摘要:

Phytoseiulus macropilis(Banks) andP. persimilisAthias-Henriot similarly suppressedTetranyehus urtieaeKoch populations on greenhouse ornamental plants in Florida and Ohio experiments. Observations indicated the importance of introducing predators into low-density spider mite populations, since 1 to 3 weeks were required to effect control.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.524

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The sunflower moth,Homoeosoma electellum(Hulst.), is a severe and frequent pest of cultivated sunflower in Texas and other southern states. It is a sporadic pest in the north central states and in Saskatchewan. Pheromone-type traps baited with virgin female sunflower moths synthetic sex pheromone or both were placed near sunflower fields at various locations in Saskatchewan. These provided data on the arrival of migrant sunflower moths and the duration of moth flight. North American weather maps were examined for the presence of sustained, warm, southerly winds blowing from the Gulf of Mexico toward Saskatchewan. Results show that, from 1976 through 1979, one or more weather systems causing warm, southerly winds capable of transporting sunflower moths from Texas northward into Saskatchewan developed during late June or early July. Increases in the number of moths caught coincided with the arrival of the winds in one or more Saskatchewan localities. This provides strong evidence that the sunflower moths are being transported on these weather systems.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.528

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The removal method of population estimation was applied to populations ofBlattella germanica(Dictyoptera: Blattellidae) aboard two ships. A preponderance of adult females was collected from both ships. A low frequency of females with oothecae indicated that many were senescent or were delaying reproduction. Instar determination was made by head capsule measurements. Female nymphs appeared to have six instars, whereas males had only five. Structure of the two ships' populations indicated that cockroaches were at near carrying capacity on the larger vessel, whereas the population on the smaller ship was less dense.Calculation of the removal method estimators for the two populations indicated that adult females are more resistant to capture than nymphs or adult males. Significant bias in estimation of population size resulted if this factor was not accounted for. Both precollection and residual population size was estimated with coefficients of variation of 3 to 13%.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.534

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Emergence of overwintering tobacco budworm,Heliothis virescens(F.), was monitored in Arizona, and the corresponding thermal accumulations were determined. Nondiapausing pupae emerged after the accumulation of ca. 176 centigrade heat units (CHU) when a threshold temperature range of 12.8 to 30°C was used. An accumulation of ca. 173 CHU from 1 January (5-cm soil depth) was required for emergence of first moths from overwintering pupae. Heat unit accumulations were less rapid with air temperature data. These data suggest that the physiological processes associated with diapause are nearly complete by early January. Alternate hosts are expected to play an important role in the early season since most, if not all, spring emergence occurs before the availability of cotton as a host plant.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.543

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

When seasonal variation of caste proportions was quantified in “nests” of the subterranean termiteReticulitermes flavipes(Kollar), workers comprised the most abundant caste, with a 2-year average of 84.0% of the individuals. Larvae comprised 8.7%, nymphs 5.0%, adult soldiers 2.1%, and presoldiers and neotenic reproductives 0.1% each. Alates and eggs were found infrequently. Caste proportions changed significantly with season, apparently varying according to the reproductive cycle. Larvae are most abundant in the summer and least abundant in the winter. Soldiers were most abundant immediately preceding alate flights, and least abundant immediately thereafter. Nymphs showed two peaks of abundance (early fall and early summer). Workers were most abundant during the spring and summer months.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.546

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The effects of various infestation levels ofForcipata locaDelong&Caldwell on the yield, tillers/plant, yield/tiller, leaf elongation rate, carbon dioxide exchange rate, specific leaf weight, leaf diffusive resistance, and water soluble carbohydrate concentration of ‘Kentucky-31’, tall fescue,Festuca arundinaceaSchreb., were studied. The growth response of tall fescue to 9 and 27 leafhoppers/9.5 cm diam. plastic pot was increased tillering with corresponding decreases in yield and yield/tiller after each of 2 infestation periods. Leaf elongation rates were less at the low infestation level of 3 leafhoppers/pot. Photosynthesis and specific leaf weight were only affected at the high feeding level (27 leafhoppers/pot) and only after a second infestation period. There was no significant reduction in leaf diffusive resistance at either infestation level. Water soluble carbohydrate concentration in the leaves decreased with increasing infestation levels.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.550

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Failure of released parasitoids to assume a host-seeking behavior often contributes to their premature dispersal and subsequent failure to adequately control target species. Results of laboratory and field studies conducted at Tifton, Ga., in 1979 showed that prerelease exposure of femaleTrichogramma pretiosumRiley to hostHeliothis zea(Boddie) eggs resulted in significantly more time (ca. sixfold) spent in host-seeking behavior in a laboratory release area and significantly higher subsequent rates of parasitization ofH. zeaeggs on peas and cotton.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.554

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The inheritance of resistance in oats,Avena sativaL. andA. byzantinaK. Koch, to greenbug,Schizaphis graminum(Rondani), biotypes B and C was studied. Results from F2progeny indicated that PI 186270 and CI 1580 had different genes or different loci which control resistance to biotype C. Each had a single completely dominant gene pair. CI 4888 had a separate source of resistance for biotype B, and resistance was also probably conditioned by a single major gene with complete dominance. The gene that controlled resistance to one biotype was not effective against the other biotype. All genes appeared to be independently inherited.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.557

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Bracon hebetorSay, a parasite ofEphestia cautella(Walker), the almond month, controlled this pest on stored inshell peanuts more efficiently when parasites were supplied at time of release with preparalyzed hosts. These paralyzed hosts provided female parasites with a readily available food source which increases parasite longevity and fecundity and an alternate oviposition site, allowing parasite numbers to increase in advance of the pest population. The simple and inexpensive methodology of this pest management strategy is already available and could be evaluated for commercial implementation.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.560

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Scolytus multistriatus(Marsham) was significantly more attracted to bolts freshly cut fromUlmus proceraSalisb., than toU. pumilaL. andU. parvifoliaJacq. and unbaited controls in a pure stand ofU. procera. Beetle attraction toU. parvifoliawas significantly lower than toU. proceraandU. pumilaand did not differ from that of unbaited controls. In contrast, the response of beetles to bolts ofU. proceraandU. pumilawas not significantly different in a pure stand ofU. pumila.

ISSN:0046-225X    

DOI:10.1093/ee/10.4.565

出版商:Oxford University Press    

年代:1981

数据来源: OUP