摘要:

‘Winoka’ wheat was infested with five levels of Hessian fly,Mayetiola destructor(Say), larvae. Plant growth traits and soluble carbohydrates were analyzed at 5 and 8 wk (3 additional weeks of cold hardening at 1.6°C) after planting. The stem and leaf number, plant weight and length, crown weight, leaf weight and length, and root weight in both plant age groups at the 1–3 larvae per plant (l/p) level were significantly less (P<0.05) than the control values, except for the 8-wk root weight. The plant traits at the 1–3 l/p level were significantly different than those at the other larval levels, with the exception of 5- and 8-wk plant lengths, and 5-wk leaf length, and plant, leaf and root weights. The greatest damage occurred at the 4–6, 7–9, and 10–15 l/p levels, usually with no significant difference between these levels. The soluble carbohydrates (fructan, sucrose, glucose, and fructose) in the crown of 8-wk plants were significantly greater than those in the 5-wk plants, whereas only sucrose and glucose were greater in the leaves.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1095

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The effect of light on host finding and parasitism byOoencyrtus kuvanae(Howard), an egg parasitoid of gypsy moth,Lymantria disparL., was studied in the laboratory. Parasitism byO. kuvanaefemales confined in light or dark cylinders was not significantly different. When parasites were given a choice between light or dark chambers, significantly more chose the light chamber regardless of the presence or absence of an egg mass. However, chambers were significantly more attractive when they contained an egg mass, indicating that an egg mass contributes to host location over short distances. Parasitism of egg masses in dark chambers in which noO. kuvanaewere found demonstrates that the parasite may leave these sites after oviposition. Implications for success ofO. kuvanaein low-density gypsy moth populations are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1101

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Three models (linear, third-degree polynomial, and one based on enzyme kinetics) were used to simulate the dependence ofCalosoma sycophantaL. developmental rate on temperature. In conjunction with a model of individual differences in development based on the Weibull distribution, the models were used to predict development ofC. sycophantaat fluctuating temperatures in a greenhouse and in nature. In the greenhouse, the reaction-rate model based on enzyme kinetics was most consistently correct. Simulated development was 1–2 d faster than actual, but this may have been partly because of the large fraction of time greenhouse temperatures were below 20°C. Simulations for one set of field data had to be adjusted for the time of larval hatch, but the same adjustment gave a good simulation of independent data. One or more of the temperature-based models, in conjunction with other studies on food consumption, may prove useful in measuring the effect of this predator on gypsy moths.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1105

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Spotted and banded cucumber beetles,Diabrotica undecimpunctata howardiBarber andD. balteataLeConte, cold-acclimated and nonacclimated, shared a common range of supercooling points (−12 to −14°C); however, LD50values showed that cold-temperature survival of the spotted cucumber beetle was higher relative to the banded cucumber beetle as the exposure temperature approached O°C. A considerable portion (41.5%) of spotted cucumber beetle adults survived ambient conditions during the winter of 1988 at Charleston, S. C, whereas all adults of the banded cucumber beetle died. Reproductive diapause did not contribute to cold hardiness in the spotted cucumber beetle, but cold acclimation increased survival to exposures of −10°C in both species.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1112

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Recoveries ofCoccygomimus disparis(Viereck) from pupae of gypsy moth,Lymantria dispar(L.), in Pennsylvania, Maryland, New Jersey, Massachusetts, Virginia, Vermont, New York, Nebraska, and Ontario, Canada, indicate that this Palearctic species is now well established in North America. This represents the first successful establishment of a natural enemy of gypsy moth in North America in nearly 50 yr. Levels of pupal parasitism in gypsy moth average 1.9% (maximum 13%). Historical records indicateC. dispariswas intentionally imported from India (1972), Japan (1976), and Korea (1984). Laboratory rearing resulted in the eventual release of more than 819,012 individuals liberated in 16 states. Details on the biology of this wasp, its foreign collection, introduction, release, and recovery (first in North America in 1978) are documented. Recovery fromThyridopteryx ephemeraeformis(Haworth) (Psychidae) andMalacosoma americanum(F.) (Lasiocampidae) in New Jersey andDioryctria auranticella(Grote) (Pyralidae) from Nebraska, as well as host data from outside the United States, indicates thatC. disparisis not specific to gypsy moth and should be searched for in other forest or shade tree Lepidoptera. Recent collections ofM. americanumin New Jersey showed 20.6% parasitism. Overall effectiveness as a biological control agent against the gypsy moth or other hosts remains uncertain but promising.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1117

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Immature development of the common green lacewing,Chrysoperla(=Chrysopa)carneaStephens, requires 20.5, 21.6, and 24.9 d at 27°C, with a photoperiod of 16:8 (L:D), when fedOstrinia nubilalis(Hübner) (European corn borer) eggs,Agrotis ipsilonHufnagel (black cutworm) eggs, andA. ipsilonneonates, respectively. Twenty-six to 40% of the individuals died when reared on eggs, 65% died when reared onA. ipsilonneonates, and all died when fedO. nubilalisneonates. Mortality ofChrysoperla carnealarvae onO. nubilalisneonates was due to entanglement in the silk produced by these larvae. An average of 377 ± 7 O.nubilaliseggs, 641 ± 43A. ipsiloneggs, and 2,056 ± 148A. ipsilonneonates were preyed upon byChrysoperla carneaduring larval development.Chrysoperla carneaandChrysopa oculataSay first instars were unable to survive on stalk borer,Papaipema nebris(Guenée), eggs. More than 80% ofChrylsopa oculatalarvae, reared on corn leaf aphids,Rhopalosiphum maidis(Fitch), as first and second instars and then switched toP. nebriseggs died as third instars, whereas only 30% of similarly rearedChrysoperla carneathird instars died. The most suitable prey, resulting in the fastest development with highest survival, forChrysoperla carneawereO. nubilalisandA. ipsiloneggs;R. maidiswas most favorable forChrysopa oculata.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1126

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Population densities of larvae of the alfalfa weevil,Hypera postica(Gyllenhal), and prevalence of parasitism byBathyplectes curculionis(Thomson) were determined in Grady and Payne Counties of Oklahoma from 1976 to 1987. After initial detection of the fungal entomopathogen,Erynia phytonomi(Arthur), in 1983, additional sampling was done to estimate the extent of fungus-induced mortality in alfalfa weevil populations. In addition, weevil larvae were dissected to determine the proportion of those infected by the fungus that also contained eggs or larvae ofB. curculionis. Epizootics of the fungus at both research sites coincided with the highest prevalence of parasitism by the second generation ofB. curculionisin 1983 through 1986, and reduced survival of the parasitic wasp by>90%. Although competition between the pathogen and parasite for hosts has resulted in a high level of mortality ofB. curculionison an annual basis, long-term reductions in parasite populations are yet to be confirmed.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1131

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The host-finding ability ofHeterorhabditis heliothidis(Khan, Brooks, and Hirschmann) andSteinernema feltiaeFilipjev in the presence of plant roots in sandy soil was investigated. During a 7-d period, host-finding ability ofH. heliothidiswas not impaired when the dried root weights of corn, tomato, or marigold plants were<1.6 g or ofS. feltiaewhen dried root weights were1.5 g had significantly lower host mortalities (range, 27–50%) compared with control treatments (range, 73–96%); treatments with root weights1.5 g were observed forH. heliothidis, this nematode species showed greater motility, hence greater host-finding ability, thanS. feltiaein the presence of roots because host mortality occurred over a shorter period of time with higher mortality rates and with fewer nematodes.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1136

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The effectiveness ofLiothrips urichiKarny introduced to control the noxious weedClidemia hirta(L.) D. Don was studied at three sites on Oahu, Hawaii. VegetativeC. hirtainfested withL. urichishowed greater mortality after 1 mo and significantly shorter internode diameters among the survivors at 4 mo than uninfested plants.L. urichihad no effect on plant height in the field but stunted the growth of young pottedC. hirtain greenhouse studies and caused a significant increase in terminal leaf drop. No effect on production of floral buds, flowers, or berries occurred at any field site over 11 mo.L. urichiwas restricted to sunny or partly sunny sites and never occurred in heavily shaded areas. Higher thrips infestations occurred during the fall and winter and lower infestations during the summer. Percentage of damaged tips also fluctuated seasonally, but the degree of damage to individual leaves was not seasonal.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1141

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Erynia aquatica(Anderson and Ringo) (Zygomycetes: Entomophthoraceae) was discovered infecting wildAedes fitchii(Felt and Young) (Diptera: Culicidae) pupae in snowpools in Upstate New York. Conidia from infectedA. fitchiipupae were used to inoculate laboratory-reared, healthyA. aegypti(L.) pupae. A total of 10.7% of the adultA. aegyptithat emerged from these pupae died from the mycosis and were filled with the resting spore stage ofE. aquatica. Mature resting spores were round, thick walled, and 31.3 ± 3.7 μm in diameter. Resting spores contained an average of 13 ± 2.8 nuclei per resting spore. Numerous rhizoids grew out of the cadavers of infected adultA. aegypti. Rhizoids varied in width from 8.4 to 21 μm and were up to 2,000 μm long. AdultA. aegyptidied from the mycosis between 8 and 17 d after inoculation. The only reproductive stageE. aquaticaproduced in infected adultA. aegyptiwas the resting spore stage. The life cycle ofE. aquaticais unusual for the Entomophthoraceae, because the pathogen produces conidia in immature hosts and resting spores in adult hosts.A. fitchiiandA. aegyptiare new host records forE. aquatica.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1147

出版商:Oxford University Press    

年代:1989

数据来源: OUP