摘要:

Considerable success in biological control has been achieved by manipulating natural enemies to control insect pests. Ecological theory and experience suggest that species which might compete with pests could be manipulated to effect biological control of the pests. A conceptual model is presented that can aid in identifying pests suitable for biological control by non-pest competitors. Such pests must require, in addition to the resource(s) we wish to protect from damage, at least one resource which is “neutral” from our economic and/or social perspective. I argue that competition for the neutral resource could lower the pest's abundance and hence reduce damage to the protected resource(s). Examples of suitable pests and methods of manipulating competitors are discussed. Biological control by non-pest competitors may be as safe and effective as biological control with predators and parasites, but it may not be as permanent in evolutionary time.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.723

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

An average of 3.9% of laboratory-reared, marked male gypsy moths (Lymantria disparL.) released uniformly across a 0.64 km2area were captured in pheromone-baited traps set out 800 m apart in a 64 km2grid. In contrast, an average of 0.9% of males released simultaneously from a single point at the center of the grid (566 m from the nearest trap) were captured. The 4.0% recapture can be used to estimate the average density and the 0.9% recapture to estimate the maximal density of a population of feral moths, based on the numbers caught in a trapping grid of the same trap density, if we assume that the feral and laboratory-reared moths behave similarly. Approximately 97% of the recaptured males from the uniform release and 80% from the grid center release were captured within 800 m of the release site and no moths were recaptured beyond 1600 m. An average of 18% of males released from the center of a smaller (0.64 km2) grid of higher trap density (80 m spacing) were recaptured. Once again, recaptures occurred predominantly in traps near the center of the grid. The proportion recaptured was highest on the warmer days. Males were released 1, 2 and 3 days after eclosion to assess the effects of adult age, and mortality plus emigration upon trap catch. A higher proportion of older moths (2- and 3-days-old) were captured than one-day-old moths. The apparent average rate of mortality plus emigration between the first and second day after release was 96%, an estimate that may be influenced by individual differences in responsiveness of males to a pheromone source.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.729

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

Construction and analysis of life tables for consecutive generations of a field population of the alfalfa blotch leafminer,Agromyza frontella(Rondani), for one growing season in central New York showed that the two most variable age-specific factors were survival of pupae and oviposition for that particular season. Observed oviposition ranged from 3 to 48% of potential oviposition; pupal survival ranged from 38 to 72% in nondiapausing generations. Large variation in these values probably resulted from the effects of alfalfa harvests on adult and pupal environments.Egg and larval survival varied little over three generations. Average survivorship from the egg to instar I, to instar II, to instar III, to the pupa, to the adult (♀ and ♂), and to the female adult, respectively, was 68, 55, 28, 16, 8, and 4%.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.738

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

Annual jack-pine budworm,Choristoneura pinus pinusFreeman, population samples and weather records from Douglas County, Wisconsin during 1959–1976 were used to formulate prediction models using forward (stepwise) inclusion multiple regression analyses. Final models for late larval and pupal counts and defoliation ratings consisted of temperature precipitation, and population terms at years t-1 and t-2. The accepted model for the late larval counts explained 64% of the variation in the observed data, the model for pupal counts explained 70%, and both models indicated an association of weather conditions with larvae overwintering in hibernaculae. While the defoliation model had an adjusted R2of 62%, abnormalities were present in the residuals suggesting caution for use in prediction. Validation showed that the models mimicked observed population and defoliation trends and hence, could be helpful in predicting future budworm outbreaks in susceptible jack pine stands.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.743

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

The selective toxic insecticidal properties of pirimicarb, carbaryl and methamidophos to the green peach aphid,Myzus persicae(Sulzer), and its predators,Coleomegilla maculata lengi(Timberlake) andChrysopa oculata(Say) were studied. Pirimicarb was less toxic than carbaryl and methamidophos toC. maculataandC. oculataand more toxic to aphids. The selectivity ratio for pirimicarb indicating selectivity favoring the predators was ca. 4000:1.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.752

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

The relationship between the southern pine beetle,Dendroctonus frontalisZimm., and one of its common phoretic mites,Dendrolaelaps neodisetus(Hurlbutt) is probably mutualistic. Beetles harboringD. neodisetushave less endoparasitism by the nematode,Contortylenchus brevicomi(Massey) Rühm.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.756

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

The response ofEucelatoriasp. females in olfactometers to test materials was: okra leaves (1.00)>cotton leaves (0.52)>Heliothis virescens(F.) larvae fed okra leaves (0.32)>H. Virescenslarvae fed artificial diet and no okra leaves (0.0) =Spodoptera eridania(Cramer) fed cotton leaves (0.0) =Estigmene acrea(Drury) fed cotton leaves (0.0). Direct comparisons revealed thatH. Virescenslarvae fed okra leaves were about half as attractive as an equal weight of okra leaves andH. Virescenslarvae fed okra leaves and artificial diet were 1:6 times more attractive than an equal weight of larvae of the same species fed only artificial diet. This is the first report that a volatile attractant, obtained when the host feeds on an attractive plant, causes an otherwise unattractive host to become attractive to its parasite.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.759

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

Constant temperatures in the range 12.5 to 30°C allowed larval and pupal development inDacus oleae(Gmelin). Larval development ranged from 37.1 to 9.2 days, and pupal development from 48.6 to 9.3 days. The logistic equation was better than thermal summation at expressing larval, pupal and total (egg to adult, calculated) development. Thermal constant values were 186.3, 186.7, and 414.5 days-degrees respectively. The period from the beginning to the end of pupation due to individual variation ranged from 12 days (12.5°C) to six days (25, 27.5°C), to seven days (30°C). Respective values for adult emergence were six to ten days (12.5, 15°C), and two days (22.5°C). Percent pupation was highest at 25, 27.5°C, larval growth at 25, 27.5°C, and adult emergence at 22.5, 25°C, and lowest at 12.5°C, at 12.5 to 20°C, and 12.5°C respectively. At 12.5, and 30°C many adults did not emerge completely from the puparia (15.8%, 48% respectively). One-day exposure of pupae at 32.5°C and then transfer at 25°C was harmful during the first day of age but not later. Two-day exposure was even more harmful in the first two days than later. Exposure before adult emergence (9th day) affected emergence adversely, indicating that upper temperature threshold for emergence is lower than that for development.Temperature effect on development is discussed within the context of rearingD. oleaein the laboratory.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.764

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

Host-finding behavior by the onion fly,Hylemya antiqua(Meigen), was observed in the field in response to sliced onions (the host plant), barnyard grass (Echinochloasp.), and a control treatment. More flies landed within 0.5 m of the onion bait than within 0.5 m of any of the other treatments. Flies which landed downwind of the onion bait flew directly or in a series of short flights toward the volatile source. These behaviors were not observed in the vicinity of the other treatments. Traps designed to assess flight direction with respect to the wind substantiated the observations of female and male upwind flight in response to distant host-plant odors. These results show that onion flies locate host plants as a result of positive taxes, of which anemotaxis plays a significant role.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.769

出版商:Oxford University Press    

年代:1980

数据来源: OUP

摘要:

Resurgence of the brown planthopper,Nilaparvata lugens(Stål) on rice was induced by applications of decamethrin, methyl parathion, and diazinon. Differential mortality of predators and hoppers did not appear to be the primary factor for resurgence. Hoppers appeared to be attracted to methyl parathion and decamethrin treated plants because of plant growth. Improved plant growth however did not compensate for the increased feeding of the insecticide-treated hopper population, and plants treated with resurgence-causing insecticides succumbed to feeding injury earlier than untreated plants.Population increases were due in part to stimulation of reproduction of the hopper, either by contact action of the insecticides or through increased plant growth. Reduction in the length of the nymphal stage and increased adult longevity resulting in a shortened life cycle and longer oviposition period respectively, were additional factors contributing to resurgence.

ISSN:1754-5692    

DOI:10.1093/ee/9.6.773

出版商:Oxford University Press    

年代:1980

数据来源: OUP