S. M. A. Mandal ¹, N. C. Patnaik ¹

Affiliations
1 Department of Entomology, College of Agriculture, Orissa University of Agriculture and Technology, Bhubaneswar - 751003, Orissa, IN

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 scuteilaris (Fab.) was overwhelmingly more numerous (80.06%) than Eumerfus albifrons Walker (19.94%). While/. scuteilaris appeared during early November, E. albifrons appeared during early December. The peak activity of/. scuteilaris 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).

Keywords

Aphidophagous Predators, Aphids, Interspecific Abundance, Seasonal Incidence, Syrphids.

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N. C. Patnaik ¹, J. N. Mohanty ², B. K. Mishra ², M. K. Ghode ³

Affiliations
1 OUAT Research Station. Post Box-10, Sunabeda-2. Koraput (Orissa), IN
2 Department of Entomology, Orissa University of Agriculture and Technology Bhubaneswar 751003, IN
3 Central Biological Control Station, Lewis Road, Bhubaneswar (Orissa), IN

Abstract

The seasonal activity and suppressive action of Epiricania melanoleuca (Fletcher), a nymphal-adult parasite of Pyrilla perpusilla (Wlk.) was studied in an endemic cane growing village of Puri district (Orissa) where the parasite had been introduced against the pest. Peak pyrilla activity was observed in the second fortnight of September whereas, the parasite activity reached its peak activity with a time lag of one month. The parasite:pest ratio which was 1:64 in the second fortnight of August, declined to 1:0.25 in the second fortnight of October, implicating the suppresive role of the parasite over the pest.

Keywords

Pyrilla perpusilla, Nymphal - Adult Parasite, Epiricania melanoleuca.

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