Phenology of Coccinellid predators in berseem (Trifolium alexandrinum)

Abstract

Phenology of coccinellid predators were studied in the fields of berseem (Trifolium alexandrinum) crop through in situ plant count method in the December to March in years (2011-2012 and 2012-2013). Coccinellids such as, zigzag, Menochilus sexmaculatus (F), 11-spotted Coccinella undecimpunctata (L.), 7-spotted, Coccinella septempunctata (L.) and striped beetle, Brumus sutuaralis (F) were recorded. The mean population of all coccinellids were maximum in 2nd and 3rd week of February in both years. The highest population of zigzag beetle was recorded in both years followed by 11-spotted, 7-spotted and striped beetle respectively. The results of predator-prey ratio were 1.18: 254 in 1st year and 1.96: 306 in 2nd year. As such predator-prey ratio was lowest 1:6.83 on 1st week of March when there were 6.6 predators against 45.15 aphids in 1st year. It was 1:5.58 in 2nd year when there were 6.26 predators against 35 aphids. The highest population of zigzag beetle was recorded in both years followed by 11 spotted, 7-spotted and striped beetle respectively.