摘要:

Larvae of black carpet beetle,Attagenus unicolor(Brahm), were isolated from a laboratory diet at weekly intervals from 5 to 12 weeks of age and thereafter at 14 and 16 weeks of age. Survival and subsequent molting to pupa stage after starvation periods of 23–29 weeks at 28°C and 55–65% RH was dependent on larva size when isolated from food. Male and female larvae had to attain mean weights of ca. 10.5 and 17 mg, respectively, before a significant percentage could survive. Larvae of this average size had essentially completed the first of two larval growth phases peculiar to this species and were found primarily in cultures 14–16 weeks of age. A 4-week feeding period on wool cloth before starvation had no significant effect on percentage of larvae that survived or on mean time until pupation. Cooling young larvae for an 8-week period at 15°C with subsequent rearing at 35°C significantly shortened development time for ca. 35% of the population. Mean time to pupation was 22.3 weeks compared with mean development time of 39 weeks for larvae reared continuously at 28°C. Adults that emerged early because of this combination of temperature treatments did not produce any offspring. Cooled larvae subsequently reared at 35°C that did not undergo early pupal molt entered a phase of arrested development that may last as long as 1 additional year.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1166

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

No parasitoids able to complete development on apple aphid,Aphis pomiDe Geer, were found in north-central Washington. However, several aphidiid species oviposited inA. pomiand developed to last instars before dying. Of these,Praon unicumSmith andLysiphlebus testaceipes(Cresson) were found attackingA. pomiin apple orchards.P. unicumwas most active in spring and parasitized a high percentage of apple aphids in some orchards.L. testaceipeswas more prevalent during summer and apparently contributed little to apple aphid control. Hosts and habitats of these and two other species,Praon occidentale(Baker) andDiaretiella rapae(M'Intosh), were investigated. Winter and spring generations ofP. unicumwere found on apple, peach, and hawthorne. The summer generation was found mainly on hawthorne, weeds, and grasses. Aphid hosts ofP. unicumon apple includedDysaphis plantaginea(Passerini),Rhopalosiphum insertum(Walker), andNearctaphis bakeri(Cowen).Myzus persicae(Sulzer) was the major host on peaches in winter and spring and on weeds during summer.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1171

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Time required for sweetpotato whitefly,Bemisia tabaci(Gennadius), to complete development of egg to adult at 26.7 ± 2°C varied depending on the host to which it wasconfined. Development was completed in 5 fewer days on wild lettuce,Lactuca serriolaL., and spiny sowthistles,Sonchus asper(L.) Hill, than on wild sunflowers,Helianthus annuusL. Catches of adults on traps adjacent to wild sunflowersand field bindweed,Convolvulus arvensisL., and of immatures on leaf samples of these plants indicated thatB. tabaciwas present throughout the year in the cultivated area of the Imperial Valley in California. Thus, movement of adults back into this area is not a prerequisite for annual establishment of the pest. Seasonal trends of the aphelinid parasites,Eretmocerusspp. andEncarsiaspp., attackingB. tabaciwere monitored on both host plants, but levels of parasitism never exceeded 40%. Therefore, effectiveness of these parasitoids in managingB. tabaciis questionable.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1179

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Population fluctuations of forest tent caterpillar,Malacosoma disstriaHübner, were investigated at two permanently flooded plots and one plot that was dry during summers of 1980–83 in southern Louisiana. Tupelo gum,Nyssa aquaticaL., and swamp tupelo,Nyssa sylvaticavar.biflora(Walt.) Sarg., made up 63% of the dry plot forest stand and 93.8 and 87% of the two wet plots. Egg parasitism ranged from 8.8 to 29.7%, and egg infertility varied from 1.2 to 6.7%. An analysis of egg mortality factors demonstrated no density-dependent relationships or significant plot differences. Pupal parasitism bySarcophaga houghiAldrich varied from 18 to 78% during 1981–82. Lower rates of parasitism were found on wet plots due, presumably, to drowning of parasite puparia. Populations of forest tent caterpillar at the dry plot were reduced by apparent density-dependent parasitism byS. houghi. We found that a generation survival rate of 0.1% resulted in population decline and that survival ≥0.7% resulted in a population increase the following season. Starvation may have been a major factor in population fluctuation at wet plots.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1184

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Distribution of beet armyworm,Spodoptera exigua(Hübner), egg batches was similar in chrysanthemum, tomato, gerbera, and geranium crops grown in a greenhouse. Most eggs were laid on the underside of foliage on leaves within 10 cm of the soil surface. In chrysanthemum, moths deposited more eggs on younger than on older plants. No correlation was found between size of egg batches and plant species, plant age, or position within a crop.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1189

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Toxicities of commonly used water hyacinth herbicides and additives to water hyacinth weevils,Neochetina eichhorniaeWarner andN. bruchiHustache, were tested in the laboratory. Weevils were either sprayed while on water hyacinth plants or dipped directly into the compounds tested. No significant mortality resulted from exposure to 2,4-D, diquat, glyphosate, or additives including a surfactant and a polymer. Exposure to an inverting oil, and its primary component d'limonene, resulted in significant mortality of both species at concentrations tested. Effects of herbicide exposure on flight muscle development seemed to be related to time of year at which exposure occurred. Effects of herbicide application on dispersive behavior were determined by placing marked weevils on artificial weed mats in the field. Mats were subsequently sprayed with a standard concentration of 2,4-D. Weevils consistently migrated from sprayed, dying plants to adjacent healthy, unsprayed plants. Implications for biocontrol strategies of water hyacinth are discussed.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1192

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

This study compared abundances of leafhoppers at three heights above ground level. Aerial suction traps and sticky traps were used. For most species, aerial abundance at 9.14 m exhibited the same pattern as the aerial abundance at 1.83 m, but neither pattern was a simple function of terrestrial abundance at 0.15 m. A common pattern was for pulses of leafhoppers to appear in the air (at both 1.83 and 9.14 m) early in the first adult generation but not at any other time. In some cases, aerial pattern was related to alary polymorphism or to reproductive maturity. Other species were rarely caught in the air, even at 1.83 m above ground level, despite high abundances on the ground. The data were used to discuss the boundary layer and wind-assisted migration, the oogenesis/flight syndrome and the relationship between migration patterns and habitat isolation and durational stability.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1199

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Egg-mass dispersion patterns of second-generation European corn borer (ECB),Ostrinia nubilalis(Hübner), were determined for 60 cornfields sampled in Shawnee County, Kans., during 1982 and 1983. Among those fields, egg masses appeared to be randomly dispersed in 53 fields. Sample number curves were developed for five-plant samples of egg masses at four precision levels, and number of samples required to adequately sample a cornfield at 8 and 32% completion of oviposition was determined. Results indicated that sampling entire corn plants was logistically and economically unfeasible; use of partial plant samples was evaluated using economic analysis techniques. Using an ECB decision model, cost of increased predictive error was determined for corrected, reduced leaf counts. Total cost associated with egg-mass sampling was determined by summing predictive (decision) error cost and sampling cost. Optimal number of leaves to sample under three economic conditions was determined by locating the number of leaves that resulted in minimum total cost.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1212

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Ips calligraphus(Germar) (80.2%),I. avulsus(Eichhoff) (11.2%), andI. grandicollis(Eichhoff) (8.2%) infested felled loblolly pine,Pinus taedaL., and slash pine,P. elliottii(Englemann), in Louisiana. Treatments designed to exclude naturalIpsspp. Predators and parasites were applied over time to infested trees. These temporal exclusion treatments revealed thatIpsspp. brood survival decreased 30.8%, while the number of insect predators and parasites found in association with theIpsspp. brood increased 3-fold.Ipsspp. brood survival was not affected by host tree species, bark thickness, or tree felling date. Twenty-seven species of insect predators, in 13 families, and 10 species of parasites, in 4 families, were associated with theIpsspp. broods. Predators and parasites composed 98.8 and 1.2%, respectively, of the total beneficial insect complex

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1220

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Ballooning spiders were monitored over Florida cornfield ecosystems using sticky wire traps. A total of 1,805 spiders, representing 15 families and at least 53 species, consisted mostly of juveniles, but adults of 25 species were also captured. Analysis of the seasonal phenology revealed five dispersal/life history strategies, the most important being widely overlapping generations and several instars ballooning throughout the year; spiders using this strategy are major components of crop field spider communities of the southeastern United States. Capture of 25 species of adult males on the traps suggested that ballooning is also a means for some species to search for females. The long legs and setae of many of the male spiders, as well as other frequent ballooners, may aid them in gaining aerial lift.

ISSN:1754-5692    

DOI:10.1093/ee/15.6.1225

出版商:Oxford University Press    

年代:1986

数据来源: OUP