摘要:

We attempt to introduce the general insect ecologist to the uses and advantages of system simulation in the study of insect population dynamics and pest management. The systems simulation approach is defined, and the methodology outlined in terms of objectives, system definition, and model formulation, validation, manipulation and adaptation. Simulation procedures are described using examples from bark-beetle (Scolytidae) population dynamics. A simple simulation model of bark beetle dispersal and host colonization is used to illustrate elementary simulation methods, and the incorporation of a management strategy, in the form of traps baited with aggregating pheromones, illustrates the potential of gaming in solving management problems.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.199

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Studies were conducted in 1967 and 1972 to determine the effects of tree, height, and sector onCurculio caryae(Horn) infestations of pecan nuts.In the 1967 study, nuts were collected from 3 height levels on “Stuart” and native pecan trees and checked for pecan weevil damage. No significant variation in infestation occurred among the height levels on the trees. There was significant difference (P<0.01) in the degree of infestation among individual trees.In 1972, nuts were examined for weevils from 3 height levels and 4 sectors on trees of the “Nugget” variety. Again, variation in infestation was apparent among trees; however, no significant differences in infestation occurred among height levels or sectors.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.208

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

An equilibrium population model is presented which involves very simple assumptions, namely that the mortality is density-dependent in the larval stages and constant for the adult. This formulation leads to a description of population levels in the presence of sterile males which predicts a threshold requirement for a sterile-male release program to be effective, as has been observed in practice, and indicates that this threshold phenomenon may hold for any populations which are density-controlled.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.211

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The effects of DDT, dieldrin, carbaryl, parathion, piperonyl butoxide and Aroclor 1254®, a polychlorinated biphenyl containing 54% chlorine, on growth and photo-synthesis in the freshwater algaChlorella pyrenoidosaChick were measured. Inhibition was most easily demonstrated by varying the concentratIon of the alga and keeping the chemical concentration constant. Aroclor 1254 was the most active inhibitor of growth and photosynthesis inC. pyrenoidosa. Piperonyl butoxide, an insecticide synergist, and parathion were also strong inhibitors of growth and photosynthesis while DDT was less active. Dieldrin and carbaryl were least potent as inhibitors.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.217

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The external agencies influencing the size of autumn populations of the green peach aphid,Myzus persicae(Sulzer), were studied. The additive processes that influenced the potential size of the populations were the natality rate, the number of actively reproducing adults, and the number of immigrating reproductives. The reductive processes were predation, emigrating reproductives, leaf fall, and weather. Leaf fall and weather (high winds, low temperatures, and rain) were the major reductive processes that determined whether the population of aphids would attain their potential size. Syrphid larvae were the primary biological control agent, and they were most effective during the peak and decline of the population of aphids. Only about one ovipara per twig survived to lay overwintering eggs from hundreds of immature oviparae found per peach twig.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.221

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Sweep-net, D-Vac®, and ground-cloth sampling methods were compared by taking weekly samples of insect pests and beneficial arthropods associated with soybeans from Aug, 2–Sept. 26, 1972. Sample means were derived from 20 samples from each of 3 one-acre soybean fields.Generally with all 3 sampling procedures, samples having low mean numbers yielded higher coefficients of variability. Linear regression of coefficients of variability on the sample means revealed high correlations, and analysis of covariance on weighted means revealed no significant difference among D-Vac, sweep, and ground-cloth sample methods.The ground-cloth method produced higher means for most of the species collected in this study (spiders,Geocorisspp. nymphs,Nabisspp. nymphs, large larvae ofPlathypena scabra(F.), and larvae ofHeliothisspp.,Trichoplusia ni(Hübner),Pseudoplusia includens(Walker), andEpilachna varivestisMulsant. The 3 methods were equally effective in sampling adults of geocorids and nabids. Larvae ofP. scabrawere sampled more effectively by the sweep-net method. D-Vac samples consistently gave very low population estimates of all lepidopterous species.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.227

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The influence of low temperature on the survival and geographical distribution ofDiatraea grandiosellawas examined. Data from both climatological and laboratory observations indicated that low-temperature mortality of diapause larvae is the principal reason that the species has not colonized northern corn-growing states within the U.S.A. Results showed that diapause larvae are susceptible to freezing and cannot successfully overwinter in field conditions where the 10-year-mean January temperature falls below −7°C. This finding correlated with information obtained about the species' coldhardiness. Diapause larvae were found to freeze at ca. −2°C and to supercool to only ca. −8.5°C. Severe mortality occurred when larvae were exposed to −4°C for 2 or 4 weeks. These results provide a basis for predicting the eventual distribution of the species within the United States.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.233

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Mass trapping for redbanded leafroller (RBLR),Argyrotaenia velutinana, and grape berry moth,Paralobesia viteana, in 2 vineyards in 1971 resulted in a substantial reduction in percent of damage compared to a check area. An extremely high population of RBLR was present, but located mainly outside the vineyard. In 1972 mass trapping experiments were continued in one vineyard, with results similar to 1971, and a mating disruption experiment initiated in the other vineyard. Data from the first year of disruption shows for both species there was almost total disruption of male orientation to attractant and live female traps, and that there was a substantial reduction in crop damage. The close proximity (12.2 m) of high populations in the check vineyard could have influenced damage counts in the disruption experiment.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.239

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The grocer's itch mite,Glycyphagus domesticus(De Geer), and the grain mite,Acarus siroL., which normally feed on grain dust, other stored foods and fungi, were exposed at 17±1°C and 75±2% relative humidity (RH) to 19 species (17 genera) of fungi and 6 species (5 genera) of bacteria. The rusty grain beetle,Cryptolestes ferrugineus(Stephens), which normally feeds on grain, and the foreign grain beetle,Ahasverus advena(Waltl) which is fungivorous, were exposed to bacteria only. Both mites thrived onSyncephalastrum racemosum,Absidia spinosa, andCurvularia geniculata, but failed to survive and multiply onAspergillus ochraceus,Gliocladium roseumorPenicilliumsp.G. domesticusmultiplied 30 times onS. racemosum, andA. siromultiplied 40 times onA. spinosa. Neither of the 2 mites fed adequately or multiplied on any bacterial species. All mites died in about 35 days and 50% died in 5 days.G. domesticusdied sooner (8 days) onBacillus subtilisthan on any other bacteria or fungi;A. sirodied soonest onB. megaterium. Both species of insects (exceptC. ferrugineusonAgrobacterium radiobacter) died in about 21 days and 50% died in 7 days when exposed to pure extracts of bacteria. We conclude that bacteria, unlike fungi, adversely affect both mite and insect pests of stored products.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.243

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

When larvae and adults ofEmbaphion muricatumSay were offered 31 types of seeds (from 28 species of plants), both stages almost always preferred seeds of introduced species more than those of species native to North America. Wheat, hulless oats, and rye were the most preferred by adults and larvae of all seeds offered. In greenhouse tests with 5 of these seed varieties, rye and wheat were preferred and were more heavily damaged than oats, barley, or soybeans. Soybans, however, were damaged to a much greater extent in greenhouse tests than in laboratory tests.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.247

出版商:Oxford University Press    

年代:1974

数据来源: OUP