摘要:

A computer-based model simulating the interaction of weather, bloom, and honey beeApis melliferaL., foraging activity that culminate in ‘Delicious’ fruit-set is described. The model predicts the percentage of blossoms setting fruit based upon weather conditions, orchard design, tree characteristics, and honey bee colonies per hectare. Simulation results indicated that temperature, ratio of pollinizer to ‘Delicious’ trees, and colonies per hectare had the greatest effect on fruit-set. The use of systems science techniques to solve pollination problems in agricultural ecosystems is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.309

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

A common study design in entomology involves repeated measurement of a binary-response variable on a set of individual insects or populations under different treatment conditions. An appropriate analysis of such data will allow patterns over time to be compared between experimental groups, while accounting for the correlations among the repeated tests of individuals or populations. We illustrate such an analysis using weighted least squares methods for repeated measurement of oviposition responses ofRhagoletis pomonella(Walsh) adult female flies to two types of test fruit at four ages. We tested for differences in host acceptance behavior of adult flies originating as larvae from naturally infested apple versus hawthorn fruit, and effect (if any) of fly age on this difference. Techniques for model development, analysis of correlation structure, and hypothesis testing are presented. In the particular study considered, there was evidence of a linear increase over age in oviposition propensity for three of four larval-origin/test-fruit groups. The difference between flies of apple versus hawthorn larval origin when tested on apples was shown to be age-dependent, whereas the difference in response to hawthorn was consistent over the range of ages tested in this study. These methods are appropriate for a variety of experimental designs commonly used in toxicological, physiological, behavioral, ecological, and genetic studies of insects.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.319

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

We make an attempt to identify the agricultural and ecological factors of greatest importance in assessing the applicability of different modalities (antibiosis, antixenosis, tolerance) and levels of insect resistance to the pest management requirements of different crops and cropping systems. Emphasis is placed on the importance of matching the type and level of resistance to the pest's biology (e.g., feeding habits, development on the crop, alternate hosts, patterns of invasion of the crop, number of generations passed in the crop) and the production requirements of the crop. We illustrate how, depending on context, the use of a particular modality and level of resistance may simplify pest management, reduce crop losses without simplifying pest management, or by changing a pest whose occurrence in damaging populations is highly predictable to one whose occurrence is irregular and unpredictable, complicate pest management. The HELSIMHeliothis zeapopulation dynamics model is used to illustrate how simulation models can be used to explore the consequences of deploying particular modalities and levels of insect resistance. In exploring genetic considerations in the use of insect-resistant germplasm, we focus on the problem of maximizing the durability of insect resistance by minimizing selection for virulent biotypes. We examine whether some modalities of resistance are inherently more stable than others regarding selection of virulent biotypes, and argue that in judging the inherent durability of a particular resistance, exclusive focus on the genetic nature of the plant resistance is inadequate. Knowledge of the genetic variability of the target pest vis à vis the plant resistance and an understanding of the direct biological effects of the resistance on the insect are also essential. The selection pressure for virulent insect biotypes exerted by resistant crop cultivars is shown to be dependent upon the modality of resistance as well as the agricultural and ecological context in which it is deployed. Simulation models are used to illustrate how different deployment strategies can affect the durability of resistance.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.327

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Predominant parasitoids reared from the four majorLiriomyzaspp. Infesting 12 different host crops in North America and Hawaii are reviewed. No single parasitoid species was found to be the predominant biological control agent in most crops.Diglyphus begini(Ashmead),Halticoptera circulus(Walker), andChrysonotomyia punctiventris(Crawford) were either the first or second most reared species in 60.9, 26.1, and 21.7% of o the studies, respectively. Because of uneven distribution of parasitoids among crops, it is suggested that effective biological control may depend on matching the “most effective” parasitoid species complex with a givenLiriomyzahost and crop. Introduction and augmentation strategies for leafminer parasitoids are suggested.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.339

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Equations for the stopping boundaries, and operating characteristic (OC) and average sample number (ASN) functions, of Wald's sequential probability ratio test (SPRT) are presented for the binomial, negative binomial, normal, and Poisson distributions. The effects of errors in Wald's OC and ASN equations due to overshooting the decision boundaries, and errors due to truncating, postponing decisions beyond the first stage, and taking more than one observation at each stage of the decision process are discussed. Monte Carlo procedures are used to show that Wald's equations overestimate the true error probabilities and underestimate the true ASN for a two-decision sampling plan based on the negative binomial distribution. A Monte Carlo procedure for modifying the decision boundaries to yield actual OC and ASN functions approximately equal to the desired ones is presented. Monte Carlo procedures are also used to examine the errors in Wald's OC and ASN functions when used to describe the OC and ASN functions of a composite three-decision sampling plan based on two single SPRT's using the negative binomial distribution. Wald's equations, in general, overestimate the true error probabilities and underestimate the true ASN even more for the three-decision case compared with the two-decision case. Recommendations are given as to the seriousness of the errors inherent in Wald's equations in relation to all of the other errors that are associated with the sampling process, and the choice between Wald's and Monte Carlo OC and ASN functions to describe the properties of a sampling plan.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.345

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Predation by green lynx spider,Peucetia viridans(Hentz), was studied on cotton and woolly croton plants in East Texas. This species feeds both diurnally and nocturnally.P. viridanswas observed feeding on insects of orders Diptera, Hymenoptera, Heteroptera, Homoptera, Coleoptera, Lepidoptera, Neuroptera, and Odonata, as well as on several spider species. Predaceous arthropods (e.g.,Hippodamia convergensGuérin-Méneville, Coccinellidae;Chrysoperla rufilabris[Burmeister], Chrysopidae) constituted more than half of the spiders' diet. In cotton,P. viridanswas found to be a predator of the pestsHeliothis zea(Boddie) andAlabama argillacea(Hübner) (together 8% of the spiders' prey). Size of killed prey in cotton ranged between 0.14- and 1.3-fold the spiders' size (average prey length, 5.90 ± 0.99 mm). On woolly croton plants,P. viridanswas often seen feeding on cotton fleahopper,Pseudatomoscelis seriatus(Reuter) (numerically almost 30% of the spiders' prey), which is a key pest in cotton. It was estimated that on cotton and croton plants in East Texas, oneP. viridanscaptured an average of less than one prey daily. Our results are compared with data in the literature on the diet ofP. viridans

ISSN:1754-5692    

DOI:10.1093/ee/16.2.355

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Investigations were conducted to determine relative suitability of eggs of sugarcane pestsEoreuma loftini(Dyar) andDiatraea saccharalis(F.) for parasitization by indigenous and exotic trichogrammatids. The eight species of trichogrammatids tested (three collected locally, the others from elsewhere) successfully developed on eggs of both hosts, with number of eggs parasitized per female ranging from 14.0 to 36.6 forE. loftiniand from 0.1 to 21.5 onD. saccharalis.The most successful species onE. loftiniandD. saccharaliswereTrichogramma retorridum(Girault) andTrichogramma fuentesiTorre, respectively. In addition, exposure ofE. loftiniegg masses concealed in paper substrata or in dry leaf material demonstrated differences among parasite species in proportion of eggs attacked, ranging from 92.0% forT. retorridumto 18.0% forTrichogramma chilonisIshii. Results indicate that although all eight species developed onE. loftiniin the laboratory, the concealed location ofE. loftiniegg masses in the field may place limits on parasitization by trichogrammatids.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.360

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Oviposition and nymphal development of the hawthorn lace bug,Corythucha cydoniae(Fitch), were evaluated on 13 species or cultivars ofCotoneaster. C. cydoniaehad high oviposition and nymphal survival on glabrous foliage ofC. dammeri‘Royal Beauty’ C. K. Schneid. Low oviposition and nymphal survival occurred on pubescent foliage ofC. lacteusW. W. Sm. Leaf pubescence seemed to have an inhibitory effect on oviposition and nymphal survival. Oviposition was not affected by application of neem seed extract to the foliage.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.365

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The Palearctic sevenspotted ladybeetle,Coccinella septempunctataL., well established in North America, has now spread through parts of five Canadian provinces and 34 contiguous eastern states of the United States. In southern coastal Delaware in June 1984, a mass appearance ofC. septempunctataoccurred where wind systems brought masses of these beetles into the area from unknown sources and dropped them into the seawater. Large numbers then washed up on beaches, and some surviving beetles annoyed vacationers and even bit some people. We speculate on the original establishment of this insect in North America. Presenting evidence previously overlooked, we add to speculation that early intentional releases led to establishment of this predator in North America. However, accidental importation on transoceanic ships cannot be ruled out.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.368

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Palisade mesophyll tissue removed from mature leaves ofPhaseolus lunatusL. by the leafmining herbivoreLiriomyza trifolii(Burgess) was replaced with photosynthetically active cells, permitting virtually complete recovery from injury. No significant differences in biomass production or levels of ribulose-1,5-bisphosphate carboxylase were observed between damaged and control plants. Decreases in photosynthesis did not exceed 10% for leaves with approximately one-fourth of the leaf area mined. Development of other, photosynthetically inactive callus cells along vascular bundles and frass deposits served to compartmentalize leafmines, generating a suitable microclimate for regeneration of cells as well as preventing intrusion of disease inoculum and arthropod pests. Such cellular regrowth not only benefits the host, but provides substantial advantages for facultatively cannibalistic larvae that are incapable of relocating to undamaged leaves.

ISSN:1754-5692    

DOI:10.1093/ee/16.2.374

出版商:Oxford University Press    

年代:1987

数据来源: OUP