摘要:

Studies were conducted in commercial sweet corn fields in upstate New York to collect information for developing a sampling protocol for egg masses and larvae of European corn borer (ECB),Ostrinia nubilalis(Hübner). Information was collected on 1) aggregation of populations in portions of the field (e.g., aggregation along borders), 2) distribution of sample observations for a whole-plant sample unit, and 3) distribution of insects within the sample unit (i.e., the within-plant distribution of eggs and larvae). Analyses of data indicated that distribution of egg masses and larvae throughout a field was essentially random with no evidence to support the hypothesis that eggs were preferentially laid near field borders where mating and resting of female adults occurred. From data on dispersion of ECB on individual plants, a Poisson series is a reasonable model for characterizing distribution of ECB egg masses. Parameters of a variance-mean model for the small larvae indicate that these larvae are highly aggregated but that aggregation becomes less pronounced as larvae mature. Since control measures are most effective against egg masses and small larvae, a sampling protocol that utilizes characteristics of both stages should be employed. An index of ovipositional activity measured via incidence of egg masses on plants can be determined by inspecting plants for presence of either egg masses or small larvae. This can be accomplished by using a binomial-based sequential sampling plan.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.501

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

A long-term study of trap catches and fruit sampling showed definitive habitat-related patterns of occurrence of populations of the Mediterranean fruit fly (medfly),Ceratitis capitata(Wiedemann), in the Hawaiian valleys of Makaha and Waianae. In general, seasonal and annual fluctuations in patterns of occurrence were influenced by seasonal and annual differences in abundance of coffee berries and distribution of other fruits. Three distinct areas of activity were observed. The most ecologically significant occurred in coffee in the upper part of Makaha and Waianae valleys with a mean catch of 0.78 and 0.32 flies, respectively, per trap per day. The other, dependent upon dispersing flies, occurred in the common residential area in the lower part of each valley, with a mean catch of 0.12 flies per trap per day in Makaha and 0.06 in Waianae. The most important host fruits were coffee, false kamani, common guava, mango, and mock orange. The stabilizing influence of coffee on the medfly population and the fly's propensity to disperse are discussed. Although several small populations exist in Hawaii, previous investigators have studied only the large populations, especially those in Kona, and in Kula, Maui. This is the first ecological study of a small population.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.507

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Studies were conducted in 1981 and 1982 to determine the general temporal occurrence of thrips in wheat, alfalfa, oat, and red clover fields adjacent to cabbage fields in upstate New York. Shifts in species composition of thrips on these crops were observed through time, and fluctuations in abundance were attributed to changes in habitat structure (e.g., maturation and senescence in wheat and oats, and cropping practices in alfalfa and red clover). All of these crops serve as a reservoir forThrips tabaciLindeman, which may move to and infest nearby cabbage plantings. By sampling the thrips populations within the foliage and utilizing sticky traps to monitor aerial populations, we may be able to predict the population buildup within these crops and the subsequent movement of thrips to adjacent crops.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.513

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The occurrence and species composition of thrips within cabbage fields were studied during 1981 and 1982. Temporal differences in abundance and species composition depended on the spatial relationship of cabbage fields to cereal and forage crops. Sticky traps within cabbage fields recorded peak flights of thrips during maturation and senescence of adjacent wheat or oat fields and cutting of adjacent alfalfa and red clover fields. These data indicate several important findings regarding the ecology of thrips in general and the possible management ofThrips tabaciLindeman in particular. First, although there are large numbers of thrips in cabbage fields during certain time periods (e.g., maturation or harvesting of crops), most will not beT. tabaciand need not be of concern to cabbage growers. Second, there are significant differences in thrips phenology and species composition in cabbage fields, and these differences appear to be dependent on phenology and management of adjacent field and forage crops. Third, although many other species are present,T. tabaciappears to be present in adequate numbers to infest cabbage at the critical period of head formation. This critical period occurs at different times depending on area, planting date, variety, and weather.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.520

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

In a 3-year study of spiders collected in weedy versus weed-free habitats in Louisiana sugarcane fields, pitfall trap catches showed no differences in diversity (as determined by the number of species and their individuals) of ground associated spider fauna. Diversity of foliage associated spider fauna was 27% higher in grass and mixed weedy than in weed-free and broadleaf habitats in 1983, based on D-Vac samples. Sweep net counts in 1984 revealed a 39% higher foliar spider diversity in weedy than in weed-free habitats. Overall spider abundance in sugarcane decreased with seasonal progression. Additionally, comparisons of weed-free, grass, broadleaf, and mixed weed habitats showed that weed floral composition seems to have little effect on the collective spider abundance and faunal diversity.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.527

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The functional response ofOrius insidiosus(Say) to densities of the European red mite,Panonychus ulmi(Koch), was studied at 18.3, 23.9, 29.4, and 35.0°C with prey densities of 5–80 mites per cage. Mite consumption was recorded during five, 3-h intervals during the day.O. insidiosusexhibited a functional response and increasing temperatures resulted in increased feeding at most prey densities. Data provided a good fit to both type-2 and type-3 functional response models.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.532

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The influence of diet and temperature onNabis roseipennisReuter feeding, development, longevity, and fecundity was investigated in the laboratory. Temperatures of 20, 25, and 30° C did not influence total consumption ofHeliothis virescens(F.) first stage larvae but did influence consumption ofLygus lineolaris(Palisot de Beauvois) first and second stage nymphs. Predation onLygusnymphs decreased at the higher temperatures. Predator nymphs consumed moreH. virescenslarvae thanL. lineolarisnymphs in developing to adulthood. Developmental times were generally independent of the prey food source. The mean consumption of prey and the mean duration of the developmental period for predator nymphs increased with each successive nymphal stage at all temperatures. The predator survived longer at 20 and 25°C than at 30°C on both prey food sources. Oviposition was not influenced by diet but was influenced by temperature. More eggs were laid at 25°C than at 20 or 30°C.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.536

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

A biologically based phenology model is described for use in integrated pest management. The model predicts the proportion of insects in a population in various stages of development as a stochastic function of accumulated degree-days. The model is based on a logistic probability distribution with mean and variance changing through time. Maximum likelihood parameters of the estimates are easily computed with nonlinear regression packages. Appropriate statistical tests are presented for comparing models. Results should be useful to researchers and biological modelers who describe insect or plant phenology.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.540

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Data were collected during 2 consecutive years on the Starkey Experimental Forest near La Grande, Oreg., to examine phenology of the western spruce budworm,Choristoneura occidentalisFreeman. The logistic probability distribution was used to describe distribution of budworm in each developmental stage (instar 2 through adult) as a function of accumulated degree-days by year, plot, and host species. The logistic distribution described phenology accurately and was simpler to compute than other methods. Results should interest insect-pest managers and researchers who model development of plants and animals.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.547

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The microhabitat distribution and spatial dispersion patterns of walnut aphid eggs and viviparae were assessed in a commercial walnut orchard in Tracy, Calif., during 1977 and 1978. Significantly higher egg densities were found on the smaller peripheral branches of walnut trees (1–2 cm diam) than on larger branches. Few eggs were found on extremely small twigs (ca. 0.55 cm diam) from the previous season's growth. Significant differences in egg density were sometimes observed between top and bottom regions and among cardinal quadrants of the tree. No significant differences in egg density were observed among tree. The spatial dispersion patterns determined for walnut aphid eggs were generally aggregated except at extremely low densities where the pattern was random. No significant differences in aphid density were observed among cardinal quadrants of the trees and only occasional differences were observed between top and bottom regions of the trees. Substantial variation in aphid density was observed among basal, middle, and terminal regions of the trees. Few significant differences in aphid density were observed among trees and none was observed among compound leaves. Significantly higher aphid densities were found on the middle and distal leaflets of compound leaves. Within-tree, among-tree, and among-compound leaf distribution patterns showed that the aphids were generally aggregated.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.555

出版商:Oxford University Press    

年代:1986

数据来源: OUP