Up to 2351 migratory alates of green peach aphid Myzus persicae were trapped from air above the top floor of a tower building in Hangzhou, Zhejiang from October 2002 to May 2005 and individually reared for 12 days on detached cabbage leaves in Petri dishes at （21±1）℃ under a photophase of 12L∶12D. During the first 7-day period, 639 alates died from mycoses caused by several obligate aphid pathogens in the Entomophthorales, representing a primary infection rate of 27.2% among the air-trapped alates. The obligate pathogens were predominated by Pandora neoaphidis at the rate of 81.4%. On average, the infected alates produced significantly fewer nymphs (2.4±0.13) than the uninfected (11.6±0.33) within 6 days after colonization. Contagious transmissions of the mycoses were observed in the progeny colonies whose mother alates were mycosed at least 2 days earlier. On day 12, 13.3% of their progeny colonies suffered from secondary infection and 4.4% from tertiary infection, which occurred among 33.3% of the secondarily infected colonies. By the same day, the progeny colonies from the infected and uninfected alates averagely consisted of （21.5±1.98) and （50.6±2.30) live aphids, respectively. The results highlight the significant role of the infected migratory alates in initiation of Entomophthorales-caused mycoses on M. persicae colonized plants where the progeny population was regulated by the developing mycoses due to contagious transmission.