摘要:

A new function was empirically derived to describe nymphal development of the migratory grasshopperMelanoplus sanguinipes(F.). This nonlinear equation was to fit to a large data set from the literature and compared with two previously proposed nonlinear models and the commonly used degree-day linear model. The functions were also compared in their ability to predict development under conditions of alternating temperatures, including temperatures that would often occur in the field. Although all models fit the data well at intermediate temperatures, the new model was shown to be preferable to the other models in the high- and low-temperature range.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.1

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The relationships between a plant bug,Lygus hesperusKnight (Hemiptera: Miridae), and carrot,Daucus carolaL. (Umbelliflorae: Umbelliflerae), arc examined as an example of interaction between a polyphagous insect and one of its host plants. Seed exposed toL. hesperusfeeding may have significantly more indole acetic acid and a wound-induced chemical stored in the seed. Feeding of the herbivore reduces seed yield and germination and slows germination and early shoot growth. but accelerates subsequent plant growth. The resultant plants and roots are heavier. Some of these plants may exhibit a virus-like foliage disorder or premature bolting. The insect may pollinate carrot and be predaceous on soft-bodied insects harmful to the plant. Carrot umbels provide food and shelter for the Iygus bugs. However, antibiosis is present in some plants and can be increased by selective inbreeding. This insect and plant have an intricate relationship even though they probably have been in contact less than 300 years. Each is benefitted and harmed, but neither is dependent on the other for survival.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.6

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Stage-structured counts of tetranychid mites (eggs, immatures, and adults) on 360 whole cotton plants were made during a single growing season in California, These counts were analyzed by using their departure from a stable stage distribution (65% eggs, 25% immatures, and 10% adults) implied by the birth and death rates from a previous life history study of the twospotted spider mite. By using these stable distributions as base lines for analysis, several questions were addressed, including: (1) What was the possible influence of migration on age structure? (2) How did the birth and death rates in the field populations compare with those determined in the laboratory? and (3) How did birth and death rates differ among the three growth phases? It is concluded that in general the stable age distribution is useful in demographic field studies because it focuses attention on age structure, any observed departure from it demands an explanation, and any explanation must take into account collective changes in proportions of stages intercoupled with commensurate shifts in growth rate.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.10

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The first case of biological control of waterhyacinth,Eichhornia crassipes(Mart.) Solms, by the weevilNeochetina bruchiHustache is reported from the Dique Los Sauces reservoir in La Rioja Province, Argentina. Four years after introduction ofN. bruchi, its population had increased to 3.5 adults per plant; waterhyacinth was reduced from the usual 50% coverage of the water surface to only 10 to 15% coverage, and 2 years later to only 4 to 8% coverage.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.19

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A small weevil,Stenocarus fuliginosus(Marsham), a pest of cultivated opium poppy,Papaver somniferumL., in Europe, was tested for potential as a biocontrol agent of illicit opium poppy. Sixtyseven species of plants in 18 families were tested in adult no-choice feeding tests. Although extensive feeding occurred in several families besides the Papaveraceae, and both oviposition and oogenesis occurred with the composite, chicory, larvae developed only on plants in the Papaveraceae.S. fuliginosushas potential as a biological control agent of various poppies.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.24

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A sampling program for postharvest surveys of the southwestern corn borer,Diatraea grandiosellaDyar, was established during 1976 and 1977 from fields in south central Kansas. Our sampling technique was adequate for an extensive sampling program (precision level = 0.25) if more than 45% of the plants were infested. Larval density in the exterior portion of a field exceeded that in the interior portion if population density was low (three to six borers per 10 plants). A sequential sampling program with a fixed level of precision was developed to minimize effort required for surveys over large areas.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.33

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Safety tests were conducted on guinea pigs and white mice to check for evidence of toxipathogenic effects ofMetarhizium anisopliaeon vertebrates and to measure the viability of conidia eliminated by the animals. The fungus was administered to the animals by ingestion, inhalation, and cutaneous and subcutaneous applications. Anatomical and histopathological examinations revealed thatM. anisopliaeis neither toxic nor pathogenic to test animals. Mycological tests of animal organs treated subcutaneously showed that the conidia remained viable for at least one month in body tissues, especially in the blood, stomach, and liver, but did not germinate. When the fungus was mixed with the diet, viable spores were eliminated with the feces. The propagation of viable spores into fields infested with susceptible host insects is able to be caused by vertebrates fed on a diet containing the fungus.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.37

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Spring activities (emergence, feeding, mating, and oviposition) of adult white pine weevils,Pissodes strobi, were monitored weekly from late April to early July 1979. Weevils emerged from overwintering sites in late April. peaked in numbers per tree by mid-May, and none were found on host trees by early July. Activity peaked in early May and appeared to be thermo-photoperiodic. Greatest activity during the 4-h interval checktimes occurred in the late afternoon to early evening (1300 and 1700 h). Adults occupied upper-branch new growth during scotophase, but moved to branch stems during photophase. Weevils are negatively phototactic, and response time to different wavelengths of light varied during scotophase. The weevils occupied the leaders of host trees the first 2 weeks of monitoring. but toward season's end were found more often on first-whorl lateral branches. Length of current-year growth of leaders was influenced by magnitude of weevil damage. Highest levels of immature weevil damage resulted in leader mortality. Leaders that sustained an intermediate level of weevil damage remained alive; however, length of new growth was significantly less than leaders with almost no weevil damage.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.43

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A binomial model is presented which enables the clumping patterns of different species or categories of cotton arthropods and plant parts to be compared, accounting for the effect of their densities. Estimates of the proportion of infested sample units derived with this model are compared with those derived with three other binomial models. Statistical comparison is made, using as a criterion the degree to which each model fit field values of the proportion of infested sample units collected by three sampling methods (visual whole-plant examination, a bag method, and sweep-net). Those models which fail to incorporate the effect of density on clumping behavior fit the data less well. Estimates of sample sizes derived by a binomial sample size equation and a numerical sample size equation both of which incorporate species clumping behavior are also compared. The sample size estimates from the two equations are most similar at low densities and for species whose distributions appear closest to random; and although binomial sampling requires a larger sample size at higher densities, less time is required to sample each unit (leaf, plant, etc.).

ISSN:1754-5692    

DOI:10.1093/ee/12.1.50

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Eotetranychus hicoriae(McGregor), pecan leaf scorch mite, overwinter as females in the rough bark area on limbs of pecan trees. Data for the 1979 year showed that overwintering mortality exceeded 70%. In the spring, overwintering females began to oviposit within 7 days after initiation of feeding. In laboratory rearings, eggs did not hatch at 18.3°C, and at 35°C 97% of the individuals died as immatures. It is suggested that these temperatures may limit population growth in the field. In the laboratory, higher mortality with increasing temperatures may be due to increasing mortality of individuals that would develop into males.

ISSN:1754-5692    

DOI:10.1093/ee/12.1.55

出版商:Oxford University Press    

年代:1983

数据来源: OUP