EFFECT OF ABIOTIC FACTORS ON INCIDENCE OF INSECT PESTS AND THEIR MAJOR NATURAL ENEMIES IN BLOND PSYLLIUM, PLANTAGO OVATA

摘要

The study was carried out to find out the effect of abiotic factors on the incidence of insect pests and their major natural enemies in blond psyllium, Plantago ovate. Aphid, Rhopalosiphum maidis; whitefly, Bemisia tabaci and Gryllus sp. were found attacking blond psyllium, but the former was recorded as the major insect pest due to its high incidence and persistence on the crop for longer duration. The population of this pest appeared in 52nd standard meteorological week (SMW) during first year (rabi 2006-07) and reached at it peak in 6th SMW (95.4 aphids/tiller). In second year (rabi 2007-08), the population of aphid appeared on 1st SMW and peaked in 6,h SMW (77.4 aphids/tiller). Among natural enemies, the population of Coccinella septempunctata was high whereas, Menochilus sexmaculatus, Adonia variegata and Xanthogramma scutellare, Diaeretiella rapae and Indian Mynah, Acridotheris tristis were low in numbers. The maximum temperature, minimum temperature and evening relative humidity showed non-significant correlation whereas, the morning relative humidity showed significant positive correlation (r= 0.65, 0.66). The population of C. septempunctata was nonsignificantly correlated with the meteorological parameters but was positively correlated with aphid population (r= 0.89, 0.85).