摘要:

Dimethoate-carbonyl-14C was applied to 3 types of soil (silty loam, loamy sand, and clay loam) contained in 10-inch-diameter cylinders sunk into the ground to give concentrations in the top one inch of 0.056 and 0.169 ppm in 2 separate experiments. Thereafter, samples were taken periodically, extracted, fractionated, and analyzed for residues of dimethoate and its metabolites. The same metabolites were found in all 3 soil types, although in varying quantities. Dimethoate was converted to its oxygen analogue and 2 unknown metabolites. Conversion to dimethoxon was faster in the more moist soils, and levels were generally greater. Dimethoate carboxylic acid was the only hydrolytic metabolite identified.No major difference in total recovery of applied radioactivity was noted between the 3 soil types. However, less radioactivity was recovered from all soils in the 2nd set of experiments where more moist soils were encountered. The ratios between radio-activity recovered in the chloroform and water fractions and the unextracted soil residues were relatively constant in all 3 soil types in both experiments. Distribution of radioactivity appeared to be influenced somewhat by soil type. Downward movement was slightly more extensive in the loamy sand soil. Increased soil moisture content also promoted downward movement in all 3 soil types and more rapid disappearance of the dimethoate-14C-equivalents.The quantity of unextracted radioactivity remaining in the soil was not significantly different between the 3 soil types. The nature of these soil residues, accounting for a high proportion of the applied dose, remains unknown. It was established that these materials are not neutral phosphorus esters.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.309

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Computer analysis of population data for mites, predominantlyTetranychus turkestaniUgarov&Nikolski, in 8 soybean fields during a 7-year period showed a significant correlation with both rainfall and maximum temperature. Rainfall accounted for 51.3% and average maximum temperature for 25.3% of the population variation. Climatological conditions during August appeared to be the most important. Correlation of rainfall totals with mite population for each of the months June through September indicated that August rainfall was most influential. Moreover, of the monthly average maximum temperatures, only those of August were significantly related to peaks of mite abundance. Measurement of soybean leaf temperatures for 2 weeks with electrical monitoring equipment showed thatT. turkestanilives under temperature conditions that can fluctuate widely within short periods.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.319

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Pruning the lower whorls of red pine branches and removing litter or scraping soil around the tree bole modifies the adultHylobius radicisBuchanan habitat and reduces weevil populations. However, conditions at the base of the tree become progressively more suitable for the weevils as new litter accumulates, and after 5 years they return to normal. Considering that it takes 3 or 4 years after that before weevil populations again are destructive, and that crown closure usually will occur in a well-stocked plantation by that time, pruning and litter removal can be expected to control the weevil for the life of the trees in these plantations. Further tests involving treatment around epicenters of infestations arc recommended.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.325

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Musca domesticaL. eggs were placed in fresh poultry manure under different temperatures (22° to 38°C) and relative humidity (19 to 80%) conditions to determine the hatchability of fly eggs, growth of larvae, production of pupae, and physical changes in the poultry manure. Moisture loss from the manure was recorded daily. The inoculation rates varied from 2 to 5 g of fly eggs per 4 kg of fresh poultry manure. Fly eggs and larvae were also placed under caged laying hens for the catabolism of the manure as it was voided.Optimum production of dry pupae was obtained with a combination of 3 g of fly eggs in 4 kg of fresh poultry manure at 27°C and relative humidity of 41%. Moisture in the manure was reduced from 78.5 to 55.0% by larval activity and aeration. When relative humidity was increased from 38 to 70%, the production of pupae at 34° to 38°C was significantly (P<0.01) increased. The combination of 2 g of fly eggs per 4 kg of fresh poultry manure produced significantly (P<0.01) heavier larvae than other combinations in the experiment.In comparison with fresh poultry manure, the manure residue after larval digestion had less odor, contained less moisture, and was granular in texture. The fly larvae developed well under the caged layers, reducing freshly voided manure to granular material within a few hours.A fungal development in digested manure was observed at 32°C when the relative humidity was increased to 80%.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.329

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Xylocoris flavipes(Reuter) were reared from egg to adult on diets of either gamma-irradiated (150 krad or 1.75 Mrad) or frozenPlodia interpunctella(Hübner) eggs. MoreX. flavipessurvived to the adult stage when thePlodiaeggs were provided in multiple feedings than when all of thePlodiaeggs were placed in the cage at the beginning of the test period. Diets of neither irradiated nor frozenP. interpunctellaeggs affected oviposition of the P1X. flavipes.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.335

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Abnormal changes in physical condition, behavior, and internal morphology were not observed when female rats were fed polyhedral inclusion bodies (PIB) of theHeliothisnuclcopolyhedrosis virus. Dams were fed 1 × 108PIB per kilogram of rat per day during the 5th to 14th day of gestation. Administration of PIB to pregnant dams did not affect number or weight of fetuses, resorption sites, or relationship between corpora lutea and implantation site. Teratologies, attributed to virus, were not encountered after detailed skeletal and visceral examinations of fetuses born of virus-fed, pregnant dams.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.337

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Paraffin-coated paper bags were used successfully to rearTrichoplusia ni(Hübner) for use as hosts of entomogenous viruses. They also reduced the cost of producing 100 pupae at least 10-fold and may make it easier to handle the pupae. Three new diets were acceptable, and one drastically reduced the cost of the rearing medium. The new techniques greatly reduced the cost of producing a nuclear polyhedrosis virus isolated fromAutographa californica(Speyer) using larvae ofT. niorSpodoptera exigua(Hübner).

ISSN:1754-5692    

DOI:10.1093/ee/2.3.339

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The impact of aphidophagous predators on populations ofMyzus persicae(Sulzer) on field-grown sugarbeets was investigated by periodically removing the predators present in control plots and adding selected predators (elytra glued to reduce dispersion) to the predator complex present in other plots. At the time when aphids were most numerous in the control plots, the plots treated with releases of geocorids + nabids or chrysopids only had significantly fewer (1/3) aphids. However, the fewest aphids were found in plots in which flightless coccinellids only had been released. In addition, these plots had substantially more coccinellid eggs and larvae, though the control plots had 4 times as many aphids per plant. The introduction of flightless coccinellids to promote a rapid increase in the population therefore appears practical. Also, coccinellids might be used as a biotic control agent on vegetable crops if a practical means of inhibiting flight could be developed.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.345

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Biotype B ofSchizaphis graminum(Rondani) indicated decreasing preference for ‘Deer’ and ‘Piper’ sorghum compared with ‘OK-8’ sorghum when the temperature was increased from 21.1 to 26.7 and then to 32.2°C. The survival of Biotype B after 4 days was reduced as the temperature increased. However, no more than 15% of the adult aphids survived when they were given a choice of only Deer and Piper, and those that did survive lived less than an average 3 days and did not reproduce at a temperature of 32.2°C. Conversely, temperature did not measurably influence the preference of Biotype C for the 3 selections of sorghum or the survival of Biotype C.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.351

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The frass of virgin femaleScolytus multistriatus(Marsham) evokes an excitant-turning reaction from walking male beetles in a laboratory olfactometer; frass from virgin males or mated beetles is relatively inactive. Walking virgin-female beetles are less responsive than males to virgin-female frass. Fragments of host material in the frass probably contribute to its stimulatory activity, especially in frass from males or mated beetles, but it is only partly responsible for the activity of virgin-female frass. We believe a pheromone contained in or on the fecal pellets is responsible for most of the activity of virgin-female frass. A pentane extract of virgin-female frass elicits the same response from male beetles as an equivalent amount of frass.

ISSN:1754-5692    

DOI:10.1093/ee/2.3.355

出版商:Oxford University Press    

年代:1973

数据来源: OUP