摘要:

An experiment was performed to investigate the effects of overcrowding in larvalAedes aegypti(L.) and to illustrate the compensatory responses to stress in highdensity conditions. Density levels tested were 40, 160, 280, 400, 520, 640, 960, and 1280 larvae per 80 ml of solution. Some of the parameters evaluated included rates of larval development, onset and rates of larval-pupal ecdysis, pupal weights, and larval survival.Rates of larval development were drastically reduced as density was increased. Pupal weights were also reduced by overcrowding. Results indicated entire shifts in patterns of larval-pupal ecdysis as the densities were increased. Relationships between sex, survival, and weight as a function of increasing density were revealed.A descriptive model dealing with density relationships is presented. It attempts to develop some uniformity of terminology, to provide better comparisons between studies of the many aspects of overcrowding.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.89

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Natural control of cotton insect pests was high throughout the season in tests in two 20-acre fields, ½ of each planted to solid cotton and the other to 50-ft strips of cotton, alfalfa, corn, oats, and soybeans.Heliothisspp. damaged 1.06% of the bolls in solidplanted cotton and 0.60% of the bolls in strip-planted cotton in 1 field, but there was no difference in the 2nd field. Damage was below the economic threshold in all plots. Predation of marked cabbage looper eggs was higher in strip-planted plots on the few dates when differences were significant. Average seasonal survival of marked eggs of cabbage looper,Trichoplusia ni(Hübner), for 72 hr was 35.4% less in the stripplanted plot in one field and 14.6% less in the strip-planted plot in the other field than in solid-planted plots. Populations of predators, primarilyOrius insidiosus(Say) and coccinellids, generally did not differ significantly between solid-planted and stripplanted plots.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.94

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

We fed herbicides to newly emerged workerApis melliferaL. in 60% sucrose syrup at concentrations of 0, 10, 100, and 1000 parts per million by weight.The following herbicides were relatively nontoxic to honey bees at all concentrations: 2,4-D, 2,4,5-T, silvex, 2,4-DB, dicamba, 2,3,6-TBA, chloramben, picloram, Ethrel®, 2-chloroethylphosphonic acid, EPTC, and dalapon. The following were extremely toxic at 100 and 1000 ppmw concentrations: paraquat, MAA, MSMA, DSMA, hexaflurate, and cacodylic acid. Two compounds, bromoxynil and endothall, were very toxic only at 1000 parts per million by weight (ppmw) concentration. Paraquat, MAA, and cacodylic acid were moderately toxic at 10 ppmw. No significant differences were noted in the toxicity of purified and commercially formulated herbicides.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.102

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Infectivity tests were conducted with several species ofBacillusand a fungus,Beauveria bassiana(Balsamo) Vuillemin, againstFannia canicularis(L.) andF. femoralis(Stein). Results of qualitative tests with bacteria were variable, and relatively few of the isolates were capable of producing moderate (40–60%) levels of mortality against larvae ofF. canicularis,which was the most susceptible of the host species. The most effective bacterium, causing 67% kill, was an unidentified variety ofB. thuringiensisBerliner. The NRRL A-6511 strain ofB. bassianaproduced higher levels of mortality against larvae of both species of host than the comparative bacteria, and caused up to 87% kill ofF. femoralislarvae after 3 successive passages through susceptible hosts.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.105

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Drainage ditches in central Washington that are fed by warm springs during the winter provided successful overwintering sites for many insects including both injurious and beneficial species. These insects and the host plants or habitat were identified. Six orders of insects were represented: Hemiptera (Heteroptera) (6 families), Hemiptera (Homoptera) (2 families), Diptera (15 families), Coleoptera (5 families), Hymenoptera (1 family), and Lepidoptera (2 families).

ISSN:1754-5692    

DOI:10.1093/ee/1.1.107

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Pounds of lint and lint quality from cotton grown within plantings of corn, soybeans, alfalfa, peanuts, or sorghum and a check (no crop planted on either side of the cotton) were determined.Heliothispopulations appeared to affect the lint yield but did not lower lint quality. The corn treatment containing the highest rate of square damage produced the longest and strongest fibers. Evidently other underlying treatment interactions resulted from the contiguous plantings.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.109

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

AdultSitophilus oryzae(L.) in wheat contaminated withSalmonella montevideoHormaeche&Peluffo (l07cells/g) were released at 1 end of a cylindrical metal chamber, 311.25×7.5 cm, filled with uncontaminated wheat.S. montevideo-positive wheat samples were recovered as far from the infestation point as 270 cm.S. montevideonumbers ranged from 0.92 to 1.60/g at 30 cm and from 0.0 to 0.004/g at 270 cm from the infestation point.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.111

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Zectran®(4-dimethylamino-3,5-xylyl methylcarbamate), was tested in aerosol form against the 5 larval stages ofPhryganidia californicaPackard, the adult of a primary parasite of the oakworm,Itoplectis behrensii(Cresson), and the adult of a hyperparasite,Dibrachys cavus(Walker). The descending order of tolerance at LD50was: 5th-, 4th-, 3rd-, 2nd-, and 1st-stage oakworm,I. behrensii,andD. cavus.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.115

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Experiments conducted during 1969 and 1970 near the upper Gulf Coast of Texas revealed that certain naturally occurring beneficial arthropods showed preference for certain cotton genotypes. Hirsute genotypes generally supported fewer beneficial arthropods than did early maturing, glabrous genotypes. Sampling of arthropods by a suction type (D-Vac®) sampler and whole-plant examination revealed that greater numbers of predators were usually found by whole-plant examination.

ISSN:1754-5692    

DOI:10.1093/ee/1.1.117

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Sterile codling moths,Laspeyresia pomonella(L.), released in a test orchard, were preyed on by yellow jackets,Vespulasp., at the release stations (White et al. 1969). In early summer 1970, yellow jackets were observed entering sex-attractant traps and removing live moths trapped by the sticky material (Stikem Special®); the yellow jackets were not trapped, because the material was usually not tenacious enough to hold them, though it did make rapid escape difficult and thus made it easier to catch the predator at work. Since this predation interfered with accurate counts of trap catches we needed a way to minimize it. The recently developed yellow jacket attractants and traps offered a particularly promising approach to the problem (Davis et al. 1969).

ISSN:1754-5692    

DOI:10.1093/ee/1.1.122

出版商:Oxford University Press    

年代:1972

数据来源: OUP