摘要:

Estimates of populations of Race BMayetiola destructor(Say) produced by sampling 3 Indiana wheat fields during 1970–72 ranged from about 0.1–1.5 million pupae (flaxseeds) per acre. The spatial distribution of the counts of the flaxseed stage was determined to be consistent with the negative binomial distribution. The relative variability (RV) of the estimates of the flaxseeds and of plant culms per acre were below 10, well within a level of acceptable variability.As few as 15 and a maximum of 30 samples per field would be required to yield an estimate of absolute population density of the insect with an error of 10% or less of the mean. Costs and relative net precision were determined based on effort expended and the level of accuracy obtained.

DOI:10.1093/ee/3.3.441

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Studies were conducted over a one-year period at 6 locations throughout the range of the imported fire ant,Solenopsis saevissima richteriForel, to determine regional variations in the seasonal activity of this pest. Threshold levels for various types of activity were found to be uniformly temperature-dependent in all parts of the range. Workers began to forage when soil temperatures exceeded 10°C. Some foraging occurred even in the winter months in the northern part of its range when the daily temperature exceeded this threshold for more than a few hours. Brood production in spring began when the weekly mean soil temperature (at 5 cm) rose above 10°C, worker and sexual pupae appeared at ca. 20°C, and the alates at 22.5°C. In Florida the period of favorable soil temperature for new colony-founding and growth (24°C) lasted ca. 198 days; in northern Mississippi it lasted 83 days. Similarly, the ants in Florida were found to consume twice as much food annually and to produce 1.5 times more brood than the ants in the northern part of the range.

DOI:10.1093/ee/3.3.446

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Lemophagus curtusTownes (Ichneumonidae), a European larval parasitoid ofOulema melanopus(L.), is established in Berrien and Kalamazoo counties, Mich. Sources of European material, releases, and recoveries are summarized.

DOI:10.1093/ee/3.3.453

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The organophosphate insecticides, parathion, monocrotophos, dicrotophos, and Gardona® [2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethylphosphate], were highly toxic to adult alkali bees,Nomia melanderiCockerell. The topical LD50values for these ranged from 0.83 (monocrotophos) to 2.69 (Gardona) micrograms per gram of bees. Two carbamate insecticides, however, were much less toxic. The LD50values for these ranged from 47.90 [Landrin® (4:1 mixture of 3,4,5– and 2,3,5–isomers of trimethylphenyl methylcarbamate)] to 86.37 (carbaryl) micrograms per gram of bees.The alkali bees were fed and topically treated with the drugs SKF 525A (2-diethylaminoethyl 2,2-diphenyl pentanoate) and chlorcyclizine [N-methyl-N-(4-chlorbenzhydryl) piperazine] to determine if they could protect the bees from parathion. Chlorcyclizine made the bees generally more susceptible, whereas SKF 525A either had no effect or protected one sex without protecting the other. The protective effects with SKF 525A were small as well as inconsistent and therefore such drug treatments probably have little potential for protecting alkali bees from parathion in the field.Electron micrographs of the gut tissue of the insects showed that chlorcyclizine and SKF 525A had significant effects upon the cellular ultrastructure. Some of these effects were similar to those observed in other insects treated with different drugs in which detoxication measurements or biological assay tests had shown that the drug had limited potential for induction of protective detoxication mechanisms.

DOI:10.1093/ee/3.3.455

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

A diverse assemblage of phytophagous insects representing 7 orders, 23 families, and more than 40 species fed or reproduced on Italian thistle,Carduus pycnocephalusL. (Compositae) in southern California. Most of the insects attacking this introduced annual weed were euryphagous, ectophagous, sap- and foliage-feeding species. Half of the identified insect associates were economic species.In southern Europe, Italian thistle hosts a far greater diversity of phytophagous insects; those detected to date represent 8 orders, 31 families, and more than 80 species. All major plant parts are damaged by one or more species of insects, unlike the situation in southern California, where this thistle was relatively free of deleterious insect injury. About a third of the European insect associates of Italian thistle were endophagous as immatures. A third of the associates identified to species were stenophagous, restricted to host-plants belonging to the tribe Cynareae.Only 3 species (ca. 4%) of the insect enemies of Italian thistle in Europe immediately appeared promising for use as biological control agents in southern California:Psylliodes chalcomeraIlliger (Coleoptera: Chrysomelidae),Ceutorhynchus trimaculatusF. (Coleoptera: Curculionidae), andRhinocyllus conicusFroelich (Coleoptera: Curculionidae). The last-named, seed-destroying species was initially colonized on Italian thistle in southern California in 1973.

DOI:10.1093/ee/3.3.464

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Wild femalePorthetria disparadults emitted attractant at any time of day but made a maximal release between 1000–1530 h. Pheromone emission is greatest during the first 3 days of a virgin female's adult life and after the 3rd day decreases until death. Wild females emit a burst of pheromone, as much as 841 ng/30 min, once in their life, usually on the 2nd or 3rd day. After the burst the amount of lure emitted decreases rapidly. Unlike wild females, laboratory-reared (lab) females show no diel periodicity in pheromone emission, and release very small amounts of pheromone (4.9 ng/30 min).Laboratory and field bioassays indicated that approximately 30% of both sexes of lab moths either did not respond to pheromone or released no detectable amount of lure, compared with 9% sexual inactivity in wild moths.

DOI:10.1093/ee/3.3.475

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Four major toxic and growth-retarding compounds isolated from an overcrowded culture of larvae of the mosquitoCulex pipiens quinquefasciatusSay were chemically identified asn-heptadecane, 7-methyloctadecane,n-octadecane and 8-methylnonadecane. The minor constituents, presumed to consist of 2-ethyl long-chain fatty acids, also contributed to the overall activity of overcrowding factors produced by mosquito larvae.Production of these compounds was dependent on the larval density rather than on the number of larvae used. The “ego space” of the 4th-instar larva is ca. 9 mm2, below which the larvae come in bodily contact through the lateral thoracic and abdominal hairs, resulting in the elaboration of detectable quantities of biologically active materials.

DOI:10.1093/ee/3.3.482

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

To confirm the larvicidal activity of 2-alkyl fatty acids occurring in the overcrowding factors of mosquito larvae, and to investigate the relationship of the alkyl substitution on the carbon chain, 43 fatty acids were tested against first instars ofCulex pipiens quinquefasciatusSay.2-ethyloctadecanoic acid, 3-methyloctadecanoic acid, and 2,3-dimethyl-octadecanoic acid were the most active materials among those tested. Their activity as determined by LC50was in the range of 0.4–0.6 ppm.The larvicidal activity of the branched fatty acids was best correlated with the steric hindrance effect of 2– and 3-alkyl fatty acids on enzymatic esterification in vitro. The characteristic timing of larval death occurring immediately after ecdysis suggests that the antigrowth activity of these branched fatty acids results in the formation of new but water-permeable cuticle in mosquito larvae during ecdysis.

DOI:10.1093/ee/3.3.487

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Cotton was planted in a factorial combination of 3 irrigation schedules and 4 plant populations in a randomized complete block design. Each treatment combination was sampled on 3 dates with a vacuum insect sampler.Lygus hesperusKnight, a complex of leafhoppers (Empoasca),Geocoris pallensStal, andOrius tristicolorWhite were present in large numbers. Significant differences in insect numbers between plant populations and/or between irrigation regimens were determined for each species or species group on one or more of the 3 sampling dates. Generally, insect populations were greatest at higher plant densities and with more frequent irrigation, factors which increased the density of plant canopies.

DOI:10.1093/ee/3.3.492

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Individual releases of 19,000–387,500Trichogrammaadults per acre on up to 48 acres of cotton at College Station, Tex., resulted in parasitism ofHeliothiseggs averaging from 33–81%, with some movement of parasites up to 400 ft within 2 days.Subsequent generations ofTrichogrammawere not produced in the field due to mortality, apparently caused by drift of methyl parathion (ultra-low volume) which killed 75% of the adultTrichogrammaat distances of up to one mile downwind from sprayed fields.

DOI:10.1093/ee/3.3.497

出版商:Oxford University Press    

年代:1974

数据来源: OUP