摘要:

Development and survival of field-collectedHypochlora alba(Dodge) (Orthoptera: Acrididae) were normal on its host plant,Artemisia IudovicianaNutt. (Asteraceae), on leaves with sparse or medium pubescence but were reduced or terminated on leaves with dense pubescence. Without pubescence. development and survival were initially retarded. Field-collectedMelanoplus bivittatus(Say) andMelanoplus sanguinipes(F.) attained only 3rd instar on normal leaves. Without pubescence, a few generally moribundM. bivittatusreached adulthood; noM. sanguinipesmore than 4th instar.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.777

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Mortality ofHeliothis zea(Boddie) andHeliothis virescens(Fabricius) larvae after treatment withBacillus thuringiensis(Berliner) was determined in bioassays with treated cotton leaves. Larval mortality depended upon dosage, species, and size of larvae tested.Bacillus thuringiensiswas also found to reduce the weight of larvae surviving treatment (7 days) when compared with the untreated check. Bioassays failed to detect differences between two commercialB. thuringiensisformulations, Dipel (Abbott Laboratories, North Chicago, III.) and Thuricide (Sandoz, Inc., San Diego, Calif.). Effectiveness ofB. thuringiensiswas usually increased when treatments were made in combination with the commercial spray adjuvants, Coax (Trader Oil Mill Co., Ft. Worth, Tex.) and Gustol (Sandoz, Inc., San Diego, Calif.). Combinations ofB. thuringiensisand nuclear polyhedrosis viruses ofH. zeaandAutographa californica(Speyer) usually resulted in mortality levels greater than that ofB. thuringiensisalone but not greater than that of either virus alone. Advantages for combiningB. thuringiensiswith the nuclear polyhedrosis virus ofH. zeaorA. californicawere not detected in this study.1

ISSN:1754-5692    

DOI:10.1093/ee/11.4.783

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Five formulations ofBacillus thuringiensisvar.israelensis(serotype H-14) were evaluated against larvae of eight mosquito species. In the laboratory, most species essentially showed similar levels of susceptibility to a given formulation. The range of activity of the various formulations against a given species was on the order of two- to sixfold. In general, the LC90against fourth-stage larvae ranged from 0.13 to 0.45 ppm, for high-potency formulations, to 0.45 to 0.9 ppm for low-potency formulations. Second instars were two to six times more susceptible than 4th instars to the various formulations. Under field conditions, the various formulations showed different activity levels. In clear, shallow, and nonvegetated water, the high-potency formulations yielded excellent control of larvae at rates as low as 112 to 280 g/ha. Formulations with low potency were needed at rates as high as 280 to 560 g/ha to yield effective control of larvae in these biotypes. None of the commercial formulations at mosquitocidal and fivefold these rates induced short-term effects on the dominant nontarget fauna. Mayfly and dragonfly naiads, diving beetle larvae and adults, and ostracods were not affected at the rates of 0.56 to 2.24 kg/ha of the formulations employed.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.788

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

All of the leaves and the fruit from a total of 360 Cotton plants were examined for tetranychid mites over the 1976 growing season in experimental plots near Five Points, Calif. Records were kept of the number of eggs, immatures, and adults by nodal position and leaf type (or fruit) on each plant. The within-plant mite distributions revealed the following: (i) up to 25% of per plant mite populations colonized fruit bracts in midseason. However, less than 10% were normally found on fruit in early and late season; (ii) the proportion of the per-plant populations found on primary branch leaves was highly variable throughout the season, ranging from 0 to 100% in June and July and from around 25 to 75% in August; (iii) by focusing on the subpopulations colonizing the single primary branch leaves at individual mainstem nodes, it was found that females appeared to usually found colonies about midway up the plant; (iv) by late season, the majority of the subpopulations on the primary branch leaves at all nodal levels consisted of immature and adult mites, with almost no eggs on any of the leaves.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.796

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The impact of mosquito control recirculation ditches on Pacific Coast salt marsh ecology is largely unknown. This study compares the arthropod community structure near mosquito control ditches and a natural channel with that in the open marsh. Biweekly D-Vac samples in two San Francisco Bay marshes were taken November 1977 to 1978. In the pickleweed-dominated Petaluma Marsh, arthropod diversity in the dry season was higher near both the ditches and natural channel than in the open marsh. This corresponded to gradients of increasing water table height, groundwater salinity, and soil surface salinity. Conversely, in the wet season, diversity was lower near the two newest ditches than the open marsh, whereas diversity near the natural channel and the oldest ditch was similar to the open marsh. These differences are best explained by higher plant structural diversity near the natural channel which offers refuge from high winter tides. There was no significant difference in arthropod biomass near a ditch and in the open marsh. In the floristically diverse Suisun Marsh, there were no significant differences between ditched, natural channel, and open marsh arthropod diversities during either season. Results suggest an eventual convergence of arthropod community structure along ditches and natural channels.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.801

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The natural history of the parasitoids attackingAsteromyia carbonifera(O.S.) (Diptera: Cecidomyiidae) was studied. Five species were recorded:Platygaster solidaginis(Ashmed)(Hymenoptera: Platygasteridae);Torymus capite(Hüber)(Hymenoptera: Torymidae);Tetrastichus fumipennis(Girault);Tetrastichus tesserus(Burkes) (Hymenoptera: Eulophidae); and a eulophid of an unknown genus3. Three aspects of parasitoid ecology were examined: (1) their trophic relationships with the host and with one another; (2) their temporal sequence of attack; and (3) foraging response to the number of host larvae per gall. All species fed parasitically on the host, butT. capitealso feeds on previously parasitized hosts, on gall tissue, and as an adult drinks host haemolymph through a feeding tube.P. solidaginisattacks in the host's egg stage,T. fumipennisduring early gall development, andT. capiteandT. tesseruslater in development. Time of attack may be related to the ability of the parasitoids to penetrate gall tissue. A negative correlation was found between the number of hosts per gall and the percent parasitism inflicted byT. tesserus; no correlation was found in the cases ofT. fumipennisandT. capite.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.809

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Adult coccidophagous beetles,Rodolia cardinalisMuls. (Coleoptera: Coccinellidae), were reared on artificial diets. On lyophilized drone honey bee brood fortified with sucrose (DPS), female beetles survived longer (76.3 days) but laid fewer eggs (106.3) than control fed on livingIcerya purchasiMaskell scales (38.6 days and 489.2, respectively). On sucrose or a chemically defined diet they also survived longer but laid only about 20 eggs. The beetles produced more eggs whenI. purchasiwas combined with DPS or other artificial diets. Beetles fedI. purchasi1 day and DPS for two days oviposited 80% of the control level and beetles fedI. purchasi1 day and sucrose for 2 days oviposited 120% of the control level. Controls were fed onlyI. purchasi. This technique makes it possible to breed vedalia beetles under controlled conditions with a small number of natural prey scales.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.816

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Sulfathiazole, one of four sulfonamide drugs separated on a PXS 1025 PAC chromatographic column, was measured in samples of honey collected from colonies fed medicated sugar solutions. Honey taken from locations in the brood nest contained up to 4 ppm of sulfathiazole, whereas honey in added supers contained less than 0.2 ppm, the detection limit for the method.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.820

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Gynoparous, oviparous, and apterous green peach aphids,Myzus persicae(Sulzer), preferred radish,Raphanus sativusL., to the winter host, peach,Prunus persicaBatsch, in laboratory tests of settling behavior. Preference for radish was strongest in the apterae and weakest in the oviparae; however, in all cases the degree of preference was significant (P= 0.01). Gynoparae discriminated between peach and a nonhost species,Acer saccharinumL., although few aphids settled on either species during the test. Although feeding preferences may allow green peach aphid to discriminate between tree species, these results indicate that such preferences cannot explain the movement of migrants from secondary to primary hosts. Apterae discriminated readily between various secondary hosts. Marked differences in preference occurred even between species which have been shown to be highly suitable for reproduction. Rates of settling were higher on preferred hosts than nonpreferred hosts, indicating that the rate of interplant movement may be significantly greater on nonpreferred hosts.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.824

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Vertical distribution of spring dispersal activity within a stand canopy was determined by trap catch at 2-day intervals. The 10-m traps consistently caught more larvae than the 6-, 2-, and 0.5-m traps except during inclement weather. A partial explanation is the filtering effect of adjacent tree crowns on the dispersing larvae before they reach the lower traps. Most larvae caught by the 2- and O.5-m traps would be lost to the system. Dispersal of 3rd and 4th instars represented about 38% of the total trap catch, indicating greater off-tree dispersal than normally expected for these instars. An explanation based on asynchrony of host and budworm is suggested.

ISSN:1754-5692    

DOI:10.1093/ee/11.4.828

出版商:Oxford University Press    

年代:1982

数据来源: OUP