摘要:

A computer-based system was developed to aid in the prediction of the occurrence of insect pests throughout Michigan. Two prediction systems were linked through computer software with sampling, weather data, temperature threshold, and biological information into a pest biological scheduling system (BIOSCHED). The first prediction system involves biological information for an array of pest events (e.g., first emergence) that are placed on computer files. These historical files contain records of field-observed events, the corresponding accumulation of degree-days, and the life stage of the pest. The second prediction system linked by BIOSCHED is the Predictive Extension Timing Estimator (PETE), which utilizes curve-filling techniques to predict pest events.A computer software system accesses current degree-days for each of the 61 Michigan weather stations and scans each pest's historical data record. Each time a pest event is predicted to occur within the range of the degree-day accumulations for a station, a record is written on a table indicating that the pest should be in a particular life stage at that station. The table produced by this method records the pest name, host crop, county, and weather station. This information is placed on the Pest Management Executive System (PMEX) and is used by field staff to assist in monitoring pest abundances and to optimize pest management decision making.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1127

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

When low (day mean, 27.0°C; range, 6.8–42.0°C), medium (day mean, 28.0°C; range, 7.2–42.4°C), and high (day mean, 32.3°C, range, 7.3–46.4°C) temperatures were produced in field cages by covering the cages 0, 80, or 98%, respectively, with clear plastic sheets placed over the Saran cloth, the population growth rates of green peach aphids (GPA),Myzus persicae(Sulzer), decreased with increasing temperatures whereas accumulated degree-hours above 0°C increased with temperature. Thus, heat units accumulated at high temperatures are not strictly equivalent to those accumulated at lower temperatures when one is calculating population growth rates. Accordingly, a model was constructed to calculate the effective growth units that contribute to population growth of the GPA. The calculations are based on a second-order curve whereby rates of increase of the green peach aphid were compared with temperature by using data taken at intervals of 5°C. The distribution provided a weighting function that specifies the relative contributions of growth units to population growth at different temperatures.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1134

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Computer simulation was used to study the evolution of resistance to pesticides under four main classes of conditions common to agricultural arthropod pests and natural enemies. Results show that the influence of biological and operational factors on the rate of resistance evolution depends on the presence or absence of immigration and the functional dominance of resistance. A high-dose strategy for retarding resistance, which requires high immigration by susceptibles and functionally recessive resistance, can disrupt biological control and promote resistance in secondary pests. A low-pesticide-use strategy which can retard resistance in pests and promote resistance in natural enemies is recommended.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1137

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The development rates of nondiapausing European corn borer (ECB),Oslrinia nubilalis(Hübner) eggs, larvae, and pupae were determined at the following constant temperatures: 15, 18, 20, 25, 30, 32, and 35°C. In each case, artificial diet, cornstalk sections, and snap bean pods were examined as larval hosts. Development rate vs. temperature curves were established for each host. Curves for artificial diet and snap bean pods were similar; the curve for corn indicated significantly slower ECB development, especially at higher temperatures. These curves were used in predictive models of ECB development. The models were validated by comparison with field cage studies of ECB development on corn, Irish potatoes, and curly dock. Models based on development data using artificial diet and snap bean pods as hosts closely tracked the actual ECB adult emergence from potatoes and dock, but ran fast when compared with ECB adult emergence from corn. Models based on development data using corn as a host ran slow compared with ECB adult emergence on all hosts. These host differences in development rate may have been due to the limiting effects of low moisture content in the corn plant tissues employed in the tests.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1145

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The presence of a host-searching stimulant (kairomone) forMicroplitis croceipes, a braconid parasite ofHeliothisspp. in the commercial formulation and four preformulation stages of theHeliothisNPY, Elcar was investigated. A petri dish bioassay was used to determine kairomonal activity of Elcar at three concentrations (1.0, 0.5, and O.1g in 100 ml of water). “Cremed” diseasedHeliothislarvae, the supernatant resulting from centrifugation of “cremed” larvae, formulated inert ingredients, and purifiedHeliothisNPY were also bioassayed at a concentration of 1 g in 100 ml of water. There was no searching response to the purified NPY, inert additives, or the lowest concentration of Elcar, but responses were observed to the high and medium concentrations of Elcar, the supernatant, and the “cremed” larvae. These data indicate the presence of kairomonal substance(s) in Elcar, and suggest that virus purification during the formulation process may reduce the potential kairomone activity.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1151

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Larvae ofHydropsyche orrisRoss (Trichoptera: Hydropsychidae) were collected on artificial substrates in the Ohio River over 10 sampling dates throughout 1979. Year-round larval instar information confirmed that this species is bivoltine. Larvae overwinter as instars III, IV, and V, with emergence of the overwintering generation in late spring. The eggs laid by the spring-emerging females quickly hatch, with the resultant larvae then taking a total of 2 to 3 months to go through the five larval instars, to pupate, and to emerge. These late-summer-, early-autumn-emerging adults produce eggs from which the overwintering larvae develop. LarvalH. orrisdensities on rock-basket substrates were high in summer and early fall, with very low densities in winter. This marked curtailment of colonizing ability in the winter is the result of both a decreased number of colonizers in the system (due to a lack of recruitment from reproduction) and a disinclination of those caddisflies in the system to drift.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1154

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Mean development time of Douglas-fir tussock moth,Orgyia pseudotsugata(McD.), reared at constant temperatures varied from 127.4 days at 15°C to 43.4 days at 30°C. Mortality was high at both temperature extremes; however, it occurred at different times in the life cycle for the low and high temperatures. Generally, larger larvae and pupae, and more fecund females, were produced at higher temperatures. When considering all factors, the optimum rearing temperature is not necessarily the temperature at which development occurs at the fastest rate. The data suggest that laboratory rearing should be conducted at 22 to 26°C.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1159

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Three techniques were compared for efficiency at extracting entomophilic rhabditoid nematodes from soil samples. The Baermann funnel extraction was superior to centrifugation flotation, and flotation sieving methods in recoveringNeoaplectana carpocapsaeWeiser dauerlarvae from sand with 71.2, 45.8, and 7.6% recovery rates, respectively. In a petri dish bioassay, larvae of the greater wax moth,Galleria mellonella(L.), were exposed to filtered Baermann funnel extracts of nematode-spiked field soil. This method was effective in detecting populations of entomophilic rhabditoids.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1164

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The association between conidial discharge (showering) and relative humidity inEryniasp. infecting larval alfalfa weevils was studied under field conditions during an 11-day epizootic. The fungus was observed to shower when relative humidities in the alfalfa canopy exceeded 91% for ca. 3 h. The showering period had a mean duration of 5 to 10 min. A general trend toward shorter periods of showering early in the showering period (1 to 30 a.m.) was observed, whereas longer periods of showering occurred between 3 and 6 a.m. Low temperatures above freezing had no observed direct effect on either time or duration of showering. Collected data provide empirical support for a relationship between accumulated relative humidity (humidity hours) and conidial dicharge in a fungal entomopathogen.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1166

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

A computer model, based on probability theory and designed to simulate efficacy of insecticides to Douglas-fir tussock moth and western spruce budworm, is described. Simulations of applications of acephate or carbaryl included the following variables: insecticide dosage at the foliage-insect level, genetically determined response characteristics of the insect population to the insecticide, instar distribution of the population on the day of spray, type of exposure, moisture condition of foliage at the time of spray, rainfall after spray, and presence or absence of larvae at the time of spray.

ISSN:1754-5692    

DOI:10.1093/ee/11.6.1170

出版商:Oxford University Press    

年代:1982

数据来源: OUP