摘要:

Edovum puttleriparasitoids reared from eggs ofLeptinotarsa texanaSchaeffer were larger than parasitoids produced from eggs ofL. decemlineata(Say), the Colorado potato beetle. Female parasitoids reared from eggs ofL. texanahad more mature oocytes in their ovaries than those reared from eggs ofL. decemlineatawhen dissected 1–7 d after their last exposure to hosts.L. texana-reared females, isolated from host eggs for 2 d to permit ovigenesis, produced significantly more offspring when they attacked a host egg mass than similarly treatedL. decemlineata-reared females. Despite this, lifetime fecundity, sex ratio, longevity, preoviposition period, and the duration of the egg-laying period were not significantly affected by host species when females were constantly exposed to hosts throughout their lifetimes. For parasitoids from both host species, 2 d was sufficient time for females to redevelop a full clutch of eggs after oviposition, and females maintained a full clutch of eggs for at least 5 d after their last exposure to host eggs.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1496

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Carabid predators of the wheat midge,Sitodiplosis mosellana(Géhin), in northeastern Saskatchewan were determined by immunoelectro-osmophoresis. Fourteen carabid species in the generaAgonum, Amara, Bembidion, andPterostichuswere identified as having fed on wheat midge larvae in the field. AdultBembidion quadrimaculatumL.,Bembidion obscurellumMotschulsky,Agonum placidumSay, andPterostichus corvusLeConte killed 9, 15, 43, and 48 midge larvae per beetle per day, respectively, in laboratory studies without alternative prey. Estimates of daily predation in the field for all carabid species combined ranged from<1 to 86 midge larvae/m2. Midge larvae were susceptible to predation during June after breaking larval diapause and during August when they were moving from the wheat (Triticum aestivumL.) heads to the soil where they overwinter in cocoons. Although carabid predation alone was not considered to have a major effect on reducing midge populations, it does contribute to overall mortality and plays a role in the natural control of this pest. Furthermore, total predation by carabids may have been underestimated because sampling may have captured mainly diurnally active species.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1503

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Nocturnal observation and collection of wolf spiders in cotton in the Delta region of Mississippi indicates that Coleoptera and Diptera are important prey.Lycosa antelucanaMontgomery represented 75.1% of the lycosid spiders observed and 89.6% of those with prey in cotton fields. Among prey taken were the cotton insect pestsHeliothis virescens(F.) andLygus lineolaris(Palisot de Beauvois).Pardosa milvina(Hentz) represented 24% of the total sample and 8.5% of those spiders observed with prey. A third lycosid species,Lycosa helluo(Hentz), captured the remaining 1.8% of the prey taken but was rarely observed (<1% of all lycosid spiders). Prey selection and temporal activity levels showed a distinct separation by species, and by developmental stage forL. antelucana. A larger proportion ofP. milvinathanL. antelucanawas observed on cotton plants (26% versus4%) in or near dens or retreats.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1512

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Fly pupae, primarily house fly,Musca domesticaL., and stable fly,Stomoxys calcitrans(L.) (Diptera: Muscidae), were collected from a poultry house in northern Indiana, and parasitoid wasps developing in them were allowed to emerge. Fly pupae density, relative species abundance, and size varied with collection date. Four species of parasitoid wasps were reared from the fly pupae:Spalangia endiusWalker,S. cameroniPerkins,S. nigroaeneaCurtis, andMuscidifurax raptorGirault&Sanders (Hymenoptera: Pteromalidae). There was some evidence of differential host species and size usage among the wasp species; but the differences were small, and there was considerable overlap. Percentage of parasitism was independent of host species forS. endiusandS. cameroni, butM. raptoremerged from house fly pupae more frequently than expected by chance and from stable fly pupae less frequently than expected.S. endiusemerged from larger hosts than didS. cameroni, despiteS. endiusbeing on average smaller thanS. cameroni. This is the first study to examine differences of host size among these parasitoid wasps.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1519

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The rate of preimaginal development ofHippodamia parenthesis(Say) was linearly related to temperatures from 14 to 30°C.H. parenthesisrequires 234.8 ± 10.0 degree days (±SE) above a lower developmental threshold (t) of 1O.8°C ± 1.1 to complete preimaginal development. Newly emerged adults from larvae reared at 18 and 22°C weighed significantly more ($\bar x$= 0.0095 and 0.0099 g, respectively) than adults reared at 14, 26, and 30°C ($\bar x$= 0.0085, 0.0087, and 0.0085 g, respectively). Total preimaginal development ofH. parenthesisreared at 22°C on pea aphids,Acyrthosiphon pisum(Harris) (Homoptera: Aphididae), averaged 22.0 d, significantly faster than the 23.4 d required on a diet of greenbugs,Shizaphis graminum(Rodani) (Homoptera: Aphididae). Immature survival was approximately 90% on both aphid diets. Adults reared onA. pisumwere significantly heavier ($\bar x$= 0.0098 g) and larger ($\bar x$= 3.15 mm wide by 5.31 mm long) than those reared on theS. graminumdiet ($\bar x$= 0.0068 g and 2.88 mm wide by 4.87 mm long).

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1523

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The tarnished plant bug,Lygus lineolaris(Palisot de Beauvois), is one of the two mirids that frequently are abundant on alfalfa in the northeastern United States. This insect also is a pest of numerous fruits and vegetables. We have established the European parasitePeristenus digoneutisLoan in northern New Jersey, and it has spread downwind into two additional counties, one of which is in New York State. Average total parasitism of tarnished plant bug nymphs in 1987–1988 was 36% in the first generation and 29% in the second, each about three times the normal rate of parasitism by native parasites.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1528

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

A four-year field survey of wheat, barley, and corn generated data on 10 species of fungal pathogens, including eight Entomophthorales and two Hyphomycetes recovered from 2,930 cadavers of aphids infesting grains grown under irrigation in southwestern Idaho. Seven species of cereal aphids, including the Russian wheat aphid,Diuraphis noxia(Mordvilko); the potato aphid,Macrosiphum euphorbiae(Thomas);Metopolophium dirhodum(Walker); the corn leaf aphid,Rhopalosiphum maidis(Fitch); the bird-cherry oat aphid,R. padi(L.); the greenbug,Schizaphis graminum(Rondani); and the English grain aphid,Sitobion avenae(F.), were recorded as hostsof one or more species of entomopathogenic fungi. The fungi were identified asPandora neoaphidis(Remaudière&Hennebert) Humber,Conidiobolus obscurus(Hall&Dunn) Remaudière&Keller,C. coronatus(Costantin),C. thromboidesDrechsler,Entomophthora chromaphidisBurger&Swain,Neozygites fresenii(Nowakowski) Remaudière&Keller,Zoophthora radicans(Brefeld) Batko,Z. occidentalis(Thaxter) Batko,Beauveria bassiana(Balsamo) Vuillemin, andVerticillium lecanii(Zimmermann) Viégas.P. neoaphidiswas the most prevalent species annually in populations ofM. dirhodumandD. noxiaand also frequently infected other hosts.Conidiobolusspp. were secondary toP. neoaphidisin occurrence, commonly infecting several aphid species.E. chromaphidis, N. fresenii, Z. radicans, andZ. occidentaliswere recovered only occasionally and on fewer aphid species. Two Hyphomycetes,B. bassianaandV. lecanii, infected aphids in the field at very low levels compared with the Entomophthorales. All species, exceptN. freseniiandZ. occidentalis, were isolated from their aphid hosts with agar media (SDAY or SEMA, or both) or liquid insect tissue culture medium.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1534

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Gypsy moth,Lymantria dispar(L.), populations in North America support 11 introduced parasitoids and recent imports are released annually. Multiparasitism effects on parasitization rates and parasitoid emergence success were assayed using the establishedCotesia melanoscelusRatzburg and recent importGlyptapanteles flavicoxisMarsh. For each species, oviposition into a parasitized host reduced emergence. The emergence rate forC. melanoscelusfell from 55.9 to 26.7%, andG. flavicoxisemergence was reduced from 22.8 to 14.2%.C. melanoscelusemerged significantly more often thanG. flavicoxisin 50% of the competitive interactions. This suggests thatC. melanoscelusout-competesC. flavicoxisfollowing multiparasitism. A second experiment showed that percent parasitism increased significantly as the proportion of searching adultC. melanoscelusincreased. We concludeC. flavicoxisshould be released for gypsy moth biological control only after the first generationC. melanoscelusoviposition period. ReleasingG. flavicoxisbeforeC. melanoscelusoviposition will not improve total gypsy moth parasitism and may reduce the effectiveness of the establishedC. melanoscelus.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1543

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The mortality ofAedes aegypti(L.) larvae treated withBacillus thuringiensisBerliner var.israelensiswas reduced by tannic acid at concentrations as low as 0.25 mM (425 mg/liter). The LC50's forB. thuringiensisvar.israelensistreatments were 45 ng/ml in deionized water and 233 ng/ml in 1.5 mM tannic acid. Compared with exposure of the test larvae to the bacteria immediately upon its addition to the tannic acid, soaking the bacteria in tannic acid for 48 h before the exposure of the test insects resulted in a significantly lower LC50value of 140 ng/ml and steeper log-probit regression slope. Although tannic acid lowers the gut pH ofA. aegyptilarvae, it is evident from the retention ofB. thuringiensisvar.israelensistoxicity after gut acidification in solutions of citric, hydrochloric, and phosphoric acid that this change did not mitigate the toxin's activity. Mortality of larvae exposed in leaf infusions or water collected from outdoor mosquito breeding sites was inversely correlated with the concentration of total phenolic compounds. The presence of tannins in mosquito breeding sites may require higher application rates forB. thuringiensisvar.israelensiswhen used by mosquito abatement personnel as a larvicide.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1547

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Japanese beetle,Popillia japonicaNewman, population densities and prevalence of the pathogensOvavesicula popilliaeAndreadis&Hanula andBacillus popilliaeDutky are reported from three locations in Connecticut over a 3-yr period. Populations decreased to very low levels (50%). Conversely, prevalence ofB. popilliaewas<30% throughout most of the study.Ovavesicula popilliaereduced fecundity 50% in heavily infected females in the laboratory. In addition, maximum prevalence ofO. popilliaein adults, collected in attractant-baited traps, peaked several weeks after peak adult emergence in the field, suggesting thatO. popilliaeslows development. However, no differences were detected in the weight or development of field-infected third instars reared in the laboratory. It is suggested that the effect ofO. popilliaeon its host is modified by environmental stress.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1552

出版商:Oxford University Press    

年代:1990

数据来源: OUP