摘要:

Maturation and hullsplit of Nonpareil almonds and concomitant susceptibility to infestation by navel orangeworm occurred earlier in areas of the tree subject to greater radiant exposure, i.e., outside before inside, south half before north half, and earlier with increasing height. Infestation of almonds by the navel orangeworm was significantly higher with increasing height and on the outside vs. the inside of the tree canopy (P<0.05). In trees stressed by mite infestations and irregular irrigation, hullsplit developed sooner and nut maturation extended over a longer period of time.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.673

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Carbaryl bioassays were conducted in the field with natural populations of three species of grassbugs (Hemiptera: Miridae). Insecticide-coated vials and a portable incubator were used. Grassbug populations differed in carbaryl LC50with respect. to species, sex, date, and location. Pretreatment of the insects with piperonyl butoxide inhibited the monooxygenase (mixed-function oxidase) system, depriving the insects of a key defense against carbaryl. The differences in synergized and unsynergized LC50values were used to calculate an estimated “percent dependency upon monooxygenase detoxification” for the grassbugs, Plotting these values against carbaryl LC50illustrated hypothetical population differences in tolerance and detoxification potential. These were tested in the laboratory with two species, Males were found to be more susceptible to carbaryl than were the females, with population LC50values falling as the season progressed.Labops hesperiusUhler was the most tolerant species, with some Over-lapping values withLabops hirtusKnight.Labops utahensisSlater was the most susceptible and contained the lowest level of monooxygenase activity.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.676

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Larvae of the common green lacewing,Chrysopa carneaStephens1, have a remarkable natural tolerance to pyrethroids, providing important selectivity in integrated control programs. A portion of this tolerance is attributable to detoxification by pyrethroid esterase(s). This larval enzyme(s) has unusually high activity and a unique specificity for hydrolyzingcis-permethrin and -cypermethrin two- to three-fold faster than the correspondingtrans-isomers. Deltamethrin is also hydrolyzed rapidly. Certain properties of the larval pyrethroid esterase(s) parallel the sensitivity of the larvae to pyrethroid poisoning. Larval pyrethroid esterase(s) increases in activity for hydrolyzingtrans-permethrin on larval growth in agreement with the increased tolerance totrans-permethrin poisoning. The relative rates of hydrolysis of deltamethrin and thecis- andtrans-isomers of permethrin and cypermethrin by the larval pyrethroid esterase(s) generally coincide with the tolerance of the larvae to these pyrethroids. Phenyl saligenin cyclic phosphonate, a potent inhibitor for larval pyrethroid esterase, synergizestrans-permethrin toxicity by 68-fold from an LD50of 17,000 μg/g to one of 250 μg/g. Although the involvement of penetration rates, nerve sensitivity, and oxidative detoxification has not been evaluated, it is clear that pyrethroid esterase(s) is a major factor contributing to the natural pyrethroid tolerance of lacewing larvae.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.681

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Indirect flight muscles in the rice water weevil,Lissorhoptrus oryzophilusKuschel, are greatly reduced in adults during winter. Muscle regeneration occurs in the spring just before adult exodus from overwintering sites. Once adults establish themselves in a flooded rice-field, the indirect flight muscles degenerate as females begin oviposition. First-generation adults possess well-developed indirect flight muscles; they exit fields in which they develop. Large numbers fly to aestivo-hibernation sites where muscle degeneration promptly occurs. Some first-generation adults move to young rice, if available, where muscle degeneration and oviposition occurs.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.685

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Field studies were conducted at Rome, Italy, onCeutorhynchus trimaculatus(F.) andTrichosirocalus horridus(Panzer), two candidate insects for the biological control ofCarduusthistles in the United States. The biologies of these weevils were similar; teneral adults appeared in the spring and fed for 2 to 3 weeks on leaves of the primary host,Carduus macrocephalusDesfontaines, before estivation in the soil. Both weevils resumed feeding in the fall. Mating and oviposition occurred from November to March. Eggs ofC. trimaculatuswere laid on the surface and under the epidermis of the leaves, whereas eggs ofT. horriduswere laid in feeding grooves in the midrib. Larvae of both species fed together in the crowns and buds from December to April, but no cannibalism was observed. More larvae ofT. horridusfed in buds than did larvae ofC. trimaculatus. Pupation occurred in the soil. Both weevils were univoltine.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.691

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Twenty-nine species of sunflower (Helianthus) andViguiera porteri(Gray) Blake were evaluated in the laboratory for resistance to the western potato leafhopper,Empoasca abruptaDeLong. Leafhopper development was significantly (5% level) prolonged and survival was significantly decreased on most of theHelianthusspecies than on cultivatedH. annuusL., hybrid variety 896 when plants were initially colonized by nymphs. Colonization of plants by adult leafhoppers resulted in significantly smaller (10% level) populations on 14Helianthusspecies but significantly larger populations on 3Helianthusspecies than on hybrid 896 1 month after the initial infestation. Injury to plants of mostHelianthusspecies ranged from no symptoms to moderate chlorosis 7 days after infestation, but plants of 20 species exhibited moderate chlorosis to wilting after 1 month. Eight of the resistantHelianthusspecies could be utilized as a source of leafhopper resistance in cultivated sunflower quite readily because of their crossing compatibility.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.697

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The abundance and activity of the striped earwig,Labidura riparia(Pallas) (Dermaptera: Labiduridae), were measured weekly in a cabbage ecosystem in central Florida over a 1-year period. Pitfall traps were most effective for monitoring earwig activity. Wire-cage traps containing live larvae of the cabbage looper,Trichoplusia niHübner (Lepidoptera: Noctuidae), adult female earwigs, or other food sources were evaluated as attractants or baits. Wire-cage traps containing cabbage looper larvae consistently caught the most earwigs, indicating that earwigs actively search for and eat these larvae. Laboratory feeding studies with caged earwigs confirmed bait preferences. The relative abundance and activity of earwigs as measured by pitfall trap catch corresponded closely to average weekly air temperature. Fewer earwigs were caught during the winter months (January through March), but earwigs were abundant and active during the entire year.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.701

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Field studies were conducted to determine the effect of artificial mulches onEmpoasca kraemeriRoss and Moore populations and bean yields. Aluminum foil and rice straw mulches significantly reduced adult populations for at least 30 days after planting. This regulatory effect was directly related to the amount of light reflected by the different mulches studied; thus, the aluminum foil, which reflected up to 20.3% of the light, effectively repelled adult leafhopper, whereas the black plastic, with only 5.3% light reflection, did not. Highest yields were obtained from aluminum foil-mulched plots. With a susceptible variety, the aluminum and rice straw treatments increased yields by 212 and 107%, respectively. With a tolerant variety, plots mulched with aluminum foil and rice straw yielded 26 and 31% more than the nonmulched plots, respectively.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.705

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Pupae ofEphestia cautella(Walker) andPlodia interpunctella(Hübner) were brief1y exposed to temperatures of 40, 45, or 50°C, and the effects on adult eclosion, mating, fecundity and fertility were determined. All males and females of both species were killed by a 2-h exposure to 50°C, butE. cautellawas significantly more tolerant of exposure to 40 and 45°C thanP. interpunctella. The median lethal time for exposure to 45°C was 7- to 8-fold longer inE. cautellathan inP. interpunctella. Generally, exposure of male or female pupae of either species to high temperature caused some failure to mate and reduced the fecundity of mated females but did not reduce hatchability of the eggs laid. The percentage of mating failure depended to some extent on which sex was exposed and increased with temperature and length of exposure. Loss of fecundity was usually more severe when females rather than males were exposed.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.708

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The effectiveness of the striped earwig,Labidura riparia(Pallas), as a predator of the rupal stage of the cabbage looper,Trichoplusia niHübner, was investigated by affixing laboratory-reared pupae to the undersides of cabbage leaves in the field and counting the number of pupae eaten per day. Two bird species the savannah sparrowPasserculus sandwichensis savanna(Wilson), and the palm warbler,Dendroica palmarum palmarum(Gmelin), were also significant predators which actively searched for and consumed pupae. By examining placed pupae both morning and evening, it was possible to ascertain the mortality caused by the earwig, the savannah sparrow, and the palm warbler. Both earwigs and sparrows were highly effective predators and consumed from 4 to 90% of the placed pupae over a 3-day period.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.712

出版商:Oxford University Press    

年代:1981

数据来源: OUP