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Occurrence of entomopathogenic fungi in migratory alate aphids was investigated by trapping air-borne aphids on cabbage and wheat plants and observing the insects for fungal infection. Potted cabbage and wheat plants put 30 m apart on yellow cloth, were placed on the top of a tall building (six-story building) in Yunnan Province, China away from cultivated fields or other vegetation. Seven species of aphids trapped on the plants collected and monitored for fungal infection in the laboratory at a daily basis from 19 February to 31 December, 2003. Aphids were trapped every day during the experimental period. A total of 3,681 aphids were trapped on cabbage and 3,028 on wheat. Myzus persicae (Sulzer), Brevicoryne brassicae (L.), and Sitobion avenae (F.) were the major aphid species accounting for 94.7 and 93.1% of the insect specimens landing on cabbage and wheat, respectively. Other aphis species encountered included, Acyrthosiphon pisum (Harris), Lipaphis erysimi (Kaltenbach), Pemphigus sinobursaris Zhang, and Rhopalosiphum padi (L.). Preference for host plant played significant role in attraction of aphids, especially of the three major species. Accumulated over the whole experimental period nearly 33% of the aphids landing on cabbage and 37% landing on wheat were infected with fungi. Erynia neoaphidis Remaudiere and Hennebert, Entomophthora planchoniana Cornu, and Beauveria bassiana (Balsamo) Vuilemin were the major fungal pathogens encountered and accounted for nearly 95% of the infested aphids on cabbage and 97% on wheat. Other entomopathogenic fungi encountered included Zoophthora radicans (Brefeld) Batko, Conidiobolus obscurus (Hall and Dunn) Remaudiere, and Neozygites fresenii (Nowakowski), Paecilomyces fumosoroseus (Wize) Brown and Smith, and Aspergillus flavus Link. Although the number of aphids trapped throughout the experimental period did not vary consistently with temperature or humidity, the fungal was directly related to relative humidity. Higher insect mortality, especially due to Entomophthorales, positively related relative humidity.

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