摘要:

A sequential-sampling plan was developed for making treatment decisions forTrichoplusia ni(Hübner) on cabbage in central Florida. Intensive and scquential samples were taken weekly from randomized replicated plots at different intervals to allow estimation from different population levels. Agreement between intensive and sequential sampling was found in 171 of 178 data sets. A savings of 4 insecticide applications resulted from treatment decisions using the sequential model in a commercial, 2.43– hectare field of cabbage during high looper infestations.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.901

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Three slow-release preparations of grandlure, the synthetic pheromone ofAntonomus grandisBoheman, were evaluated in the field at 3 locations in Texas and Mississippi, to compare their relative attractancy to adult weevils during the period of fall dispersal. All 3 formulations, at both low (3 mg per unit) and high (12 mg per unit) doses of grandlure, were more attractive throughout 14-day test periods than were caged males or fast-release formulations that were both replaced at 2-day intervals. The combined results of field tests at all locations, and of laboratory analyses of weathered samples, suggested that a physical-barrier system might yield more consistent results, but no single formulation was decidedly superior to the others. Tests demonstrated also that slow-release formulations could be used effectively in the different types of boll weevil traps currently in use.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.905

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Catches of bollworms,Heliothis zea(Boddie), and tobacco budwormsH. virescens(F.), in saucer-type pheromone traps and in 15-watt blacklight traps at 3 locations in cultivated cotton in the lower Rio Grande Valley and in 3 locations in uncultivated brushy areas were compared to determine which was the more effective in detecting low populations. The pheromone traps detected low levels ofH. virescensbctter than light traps, but the blacklight traps detectcd populations ofH. zeabetter than the pheromone traps. Relatively high populations of either species seemed to reduce the overall performance of the pheromone trap, probably because of increased competition for males by native females. MostH. virescenswere captured in cultivated areas by either trap type. Light traps caught moreH. zeain uncultivated areas than did pheromone traps.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.911

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

In greenhouse and field studies, liquid and granular combinations of disulfoton and cycloate at 1 and 4 lb AI/acre, respectively, were incorporated in soil before planting sugarbeets. In the greenhouse, the stand of sugarbeets and dry weights of seedlings were reduced most by the liquid-herbicide granular-insecticide treatment. In the field study, the disulfoton-cycloate mixtures produced necrotic cotyledons and leaves, as well as extensive stunting. The liquid-herbicide liquid-insecticide mixture was the most damaging combination, followed by the granular-herbicide liquid-insecticide, liquid-herbicide granular-insecticide, and the granular-herbicide granular-insecticide treatments. Mixing the herbicide with the insecticide did not reduce the ability of the herbicide to control weeds effectively: injured sugarbeet seedlings recovered fully after 3 months of growth and there was no significant difference between root weights, percent sucrose, or sucrose production for the various treatments at harvest.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.915

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The combination of a reduced rate (from 1 lb to 0.5 lb) and fewer applications (5) of insecticide, for control ofHeliothis zea(Boddie) to a resistant sweet corn hybrid, (471–U6X81–1) resulted in significantly fewer damaged ears than with 7 applications of insecticide to a susceptible hybrid. Also, one application of insecticide at the reduced rate to the resistant hybrid gave control equal to that achieved with 7 applications to the susceptible hybrid. Thus, a program of insect control involving this resistant variety plus less insecticide would be more economical and would reduce pollution of the environment.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.919

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The host-finding activity ofLeiophron pseudopallipesLoan centers on floweringErigeronplants. Several plant-related variables that could affect host-finding success were studied. These included plant height, plant density, host density per plant, the presence of unattractive plants in the habitat, and the background color ofLygus lineolaris(Palisot de Beauvois) feeding sites on the plants. Although the highest percentage ofLygusnymphs parasitized was associated with the same plant-height class in all fields sampled, plant height is probably unimportant in the host-finding behavior ofL. pselldopallipes. Plant height is influenced by plant density, and evidence suggests thatL. pselldopallipesis differentially attracted to areas of the habitat with the greatest density ofErigeronplants.Lygusdensities are also higher where theErigerondensities are greatest, which sometimes gives rise to a correlation between parasitization andLyglisdensity.The presence of other herbs inErigeronpatches appears to lower the attractiveness of these stands toL. pseudopallipes. It is suggested that these plants may disrupt the olfactory cues used in host finding. The contrasting background color of theErigeronplants also influenced parasitization. ReddishL. lineolarisnymphs, which tend to contrast with green plant background, were 3 times as apt to be parasitized as the green nymphs.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.921

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

A study was conducted on the intratree dispersal ofCurculio carvae(Horn) in 4 pecan trees about 35 ft high. For 4 consecutive days in August, 66 pecan weevils were released at each of 3 height levels (top = 35 ft, middle = 20 ft, and lowest limbs = 5 ft) of one quadrant of the 4 trees, starting with the north side of the tree and rotating clockwise each successive day. Weevils totaling 3168 were marked and released in this experiment: 198 weevils per quadrant (66 weevils for each of the 3 height levels) and 792 weevils per tree on each of the 4 trees. On the fifth day after the weevils were released in the first quadrant, recapture of the weevils was accomplished by jarring the lower half of the tree and by using a modified crane and platform for the upper portion of the tree.Approximately 10% of the marked weevils were recovered by the mechanical recapture method, and 7% by using insecticide after mechanically harvesting the weevils from the trees. Our study indicated that weevils move considerably in a tree—from the top of the tree to the lowest limbs and from the lower heights to the upper portion of the tree, as well as around the tree. The significance of dispersal of the pecan weevil to possible control measures is discussed.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.927

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

AdultOryzaephillls surinamensis(L.) showed a strong hygronegative response to a choice between relative humidity alternatives of 60 and 100% and a moderate hygropositive response to a choice between 10 and 50%, but they were indifferent, or nearly so, to alternatives of 0 and 40%RH. In uniform humidities they showed a strong photonegative response and a strong preference for a high level of contact stimulation.When the photonegative and hygronegative responses were opposed, they canceled one another. When the tactile and hygronegative responses were opposed, the hygronegative response was suppressed and the tactile response was weakened. The light and tactile responses both suppressed the hygropositive response without being weakened. When 2 responses (light and humidity or tactile and humidity) operated in the same direction, the resulting compound response was typically no stronger than the strongest of its components. The light and tactile responses were not influenced by humidity alternatives of 0 and 40%RH.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.931

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Ethylene oxide fumigation reduced the content of histidine in stored dandelion pollen and of histidine and methionine in rape pollen.Apis melliferaL. colonies reared fewer larvae than control colonies when fed fumigated pollen. Ethylene oxide fumigation also destroyed some unidentified lipid attractants contained in pollen. Foraging bees collected less, and bees in the hive consumed less fumigated pollen than unfumigated pollen.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.937

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Parasitism and predation of eggs ofManduca sexta(L.) (Lepidoptera:Sphingidae) on tobacco; jimson weed,Datura stramoniumL.; tomato; and potato were investigated in central Kentucky throughout the season in 1970 and 1971. Heavy parasitism of eggs was found on jimson weed, tomato, and potato. In both years, parasitism of the eggs was greater on jimson weed than on tomato, but the seasonal peak on both plants occurred between mid-August and early September. Parasitism of eggs on potato was less than on jimson weed and tomato, and no egg parasitism occurred on any of the varieties of tobacco: ‘By 21,’ ‘Low alkaloid By 21,’ ‘Ky 12’ and ‘Ky 170.’ However, parasitized eggs were found on one foreign tobacco variety, ‘TI-1298,’ being grown for other tests. The eggs were parasitized by two hymenopterous species:Telenomus sphingis(Ashmead) andTrichogramma minutumRiley;T. sphingiswas the predominant species. Parasitism byT. minutumwas greater in eggs on tomato than on jimson weed.Predation ofM. sextaeggs was low, and the extent of predation varied with the host plants but increased in late-season on all hosts. The stilt bug,Jalysus spinosus(Say), was the major predator.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.939

出版商:Oxford University Press    

年代:1973

数据来源: OUP