Acta Entomologica Sinica (2000) 43, 380-386

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Cai-Ling Liu and Ming-Guang Feng (2000)
Impact of temperature and humidity combinations on development of mycosis in Myzus persicae with the entomophthoralean fungus, Zoophthora anhuiensis
Acta Entomologica Sinica 43 (4), 380-386
Abstract: The development of the mycosis of the green peach aphid, Myzus persicae (Sulzer), caused by the entomophthoralean fungus, Zoophthora anhuiensis (Li) Humber, at a dosage of 79 ~ 90 conidia/mm2, was investigated at regimes of various temperature constant (10, 15, 20, 25, and 30°C ) or fluctuating (1. 5~16.6°C and 8.5~20.2°C) and relative humidities (50, 65, 80, 90, 95, 100% RH) . Each of the 42 batches of aphids exposed to spore shower consisted of 30~60 7-day-old nymphs and was placed in an incubator at a given regime after being maintained at 20°C with nearly saturated humidity for 24 h for initiation of infection. During a 19-d period of observation, death of aphids caused by Z. anhuiensis occurred at all regimes and the cumulative mortalities differed greatly among the regimes of temperature (F= 7.46, P < 0. 01) or relative humidity (F = 12.54, P < 0. 01). The optimal temperature for the development of mycosis was 20°C constant or 8.5~20.2°C fluctuating daily.(12.4°C on average), at which the mortality increased with relative humidity. Among the regimes of 10~25°C with 100% RH, the increase in temperature had little effect on the cumulative mortality of aphids but greatly affected the developmental rate of mycosis with LT50s being 8.4, 7.1, 4.0, and 3.4 days at 10, 15, 20, and 25°C, respectively. Linear regression of 1/LT50 against temperature suggests a threshold temperature of 1.65°C for the mycosis development. Production of conidia from aphid cadavers required >80% RH at 10 ~ 15°C and at the two temperature-fluctuating conditions, and >90 % RH at 20 ~ 30°C . Resting spores of the fungus were not found in aphid cadavers from any group of the 42 regimes tested.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Myzus persicae China (south)
Zoophthora anhuiensis (entomopathogen) Myzus persicae China (south)