摘要:

Aedes togoi(Theobald) larvae were reared under controlled laboratory conditions at 22 ± 0.5°C, LD 16:8, in commercial sea salt concentrations of 0, 10, 20, and 35 g/liter of dechlorinated tap water, and time to 50% pupation was compared. Development was faster in 10 g of sea salt per liter (P<0.01) than in 20 g/liter, 35 g/liter, and dechlorinated tap water, and faster in 20 g and 35 g of sea salt per liter (P<0.05) than in dechlorinated tap water. Mean larval mortality for all treatments was not significantly different. Development of larvae in 10 g of sea salt per liter was also compared at five temperatures: 18,22,24,30, and 35°C (all ± 0.5°C). Times to 50% pupation ranged from 18 and 19 days for males and females, respectively, at 18°C to 6.5 days for both males and females at 30°C. At 35°C, larval mortality was high and none pupated, but 41% of the larvae reached the 4th instar by 21 days of age.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1406

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Standardized chrysanthemum plants,Chrysanthemum morifoliumRamat, were exposed to selected numbers of ovipositing adult femaleLiriomyza trifolii(Burgess) (Diptera: Agromyzidae) to analyze thc effects of intraspecific competition on the survivorship of larvae and quality of emergent adults. The effect of intraspecific competition on the ratio of emergent pupae to newly eclosed larvae (P:L ratio) and pupal size was determined. Pupal size was found to be a positive indicator of longevity and oviposition of adults. The P:L ratio was inversely related to intraspecific competition and ranged from 0 (severe competition) to 1.0 (no competition). Smaller pupae were obtained from plants with low P:L ratios. A maximum of 30 larvae could complete development in a standardized chrysanthemum plant without adversely affecting the P:L ratio.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1412

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

In short-term, small-scale field experiments, population densities of two specialist herbivores differed significantly among different-sized patches of host plants. Eggs and larvae ofPieris rapae(L.) (Lepidoptera: Pieridae) were more abundant on collards planted in small (four- or nine-plant) patches than on those in large (64- or 81-plant) patches. Larvae ofplutella xylostella(L.) (Lepidoptera:Plutellidae) were more abundant on collards in large (81-plant) patches.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1415

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Strains ofTyphlodromus arboreusChant resistant to azinphosmethyl and carbaryl occur in intensively sprayed apple orchards of the Willamette Valley, Oreg. These mites are equally resistant to these compounds as are resistant strains of the congeneric species,Typhlodromus occidentalisNesbitt, but they are more susceptible to diazinon and phosalone thanT. occidentalis. ResistantT. arboreusare more resistant to azinphosmethyl and carbaryl, but are almost equally susceptible to diazinon and phosalone as another associated species,Amblyseius andersoniChant. The implications of these resistance features to colonization by these mites of intensively, moderately, and seldomly sprayed apple orchards in the Willamette Valley are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1420

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The potential bacterial mutagenicity of the beta-exotoxin ofBacillus thuringiensisvar.thuringiensiswas detennined by theSalmollella-microsomalassay (Ames test) and found to be nonmutagenic. The activity of three experimental preparations ofB. thuringiensisvar.thuringiensiswere determined by feeding the preparations to house fly larvae and to neonateColorado potato beetle larvae,Leplinotarsa decemlineala(Say). Comparisons with controls were made as to food consumption and mortality rates, and the LDIOthrough LDQ, were calculated. In field tests of 0.05-ha plots of potatoes, an experimental preparation ofB. lhuringiensisvar.lhurillgiellsisprovided excellent control of the Colorado potato beetle when applied weekly at the rate of 1,892ml/O.4ha.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1424

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Sampling techniques for larvae of the grass webworm,Herpetogramma licarsisalis(Walker) (Lepidoptera: Pyralidae) in turfgrass were studied. Sprinkling 1 liter of a 0.0015% aqueous solution of pyrethrins or 0.25% detergent into a 1,860-cm2frame forced 61 and 55% of the larvae to the surface, respectively, compared with 4 liters of each irritant. The need for a greater volume of water than the commonly used technique of applying 4 liters/0.84 m2was apparent. Continuous observation was required during the 10 min after application of either irritant to assure an accurate count, since 29% of the surfaced larvae reentered the thatch within 5 min and 38 to 39% reentered within 10 min. The detergent forced>50% of the larve to surface within 2 min. compared with 4 min with pyrethrins. Liquid irritants surfaced ca. 3 times more larvae in 5 to 10 min than plywood set out overnight. Similar responses to the presence of minor populations of the lawn armyworm, the black cutworm, and the fiery skipper indicate that other turf-infesting lepidopterous larvae may be sampled with the same techniques.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1428

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Spider predation onColeophora parthenicaMeyrick (Lepidoptera: Coleophoridae), an insect introduced into the western United States for control of Russian thistle,Salsola australisR. Brown (Chenopodiaceae), was studied at Indio, Calif., during April through October 1980. The two most common of seven species of spiders observed feeding onC. parthenicaadults were studied in detail.Dictyna reticulataGertsch and Ivie (Dictynidae) reached mean densities of 93 per plant, and each spider captured up to five moths in each of three emergence periods. There was a positive correlation between the numbers ofD. reticulatawebs and moths captured per plant.Dictyna reticulataalso captured moreC. parthenicaper web as the density of the insect increased.Diguetia mojaveaGertsch (Diguetidae) reached densities of 170/ha, and mature females captured up to 221 moths during the summer.Coleophora parthenicacomprised a mean of 71% of the arthropods in the diet ofD. mojavea. Web site location on Russian thistles influenced the number of moths captured byD. mojavea, unlikeD. reticulata. The total numbers of prey captured byD. mojaveafemales, but not the numbers ofC. parthenicaalone captured, affected the number of egg sacs this spider produced. Field data suggested that these spiders were responding functionally and numerically to their prey densities augmented by the introduction ofC. parthenica.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1433

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Four manure treatments were utilized in an experimental caged layer house. One excluded soldier flies,Hermetia illucens(L.), and other dipterous larvae chemically; one was a check; one initially favored the soldier fly with a single addition of 2.5 cm water; and one allowed periodic development of house fly,Musca domesticaL., and lesser house fly,Fannia canicularis(L.), larvae by monthly removal of all manure and soldier fly larvae. Soldier fly larvae were demonstrated to cause significant reductions in house fly and lesser house fly populations and manure moisture. Manure accumulation was also reduced.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1439

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Selected central Iowa confields were sampled for corn rootworm larvae in 1978 and 1979, using core and cube sample units. Dispersion patterns were examined by field for each year with the variance-to-mean ratio. Spatial dispersion across fields was estimated from the 1979 sample counts by using s2/m and Taylor's power law. Most populations of corn rootworm larvae exhibited aggregated dispersion patterns. A discussion of possible reasons for aggregation is presented.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1443

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A generally accepted hypothesis is that lodgepole pines infected by dwarf mistletoe,Arceuthobium americanum, are less susceptible to mountain pine beetle,Dendroctonus ponderosae, because they have thinner phloem than uninfected trees. This Colorado study, based on 1,051 trees, indicates that there is little relationship between dwarf mistletoe intensity and phloem thickness. Therefore, we conclude that there is little correlation between dwarf mistletoe and mountain pine beetle activity, at least in Colorado.

ISSN:0046-225X    

DOI:10.1093/ee/12.5.1447

出版商:Oxford University Press    

年代:1983

数据来源: OUP