摘要:

From 1966 through 1969 an investigation was conducted on the influence of alfalfa resistance on populations ofAcyrthosiphon pisum(Harris) and their associated parasites, predators, and competitors. One sixth as many pea aphids were found on the Kansas (‘KS 10’) variety than on the ‘Vernal’ alfalfa variety. The number of aphids on ‘DuPuits’ was about 4-fold that on the Kansas variety. The different numbers of pea aphids on the various alfalfa varieties did not affect parasitism rates or predator numbers associated with the high and low aphid numbers on the 3 alfalfa varieties. In the pea aphid, there appears also to be no direct effect of the plant host on parasitism. This finding differed from other studies with various parasite-host systems which showed that the plant host may have a significant effect upon parasitism rates. Of the pea aphid competitors, leafhoppers were most abundant on Vernal but least abundant on DuPuits. However, DuPuits had the largest number of alfalfa weevils, mirids, and other miscellaneous herbivores. No means was evident to predict how resistance to one insect species will influence the pest enemies and associated herbivores.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.1

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Larvae ofOestrus OvisL. harbored by lambs maintained at a higher temperature had a greater survival rate and matured more rapidly than larvae harbored by lambs maintained at a lower temperature. However, the smaller population of surviving larvae harbored by lambs maintained at a lower temperature produced more mature larvae. Larvae matured more rapidly and in greater quantities in lambs than in yearlings.Although relative humidity had no influence upon the number of adults emerging from pupae, temperature did; 27°C was optimum. Pupae subjected to a temperature below 0°C for brief periods survived, while constant temperatures below 16°C and above 32°C were fatal. A constant temperature of 16°C permitted development of pupae but inhibited emergence of adults.Estimated mortality during the immature stages ofO. ovisin wild populations ranged from 90.2–93.8% for the 1st generation and 98.5–99.1% for the 2nd generation.The incidence of infested sheep during November through February exceeded 90%. The annual mean infestation was 21.9 larvae per sheep. During October and November the sheep harbored a mean of 45 larvae per head.Oestrus Oviswas found to complete 2 generations per year in Kentucky.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.11

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Diapause inMegachile rotundata(F.) is only partially facultative, since neither induction nor termination is under the exclusive control of environmental conditions. Induction is apparently controlled by an endogenous system, since the 1st offspring of spring generation females always contain the greatest number of emergent individuals. Although the diapause-terminating processes are favored by low temperatures, diapausing prepupae placed immediately into incubation will emerge slowly over an extended period of time. Emergent larvae and pupae are killed by prolonged storage at 1.7°C and by incubation at relative humidities below 50%. The optimum temperature for diapause development is approximately 10°C.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.23

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Selective toxicity of carbophenothion and trichlorfon to the honey bee,A pis melliferaL., and the alfalfa leafcutting bee,Megachile rotllndataF., was established in dosage-mortality studies using the topical drop method. LD30values of trichlorfon for the honey bee, the male leafcutting bee, and the female leafcutting bee were 28.5, 250.0, and 515.0 μg/g, respectively. LD30values for carbophenothion were 12.6, 4.3, and 6.2 μg/g. Trichlorfon was 18–34 times more toxic to the honey bee than to the female leafcutter at LD30and LD95. Carbophenothion was 2–3 times more toxic to the leafcutting bee at both dosage levels. The differential toxicity of trichlorfon may be related to pH of the body fluid, which was 6.0 for the honey bee and 6.8 for the leafcutting bee. Trichlorfon is known to be highly unstable at neutral or higher pH levels. Trichlorfon at the topical LD50levels was a stronger acetylcholinesterase inhibitor than carbophcnothion to both test insects.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.27

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The host specificity ofAmynothrips andersoniO'Neill was determined in a series of feeding behavior and starvation tests conducted in the laboratory in Argentina and Uruguay. The host plant spectrum tested involved 21 different plant species belonging to 5 families and 11 genera. A slight amount of adult feeding (1–2%) was obtained on the test plant,Polygonum aviculareL., but was not observed to occur on field plants. Observation and study of 46 plant species in nature also demonstrated an absence of thrips or their feeding. The results of these laboratory tests and observations confirm earlier observations indicating that this thrips is associated only withAlternanthera philoxeroides(Mart.) Griseb. andA. hasslerianaChod.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.30

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

When males ofCeratitis capitata(Wiedemann) were irradiated either in the late pupal (2 days before eelosion) or the adult stage (1 to 24 hours old) with 7, 9, and 11 krad in air and in nitrogen, exposure to nitrogen before and during irradiation decreased sterility. No significant differences in sterility were found among nitrogen exposure periods of 5, 15, 25 or 35 minutes before irradiation. Adult longevity decreased with increasing radiation dose regardless of whether the adults or pupae were irradiated in air or nitrogen. However, at any of the doses, individuals irradiated in nitrogen as pupae were longer lived than comparable pupae irradiated in air. By contrast, those irradiated in nitrogen as adults lived as long as when irradiated in air. Competitiveness of males irradiated as adults in nitrogen atmosphere was higher than that for males irradiated in air, but the differences were not statistically significant. Males irradiated as pupae in nitrogen were significantly more competitive than those irradiated in air. Differences between competitiveness of males irradiated in air as pupae and males irradiated as adults were not significant. In contrast, when irradiation was applied in nitrogen atmosphere, competitiveness of males irradiated as adults was significantly less than that of males irradiated as pupae.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.37

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

This investigation concerned the population dynamics and the possible control ofTribolium confusumJacquelin duVal andT. castaneum(Herbst) subjected to chronic irradiation. At 3 dose levels of60Co gamma radiation (24, 49, and 170 R per day) 5 replicate populations of single species (20 pairs in each) and of mixed species (10 pairs of each species) were established in 5 g of food in lucite test tubes. Larvae, pupae, and adults were counted monthly and along with eggs were transferred to new food. Culture conditions were 25 and 32°C in 70–75% relative humidity.In general, at 25°C the single-species reproductive performance, measured as the number of larvae and adults, was impaired by exposure to radiation. Poorest performance appeared at 170 R per day; whereas, 24 and 49 R per day resulted in reduced, but comparable productivity. Larvae were more radiation-sensitive than adults. Numbers of adults reached zero more slowly than larvae at 170 R per day, indicating no adult replacement. Results were accentuated at 32°C.Responses to radiation of mixed- and single-species populations were comparable at 25°C. There was greater survival of larvae and adults in mixed-species populations at 32°C than at 25°C.Data from this experiment showed that 170 R per day dose rate was sufficient to stop larval development; but 49 R per day was not enough to eliminate flour beetle populations. The radiation effects on population performance were attributed to induced genetic aberrations rather than to physiological impairment. The feasibility of implanting radiation sources in a grain storage facility to control insects is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.41

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

MaleManduca sexta(L.) irradiated as pupae with an average dose of 37.7 krad of gamma irradiation from a cobalt-60 source were released on Vieques, a 56 mile2Caribbean island, over a 17-month period to determine the effect on the native population. The highest ratio of released (sterile) to native males collected subsequently in blacklight traps was 3.7:1, but egg hatch in the native population was not reduced proportionately, and the population increased during the releases. Collections of tobacco hornworms from BL traps baited or unbaited with virgin females showed that the released males were less attracted to the bait females than the native males. Similar sterile male moths from pupae that were irradiated when they were 1–2 days older than those released on Vieques appeared more competitive when they were released on St. Croix island, based on the greater reduction in egg hatch.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.48

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Three entomogenous fungi,Beauveria bassiana(Balsamo) Vuillemin,Aspergillus flavusLink, andFusarium solani(Martius) Appel&Wollenweber, were tested against healthy adults ofDendroctonus frontalisZimmerman at temperatures ranging from 5 to 30°C and relative humidities of 55, 75, or 94%. The greatest difference between the times for the beetles inoculated with the various fungi to achieve 50 or 90% mortality occurred in the range from 15 to 20°C. Variations in humidity did not significantly affect mortality. At the humidity levels tested, all inoculated beetles died sooner at 30°C than at the other temperatures. Mortality of mycotic beetles averaged 50% in 6.3 days and 90% in 11.0 days and was significantly different from that of the controls except at 5 and lO°C.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.54

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

To study the efficacy of chemical larvicides; several materials were evaluated in two warm-water southern California artificial lakes, (Lake Calabasas and Westlake) and the residues of an effective larvicide (chlorpyrifos) in various components of one of the lakes were investigated.Abate®(O,O'-(thiodi-p-phenylene)O,O,O',O'-tetramethyl phosphorothioate) gave excellent control of Chironomine midges (ChironomusandDicrotendipesspp.) but only mediocre or poor control of the smaller Tanypodine midges (CricotopusandTanypusspp.). Carbaryl yielded poor control of both groups, and fenitrothion yielded good control of both groups at a higher rate of application.Chlorpyrifos gave excellent control of both groups of midges. It was more effective against the Chironomine larvae. This material at 0.2 lb active ingredients per acresurface yielded complete control of Chironomine midges for 12 weeks or longer, but suppressed the Tanypodine larvae for only 7–8 weeks.Residues of chlorpyrifos (used as 2% granules) were generally higher in the bottom water, even though maximum residues in both layers reached 0.6 ppb. Residues were much higher in the mud, reaching a mean maximum of 0.3 parts per million in the top 1-inch section of mud samples, but only traces were found in the remaining section of the mud. Maximum residues in water were obtained one day after treatment, declining to below 0.1 ppb within 4 weeks after treatment. The maximum residues in the mud were obtained one week after treatment, declining to below 0.1 ppm in 28 days. Slightly higher levels of residues were found in water and mud when the whole lake was treated.Bottom-dwelling and -frequenting fish, such as channel catfish (Ictalurus punctatusRafinesque) and, to some extent, black crappie (Pomoxis nigromaculatusLeSueur), contained much higher quantities of chlorpyrifos than the nonbottom dwelling fish such as largemouth bass (Micropterus salmoidesLacépède) and bluegill (Lepomis microchirusRafinesque). Mean maximum residues in channel catfish and black crappie were 0.8 and 0.5 ppm after 3 and 2 weeks posttreatment, respectively, declining to barely detectable levels 25 days after treatment. The residues in largemouth bass and bluegill were minimal, with maximum approaching 0.2 ppm but remaining 0.1 or below this level most of the time.

ISSN:1754-5692    

DOI:10.1093/ee/2.1.58

出版商:Oxford University Press    

年代:1973

数据来源: OUP