摘要:

The first field study of a genetically altered virus in the United States was performed with an isolate of theAutographa californicanuclear polyhedrosis virus (AcMNPV), which lacks a polyhedrin gene. In the first year of the study, three applications of 7.4 × 1011AcMNPV polyhedra containing 48% genetically altered and 52% wild-type virus particles (co-occluded) were made on a O.1-ha circular plot of cabbage plants. The application area was surrounded by a 0.7-ha circular buffer zone. Before each application, the plants in the application area were infested with 4,500 third-ins tarTrichoplusia ni(Hübner) larvae. After each application, 100% of theT. nitest larvae sampled 5 d after infection were infected with AcMNPV and produced progeny polyhedra containing an average of 42 ± 17.6% genetically altered virus particles. At the end of the 1st yr, the progeny polyhedra population in the application area was estimated at 1.6 × 1013polyhedra. In the 2nd yr, the application and buffer sites were replanted with cabbage plants. At four times during the growing season, the plants were seeded withT. nilarvae or eggs. Less than 2% of the test larvae became infected with AcMNPV. Polyhedra were extracted from soil samples collected in the application and buffer areas. Using neonate larval bioassays with the soil extracts, it was estimated that the soil in the application and buffer areas contained an average of 1,652 ± 3,370 and 832 ± 2,539 biologically active polyhedra per gram dry weight, respectively. Seventy-five larvae infected with polyhedra extracted from application area soil samples produced progeny polyhedra containing a mean of 9 ± 19% genetically altered virus particles. In the 3rd yr, the application area soil samples contained an average of 1,671 ± 3,274 biologically active polyhedra per gram dry weight. Eighty-four progeny polyhedral samples contained a mean of 6 ± 14% genetically altered virus particles. The co-occlusion strategy did not alter the environmental persistence of the polyhedra containing both wild-type and polyhedrin-minus virus particles. However, the data show a decline in the percent of polyhedrin-minus particles in the polyhedra and demonstrate that the persistence of a polyhedrin-minus virus in a cycling virus population is limited by the co-occlusion process. The environmentally desirable attributes of using the co-occlusion process for genetically enhanced baculovirus pesticides and possible problems are discussed.

DOI:10.1093/ee/23.2.211

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

From 1989 through 1992, preserved insect fauna of Knife Point, Bull Lake, and Upper Fremont glaciers (Wind River Range, Fremont County, Wyoming) was examined. Knife Point Glacier contained the first intact, glacially preserved grasshopper specimens found in the past 40 yr. These specimens were found below a crevassed region, and available evidence indicates that they may have been concentrated and preserved within a crevasse 140 ± 50 yr ago. Morphological assessments of these bodies and cluster analyses of mandible and tibia measurements established that all but one or two of the exposed deposits were comprised of the extinct Rocky Mountain locust,Melanoplus spretusWalsh. Examination of distinct summer-melt strata indicates that this species was deposited at random intervals over a period of 300 yr. The Boating section of strata also contained the first known glacial remains of swarms of the extant migratory grasshopper,Melanoplus sanguinipes(F.), and the first record of an insect other than grasshoppers (a parasitic wasp,Copidosomasp.) having been periodically deposited. A total of six insect orders was found on this glacier. Aerial and runoff samples indicated that the rate ofaccidentalinsect deposition on the glacier is very low, and the rate of loss of material from the surficial runoff may exceed a million specimens per year. Bull Lake Glacier also contains at least one very rich deposit of well-preservedM. spretus, but other grasshopper remains appear to be widely scattered across the surface. Grasshopper remains from ice cores of Upper Fremont Glacier were dated from as early as 840 ± 85 yr before the present, making this the oldest known glacially preserved insect deposit.

DOI:10.1093/ee/23.2.220

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Seasonal changes in within-vineyard distribution and abundance ofErythroneura comes(Say) adults and nymphs were investigated from 1989 to 1992. Trap catches of adults were highest in May and were concentrated in wooded areas next to vineyards. In 1989 and 1990 surveys, nymphal densities did not decline as distance from the vineyard edge increased. In 1991, however, nymphal densities were significantly higher at vineyard edges than in vineyard interiors in July, suggesting that oviposition initially was aggregated at vineyard edges. Subsequently, nymphal densities at vineyard edges and interiors were similar. Cumulative degree days (DD) for mean observation of first nymphs, first-generation, and second-generation peak populations, sampled at 14 vineyards in 1989, 1990, and 1991, were 390 ± 71, 648 ± 86, and 1,190 ± 154 DD (mean ± SD; base 10°C), respectively. Nymphal densities exceeded a provisional threshold of five per leaf in only 2, 25, 13, and 8% of vineyards untreated with insecticides in 1989, 1990, 1991, and 1992, respectively. These results show that leafhoppers do not cause economic injury in most New York vineyards in most years. Reduced insecticide strategies recently implemented for grape berry moth control will not greatly increase the need for insecticide applications directed at leafhoppers in New York.

DOI:10.1093/ee/23.2.236

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Effects of early-season damage by the citrus rust mite,Phyllocoptruta oleivora(Ashmead), on ‘Hamlin’ orange fruit growth and drop were studied from 8 June through 17 December 1991, in Hendry County, FL. ‘Hamlin’ fruit drop increased with increasing fruit surface damage by the citrus rust mite. The data also indicated a slightly accelerated fruit drop with increasing mite damage and time. The overall data suggested a slight negative relationship between fruit size and mite damage. Cumulative percentage drop and percentage diameter increase were fitted to two-variable logistic functions of damage and time. These functions could be used in management models for calculating volume losses from rust mite damage.

DOI:10.1093/ee/23.2.244

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Previous studies have investigated the use of head capsule widths from various insect species to describe the distributions of each instar. We present a unique method to classify instars of the gypsy moth,Lymantria dispar(L.), based on head capsule width. Our method uses nonlinear least squares parameter estimation to describe the distributions of each gypsy moth instar. Head capsule measurements from 3,903 field collected larvae were used to derive instar class ranges. Class boundaries were assigned at the point of distribution overlap between adjacent instars. Probabilities of misclassification were determined from probability distributions fitted to each instar. A final classification rule was developed that will provide managers with a tool for determining the phenological distribution of a gypsy moth population from field collected data. The distribution of field collected frass widths was also evaluated as a means for classifying instars and did not result in a useful instar classification method.

DOI:10.1093/ee/23.2.248

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Studies were conducted to examine distributional patterns ofBemisia tabaci(Gennadius) eggs and nymphs on two cultivars of upland cotton,Gossypium hirsutumL., and one American Pima cotton,G. barbadenseL., and to develop efficient sampling plans for estimating densities of immatures. On a per square centimeter basis, both eggs and nymphs were equally distributed among the four leaf sectors delineated by the major leaf veins. This pattern was independent of the nodal location of the leaf, cultivar, or sampling date. However, based on counts on 3.88-cm2disks near the petiole of the leaf, both egg and nymphal were aggregated at the proximal end of each sector. The relationship between disk and whole leaf counts varied with nodal position and cultivar. The greatest number of eggs and nymphs were found on mainstem leaves from nodes 2–4 and 4–7 (mainstem terminal = node 1), respectively. This pattern changed slightly with time but was similar among the three cultivars. The lowest coefficients of variation were associated with leaf counts from nodes 4–5 and 5–6 for eggs and nymphs, respectively. Based on variance partitioning and sampling cost analysis, a single 3.88-cm2disk from the base of the second sector of the fifth mainstern node leaf was determined to be the most efficient sample unit for estimating egg and nymphal densities. Sequential sampling stop lines were calculated for this sample unit using Green's (1970) method. Sample plan validation using Monte Carlo simulation indicated that actual levels of precision (SEM/mean) were poorer than those specified at low densities of immatures and better than specified at high densities. Further simulations indicated that stop lines for specified precisions of 0.20, 0.25, or 0.30 would maintain an average precision of 0.25 when egg or nymphal densities are100 per leaf disk, respectively. These sampling plans allow efficient monitoring for pest management application and will aid the study ofB. tabacipopulation dynamics in cotton.

DOI:10.1093/ee/23.2.254

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Native male population, new recruits (young indigenous and immigrant flies), and survival rate of oriental fruit fly,Bactrocera dorsalis(Hendel), were estimated, by mark-release-recapture technique using methyl eugenol–baited traps, in two villages in Penang Island, Malaysia. Population size and new recruits were significantly higher in Tanjong Bungah (TB) than in Batu Uban (BU). This was caused by the higher number of fruits damaged in TB, although BU had more varieties of fruit trees. However, survival rate of fruit flies in both villages was the same. The most important component of the environment affecting adult populations ofB. dorsalisin the tropics is the availability of suitable host fruits. In both villages, among a variety of host plants grown, starfruit played the most important role in this regard. The abundance of damaged fruits fluctuated and lagged behind estimated populations and new recruits ofB. dorsalismales by 3–5 and 2–4 wk, respectively. Peak numbers ofB. dorsalismales and host fruits occurred entirely within the wet seasons of the year. During dry seasons, the fly population declined because of less fruit. However, rainfall (as well as temperature, relative humidity, and wind speed) had no significant correlation with estimatedB. dorsalismale population parameters or host fruit abundance.

DOI:10.1093/ee/23.2.267

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The algaeNitzschia latensHustedt,Ctenocladus circinnatusBorzi, and two species ofOscillatoriawere isolated from Mono Lake, which is near Lee Vining, CA, and used to produce cultures containing only one algal species (unialgal cultures). Survival to pupation and rates of larval growth and development were compared among larvae ofEphydra hiansSay, which were reared on one of these algal species or on a diet prepared using the fish food Tetramin. It was found that larvae could be reared from the second larval molt to pupation when fed on a single species of algae. Larvae reared onNitzschiashowed significantly increased weight gain and survival compared with larvae reared onCtenocladus.Growth performance was always orderedNitzschia, Oscillatoria, thenCtenocladus.Larvae reared onNitzschiaorOscillatoriadeveloped significantly faster than those reared on Tetramin. The results indicate that single species ofNitzschiaandOscilatoriaare adequate food sources forE. hiansgrowth. Although larvae of this fly appear to be generalist algal herbivores, food quality varies between algal species.

DOI:10.1093/ee/23.2.276

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Effects of relative humidity on reproductive behavior of smokybrown cockroaches,Periplaneta fuliginosa(Serville), were studied. Groups of five field-collected females (newly molted and mated) were placed in aquaria containing four substrate choices for oviposition (peat, marble chips, a simulated wall void, or bare floor). Aquaria were maintained in humidity chambers set at either 50–55, 65–70, or 80–85% RH. After 49 d, adults were removed from the aquaria and location and number of oothecae were recorded. Oothecae were kept separately until nymphs were counted after eclosing. Peat was the substrate used most often for oviposition. Variations in humidity did not have a significant effect on substrate choice, numbers of oothecae produced, or eclosion rate of oothecae. Oothecae that were glued to a substrate had a significantly greater eclosion rate than those that were not glued. It is not known whether a female can detect which oothecae are viable and subsequently invests the time and energy to glue them to a substrate or whether gluing oothecae enhances their eclosion rate.

DOI:10.1093/ee/23.2.299

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

In open-field patches of five potted host trees containing varying amounts of proteinaceous food and host hawthorn fruit, we investigated the comparative influence of varying fly physiological and experiential states on the location and duration of residence of 18-d-old released apple maggot,Rhagoletis pomonella(Walsh), females. Several patterns of fly response were consistent with our preexperimental expectation. Thus, duration of residence was greater in patches where proteinaceous food and host fruit were present on all trees than in patches where either or both resources were absent from one or more trees, largely irrespective of fly physiological or experiential state. Flies that had no access to protein up to day of release (low egg load flies) were sighted in greater numbers on proteinaceous food than were flies that had continuous access to protein up to day of release (high egg load flies), whereas the reverse was true for flies sighted on host fruit. Flies that had partial access to protein up to day of release (intermediate egg load flies) were sighted in intermediate numbers on proteinaceous food and fruit. Flies that had continuous access to protein up to day of release were observed in greatest numbers on fruit if they received brief experience with fruit (as opposed to water or proteinaceous food) just before release. Presence on fruit of flies that had partial access to protein up to day of release was unaffected by type of brief experience just before release. Some patterns of fly response were not consistent with our preexperimental expectation. Thus, flies that had no or partial access to protein up to day of release were observed in fewer numbers (not greater or equal numbers, respectively) on proteinaceous food if they had brief experience with proteinaceous food just before release compared with brief experience with water or fruit. Flies that had no access to protein up to day of release and received brief experience with proteinaceous food just before release were found on tree foliage and in total in greater numbers (not equal numbers) than flies that had continuous access to protein up to day of release and received brief experience with fruit just before release. These and other findings are discussed in relation to previous knowledge of the resource foraging behavior of tephritid flies and in relation to improvement of behavioral methods of managingR. pomonellaflies in commercial apple orchards.

DOI:10.1093/ee/23.2.304

出版商:Oxford University Press    

年代:1994

数据来源: OUP