摘要:

As a pre-requisite to full-scale collection of southern pine beetle population data, determination of optimum sample unit size and numbers have been made. Optimum sample unit size was developed as a function of the variables to be measured (i.e., attack density, egg gallery length, total brood, parasite complex and predator complex). A series of permanent 2,000 cm2X-ray maps, depicting southern pine beetle life stages plus natural enemies occurring at varying heights in trees of different sizes, were made. These map data were stored, as addressable grid cell values in the computer. Programs were written for randomly selecting a series of defined experimental sample unit sizes. From these observations, the relationship of sample number to sample unit size was determined, and a procedure was outlined for estimating density of the bark beetle and its natural enemy populations throughout an infested area.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1001

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

A comparison of the use of pheromone and light traps for monitoring populations ofOstrinia nubilalis(Hübner) was made at 3 locations in southwestern Ontario during 1975. Pheromone traps decreased in attractiveness with time even though weekly changes of the pheromone dispensers ensured a fairly constant level of pheromone. A number of possible reasons for this observation are suggested.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1008

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

This paper presents a theoretical analysis of the rate of water loss from abscissed flower buds of cotton,Gassypium hirsutumL., under any given set of environmental conditions. The bud drying model provides a link between larval boll weevil,Anthonomm grandisBoheman, mortality, and crop environment. Derived from assumptions relating to diffusive water loss, the model shows excellent agreement with experimental results for buds ranging in initial weight from 0.2–0.7 grams. The bud drying model provides a means of calculating the drying time of abscissed cotton buds for any given microclimate.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1011

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Six insecticides (lindane, phosmet, diazinon, acephate, propoxur, and carbaryl) were tested to determine effects on predators and parasites associated with southern pine beetle,Dendroctonus frontalisZimmerman, in eastern Texas. Eleven species of parasites and predators emerged from insecticide-treated pine bolts. The most prevalent species wasCoeloides pissodisfollowed byMedetera bistriata, Roptrocerus xylophagorum, Corticeus glaber, andThanasimus dubius. In terms of emergence from treated pines, only diazinon significantly reduced the total number of associated insects. They were 65% fewer in number following diazinon treatment. The insecticides differed in their effects on the 11 associates.C. glaber, C. pissodis, M. bistriata, R. xylophagorum, andDinotiscus dendroctoniwere the only species showing significant effects due to chemical treatment.R. xylophagorumemergence was significantly greater from all insecticide treatments than from the untreated pines.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1017

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Workers of the desert termite,Gnathamitermes tubiformans(Buckley), were fed on a natural diet of blue grama leaves and cattle manure, and on artificial diets containing various amounts of cellulose, amino acid nitrogen (AAN), and non-protein nitrogen (NPN). Survival was highest on the natural diet and somewhat lower on low levels of AAN and NPN. Survival and consumption of artificial diets decreased as dietary NPN level increased. Survival decreased slightly, but consumption increased, as dietary AAN level increased. Survival as well as consumption was lowest on the 100% cellulose (actually contained 0.039% nitrogen) diet.G. tubiformansworkers are better adapted to diets containing low levels of protein or nitrogen but are not adapted to diets of pure cellulose.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1022

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

The response of ♂ gypsy moths to disparlure released at a controlled rate insde a forest was observed at various distances from the source. Measurements of wind inside the forest and the theory of relative turbulent diffusion allowed us to estimate the peak concentration eliciting this pheromone response. Within several meters of the source, the peak concentration is as much as 25 times greater than would be calculated by the usual average diffusion equation, e.g., Sutton's equation. Since moths respond quickly to pheromone, the peak rather than the average is the concentration of interest.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.1026

出版商:Oxford University Press    

年代:1976

数据来源: OUP