摘要:

To approach the management of populations by way of “population quality” is to attempt to see the world from the organism's point of view. From that vantage point, “populations” no longer appear to be inert masses passively responding to changing environmental pressures. Instead, they become heterogeneous mixtures of individuals differing markedly in their ability to survive particular stresses. Consequently, whether they are to be managed protectively, to sustain yields, or destructively, to dispose of pests, such populations will respond most consistently and predictably to management policies that exploit the effects which some of their members have on the numbers and structure of subsequent generations. Pest management, for example, would be better served by methods that would selectively discriminate against reproductively superior members of a generation than by methods that merely increase mortality indiscriminately, with no thought for the qualities of the survivors. Examples from laboratory, field, and simulation studies of the western tent caterpillar,Malacosoma californicum pluviale(Dyar), illustrate these points.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.1

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

Food preferences of 5 species of adult carabids,Scarites substriatus, Evarthrus alternans, Pterostichus chalcites, P. lucublandus, andHarpalus pensylvanicus, were investigated under laboratory conditions. Various plant and animal material, as well as detritus were tested. Dead black cutworm larvae were the most preferred food for all species tested.H. pensylvanicusandE. alternansdid, however, feed on a number of seeds.H. pensylvanicusmay be quite omnivorous in its feeding habits. In general, dead crickets and both live and dead smooth-skinned Lepidoptera larvae were attractive food items, while isopods, phalangids, slugs, and earthworms were not.E. alternans, P. lucublandus, andH. pensylvanicussignificantly preferred dead invertebrates over live ones. The attractiveness of dead animal material has special significance. The application of insecticides, which kill large numbers of insects, may be indirectly poisoning potential predators because of the carabid's willingness to feed on dead or dying insects.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.9

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

Populations of the bollworm,Heliothis zea(Boddie), and the tobacco budworm,H. virescens(F.), and 8 arthropod predators were studied following in-furrow and sidedress applications of aldicarb and foliar applications of monocrotophos to cotton. In 3 field tests, the arthropod predator populations were reduced but there were increases inHeliothisspp. infestations. The reduction in predator populations apparently was not great enough to cause all of the increases inHeliothisspp. that occurred. When tobacco budworm moths were given a choice between cotton in field cages treated with a sidedress application of aldicarb and foliar applications of monocrotophos and untreated cotton, the moths preferred to oviposit on the cotton treated with the insecticides.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.13

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

The mating frequency of the Indian meal moth,Plodia interpunctella(Hübner) and the almond moth,Cadra cautella(Walker) was population density dependent in the presence of synthetic sex pheromone. The pheromone substantially reduced population growth rates of these insects at low population densities.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.17

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

The grape thripsDrepanothrips reuteriUzel, was not abundant in the primary bloom clusters of Thompson Seedless grapes and was not associated with scarred fruit. It was the only thrips abundant on Thompson Seedless foliage. Leaves that were infested with the grape thrips grew distorted. The population in the foliage may have been regulated by the type of interrow ground treatment, irrigation method, and type of rootstock, when these cultural practices had a direct effect on the vigor of the vines. Growing vines appeared to support greater populations of thrips. When the number of grape thrips was compared on leaves in different positions along the cane, most of the thrips were found on the young foliage near the growing end. The grape thrips was a chronic inhabitant of the foliage and existed in such low endemic numbers that control of the species was considered unnecessary.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.21

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

The dispersal peak of the western flower thrips,Frankliniella occidentalis(Pergande), occurred during the spring grape bloom period and the insects were attracted to the flowers. The thrips oviposited in the young berries and eggs were dissected from the wounds. The insects were very prolific when 25, 75, and 100 adults were caged on Thompson Seedless clusters at either 0, 50, or 100% bloom. The thrips scarred the rachis, laterals, and berry pedicels of Thompson Seedless and Calmeria grapes but did not cause necrotic scars on the surface of the fruit. Clusters that supported up to 1,582 adults and nymphs did not have a greater amount of surface scars than non-infested clusters. Total berry to rachis length ratios indicated that exposure to thrips may have improved fruit set. Surface scars were mechanically induced with a platinum wire. The light halo around an ovipositional scar was unique to a deposited egg. The amount of ovipositional scars on Calmeria grapes was proportional to the number of thrips introduced on the clusters and the amount of time the clusters were exposed to natural infestations.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.25

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

The ovipositional rate, fecundity, and longevity ofB. anurusinH. posticalarvae was determined under constant 70°F (21.1°C) and fluctuating 44°/65°F (6.7°/18.3°C) temperatures, while a 12:12 h photophase:scotophase was maintained under both temperature regimes. The daily ovipositional rate was higher at a constant 70°F, but the mean fecundities per female of 1022.8 eggs at 70°F constant and 865.2 eggs at 44°/65°F were not significantly different (P>.10). The lower daily ovipositional rates under the fluctuating temperatures were offset by increased longevity under the same conditions. The mean longevity of 35.1 days at 44°/65°F was Significantly greater than the 22.1 days observed at constant 70°F. Analysis of the distribution pattern of the eggs among the host larvae showed that more than 50% of the data sets conformed to the Poisson distribution, while 99.2% of the remaining cases indicated a uniform dispersion pattern.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.31

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

At 22°C, time required for the false celery leaftier (FCLT),Udea profundalis(Packard), to complete the 5 larval stadia is 17.58 days. During this period, a larva usually consumes 14.67 cm2of leaf, about 79% in the last larval stage. FCLT are abundant on sugarbeets in August and September when the leaf area of the plant is too great for the feeding to make an appreciable impact. At the observed population levels in sugarbeets in Washington, the FCLT is not an economically important pest.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.35

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

Transmission of filaree red-leaf virus (FRLV) byAcyrthosiphon pelargonii zerozalphum(Knowlton) was further characterized. Acquisition and inoculation efficiencies were similar at 20 and 25°C, but young larvae were more efficient than apterae. The proportion of aphids transmitting virus/hour of inoculation access time tended to decrease exponentially with time.The median latent period in larvae that were born on and that acquired virus from FRLV-infected white-stem filaree,Erodium moschatumL'Her., was ca. 48 h at both 20° and 25°C. The average retention period was 9.5 days at 20° and 7 days at 25°C. Infective aphids lived as long and produced as many larvae as did noninfective ones.Twelve-day old aphids that had acquired virus as 1st instar jarvae, and whose rate of transmission had declined increased their rate of transmission after being fed on a virus source. Another latent period followed the 2nd acquisition access period. The maximum rate of transmission following reacquisition of virus was less than that attained after the initial larvae acquisition feeding, but it was comparable to that found with aphids that first acquired virus when they were 12 days old.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.39

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

A survey of the domestic fly population of Nsukka, a semi-urban University town in the guinea-savannah belt of West Africa, showed infestation of human and animal shelters with at least 19 species, comprising 5 types of biting flies (viz: tse tse fliesGlossinaspp.; horn fliesHaematobiasp.; stable fliesStomoxyssp.; horse fliesChrysopsspp. and louse fliesHippoboscasp.); and several types of non-biting flies (including house fliesMuscaspp.; blow fliesLuciliasp., andChrysomyiasp.; flesh fliesSarcophagasp., and warble fliesOestrussp. etc.).Preferred breeding sites and areas of aggregation of the insects were studied against the background of the relative fly infestation rates of such habitats as human homes, animal sheds and abattoirs; food houses; sewage and refuse dumps, and open air locations. Also, variations in the diurnal, daily and monthly availability of the flies were noted and related to seasonal changes in temperature and humidity and to ecological aspects of the insects' life cycles.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.43

出版商:Oxford University Press    

年代:1977

数据来源: OUP