Environmental Entomology (1984) 13, 252-258
J.R. Fuxa (1984)
Dispersion and spread of the entomopathogenic fungus Nomuraea rileyi (Moniliales: Moniliaceae) in a soybean field
Environmental Entomology 13 (1), 252-258
Abstract: A 0.84-ha soybean field was divided into 64 plots and sweep sampled for lepidopterous pests at 2- to 7-day intervals. Green cloverworms, Plathypena scabra (F.), velvetbean caterpillars, Anticarsia gemmatalis Hübner, and soybean loopers, Pseudoplusia includens (Walker), were detected initially in the field on 3, 8, and 10 August, respectively. The entomopathogenic fungus Nomuraea rileyi (Farlow) Samson was detected on 13 August in sampled insects reared in the laboratory. The disease first appeared in relatively limited foci within the field and was present in 37 of the plots by 24 August, at which time only 4.3% of susceptible insects in the field were infected. Between 30 August and 6 September, prevalence of the disease declined from 16.5 to 0.6% after heavy rainfall. Dispersion of the three host species as well as Nomuraea-infected larvae best fit the negative binomial distribution. Infected hosts were more aggregated than uninfected.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
population dynamics/epizootiology