Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Interspecific abundance and seasonal incidence of aphids and aphidophagous predators associated with cabbage.

Abstract

Among the three species of aphids that damaged the cabbage crop, Myzus persicae (Sulz.) constituted 45.30% of the total population, followed by Brevicoryne brassicae (L.) (33.88%) and Lipaphis erysimi (Kalt.) (20.82%). M. persicae was prevalent throughout the cropping season, but was most active during December and January (159.83-239.90 nymphs and adults/3 leaves). L. erysimi was active during the early part of the cropping season with peak activity during November and first fortnight of December (118.82-136.09 nymphs and adults/3 leaves). B. brassicae was a late starter which commenced its activity from mid-December and lingered on the crop till harvest during March end. Its peak incidence was noticed during January and February (119.69-263.18 nymphs and adults/3 leaves). Out of the four species of coccinellid predators, Coccinella transversalis F. was the dominant species constituting 55.08% of the total population followed by Cheilomenes sexmaculata (Fab.) (27.73%), Micraspis discolor (Fab.) (12.05%) and Coccinella septempunctata L. (5.14%). C. transversalis and C. sexmaculata appeared during mid-November and attained their peak population during January and February (7.27-10.94 and 4.26-5.08 grubs and adults/10 plants, respectively). M. discolor and C. septempunctata appeared during mid-December and mid-January, respectively. They reached the peak population during February (2.44-3.34 and 1.29-1.83 grubs and adults/10 plants). Of the two species of syrphid predators, Ischiodon scutellaris (Fab.) was overwhelmingly more numerous (80.06%) than Eumerfus albifrons Walker (19.94%). While I. scutellaris appeared during early November, E. albifrons appeared during early December. The peak activity of I. scutellaris was observed during January and first fortnight of February (8.64-11.45 larvae/10 plants), whereas that of E. albifrons during the second fortnight of January and first fortnight of February (2.79-4.06 larvae/10 plants).