摘要:

Infectivity of an undescribed UruguayanNeoaplectanaspecies to the mole cricketsScapteriscus vicinusScudder andS. acletusRehn and Hebard was tested under a variety of conditions in the laboratory. At 30°C, soil moisture in the range of 5–15% had no effect on infection of the mole crickets. There was no consistent difference in infection of mole crickets exposed to nematode-infested soil for 24 h and those exposed for 72 h. There was no decline in infection of crickets for the first 7 d after introduction of nematodes into the soil at 30°C, but after 14d at that temperature, there was significant reduction in infection. Crickets exposed to nematodes at 10°C were infected significantly less often than those exposed at 30°C. Increasing nematode density from 100,000 to 1 million per m2did not increase the incidence of infection but did decrease the variability of results.

ISSN:0046-225X    

DOI:10.1093/ee/18.4.719

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Food consumption by healthy fifth-instar gypsy moths,Lymantria dispar, and larvae infected withEntomophaga maimaigawas compared. Infected larvae ate less food than healthy larvae during the two days before death. Weight gain of infected larvae was less than weight gain of healthy larvae from 3 d after inoculation. Although death of infected larvae was hastened by starvation,E. maimaigawas able to develop successfully in larvae that received no food after infection, suggesting that larval feeding during the associated period of incubation is not necessary for fungal development.

ISSN:0046-225X    

DOI:10.1093/ee/18.4.723

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The solitary pupal parasiteUrolepis rufipes(Ashmead), a recent isolate from house fly and stable fly puparia in eastern Nebraska, was studied to evaluate its potential as a biological control agent for these fly species. Parasitism was highest at 25°C for two age classes of host pupae. Parasite-induced mortality attributed to host stinging, excluding emerged parasites, increased with temperature, and generally was significantly higher than parasitism. The number of emerging male to female parasites was about equal and males generally began emerging 1 d before females. Development was more rapid than for most other pteromalid parasites of filth flies requiring 10–15 d for first male emergence at 25°C. Apparent diapause was evident with this species and was activated by the temperature at which the developing progeny were subjected.

ISSN:0046-225X    

DOI:10.1093/ee/18.4.728

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The effect of natural enemies on survival of southwestern corn borer,Diatraea grandiosella(Dyar), eggs and larvae was measured in Texas High Plains corn using exclusion cages.Orius insidiosus(Say) and spiders were the most abundant predators on corn plants. Predation of corn borer eggs was uncommon and insignificant. Survival of first-generation larvae in whorl stage corn where predators were excluded was significantly greater than survival on plants accessible to predators in two of three years. Survival of second-generation larvae on tassel stage corn was significantly greater during both years on caged plants (excluding predators). However, during the second generation, mortality of first and second instars was replaceable by cannibalism among mature, prediapause larvae. Egg and larval parasites were not observed.

ISSN:0046-225X    

DOI:10.1093/ee/18.4.732

出版商:Oxford University Press    

年代:1989

数据来源: OUP