摘要:

AbstractZ. suturaliswas introduced into Russia in 1978 to control against the common ragweed. Weed and insect population densities were estimated in 1988–1989 over 250 km2. Absolute (beetles per m2) density ofZ. suturaliswas almost linear with the ragweed density (wet weight per m2). Relative (beetles per kg of ragweed) density was independent of ragweed density. Last year's absolute density ofZ. suturalissignificantly influences current relative insect density, but its influence on the absolute insect density is overpowered by the influence of the current ragweed density. Obviously, just the plant and not the insect is the driving force in their interactions. The introduction results can be considered as establishment and moderate biological success, but not as control success. Host impact is very low because of low relative population density ofZ. suturalis.Local patches with highZ. suturalisdensity, which are usually located in field margins, do not play an important role in total population density determinations. Possibly, field nurseries, i.e. large uncultivated sites grown with ragweed, could be a promising method ofZ. suturalispropagatio

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractField experiments with habitat manipulations were conducted in Belgian crop fields in order to follow changes in abundances and species composition of the spider taxocoenosis. Spider densities increased spectacularly in plots with holes (up to 13 times) in the soil. Moreover, this density increase depends on the diameter of the holes, with diameter 9.5 and 5 cm being the most effective. Species composition in the plots with holes also changed considerably compared to control plots. Exclusively web building Linyphiidae (Bathyphantes gracilisandLepthyphantes tenuis) took far more advantage of the new possibilities offered by the habitat for web construction than non web‐building spiders.B. gracilispreferred holes with a diameter of 5 cm whereasL. tenuiswas more abundant in the D9.5 cm plots. It is concluded that this kind of relatively simple habitat manipulations are advantageous for population levels of certain beneficial polyphagous predators, such as spiders. This might offer possibilities for biological control of pest population

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractOn potted orange trees, infested with the citrus mealybugPlanococcus citri(Risso), in a greenhouse the predatorCryptolaemus montrouzieriMulsant was released in 3 predator: prey ratios (1:10, 9 beetles; 1:15, 6 beetles; and 1:30, 3 beetles).The effect ofC. montrouzierion populations of the citrus mealybug was also compared withNephus reunioniFurs (Col., Coccinellidae) and a chemical (methidathion) under controlled temperature (25–30°C) and relative humidity (55–70%), where mealybugs were maintained on pumpkins (Cucurbita moschata(Duch.)). Five adults beetles of each predator were released. Methidathion was applied at a concentration of 0.1%.In this study the predatorC. montrouzierieffectively reduced mealybug populations. The predator: prey ratio 1:15, 6 in most cases, resulted in lower mealybug populations. When compared withN. reunioni, C. montrouziericaused a significant reduction in mealybug populations. In most cases, significant differences were not detected betweenC. montrouzieriand methidathion. This indicates the effectiveness of the predatorC. montrouzieriin the control of the citrus mealybug populat

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractExperienced females of the aphid parasitoidEphedrus cerasicolaStary were released into a glasshouse compartment or into a cage, where they could choose between an equal number of cucumber and swede plants. The plants were uninfested in some experiments, or cucumbers were infested withAphis gossypiiGlover and swedes withMyzus persicae(Sulzer). The parasitoids were reared onM. persicaeon swedes. In all experiments, both with uninfested and infested plants, the females colonized the cucumber plants much more frequently than the swedes. Also mummy production was higher on the cucumber plants.In some additional cage experiments with a single infested plant (no choice),A. gossypiion cucumbers were more parasitized thanM. persicaeon swedes in three of four experiments.The results indicate that even ifE. cerasicolais reared onM. persicae/swedes, parasitoid females released into a cucumber glasshouse will probably readily spread to the cucumber plants and parasitizeA. gossypiithere.

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractPredatory arthropods on flowers and fruits of the grapevine as antagonists of the grape moth, Eupoecilia ambiguella (Hbn.) (Lep., Cochylidae)Over a period of 4 years, predatory arthropods on flowers and fruits of the grapevine have been caught in two vineyards with different undergrowth. The species that were caught and examined belong to the Araneae, Coleoptera, Heteroptera, Planipennia and Dermaptera species. Feeding experiments showed the feeding behaviour of some of these species concerning several developmental stages ofEupoecilia amliguella.Eggs of the grape moth were accepted by larvae ofChrysoperla carnea(Planipennia; Chrysopidae), by anthocorids (Heteroptera) andForficula auricularia(Dermaptera; Forficulidae). The latter species andAptus mirmicoides(Heteroptera; Nabidae) fed on well developed larvae.F. auriculariaalso fed on pupae ofE. ambiguella.First, second and third instar larvae were eaten by almost all predatory species examined. The artificial exposition of eggs in the two vineyards generally showed a low rate of predation after 12 h. On the area where the vegetation was often mulched,F. auriculariacaused a slightly enhanced loss of eggs (4.6%) compared to 1.8% on the area which had been superficially ploughed. Further predators of eggs are the larvae ofCh. carneaand anthocorids. These results do not support the claim that a herbal undergrowth which is rich in structure and species diversity generally promotes the abundance and effectiveness of beneficial arthropods in vineyards.ZusammenfassungWährend vier Jahren wurden auf zwei unterschiedlich bewirtschafteten Rebflächen Badens räuberische Arthropoden an Blüten und Früchten der Rebpflanze mittels Klopftrichter gefangen und bestimmt. Die untersuchten Arten stammen aus den Gruppen der Araneae, Coleoptera, Heteroptera, Planipennia und Dermaptera. In Fütterungsversuchen im Labor wurde das Fraβverhalten einiger dieser Arten gegenüber einzelnen Entwicklungsstadien vonEupoecilia ambiguella(Hbn.) getestet. Eier werden von Chrysopidenlarven, Blumenwanzen und Ohrwürmern gefressen.Forficula auriculariaundAptus mirmicoidesfraβen im Labor weit entwickelte Larven (L4‐L5);F. auriculariafraβ auch Puppen des Einbindigen Traubenwicklers. Junge Larven (L1‐3) wurden von nahezu allen getesteten Prädatorengruppen gefressen. Aufgrund der Biologie vonE. ambiguellaauf der Rebe kommen im wesentlichen nur die Ei‐ und Larvenräuber als wirksame Antagonisten der Art in Betracht. Das Ausbringen von Eiern auf die beiden Untersuchungsflächen zeigt nach 12 h einen generell sehr geringen Verlust. Auf der regelmäβig gemulchten Fläche B (Freiburg) sorgtF. auriculariafür einen leicht vermehrten Eifraβ gegenüber der unregelmäβig gepflügten Fläche A (Achkarren). Weitere Eiräuber sind die Larven vonChrysoperla carneaund Blumenwanzen.Aufgrund der vorliegenden Ergebnisse kann die Vermutung, daβ eine artenreiche, reich strukturierte Krautschicht in jedem Fall einen positiven Einfluβ auf die Nützlingsfauna und ihre Effektivität gegenüber phytophagen Organisme

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractBiological aspects ofTrichogramma pretiosumRiley, 1879, reared on artificial hostEphestia kuehniella(Zeller, 1879), were studied in incubators at 25°C (± 1°C); 60% (± 10%) RH and 14h photophase with the aim of obtaining basic information for the biological control ofHeliothis zea(Boddie, 1850) in corn crop. The average duration of the life cycle (egg‐adult) ofT. pretiosumwas similar when reared on natural and factitious host. Sexual ratio of the parasitoid was not affected by the natural or factitious host. The longevity ofT. pretiosumwas higher when reared on factitious host relating to natural host. The parasitism capacity of the two strains ofT. pretiosumonE. kuehniellaeggs was similar, with a high rate of parasitism in the first four days of the female's

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe mitesAmblyseius cucumerisandA. barkeriare used in biological control commercial program againstFrankliniella occidentalis.The diapause influence is essential to know the efficacy in climatic extreme conditions. The experiments were designed to verify the following: a) the effect of night temperatures on diapause induction; b) the effect of continuous darkness and low temperatures on diapause induction. In the first caseA cucumerisat 12°C temperature in ecotophase diapause incidence was 100%.A. barkeriwas not affected by 3 night temperatures. In the second case it could be seen that the test conditions did not induce diapause in either case

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractWhile Insegar and the sulfenylated carbamate juvenoid NKI‐43049 totally inhibited the egg production ofCarulaspis juniperi(Hom., Diaspididae), only approximately 1% of the Applaud or NKI‐35120 treated females laid eggs. Applaud and the sulfinylated carbamate derivative NKI‐35120 resulted a very low egg‐production (16% and 4% of the untreated control, respectively). Importantly, the tested fenoxycarb‐related compounds did not reduce the rate of parasitization caused byAphytis mytilaspidis(Hym., Aphelinidae), Applaud, however, had a moderately adverse effect on it.NKI‐35120 gave an excellent result at a concentration of 0.1 a.i.% onLepidosaphes beckii(Hom., Diaspididae). Insegar (0.1 a.i. %) and Applaud (0.05 a.i%) had good activity as well. Males were more sensitive than females for the treatments. NKI‐35120 and Insegar strongly reduced the egg production of the females. The treatments did not reduce significantly the rate of parasitization caused byAphytis lepidosaphes(Hym., Aphelinidae).NKI‐35120 and Insegar at a concentration of 0.025 a.i. % strongly affectedCeroplastes japonicus(Hom., Coccidae) development since none of the treated larvae could develop to female. Surprisingly, Applaud had only moderate affectivity

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe surface area of pre‐oviposition female scale insects was closely correlated with their dry and wet weight biomass, and was used as a convenient, indirect method of adult size assessment. Adult females at oviposition were on average bigger when in low density populations than those in high densities, an indication of intraspecific competition in the nymphal stage. Larger females were found to be more fecund (laid more eggs), and produced larger eggs, than smaller females. No significant differences were detected between fecundities of females which had fed as nymphs on different species of host tree, and the general adult size/fecundity relationship was of sigmoid form, indicative of a maximum reproductive potential, which was independent of host tree species. Comparisons with other Hemipteran species indicated the generalist nature ofP. regalis, adapted to widespread dispersal and large first instar losses from population

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractInvestigation of the temperature dependence of the eonymph‐pronymph transformation of the spruce webspinning sawfly Cephalcia abietis L. (Hym., Pamphiliidae)The larvae of the Spruce Webspinning Sawfly,Cephalcia abietis L., a pest infesting old spruce stands, show very different diapause behaviour. The different diapause in the eonymph stages causes a differing generation‐development duration (1–3 years) which renders difficult a prognosis of the hatching time. The present study was carried out in order to estimate the temperature dependency of the development of the eonymph‐pronymph transformation.ZusammenfassungDie Eonymphen‐Pronymphen Umwandlung der FichtengespinstblattwespeCephalcia abietisL. ist von der Temperatur abhängig. Erst ab Temperaturen von 13°C entwickeln sich Eonymphen unter Laborbedingungen zum Pronymphenstadium P4 weiter. Die optimale Entwicklungstemperatur liegt dabei zwischen 13°C und 22°C. Die Entwicklungsdauer dieses Umwandlungsprozesses wird wesentlich vom Zeitpunkt der Probeentnahme der Eonymphen im Freiland bestimmt. Eine Verpuppung der Pronymphen erfolgte erst nach einer Wintersimulation von mindestens 2 Monaten bei Temperaturen von — 1°C.Die Dauer des Überliegens bei der Fichtengespinstblattwespe wird nach den vorliegenden Untersuchungen durch den Temperatur

ISSN:0931-2048    

DOI:10.1111/j.1439-0418.1994.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY