9; 53.6; 42.6 and 53.2 on Anhime, Cayenne, Pical, Pip, Sonar and Video, respectively. Moreover, there was a positive reaction between fecundity and longevity of the aphid on the different cultivars (r=0.943). The mother weight was related to the number of developed embryos inside the aphid (r=0.819). The intrinsic rate of increase (r sub (m)) slightly differed among cultivars. r sub (m) for Myzus persicae was 0.165; 0.160; 0.163; 0.166; 0.168 and 0.165 on Anhime, Cayenne, Pical, Pip, Sonar and Video. Flight activity of Aphis gossypii and Myzus persicae showed two main periods during each of 1986, 1987 and 1988. The first period was in the spring and the second -in the autumn
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