摘要:

We investigated the feasibility of applying the aesthetic injury level (AIL) concept to pests such as cockroaches in urban pest control programs. A random survey was conducted in public housing projects in Roanoke, Va., Norfolk, Va., and Baltimore, Md. One hundred surveys were taken in each of the cities. The results of the survey indicate that the AIL is variable based on the extent of the pest infestation. The larger the infestation, the greater the tolerance to some level of pest infestation. However, we speculate that as infestation level declines, tolerance of the pest will also decline. This will require designing pest control programs to address the specific attitudes of the target audience.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1453

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Sequential decision rules based upon defining a relationship between the mean and variance of a population and using this relationship in a confidence interval about a sum of counts on sample units have been developed and used for sampling insect pests. The actual error rates that arise from the use of these rules are much larger than the nominal ones. This occurs for three reasons: The confidence interval is incorrectly used as a sequential decision rule; it is assumed that random variables are normally distributed; and variances are not constant. If these sequential decision rules are to be used, we suggest that actual error rates be determined through simulation.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1459

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

A field study was conducted to examine the foraging pattern of the Formosan subterranean termite,Coptotermes formosanusShirah A dye, Sudan Red 7B, was used as a marking material to identify foragers feeding at specific foraging sites. The results showed that the termites selected their foraging sites at random. No preferences in foraging site were observed. Since foraging sites were selected at random, all of the foragers in a given colony would visit a specific foraging site, given sufficient time. It is theoretically possible, therefore, to introduce a suitable control agent in a single foraging site and eliminate the entire colony.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1466

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

The quantitative and qualitative losses of simulated bagged wheat (Triticum aestivumL.) infested bySitotroga cerealella(Olivier),Sitophtlus oryzae(L.), or both species were studied at 28°C and 60% RH for 22 weeks. Ventilated bottles with 130 g of wheat of 11.5% moisture content were placed inside 44-kg bags of wheat for evaluation of four treatments to simulate the environment inside a grain bag, the most popular method of storing grain in the tropics and subtropics. The treatments consisted of wheat with no insects, withS. cerealellaby itself, withS. oryzaeby itself, and with a mixture ofS. cerealellaandS. oryzae.The variables measured were insect numbers, temperature, CO2concentration, moisture content of wheat, microflora, seed germination, 100-kernel weight, dust weight, and fat acidity value (FAV). The numbers of liveS. cerealellaincreased rapidly until week 15 and then decreased in both single- and mixed-species treatments. The rapid growth ofS. cerealellain single- and mixed-species treatments resulted in increases in temperature, CO2concentration, moisture content, bacterial infection, dust weight, and FAV and decreases in germinability and 100-kernel weight. The infection level of fungi of theAspergillus glaucusgroup in wheat increased during 10–15 weeks but then decreased after severe deterioration had occurred. The numbers ofS. oryzaeincreased slowlyin single- and mixedspecies treatments but did not appreciably affect other variables during 22 weeks.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1471

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Examination of data from Florida (United States) and Queensland (Australia) revealed a close relationship between numbers of adult waterhyacinth weevils (Neochettna etchhomtaeWarner) and the number of feeding scars on waterhyacinth leaves. Regression analysis produced nearly identical results for samples from both countries even though data collection techniques differed. The empirical formulaI= 0.036650.775, whereI= weevils per plant andS= feeding scars per lamina, effectively predictedIfor both countries. The errors associated with the prediction of weevil populations using this formula are discussed. This technique for estimating adult weevil populations is suitable for use in other regions where monitoring of biological control of waterhyacinth is undertaken; its application, advantages, and limitations are discussed.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1478

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

A wasp parasite of ice plant scale,Encyrtus saliensPrinsloo and Annecke, was studied to determine the effect of simulated malathion-Staley's bait spray residue on the walking speed of the parasite and whether the bait alone was attractive or repellant.Trioxys pallidus(Haliday), a parasitic wasp of walnut aphid, andEuderauphale fiavimedia(Howard), a parasitic wasp of iris whitefly, were similarly tested for response to the bait. Walking speeds of intoxicated wasps and controls were determined with a video cameramicrocomputer tracking system. Baseline data on the effect of temperature and time of day were established. Attraction to the bait was tested in 50-mm arenas with single sources of bait and honey or bait only. The ice plant scale parasite was extremely susceptible to the simulated spray residue. However, increased walking speeds were found following sublethal intoxication from degraded diluted spray residues. The three wasp species demonstrated neutral or negative responses to Staley's bait in all but 1 of 45 cases. The net impact of a toxicant-bait spray program on parasitic wasps needs to be determined under field conditions, but this study identifies the phenomena that may contribute to that net result.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1483

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Tree nitrogen, assessed as foliar % N, phloem-cortex free amino acids, and leaf color all increased with tree fertilization, indicating an increase in nitrogen availability to pear psylla,Psylla pyricolaFoerster. Free amino acid levels in psyllids increased with tree fertilization rate in orchard and growth room tests. Protein levels, however, were higher in psyllids from seedlings of medium nitrogen content than in those from low- or highnitrogen seedlings. Psyllids from low-nitrogen seedlings weighed more than those from medium-nitrogen seedlings. Psyllid feeding rate, estimated by honeydew production, was compared on low- and high-nitrogen seedlings. Nymphs on very-low-nitrogen leaves produced more honeydew, suggesting a compensatory feeding response to low dietary nitrogen. Physiological, morphological, and ecological ramifications for pear psylla include effects on (1) adult protein content, (2) adult body size, and (3) nymphal developmental rate.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1487

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Data from a 10-year study were analyzed to understand the epidemiology ofNomuraea rileyi(Farlow) Samson in green cloverworm (GCW),Plathypena scabra(F.), populations in Iowa. Larvae were collected by sweeping in soybean fields each year from 1971 through 1980 and were maintained in the laboratory until completion of development or death. Six endemic and 4 outbreak GCW population types were identified from the 10 collection years.N. rileyiwas a major agent of GCW mortality, especially during the second GCW generation of outbreak years. The seasonal increase in percentageN. rileyi-caused mortality in outbreak populations is described as a function of the number of days after the date of initial detection of infected larvae. In all years, the mortality rate of the second GCW generation fromN. rileyiinfection is significantly dependent on the size of the first GCW generation. The date of first prominent (2%)N. rileyi-caused mortality is significantly explained by the accumulated larva-days and accumulated precipitation from 1 June. These results support and supplement existing explanations of GCW population dynamics in Iowa by providing quantitative expressions ofN. rileyiepidemiology.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1491

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Aqueous homogenates of terminal-instar larvae of fall armyworm,Spodoptera frugiperda(J. E. Smith), and corn earworm,Heliothis zea(Boddie), were evaluated against field populations ofS. frugiperdain whorl-stage field corn near Tifton, Ga. The number of fall armyworm egg masses oviposited on corn treated with either 1.0 or 0.1 larval equivalent per plant of either fall armyworm or corn earworm was significantly lower than that of controls. Multiple applications of 1.0 larval equivalent per plant of fall armyworm and corn earworm reduced the subsequent establishment of fall armyworm larvae by 66.5 and 63.6%, respectively. Plots treated one, two, or three times weekly with 1.0 fall armyworm larval equivalent per plant all received significantly fewer fall armyworm egg masses than did the control plants. Plots treated two or three times weekly contained significantly fewer subsequent fall armyworm larvae-infested plants than did plots treated once weekly. Although deterrent mechanisms have not been specifically identified, semiochemicals associated with terminal-instar larvae of fall armyworm and corn earworm and/or their byproducts may be responsible for inducing fall armyworm females (and, to a lesser extent, newly emerged fall armyworm larvae) to seek uncontaminated sites for oviposition and establishment, respectively.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1498

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

The alarm pheromone of southern California populations of the antForelius foetidus(Buckley) was identified as 2-heptanone. This compound (2.9µg per worker) occurs in an admixture withcis, trans-iridodialand a minor unidentified iridodial isomer, which together constitute a defensive secretion emitted posteriorly from the gaster. Secretory components were isolated and quantified from extracts by gas chromatography and structurally elucidated by1H and13C nuclear magnetic resonance analyses. Videorecordings of agonistic encounters with foreign ants revealed a stereotypical defense behavior ofF. foetidusworkers culminating in aerial transfer of their secretion onto the heterospecific worker. The defensive spray was repellent but not toxic to eitherSolenopsis maniosaorCrematogaster califomicaChemical and behavioral comparisons betweenF. foetidusandF. (=Iridomyrmex) pminosusindicate a high degree of similarity between these sympatric ants and support the generic reclassification of the latter species.

ISSN:1754-5692    

DOI:10.1093/ee/13.6.1502

出版商:Oxford University Press    

年代:1984

数据来源: OUP