摘要:

Laboratory tests were performed to determine the oxidation of terbufos (Counter®),O,O-diethylS-[(tert-butylthio) methyl] phosphorodithioate, in 3 Iowa surface soils (Clarion, Harps, and Webster). The insecticide was applied to 10-g soil samples at a rate of 1 ppm, which is equivalent to a field application rate of 1 lb/acre. Soil samples were incubated at 22±1°C for 0, 1, 3, 7, 14, and 21 days. Terbufos was rapidly oxidized to its sulfoxide. The parent compound had an approximate half-life of 4 to 5 days. Terbufos sulfoxide reached a maximum concentration after 2 weeks of incubation, and terbufos sulfone did not appear until 1 week after the incubation was started. Significant differences (P=0.01) were found in the ability of the 3 soils to oxidize terbufos. The sulfoxide and sulfone had no inhibitory influence on soil microbial activities.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.715

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

A guild of wandering spiders was studied in an oak-tuliptree-maple forest in northern Delaware. Specimens were collected by pitfall trapping and weather data recorded at weekly intervals over the summer season (3 months). A seasonal peak in species diversity (H') and species richness in midsummer was significantly correlated with prey abundance but not with seasonal temperature, humidity, or rainfall. Annual patterns of detritivore productivity in temperate forests and their influence on niche partitioning and seasonal abundance of species are discussed as a possible explanation. Spatial differences in species diversity were significantly correlated with the amount of litter and a measure of habitat space, but not with microclimatic moisture and temperature, vegetative diversity, or prey abundance. Physical aspects of the litter habitat, either as structural microhabitats or refuges from predation, are suggested as being important in regulating within-habitat species diversity. Interaction of diversity-regulating environmental factors in space and time are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.719

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

In 1972 and 1973, numerous wild host plants in the Pee Dee area of South Carolina were surveyed for populations of larvae ofHeliothisspp. Carolina geranium,Geranium carolinianumL., toadflax,Linaria canadensisL., beard-tongue,Penstemon laevigatusAiton, and crimson clover,Trifolium incarnatumL., were primary spring hosts; later in the season, beggarweed,Desmodiumspp., deergrass,Rhexiaspp., morning glory,Ipomoeaspp., prickly sida,Sida spinosaL., and bicolor lespedeza,Lespedeza bieolorTurcz., were favored. Only the parasitiesCardioehiles nigrieepesViereck andCampoletisspp. and the diseaseSpiearia rileyi(Farlow) Charles occurred frequently enough to deter the development of populations ofHeliothisspp. in the Pee Dee area of South Carolina.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.725

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

The proportion of the “active” form of the cowpea weevil,Callosobruchus maculatusF., among a population emerging from infested cowpeas in the laboratory is greatly reduced in small seeds. It is replaced by a “miniature” form of the weevil. The factors conditioning production of the “active” form appear to operate when sufficient food is supplied.Small-seeded varieties would have a limiting effect on population increase of the weevil. However, breeders have to select cowpeas for a size acceptable to consumers and, in addition, for intrinsic characteristics conferring resistance to the cowpea weevil, preferably a deterrent seed coat and/or reduced nutritional value to the weevil. Frequency of miniature forms deserves attention as a more dependable parameter than that of the active form in rapid screening of large numbers of entries for sources of resistance.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.729

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Twelve soybean varieties were tested for possible tolerance to the two-spotted spider mite,Tetranychus urticaeKoch. Dare and Hill varieties showed low tolerance to these mites while the other 10 varieties showed moderate to high tolerance.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.733

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

A method for mass-rearingOnthophagus gazella(F.), an Afro-Asian dung-beetle useful in suppression of dung-breeding Diptera and in recycling of manure on pastures, is described. The developmental period (egg to adult) averaged 29.8 days and average total production of progeny was ca. 90 per female.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.735

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

When males ofTrichoplusia niwere continuously exposed to female sex pheromone, their pheromone-induced activity diminished more rapidly than it did for males exposed to repetitive pulses of pheromone. The males remained partially habituated for at least 15 min following many hours of pre-exposure to either the continuous supply or repetitive pulses of pheromone. When the males were continuously exposed and presumably habituated to pheromone throughout the night, there was no apparent effect on the timing of their flight or feeding behavior. An understanding of the behavior of male moths during and following prolonged exposure to sex pheromones may enhance man's utilization of the pheromones for pest control.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.737

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Behavioral differences between the eastern and western strains of the alfalfa weevil,Hypera postica(Gyllenhal), in response to parasitization byTetrastichus incertus(Ratzeburg) were observed and described. Behavior was found to influence the length of time parasites remained on larvae of the host and success of parasitization. Larvae of the eastern strain generally were found to be docile in respect to parasitization. The majority of eastern larvae were parasitized successfully and judged to be more favorable hosts forT. incertus. Larvae of the western strain generally responded to parasitization with a prompt, vigorous evasive behavior and were not parasitized. This reaction to parasitism was determined to be a contributing factor inhibiting the establishment ofT. incertusin Colorado.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.742

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Yellow sticky trap and transect foliar sampling were used to study the spatial distribution of the blue-green sharpshooter,Hordnia circellata(Baker), in and near vineyards infected with Pierce's disease. From April through June, adults concentrated most heavily in riparian vegetation and within vineyards on grapevines nearest riparian vegetation. The spatial pattern of nymphal distribution reflected early season movements of females in grapes. Adults Were more evenly distributed within vineyards after midgrowing-season.The percentages of sharpshooters collected from vineyards plots and tested for their ability to transmit the causal agent of Pierce's disease to test grape plants rose from 13% in July 1972 to 45% the following June. In 1973, infectivity increased from 30% in July to 45% in September. Of sharpshooters collected from areas of vineyard plots where the incidence of Pierce's disease was below 5%, 14% were Infections in 1972 and 33% in 1973.The early season distribution of sharpshooters in vineyards coincided in many ways with the pattern of Pierce's disease. After mid-season, the pattern of sharpshooter distribution varied widely from that of Pierce's disease.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.745

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Survival of 10 populations ofOstrinia nubilalis(Hübner) was progressive from north (Morris, Minn.) to south (Portageville, Mo.) except that survival decreased again at Tifton, Ga., because of the stunted condition of the corn and the density of the test insect populations. In the south, increasing temperature overrode photoperiod (shorter photophase, longer scotophase) and reduced the number of borers that diapaused. Conversely, in the north, photoperiod (longer photophase, shorter scotophase) overrode decreasing temperature, but again the result was a reduction in diapause. The highest percentage diapause occurred at the latitude where the photoperiod-temperature interaction was most severe. From the diapause response, populations of European corn borers in North America fit 3 ecotypes: a northern one represented by the Minnesota and Quebec populations; a central one represented by the Iowa, Nebraska, Ohio, and Frederick Co., Md., populations; and a southern one represented by the Alabama, Georgia, Missouri, and Somerset Co., Md., populations.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.753

出版商:Oxford University Press    

年代:1975

数据来源: OUP