Predation efficiency of five coccinellid beetles on Aphis craccivora Koch infesting cowpea

摘要

The predation efficiency of five species of coccinellids, namely, Coelophora biplagiata (Swartz), Coccinella transversalis F., Menochilus sexmaculatus (F.), Cryptolaemus montrouzieri Mulsant, and Chilocorus nigrita (F.), against cowpea aphid, Aphis craccivora Koch, was evaluated in the laboratory. Maximum consumption of A. craccivora (65.20 +- 0.59 to 214.60 +- 2.60) was observed in C. biplagiata released under various predator densities, whereas C. montrouzieri consumed the minimum numbers (19.40 +-0.36 to 84.60 +- 0.73). C. biplagiata was closely followed by M. sexmaculatus and C. transversalis. It was also observed that C. biplagiata, M. sexmaculata and C. transversalis exhibited higher predation efficiency with a mean aphid consumption of 43.60+- 0.46 to 485.80 +- 5.18, 41.20 +- 0.33 to 377.00 +- 3.35 and 40.60 +- 0.96 to 370.00 +- 3.74, respectively, under different prey densities of 45 to 720. When C. biplagiata was released, significantly lowest aphid population (23.06) was recorded, followed by M. sexmaculatus (35.26), C. transversalis (43.00) and C. nigrita (49.13) as against unreleased control (191.86). The highest aphid population (54.26) was recorded in the treatment where C. montrouzieri released.