摘要:

Abstract:A population of the predatory miteAmblyseius aberras(Oud.) (Acarina, Phytoseiidae) was reared onVitis viniferavar. Perera plants in the absence of prey. During summer 1993 samples of leaves were collected on 29 different dates. The number of phytoseiids per leaf was positively correlated with the leaf area. The regression coefficient between the variables is significantly different from zero. Nevertheless, when population density is indicated as mites/leaf, the error is too small to affect analysis of data. During the season the growth rate of populations fluctuated between −0.15 and +0.57 mites/mite × day. The ovipositional rate assumed values between 0.005 and 0.17 eggs/female × day. The unit of measurement employed to represent the population density appeared to be relevant in some biological studies. The increase in the number of adults per cm2of leaf surface is correlated with a decrease in the ratios juvenile/adults and eggs/adults suggesting the existence of a self‐regulating mechanism of fecundity or survival inA. abe

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01559.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:The taxa of theAphis fabaegroups.str.are morphologically difficult to separate or inseparable. Vertical starch gel electrophoresis of members of theAphis fabaecomplexs.str. ands.l.was carried out to find specific isozymic characters. Analysis of the banding patterns of 17 genetic loci reveals that each of the 18 taxa investigated can be clearly identified. A biochemical key is presented.

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01560.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:Dendroctonus ponderosaeHopkins andIps pini(Say) are often found cohabitating inPinusspp. hosts, especially whenD. ponderosaeis in the endemic population phase. Although the adult stages are morphologically distinct, distinguishing between the species is difficult when only the larval stages are present. Using field collected specimens, several taxonomic characters of the larvae were identified which may be used to differentiate the two species. These results have application in studies of endemicD. ponderosaepopulations and competitive interactions betweenI. piniandD. ponderosaepopulations.

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01561.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:In southern Norway, the grassFestuca pratensissupported the emerging overwintered population of the agromyzidChromatomyia fusculauntil the appearance of the primary host plant, spring barley (Hordeum vulgare). Oats (Avena sativa), rye (Secale cereale) and the grass species,Dactylis glomerataandAlopecurus paratensiswere alternative secondary hosts.C. fusculafemales preferred the upper surface of the two youngest barley leaves for feeding and oviposition. This behaviour is advantageous for the farmers when applying an insecticide spray because the distribution of a contact insecticide on the upper two leaves is the easiest possibility for plant protection practice. The earliest (1st and 2nd) leaves of barley died quickly due to unusually warm and dry weather conditions. Consequently, larval survival on these leaves was low. Leaf numbers 3–5 supported the greatest population of successful larvae. Overwintered caged, gravid females ofC. fusculamade an average of 3–4 punctures and laid one egg per h

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01562.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:At fixed bait stations in a large institutional setting in Brazil, the temporal and spatial pattern of usage of the dominant species of ant was studied. The antCrematogastercf.magnifica, was found in 91 % of sampling points. These studies were conducted using the same points as a previous study of the then dominant ant,Monomorium pharaonis, which was found to have declined from 93% to 3% spatial point occupation. The frequency of point usage during this study was significantly different from the Poisson distribution for both species, indicating non‐random use of space.Crematogastercf.magnificawas significantly more spatially exclusive than had been documented forM. pharaonis, and the probability of points originally occupied byM. pharaonislater becoming occupied byC.cf.magnificawas in excess of 90%. Temporal bait exploitation patterns of the two species did not differ. These data demonstrate that structural ant communities can change over time without human intervention, although short‐term stability is characteristic of the urban dominant ants in subtropical Bra

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01563.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:With the aim of improving the dispatches ofEncarsia formosato the agriculturist's greenhouses increasing wasp efficiency, a new method of conditioning by changing the substrate of black pupae was performed.Three groups of parasites to which pupae were glued with or without sugar and compared to a control were studied. This new method of conditioning (pupae were removed from the host‐plant then glued on a cardboard plaquette) did not disturb the wasp's biological potentialities (daily fecundity, longevity) and adding sugar increased the daily fecundit

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01564.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:During 1989 and 1990 an inventory was made of beetles (Coleoptera), in the families Carabidae and Staphylinidae and spiders in carrot fields with a ley clipping mulch, a bark mulch, or lucerne (Medicago littoralis) as an intercrop. Two sites in central Sweden were included in the study. The most common carabid species at Uppsala wereBembidion quadrimaculatum, B. lampros, andTrechus quadristriatus. At Torslunda,B. lampros, Calathus melanocephalus, T. quadristriatus, Amara bifrons, andHarpalus rufipeswere the most abundant. The most abundant staphylinid genera at Uppsala wereAnotylus, Arpedium, Philonthus, andAleochara, while at TorslundaPhilonthus, Aleochara, andAnotyluswere the most abundant. Differences in occurrence, measured as trap catch or numbers per soil sample, between treatments and over the season are presented and discussed. Emphasis was placed on assessing the potential importance of these predators in suppressing carrot fly populations.

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01565.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:Populations of predatory and phytophagous mites were sampled weekly throughout the growing season in first‐ and second‐level integrated pest management (IPM) blocks in 12 commercial apple orchards in Massachusetts in 1993. In first‐level blocks, insecticides were used throughout the growing season. In second‐level blocks, no insecticides were sprayed after early June. Among the 12 orchards, 92% containedAmblyseius fallacis, 8% containedTyphlodromus pyriand 50% containedZetzellia malias predaceous species, while 100% containedPanonychus ulmiand 58% containedTetranychus urticaeas pest species. When averaged over the entire season, populations of predaceousA. fallacisandZ. maliand populations of pestP. ulmiwere numerically, but not statistically, greater in second‐level blocks than in first‐level blocks. The opposite was true forT. urticae. Initial time of appearance of each species was about the same in both types of blocks.Panonychus ulmipeaked in mid‐July, much earlier thanA. fallacis, the most frequently observed predaceous mite. Populations of the latter peaked in September at relatively low densities, too late in the growing season for this species to provide, by itself, timely biological control of pest mites. Winter mortality from cold temperatures and spring/summer mortality from the use of fungicides are suspected to be the principal agents responsible for the slow build‐up ofA. fallacis. Zetzellia maliwas present in early spring and increased slowly until reaching peak levels in autumn. Absence of pre‐bloom oil and other acaricide sprays in a small portion of each second‐level block did not facilitate build‐up of predaceous mites, but did result in rap

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01566.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract:The effects of four mycotoxins: aflatoxin B1(AFB2), aflatoxin B2(AFB2), aflatoxin G1(AFG1) and kojic acid (KA) onSpodoptera littoraliswere investigated. Second instar larvae were allowed to feed on an artificial diet containing various concentrations of either AFB1(0.5, 1, 2, 2.5, 3 and 3.5 ppm), AFB2(2, 3 and 4 ppm), AFG1(1, 2, 3 and 4 ppm), or KA (up to 100 ppm). Mortality, development time, fecundity, egg hatchability and adult longevity were determined for each treatment and compared to control values. AFB1(2–3.5 ppm) and AFG1(3 and 4 ppm) delayed the larval and pupal development and reduced the fecundity and hatchability. AFB2(4 ppm) reduced fecundity and hatchability but did not affect the development rate. The highest mortality was caused by AFB1(3.5 ppm). KA had no remarkable effect when given alone, even in concentrations up to 100 ppm. Yet it potentiated the toxicity and sterilizing activity of AFB1. A combination of AFB1(3.5 ppm) and KA (75 ppm) caused more than 92% sterility among male and female moths. Sterilized males exhibited good, though not fully equal, mating competitiveness against control males. The possibility of making use of the chemosterilizing activity of these mycotoxins is discusse

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01567.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Book reviewed in this article:Mamaev, B. M.; KrivosheinaN. P.:The Larvae of the Gall Midges (Diptera, Cecidomyiidae) Comparative morphology, biology, keys.Norton, G. A.; Mumford, J. D (Eds).:Decision Tools for Pest Management.Rosen, D.; Bennett, F. D.; Capinera, J. L. (eds):Pest Management in the Subtropics.Strouts, R. G.; Winter, T. G.;Diagnosis of Ill‐Health in Trees.Büning, J.The Insect Ovary. Ultrastructure, Previtellogenic Growth and Evolution.Rosen, D. (ed):Advances in the study ofAphytis(Hymenoptera: Aphelinida

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1996.tb01568.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY