Sweep-net Collections Research Articles

Reproductive Condition of Female Corn Earworm (Lepidoptera: Noctuidae) Moths from Sweep Net and Blacklight Trap Collections in Corn

The reproductive conditions of female corn earworm, Heliothis zea (Boddie), moths caught in blacklight (BL) traps and those captured in sweep nets in corn during 1988 and 1989 were compared. There was no significant difference in mean number of spermatophores per female between moths captured in sweep nets and those caught in BL traps. Number of spermatophores averaged 2.2 per female. The pattern in the number of spermatophores per female over time in corn earworm moths caught in BL traps closely approximated that of females captured in sweep nets. The pattern of change in sex ratio in corn earworm moth catches in BL traps closely approximated that of moths captured in sweep nets, with some exceptions. Profiles describing relative number of chorionated eggs and amount of fat were similar in moths collected by sweep nets and those caught in BL traps. Data indicate that catches in BL traps may be used as an alternative to nocturnal sampling of adults with sweep nets for describing the reproductive condition of female corn earworm moths in corn.

Phenology of Cerotoma trifurcata on Soybean and Alfalfa in Central Iowa

Bean leaf beetle, Cerotoma trifurcata (Forster), adults were sampled from 1986 through 1988 in soybean and alfalfa in central Iowa to ascertain the seasonal phenology of this pest. Data from all 3 yr indicate that two generations of this insect occur in Iowa. Overwintering adults inhabit alfalfa before soybean emergence, colonize soybeans immediately after seedlings emerge, and die by late June. F1 adults are abundant from late June to middle or late August, and F2 adults are present from early August to soybean maturation. Females are more abundant than males among overwintering and F1 adults, but neither sex of F2 adults is more numerous. The yellow/red adult ratio is greater during the fall than in the spring, indicating greater winter survivorship of red adults. Adults were present in soybean from seedling emergence to crop maturation but were found in alfalfa only in late spring, before soybean emergence, and in August–September as soybean matured. Captures of adults during diurnal sweepnet collections made from 0830 to 2030 hours (CST) on 21 July 1988 were least at 0830 and 1000 hours, the period of heavy dew on the soybean canopy. From 1300 to 1600 hours, the number of females with developing ovaries declined, whereas the number of females with fully developed eggs increased.

SEASONAL ACTIVITY OF FEMALE BLACK FLIES (DIPTERA: SIMULIIDAE) IN PASTURES IN NORTHEASTERN SASKATCHEWAN

AbstractThe black fly species Simulium luggeri Nicholson and Mickel s.l., S. vittatum Zetterstedt s.l., S. venustum Say s.l., S. verecundum Stone and Jamnback s.l., and S. decorum Walker s.l. were collected in silhouette traps near Prince Albert, Sask., in 1986, and near Choiceland, Sask., from 1986 to 1988. The Prince Albert site was located between and within 2 km of the North and South branches of the Saskatchewan River and was 25 and 60 km south of the Whitefox River and Torch River systems. The Choiceland site, 60 km east of the Prince Albert site, was 15 km north of the main branch of the Saskatchewan River and 1/2 and 25 km south of the Whitefox River and Torch River, respectively. Simulium luggeri was the most abundant species collected at the Prince Albert site whereas S. luggeri, S. vittatum, and the S. venustumlverecundum complex were approximately equally abundant in trap catches near Choiceland over the entire season but in each study year a seasonal progression in peak abundance occurred. Black fly numbers in sweep net collections taken once, in the middle of the day, were weakly correlated with numbers in silhouette trap collections taken during an entire day.

Seasonal Abundance of Anthropophilic Simuliidae from the Adirondack Mountains of New York State and Effectiveness of an Experimental Treatment Program Using Bacillus thuringiensis var. israeliensis

A 154-km2 study area near Loon Lake, Town of Franklin, Franklin County, N.Y., was used for sampling the nuisance activity and seasonal occurrence of anthropophilic Simuliidae within the Adirondack Park. Black flies were monitored at 47 sites on a biweekly or weekly basis throughout two consecutive flight seasons. Population data were acquired from over 1,800 10-min aerial, sweep-net collections of black flies swarming around stationary human collectors from 17 May–6 August 1982 and from 2 May–2 September 1983. Thirteen species in four genera of black flies were represented in combined collections of over 171,000 females. Of the 13 species collected, 12 represent new black fly distribution records for Franklin County, N.Y. Intensity and duration of predominant species' seasonal flight patterns were monitored and compared. In addition, mean numbers of black flies captured inside and outside a partially overlapping area that had been experimentally treated with Bacillus thuringiensis var. israeliensis ( Bti ) were compared on a weekly and seasonal basis. Despite evidence of effective control of several Simulium species, the application of Bti did not result in the control of anthropophilic Prosimulium .

Peri-Domestic Ecology of Dry-Season Populations of Aedes ( Stegomyia ) Mosquitoes 1 in Uyo, Cross River State, Nigeria

The ecology of the dry-season populations of Aedes Stegomyia mosquitoes was studied in Use, Uyo, Cross River State, Nigeria, between November 1977 and May 1978. The adult insects were sampled by two collection methods: (1) crepuscular human bait and (2) sweep-netting from forest and village (outdoor and indoor) locations. Oviposition and breeding habits of the insects were assessed from CDC ovitrap collections and from a survey of larval presence in domestic and peri-domestic containers. In each case, insects were sampled in the months of November, January, March, and May, corresponding with the early, mid, and late dry season, and the early rainy season, respectively. Fourteen species of Aedes mosquitoes, including four Aedes ( Stegomyia ) species, were found. Numbers and distribution of the species varied with the months and sampling methods. Adult Aedes ( Stegomyia ) were most numerous in indoor and outdoor crepuscular human bait collections and least in forest sweep-net collections. Aedes aegypti and A. africanus were the most collected species. Unlike most other Aedes spp., they were consistently well represented in all the dry-season samples. Larval indices showed predominant breeding of Aedes ( Stegomyia ) species in peridomestic locations throughout the dry season, as well as the ecological adjustment to a container breeding habit by some otherwise well-known tree hole and pool breeding forms. Factors involved in the dry-season survival of the various Aedes spp. are discussed with reference to the possible implications of the insects' domesticity and year-round breeding activity.

Ecological Studies on Aedes Simpsoni (Diptera: Culicidae) in Southeastern Nigeria1

This study was undertaken to determine the productivity and survival rates of immature Aedes simpsoni in plant axils in Nigeria; host preferences and resting sites of the adults were also studied. In the vicinity of Enugu the larval densities were highest during July, August and September. The axils of cocoyam ( Colocasia esculenta ) were the most effective producers of immatures, followed by banana/plantain ( Musa spp.), pineapple and Dracaena sp. Since Ae. simpsoni preferred fresh, fully formed axils to experimental oviposition sites, the larval densities obtained in surveys with bamboo cups and CDC black-jar ovitraps declined as the natural habitats became available during the wet season. The highest mortality rates of Ae. simpsoni in cocoyam axils occurred during the 3rd and 4th instars; the overall mortality rate was 97.9%, which was in agreement with the daily emergence rates. In comparisons of bait-net catches from human bait and other animals, and sweep-net collections from different biotopes, too few Ae. simpsoni were collected to draw formal conclusions with respect to host preference and preferred resting sites, although there is evidence that Ae. simpsoni bites man near human habitations in southeastern Nigeria.

Preemergence Systemic Insecticides for Establishment of New Alfalfa Seedings, 1979

Abstract Furadan insecticide was applied as preplant incorporated soil applications to a new planting of alfalfa in spring seeding. These applications were made with both granular and liquid formulations to assess not only the insecficidal benefit of establishing new stands of alfalfa but the effect on stand, reduction of seeding rate, yield, and spectrum of insect control. At planting incorporated broadcast treatments were mode to the seed bed after Eptam and fertilizer were incorporated into the topsoil. Treatments were applied May 11’79 to plots 3 × 15 ft randomized in a complete block design with 3 replications. Granular applications were made with a hand held shaker can combining seed amount and insecticide with a small amount of sand added and thoroughly mixed to aid even distribution of mixture. Liquid Furadan 4F applications were sprayed on with a CO2 bottle sprayer at a volume of 30 GPA after seeding. All treatments were then raked lightly to incorporate seed and treatments into the well fitted soil. Three rates of alfalfa seeding (10, 15 and 20 lb) were used with Furadan 10G. Stand populations were sampled twice with post treatment insect samplings done at 75 days using 5-180° insect sweep net collections per plot. Yields were sampled at 75 days by taking square foot samples out of plot centers and weighing all the cut hay to determine green weights.

Second Cutting on New Seeding Alfalfa Study, 1978

Abstract Alfalfa was planted at the Agway Farm Research Center, Fabius, NY, on May 19‘78. Plots were established in a randomized block design of 3 replications (plot size 12 ft x 25 ft - 300 square feet/plot). Fertilization consisted of 600 lb/A of 1-10-40 with boron. Eptam preplant incorporated and Premerge early postemergence were used as herbicides. Insecticide treatments were applied on Aug 2‘78 with CO2 bottle sprayer using .5 gallon bottles to deliver 72.6 GPA at 30 psi. Post treatment insect samplings were done at 8 days on Aug 10‘78 and at 21 days on Aug 23‘78 by using 10-180° insect sweep net collections per plot. Yields were taken at harvest on Sept 7‘78 by cutting a 1/1000 acre swath out of plot centers and weighing all hay cut. Samples were taken to determine percent DM by oven drying analysis.

Second Cutting Alfalfa Insect Control Study, 1977

Abstract Alfalfa was planted at the Agway Farm Research Center, Fabius, NY, on Apr 23‘75, in a randomized block design of 3 replications (plot size 12ft x 25 ft - 300 square feet/plot). Six hundred lb/acre of 1 -10-40 with boron used for fertilization and Eptam and other PPI herbicides were used. Treatments were applied on Jun 30‘77 with CO2 bottle sprayer using 0.5 gallon bottles to deliver 72.6 GPA at 30 psi. Post treatment insect samplings were done at 11 days on July 11‘77 by using 10-180° insect sweep net collections per plot. Yields were taken at harvest on Jul 29‘77 by cutting a 6 x 21.5 (130 square feet) swath out of plot centers and weighing all hay cut. Samples were taken to determine percent DM by over drying analysis.

STUDIES ON THE ARTHROPOD FAUNA OF ALFALFA: V. SPIDERS (ARANEIDA)

AbstractThe spider fauna of alfalfa was studied at Ithaca, N.Y., in three experimental plots and in nearby fields during 1966–69. As part of an overall study of the arthropod fauna of alfalfa, the spider populations in the study plots were recorded weekly during visual examination of the terminal 6 in. of five stems for 100 plants in each of the plots. Additional information was obtained from sweep-net and pitfall trap collections in the study plots and from sweeping several commercial plantings. The spider fauna of alfalfa was found to consist of 78 species, 10 of which were collected only from the ground layer. Tetragnatha laboriosa Hentz and Dictyna volucripes Keyserling were the most abundant species found in the weekly samples. Notes on the seasonal occurrence, location on the plants, and feeding habits are given for the common species.

Some Observations on Fecundity and Sex Ratios of the Potato Leafhopper12

In laboratory rearing studies and 2 types of field studies, Empoasca fabae (Harris) oviposition rates ranged between 2.5 and 3.8 eggs per female per day, and the average number of eggs per female ranged between 33.7 and 57.4. In 9 separate studies conducted in the laboratory over a period of 13 months the percent females produced ranged from 47.7 to 56.3 and averaged 52.8. In 10 cage studies under field conditions conducted over a period of 3 years, the percent females in the progeny ranged from 48 to 52 and averaged 50.2. Likewise, over a period of 4 years, in sweep-net collections of breeding populations of E. fabae in alfalfa, the sex ratios were consistently close to 1:1.

Emergence and Flight Activity of Salt-Marsh Horse Flies and Deer Flies1,2

Bionomics of 4 common Tabanidae (Diptera) was studied by use of emergence traps, Manitoba fly traps, and insect sweep-net collections. Emergence locations and sex ratios are presented. Female Tabanus nigrovittatus Macquart predominated on a New Jersey salt marsh near an upland area, apparently being concentrated by southeast breezes. The tall, dense, marsh-upland border vegetation apparently presented a geographical barrier to flight farther inland and formed an environmental trap at some locations. Aggregation to geographically pronounced locations occurred on the marsh. Many female Chrysops atlanticus Pechuman sought a blood meal on the marsh during the period of adult emergence, but those seeking blood shifted entirely from the marsh to the upland, about 150 yards from the marsh edge soon after adults had ceased emerging.

Investigation into the Source of a Summer Alfalfa Weevil Larval Population in New Jersey1

Sweep-net collections during the summers of 1962 and 1963 showed that a reduced population of the alfalfa weevil, Hypera postica (Gyllenhall), was present in northern New Jersey alfalfa fields. Larvae and adults were consistently collected. Investigations into the source of the larval populations were based primarily on dissections of field-collected and laboratory-reared female adults. From the present data it appears that the summer larval population is the result of late maturing, overwintered adults.

Spanogonicus albofasciatus and Rhinacloa forticornis on Cotton in Arizona1

Sweep-net collections of Spanogonicus albofasciatus (Reuter) and Rhinacloa forticornis Reuter on cotton in 3 different years showed that S. albofasciatus was dominant in all years with its seasonal peak larger than and preceding that of R. forticornis . R. forticornis appeared to be a predator. Both species were abundant on weeds in cottonfields without being abundant on cotton itself. In cage tests the cotton plants easily tolerated feeding damage by S. albofasciatus and recovered quickly. Square shedding in the presence of this insect should probably be attributed to lygus bugs or to physiological causes. Test results indicated that natural populations would rarely damage cotton except in the seedling stage. A low reproductive rate of S. albofasciatus on Acala 4–42, Acala 44, and Deltapine Smoothleaf 3798 cotton varieties is suggested.

Populations of Certain Insects and Spiders on Cotton Plants Following Insecticide Applications

In 1959, 1960, and 1961 sweep-net collections were made in several field-plot experiments on cotton in the vicinity of Stoneville, Mississippi. The numbers of several species of insects and spiders were recorded following applications of various insecticides and insecticide mixtures. Early-season applications for thrips control had little effect on the insect populations studied several weeks later during the fruiting period. Applications made during the fruiting period of the cotton plant resulted in population reductions of many of the insect species and spiders studied. The species affected and the amount of reduction were quite variable, depending on the insecticide or mixture used, dosage, number of applications, and timing of applications. Insecticide mixtures containing DDT were in general more toxic to most species than any single insecticide.