POPULATION DYNAMICS OF CITRUS WHITEFLIES, APHIDS, CITRUS PSYLLA LEAF MINER AND THEIR BIOCONTROL AGENTS IN KHYBER PAKHTUNKHWA

Population densities of different sucking pests of citrus and their biocontrol agents were studied during 2001-2003 at Charbagh (Swabi), Palai (Malakand Agency) and Khanpur (Haripur) areas of Khyber Pukhtun Khawa. Data at all sites were recorded at fifteen days interval. Population density of whiteflies and citrus psyllids were recorded as number of adults per leaf, while the leaf miner infestation was recorded as % infested leaves and the aphid’s infestation was recorded as % infested shoots. The type and number of predators were counted per tree at the same time and collected for identification. Parasitoids were collected from infested leaves and shoots. Maximum infestation of whiteflies (2.27 adults per leaf) was recorded from Khanpure in April followed by Palai (1.96 adults per leaf) and Charbagh (0.25 adults per leaf) in August. Leaf miner was active throughout the year especially on fresh growth. The heaviest leaf miner infestation (55%) was recorded at Charbagh and Palai (49%) in October; while at Khanpur highest infestation (29%) was recorded in September. Citrus psylla population was highest (34 adults/leaf) in May at Khanpur followed by Palai (5.5 adults/leaf) in June. Lowest population (0.7 adults/leaf) was recorded in August at Charbagh. Maximum infestation 38.5% of aphids was observed at Khanpur in January followed by Charbagh 35.5% in November and 29% at Palai in March. Eight species of spiders and eight species of coccinellids were recorded at all locations. Green lace wing (Chrysoperla carnea) and syrphid fly (Syrphis sp.) were recorded only at Charbagh (Swabi). Binodoxys shillongensis was found as aphid parasitoid. Leaf miner was found to be parasitized by Allocerastichus obscurus and an unidentified chalcidoid wasp was reared from citrus psylla nymphs. No parasitoid was recovered from whitefly nymphs.