摘要:

Honeydew produced by the brown soft scale,Coccus hesperidumL., is a search stimulant for the parasitoidMicroterys flavus(Howard). Solvent extraction and paper chromatography were used to characterize and identify the active chemicals. The results indicate that fructose and sucrose and an unidentified ninhydrin component are active.The role of the honeydew in stimulatingparasitoidsearching and retention in host infested areas is discussed. Although honeydew was a major factor in host searching, shape also played a role in the host selection process.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.874

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The life history, habits, and prey preferences of the orb weaving spider,Tetragnatha laboriosaHentz, were studied in central Illinois where this species is the most abundant foliage spider in soybean fields, comprising more than 60% of the total spider population during the summer months. Field and laboratory observations established that development from the egg to adult stage requires ca. 12 mo. There are 9 instars including the adult stage. Adults occur in undisturbed grassy areas adjacent to soybean fields. Males first appear in late May followed by females a week later. Males live an avg of 16 days while females live an avg of 21 days. Mating, oviposition and egg development are described. Three distinct courtship patterns were observed forT. laboriosa. Mating occurs in early June and the 1st instar spiderlings begin emerging 11 days later. By mid-June 2nd-instar spiderlings are dispersing into the fields by ballooning.Early instars spin their webs on the lower two-thirds of the soybean plant in the axillary region of the leaf or between the small trifoliolate leaves. As the spiderlings grow they construct webs progressively higher and toward the periphery of the plant. Web spinning reaches its peak from ca. ½ h before sunset until sunset. A new web is usually constructed each day near the old web site in 20–30 min. Growth continues throughout the summer months and the 5th and 6th instars are reached by early Oct. when growth slows down or ceases. Most individuals overwinter in the 5th or 6th instars. Growth resumes in the spring and continues until the adult stage is reached in late Mayor early June.Feeding in this species reaches its highest level from sunset to just after dark during the summer months. Prey consist predominantly of insects of the families Cicadellidae (Homoptera), Miridae (Hemiptera), Chironomidae and Drosophilidae (Diptera), and feeding is restricted to insects trapped in the web.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.879

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Eight accessions of bermudagrass,Cynodon dactylon(L.) Pers., were evaluated for susceptibility to the bermudagrass mite,Eriophyes cynodoniensisSayed, under hydroponic culture in the greenhouse. Mite populations failed to become established on FB-119 during an 8-mo experiment. ‘Tifway’ and FB-141 became infested in only 44 and 50%, respectively, of the plants. No difference in infestation level resulted from varied N levels available to the plants. FB-119 has been observed and sampled in field plots adjacent to bermudagrass mite infestations, for ca. 6 yr with no infestation of this eriophyid mite. Susceptible cultivars, however, had continual infestations. The hydroponic culture technique was satisfactory for holding and screening the accessions for resistance.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.885

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The influence of temperature on developmental rate ofZelus renardiiwas studied in the laboratory. Studies were made at constant temperatures of 20°, 25°, 30°, and 35°C. The highest survival rate of the nymphs and the greatest longevity of adultZ. renardiioccurred at 25° C. The developmental period of each instar decreased with each increase in temperature.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.889

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Light intensity is a critical variable of the dye-sensitized photooxidation reaction, and the rate of house fly,Musca domestica, mortality is observed to increase with increasing light intensity. Relative toxicities were described for 6 xanthene dyes (rose bengal, octabromofluorescein, erythrosin B, phloxin B, eosin Y, and tetrachlorofluorescein) as a function of the 3rd-order rate constant of photooxidation, k3, obtained for each dye and determined from the LT50, tissue dye levels, and light intensity measurements. The ranking of these 6 xanthenes by their respective k3values is almost identical to the ranking of these same dyes by their k2, or second-order rate constant. The number of accumulated photons needed to produce 50% mortality was observed to decrease with an increase in light intensity.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.891

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Traps which captured click beetles as they emerged from the sod showedMelanotus decumanus(Erichson) to be the predominant species (162,080/ha in 1974) in the Appalachian Mountains, whileConoderus lividus(DeGeer) predominated (109,000/ha in 1975) in the Piedmont Plateau.Melanotus verberans(LeConte) andLimonius griseus(Beauvois) were also consistently captured. Wireworm feeding damage in grasslands could not be detected, but many wireworm species were economic pests of several agronomic crops.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.895

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

A chemical that stimulates oviposition by females ofEucelatoriasp. was extracted from cuticles of the larvae ofHeliothis virescens(F.) by chloroform-methanol (2:1), and was found to be active when reapplied to agar-filled extracted cuticles. Although ovipositional activity was present in both phases after the chloroform-methanol extracts were partitioned with water, most was in the nonaqueous phase. Concentration effects were important: natural levels of the reapplied stimulant gave the greatest ovipositional activity. Hemolymph applied to the cuticle inhibited oviposition and storage ofH. virescenslarvae at 15°C for 2 days greatly reduced the levels of ovipositional stimulant present on the cuticles.Eucelatoriafemales parasitized round but not flattened cuticles; host movement was not essential for oviposition.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.897

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Experiments were conducted in 1972–73 to study interrelationships between red imported fire ants,Solenopsis invictaBuren, and associated arthropods in pastures. The fire ant populations were suppressed with one application of mixrex bait each year. Frequencies of 30 arthropod taxa caught in pitfall traps and 5 insect taxa in dung samples were determined in mirex treated and untreated pastures. The population ofVacusus vicinus(LaFerte) (Anthicidae),Lycosa riparia-helluocomplex (Lycosidae) and pupae of hom flies,Haemotobia irritans(L.) (Diptera) were significantly higher (P<0.05) and Aphodiinae (Scarabaeidae),S. invictaandNylanderiaspp. (Formicidae) were significantly lower (P<0.05) in treated compared to untreated pastrues in 1972. In 1973 significantly greater numbers ofTrachelas deceptus(Banks) (Clubionidae), Carabidae, andH. irritanspupae were found in treated pastures. Significantly lower numbers ofSchizoeoza avida(Walkenaer) (Lycosidae),Xyleborinus saxeseni(Ratzeburg) (Scolytidae), Staphylinidae, Aphodiinae, (Scarabaeidae), Gryllidae,S. invictaandNylanderiaspp. were detected in the treated pastures (P<0.05).Examinations showed thatS. invictapreyed upon immature forms ofH. irritansin cattle dung pats. Where predation of immature horn flies was intense, associated rove beetles also were apparently preyed upon.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.901

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

One hundred nine species of phytophagous insects from 6 orders and 33 families fed or reproduced on the thistle,Carduus macrocephalusDesfontaines, a biennial or winter annual in Italy. About ½ the species attacking this plant were polyphagous. Fifteen species were restricted to the tribe Cynareae; and another 16 species were restricted to the subtribe Carduniae. Only 42 of the 109 species were endophagous. Among species host specific enough to permit consideration as biological control agents, onlyPsylliodes chalcomera(Illiger),Ceuthorrhynchidius horridus(Panzer), andRhinocyllus conicus(Frolich) have been studied;Ceutorhynchus trimaculatus(F) andCheilosia grossa(Fallen) are being studied; andUrophora stolstitialis(L.),U. sibynataRondani,Cheilosia cynocephalaLoew,Epiblema pflugianaHaworth, andAgromyzan.sp. nearreptansshould be studied.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.904

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Studies of loblolly pine during 1972–74 demonstrated that there was significantly less height increment, numbers of available tips, and total tip growth resulting from continual attack from Nantucket pine tip moth. Annual percent damage (total dieback/total growth per tree) was 19.6, 25.8, and 17.7%, respectively, for each of the 3 yr. Percent infested tips overestimated percent damage and does not vary in the same manner as percent infested tips.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.910

出版商:Oxford University Press    

年代:1978

数据来源: OUP