摘要:

Laboratory data for preference, antibiosis, and tolerance of the greenbug,Schizaphis graminum(Rondani), on selections of barley, wheat, and sorghum were used in a computer simulation of the field populations that would develop on different cultivars. Although refinement and additional parameters would be needed for greater accuracy, the predictions were fairly accurate and provided a means of assessing potential economic loss.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.205

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Fluorescent pigment in a self-marking device on a Malaise trap baited with CO2(released at rates of 100 or 500 ml/min) was used to estimate the size of the tabanid population in the Delta Experimental Forest, Stoneville, MS. The estimated daily average for the 1st test from August 1–25, 1974, was 989,195 ♀ tabanids in the 4-mile2(10.4 km2) area. The estimated daily average for a 2nd test from Sept. 10 to Oct. 7, 1974 was 275,497 ♀ tabanids in the same area.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.210

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Callosobruchus maculatus(F.), the cowpea weevil, previously known to prefer smooth over rough seeds, readily distinguishes between rough and smooth varieties of cowpeas,Vigna sinensisL. The Hopkins' host-selection principle does not apply to weevils ovipositing on cowpeas. The surface of the underlying cotyledons is the same texture in both rough and smooth seeds and the seed coat is not a reprint or replicate of this surface. More 1st instar larvae successfully penetrate the seed coat in smooth than in rough seeds. The arrangement of macrosclereids of the epidermal layer of seed coats and how eggs are attached to the seed surface account for differences in larval penetration of rough- and smooth-coated varieties.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.213

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

A sex pheromone from females of the western corn rootworm (WCR),Diabrotica virgiferaLeConte, was collected by a semi-continuous, nondestructive method; and an improved laboratory bioassay was developed. Field studies with the unfractionated pheromone showed that males of the WCR and northern corn rootworm (NCR),Diabrotica longicornus(Say), were attracted to traps baited with WCR pheromone. The NCR males displayed a distinct quotidian variation in their response to the baited traps. The field traps remained attractive for at least 22 days after a single application of pheromone providing a triglyceride extender was incorporated into the pheromone solution.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.219

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

During 1972, 1973, and 1974, 4615 larvae ofHeliothis zea(Boddie),H. virescens(F.), andH. subflexa(Guenee) were obtained from 9 host plants (wild and cultivated) in the Central Yazoo Mississippi Delta by whole plant examination and sweep net collection. After the larvae were identified, the number of parasitized and diseased specimens of each species was determined. The percentage of parasitized and diseased larvae was highest during early and late season.Microplitis croceipes(Cresson) andCardiochiles nigricepsViereck were the predominant parasites found, andNomuraea(Spicaria)releyi(Farlow) Samson was the predominant insect pathogen.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.224

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Dispersion statistics parameters of Taylor's power law (b) and the common k of the negative binomial distribution to be used in establishing a sampling survey system for integrated pest management were calculated for the mite speciesPanonychus ulmiandAmblyseius fallacisoccurring in Michigan apple orchards of ≤ 10 acres in size. For both species, a data set consisting of 6600 tree samples was analyzed and forP. ulmiseveral smaller data sets were also evaluated. Sample data for either species was adequately described by a negative binomial distribution. Whenband commonkvalues were compared for all life stages of both species, they were very similar. Based on the assumption of a negative binomial distribution, sample size estimates for both species at varying densities and error margins (expressed as ratios of standard error to mean) were determined.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.227

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Interspecific competition was hypothesized to exist as a result of foraging byMonochamus titillatorFabricius in the sub-cortical region of loblolly pines attacked byDendroctonus frontalisZimmerman. The existence of the interaction was demonstrated experimentally; first by defining the distributional pattern ofD. frontalisprogeny adults in samples of bark in whichM. titillatorforaging was absent. Next, using data in which foraging occurred the observed number ofD. frontalisinside the foraged area was compared with the expected number if no foraging were present. The observed and expected values were demonstrated to come from different distributions which substantiated the existence of competition.The specifications for developing mathematical models of the competitive process included consideration of the extent and distribution ofM. titillatorforaging over the entire bole of the tree andD. frontalisdensity in the infested portion of the tree bole. The form of the data used in model development was appraised from the standpoint of providing the most realistic account of the process under consideration and the results of the use of unmanipulated data were compared with 2 separate types of manipulations commonly employed in the analysis of bark beetle populations.A series of nonlinear mathematical models based on unmanipulated data was developed which provides the expression of mortality resulting toD. frontalisas a consequence ofM. titillatorforaging as well as a survivorship model. These models include a definition of the following components: the relationship between the expected number ofD. frontalisin the area foraged byM. titillator[E(SPB¯1)] and the normalized tree bole (obtained by dividing the sample height, S.H., by the infested bole height, I.B.H.); the difference between observed number ofD. frontalisin the foraged area (SPB¯1) and E(SPB¯1)=∆(SPB¯1) and S.H./I.B.H.; the relationship between the area foraged byM. titillatorA¯1and S.H./I.B.H.; the relationship between ∆SPB¯1andA¯1, which is the mortality expression; and the relationship between (SPB¯1)/E(SPB¯1) andA¯1, which is the survivorship expression.The object of competition between the 2 species is the limited area of inner-bark necessary for development of both species. The form of the competitive process contains elements of both interference and exploitation.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.235

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

The number of pecan weevil larvae per infested pecan is apparently independent of nut size and weight, kernel weight and the infestation level of the nuts in the tree. Consequently, yield losses sustained by the larger fruited improved cultivars exceed those in native groves exposed to the same level of weevil infestation.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.248

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Bean selections Diacol-Calima, Brazil 3624, and Brazil 1087 were preferred over ICA-PijaO, Brazil 343, and ICA-Tui by a leafhopper,Empoasca kraemeriRoss and Moore, for ovipositing. ICA-Tui was least preferred for feeding by adult males. The petiole was preferred over the leaf as an oviposition site (all varieties, but especially in Brazil 3624). No antibiosis was found among the 6 varieties studied in detail nor in 48 other accessions possessing some resistance toE. kraemeri. An excised leaf technique revealed that Brazil 3624, Brazil 1087, and Brazil 343 had the greatest tolerance forE. kraemeri.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.251

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Egg masses ofChironomus ripariusMeigen were tested in graduated aqueous solutions of CaS, ranging from 1–100 mg/l. Results showed that the number of unhatched eggs/given sulfide concn fit an exponential function of the form y = a ebx. The median lethal tolerance at 72 h after oviposition (TLm, 72) was established at 9.15 mg sulfide/l.

ISSN:1754-5692    

DOI:10.1093/ee/5.2.256

出版商:Oxford University Press    

年代:1976

数据来源: OUP