摘要:

TheTrichoplusia ni(Hübner) sex pheromone,cis-7-dodecenyl acetate, was successfully incorporated into a solid plastic formulation which used a polyvinyl chloride plastisol as the basic matrix. Samples of the formulation were still attractive in the field 15 months after initial exposure.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.607

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Postlarval, early, and late juvenile stages of two species of penaeid shrimp,Penaeus aztecusIves andP. setiferus(L.), were tested for susceptibility to a nuclear polyhedrosis virus fromAutographa californica(Speyer). Shrimp were exposed to the virus by intramuscular inoculation of polyhedral protein-free virus and by feeding a diet containing virus polyhedra. Mortality attributable to viral infection did not occur dunng the 30-day test period, nor was there histological evidence of viral activity in shrimp hepatopancreas, gut, gill, striated muscle, ventral nerve, and segment nerve ganglia, or hypodermis.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.611

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Seven species of parasites were recovered from the puparia ofOscinella frit(L.) over a three-year period at Blacksburg, Virginia. They were:Spalangia drosophilaeAshmead (Pteromalidae),Hexacola hexatoma(Hartig) (Cynipidae),Bubekia fallaxGahan (Pteromalidae),Trichomalus statutus(Foerster) (pteromalidae),Callitula bicolor(Spinola) (Pteromalidae),Halticoptera aenea(Walker) (Pteromalidae), andHorismenus texanus(Girault) (Eulophidae).H. hexatomaandT. statutuswere new North American records:O. fritwas apparently a new host record forB. fallaxandH. texanus. The parasitism rate was generally low in each of the three generations ofO. frit. Either the parasites were not strongly oriented to the frit fly, or they were not well adapted to its environment, as none of the parasites were collected during each year of the study

ISSN:1754-5692    

DOI:10.1093/ee/2.4.615

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Larvae ofColias eurythemeBoisduval were reared under controlled environments to dctermine if seasonal color variation among adults is a response to the physical environment. A temperature effect was discovered, but it was not expressed until the adult stage of the generation subsequent to the treated generation. Temperatures of 26.6°C or 32.2°C produced the orange summer form, whereas 18.3°C produced the yellow winter form.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.619

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The hypothesis that parasitoid complexes develop in relation to plant succession is supported. Early colonizers have high fecundity and low competitive ability (r strategists) and later colonizers have low fecundity and high competitive ability (K strategists), and species diversity in the complex tends to increase as succession proceeds. These trends are evident also in a succession of increasing host densities from year to year and in decreasing host abundance within each host generation.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.623

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The feeding behavior ofPlodia interpunctella(Hübner) larvae was analyzed by using separate bioassays for stimuli eliciting short-range orientation responses and for stimuli involved in the maintenance of feeding. Nonpolar and polar extracts of wheat, corn (maize), and peanuts elicited both orientation and feeding responses in this polyphagous insect. When the role of carbohydrates in larval feeding behavior was studied, sucrose, fructose, glucose, maltose, fucose, and melibiose were powerful feeding stimulants. Also, tests with combinations of active and inactive sugars demonstrated that the total concentration of sugar directly influenced larval feeding. Thus, behaviorally inactive sugars could affect feeding behavior positively in a synergistic manner or by increasing the total concentration. Amino acids had little effect on feeding, even when used in combination with sucrose. Fatty acids and sterols had no effect by themselves, but when linoleic, oleic, and palmitic acids were used in combination with subthreshold levels of sucrose, a definite synergistic feeding effect occurred.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.627

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

In experimental apple orchard plots where a nonselective acaricide had been intensively applied, patterns of acaricide resistance, control failure, and spider mite outbreaks were documented by toxicological and field-sampling experiments. Contrasting examples of effective chemical control associated with initial application of the chemical and effective biological control interactions where the chemical was omitted also were characterized. In each treatment interactions of the spider mitesPanonychus ulmi(Koch) andTetranychus urticaeKoch with the phytoseiid mite predator,Amblyseius fallacisGarman, were studied in orchard tree or ground cover habitats and related to the development of an effective spider mite control program in Michigan fruit orchards.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.633

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

A three-year period of observations, collecting, and recording data on cocoons ofRothschildia aromaSchaus showed that parasitism is still high enough (63.1 percent) in areas free of insecticide applications to account for an undisturbed natural balance, with moth survival only 11.4 percent. In contrast, in areas where intense and continuous applications have been going on for the past ten years, the percentages have been practically reversed, parasitism reaching only 18.1 percent and moth survival 68.4 percent. Emphasis is made on this previously cryptic case of natural biological control and others that may have been or are being disrupted in EI Salvador and other countries in Central America. It is suggested that insecticides should be judiciously employed to conserve the beneficial insects.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.639

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

A continuing study of possible impact of extreme low-frequency electromagnetic fields (Sanguine effect) on soil arthropods was enlarged in summer 1972 to include 11 test plots and six control plots. This report analyzes mite and collembolan populations in plots that have been under investigation for at least two years. New plots, initially sampled in 1972, will be sampled again in summer 1973 to provide a time dimension, and they will be reported on subsequently. These annual censuses provide data on within-year and between-year population changes of soil microarthropods in various habitats. As in 1971, no significant differences occurred between each of four groups of arthropods in the Main test and control subplots. In 1972, statistically significant differences were observed among the microfauna in some of the other plots that were absent in 1971. In some cases the density of a group was greater in the control plot; in other cases, the density was greater in the test plot. A general feature of the population curves of all groups in test and control plots is the midsummer peak with return to spring levels by mid-September. Within-plot peak amplitude varies from one year to the next, and both chronicity and amplitude appear to be independent of a Sanguine effect and are attributable to random, natural causes. Consequently, variations in absolute numbers are less reliable than intergroup ratios and annual population curves as evidence for significant population shifts. Four-year ratios of Cryptostigmata: Collembola in Hazleton plots disclose that populations of these two most numerous groups of decomposers are remarkably parallel in test and control plots. Numerous other examples are given of between-year populational changes which, because they occur in test and control plots alike, rule out a Sanguine effect.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.643

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

When adult malePectinophora gossypiella(Saunders) less than 24 hours old were irradiated with 2.5, 5.0, 7.5, 10.0, or 12.5 krad of gamma irradiation and caged with virgin untreated females, the ability of the treated males to mate and transfer eupyrene sperm appeared to be unaffected, but fertility was reduced. Survival of the immature stages of the F1progeny was significantly decreased at all doses to P1males, and the sex ratio of the F1generation was significantly skewed in favor of males except at the lowest dose. When adult F1males and females were outcrossed to untreated mates or crossed with unrelated F1adults, the F1males mated but often failed to transfer normal quantities of eupyrene sperm; this effect was related to the dose received by the P1male. Thus, fertility of the F1males and females was significantly less than that of the controls, at all doses to the P1male above 2.5 krad. At doses of 7.5 krad and above, the F1males mated more often than the controls. In control programs that produced partial sterility in irradiated males, thus introducing conditional lethal mutations into native population, doses below 7.5 krad should be considered, because at higher doses lack of sperm transfer and lower fertility of the F1males would not favor the incorporation of the released genotype into the native population.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.653

出版商:Oxford University Press    

年代:1973

数据来源: OUP