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Insect Science, Ecology, General Medicine, PEST analysis, Bollworm, Lygus hesperus, biology.organism_classification, biology, Infestation, medicine.disease_cause, medicine, Cabbage looper, Toxicology, Botany, Chrysopa, Pest control, business.industry, business, and Beneficial insects

Five season-long insecticidal control programs were compared for their impact on pest and beneficial insects in a 240-acre cotton field. The pest species encountered were Lygus Hesperus Knight; the cabbage looper, Trichoplusia ni (Hubner); and the bollworm, Heliothis zea (Boddie). The beneficial insects assessed were a minute pirate bug, Orius tristicolor (White); a big-eyed bug, Gcoeoris pallnes Stal; a collops beetle, Gollops vittatus (Say); a damsel bug, Nabis americoferus Carayon; and a green lacewing, Chrysopa carnea Stephens. L. hespems was suppressed most effectively by 5 applications of toxaphene-malathion, 4 applications of Bidrin® (3-hydroxy- N, N -dimethyl- cis -crotonamide dimethyl phosphate), and 5 applications of toxaphene-DDT, All chemicals were applied when an average of 2 or more L. hesperus per 50 net sweeps was encountered. In another toxaphene-DDT program, 3 treatments applied each time an average of 10 L. hesperus per 50 net sweeps was found resulted in moderate reduction of this species. The abundance of L. hesperus in the control exceeded the recommended treatment level of 10 bugs per 50 net sweeps in 7 out of 13 weekly samples taken from June 6 to August 30. During the period of L. hesperus control, predator abundance was severely reduced in the toxaphene-malathion and the 2 Bidrin programs. It was moderately reduced where 5 applications of toxaphene-DDT were made and less severely so in the limited toxaphene-DDT program (3 applications). In August, an outbreak of cabbage looper occurred in all the chemical programs. By contrast, the control which had retained its predator populations suffered the lowest infestation and the least damage. One of the Bidrin programs was not treated and was extensively defoliated by cabbage looper. The other Bidrin program was treated at weekly intervals with Bacillus thuringiensis Berliner and was not seriously damaged. Two applications of toxaphene-DDT gave the most effective chemical control of cabbage looper. In late August and September, bollworm was significantly reduced in the programs receiving I and 3 applications of toxaphene-DDT, but unaffected by 3 applications of toxaphene-carbaryl and 4 of B. thuringiensis . The Bidrin program, which had been heavily defoliated by cabbage looper, was not treated for bollworm, yet the bollworm infestation remained below that found in the control. Four evaluations of boll set made during the season at periodic intervals showed no significant differences between any of the chemical programs and the control. However, in the final boll count made following the period of bollworm infestation the degree of bollworm damage was lowest in the 2 toxaphene-DDT programs followed by the Bidrin program, which had not been treated for bollworm. Correspondingly, at harvest, the highest yields were produced in the 2 toxaphene-DDT programs followed by the latter Bidrin program. But, only the toxaphene-DDT program which had received the least number of applications produced a significantly greater amount of cotton than the control.

Insect Science, Ecology, General Medicine, Leafhopper, biology.organism_classification, biology, Nymph, Macrosteles fascifrons, Aster yellows, Hordeum vulgare, Horticulture, Transmission (mechanics), law.invention, law, Incubation period, Aster (genus), and Botany

When nymphs and adults of Elymana virescens (F.) were caged for 7 days on barley plants, Hordeum vulgare L. var. ‘Vantage’ infected with aster yellows casual agent (AYCA), 26% and 24%, respectively, of the exposed insects subsequently transmitted AYCA to barley seedlings. In comparable concurrent experiments with the aster leafhopper, Macrosteles fascifrons (Stal), 48% and 78% of the nymphal and adult groups, respectively, transmitted the causal agent. An incubation period of 39-46 days was required before 95% of the inoculative E. virescens could transmit, whereas less than 32 days were needed before 85% of the inoculative M. fascifrons transmitted. However, once the leafhoppers of both species became inoculative they were equally consistent in transmitting. When adult E. virescens and M. fascifrons were injected with an inoculum containing AYCA, 16% and 55% of the injected insects, respectively, became inoculative. The concentration of AYCA in the extracts of inoculative E. virescens was about equal to that of inoculative M. fascifrons when the extracts were prepared on the basis of leafhopper weight.

Insect Science, Ecology, General Medicine, Rhodnius prolixus, biology.organism_classification, biology, Chlorpyrifos, chemistry.chemical_compound, chemistry, Xenopsylla, Toxicology, Resmethrin, Triatoma infestans, Aedes aegypti, Aerosol, Anopheles albimanus, fungi, complex mixtures, and parasitic diseases

The effectiveness of selected aerosols and micronized dusts in controlling insects in aircraft, was evaluated in simulated field trials against 3 mosquito species ( Aedes aegypti L., Anopheles albimanus Wiedemann, and A. quadrimaculatus Say), 2 house fly ( Musca domestica L.) strains, oriental rat fleas ( Xenopsylla cheopis Rothschild), and cone-nose bugs ( Triatoma infestans Klug and Rhodnius prolixus Stal). Micronized dust and aerosols containing resmethrin alone or in combination with certain other toxicants were highly effective against the test species. Chlorpyrifos dust and G-I730 aerosol ( d-trans allethrin) also gave promising results. The data indicate that lower concentrations of active ingredient(s) in dusts and aerosol treatments and/or the application of lesser amounts of formulation per unit volume of space may be satisfactory against the insects of public health importance included in the tests.

Insect Science, Ecology, Ecology, Evolution, Behavior and Systematics, Population, education.field_of_study, education, Lygus hesperus, biology.organism_classification, biology, Integrated pest management, Beet armyworm, Chrysopa, Predation, Toxicology, Dimethoate, chemistry.chemical_compound, chemistry, Botany, PEST analysis, and fungi

Spodoptera exigua (Hubner) on cotton in California is typically a secondary pest, likely to become abundant after insecticide applications against Lygus hesperus Knight. In this study local outbreaks were generated experimentally in an area of one square mile of cotton, subdivided into 4 randomized blocks of 4 treatments. Applications of dimethoate triggered significant increases in abundance of beet armyworm larvae. Levels up to 4 times as high as those in the untreated control were reached. Analysis of results of population censuses of both beet armyworm and its natural enemies in the experimental area, supplemented by observational evaluation of predator activities on early developmental stages, indicated impairment of predation on eggs and newly hatched larvae as the calise of outbreaks. Especially important in this context were the hemipterous species Geocoris pallens Stal, Orius tristicolor (White), and Nabis americoferus Carayon, which were severely reduced by the treatments. Another important predator of eggs and caterpillars, the larva of Chrysopa carnea Stephens, appeared immune to the insecticide. Field observations further revealed some egg predation by the otherwise predominantly phytophagous L. hesperus . The relevance of this study to pest management procedures for cotton is discussed.

Insect Science, Ecology, Ecology, Evolution, Behavior and Systematics, Cabbage looper, biology.organism_classification, biology, Trichoplusia, Horticulture, Chrysopa, Nuclear Polyhedrosis Virus, Botany, Nymph, Predation, Dimethoate, chemistry.chemical_compound, chemistry, Larva, and fungi

A comparative life-table analysis of Trichoplusia ni (Hubner) populations on cotton in California revealed that, where predators were suppressed with properly timed applications of dimethoate insecticide, increases in larval survival of T. ni occurred. When the populations of predators were allowed to reach density levels comparable to those in the nontreated control, survival rates for T. ni larvae did not differ significantly between nontreated plots and previously treated plots. The results suggest that predators, particularly adults and nymphs of Orius tristicolor (White), Geoeoris pallens Stal, Nabis americoferus Carayon, and larvae of Chrysopa carnea Stephens, inflict a major intrageneration mortality on T. ni larvae on cotton, and that, when these natural enemies are suppressed, a secondary pest outbreak of T. ni can occur. Rates of parasitization and polyhedrosis of T. ni developmental stages were not, in general, adversely affected by the dimethoate sprays. A nuclear polyhedrosis virus and an egg-larval parasite, Copidosoma truncatellum (Dalman), appeared to cause mortality which was density related. Two apparently new parasite records for T. ni are recorded: Chelonus texanus Cresson and Patrocloides montanus (Cresson).

Insect Science, Ecology, General Medicine, Maize chlorotic dwarf virus, biology.organism_classification, biology, Virology, Virus, Deltocephalus, Transmission (mechanics), law.invention, law, Vector (epidemiology), Nymph, Leafhopper, and Macrosteles

Maize chlorotic dwarf virus (MCDV), an isometric virus associated with a stunting disease of maize, has a semipersistent relationship with its leafhopper vector, Graminella nigrifrons (Forbes). Leafhopper’s lose their ability to transmit MCDV within 48 h after virus is acquired. Leafhoppers given a 96-h virus-acquisition access period (AAP) were more efficient vectors than leafhoppers given a 24-h AAP. The leafhoppers can transmit MCDV following a 2-h AAP and a 2-h inculation period. None of 100 nymphs which previously fed on infected corn and then molted transmitted MCDV, whereas 25 of 100 nonmolted nymphs transmitted virus. Both adult males and females transmit MCDV. The leafhopper Deltocephalus sonorus Ball also is a vector of MCDV, although it is inefficient when compared to G. nigrifrons . The leafhoppers, Dalbulus elimatus (Ball), D. maidis DeLong and Wolcott, and Macrosteles fasifrons (Stal), failed to transmit MCDV.

Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Electron diffraction, Atmospheric temperature range, Analytical chemistry, Electrical resistance and conductance, Condensed matter physics, Electron microscopic, Electrical measurements, Short range order, Transmission electron microscopy, and Chemistry

The order-Disorder transformation in CuPt has been investigated by means of electrical resistance measurements, transmission electron microscopy, and electron diffraction. Upon heating disordered CuPt, short range order is developing in the temperature range 20 to 190 °C by the formation of microdomains which grow into long range order domains upon further heating. This development of short range order gives rise to an electrical resistance increase, followed by a decrease due to the formation of long range order. The electrical measurements are correlated with electron microscopic observations. Der Ordnungs-Fehlordnungsubergang in CuPt wurde mit Hilfe von Messungen des elektrischen Widerstandes, von Transmissionselektronenmikroskopie und Elektronenbeugung untersucht. Beim Tempern von fehlgeordnetem CuPt entwickelt sich im Temperaturbereich 20 bis 190 °C Nahordnung durch die Bildung von Mikrodomanen, die bei weiterer Temperung zu Fernordnungsdomanen wachsen. Diese Entwicklung von Nahordnung gibt Anlas zu einem Ansteigen des elektrischen Widerstands, dem ein Abfall infolge der Ausbildung von Fernordnung folgt. Die elektrischen Messungen werden mit elektronenmikroskopischen Beobachtungen korreliert.

Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Homogeneous, Electron diffraction, Condensed matter physics, Critical point (thermodynamics), Electron microscope, law.invention, law, Transmission electron microscopy, Electrical resistance and conductance, Chemistry, Electron microscopic, and Stress relief

The ordering mechanism in CuPt has been investigated by means of electrical resistance measurements, transmission electron microscopy, and electron diffraction. A complex ordering mode consisting of homogeneous and heterogeneous processes is found below 475°C between 475 and 620°C the dispersed ordered domains stop growing. Transformation twins observed near the critical temperature for ordering are related to stress relief in the larger domains. The electrical resistance measurements are correlated with the electron microscopic observations to substantiate this model. Der Ordnungsmechanismus in CuPt wird mit Messungen des elektrischen Widerstands, Transmissionselektronenmikroskopie und Elektronenbeugung untersucht. Eine komplexe Ordnungsmode, die aus homogenen und heterogenen Prozessen besteht, wird unterhalb 475°C gefunden, zwischen 475 und 620°C horen die dispersen, geordneten Domanen auf zu wachsen. Transformationszwillinge, die in der Nahe der kritischen Ordnungstemperatur beobachtet werden, werden mit dem Spannungsrelief in den groseren Domanen verknupft. Die Messungen des elektrischen Widerstands werden mit elektronenmikroskopischen Beobachtungen korreliert, um das Modell zu stutzen.

Insect Science, Biology, Labidura riparia, biology.organism_classification, Predation, Lycosa, Introduced species, Beauveria bassiana, Riparia, Geocoris, Sinea, and Botany

Biotic control agents which feed on the southern chinch bug, Blissus insularis Barber, in Florida were investigated from 1971–77. A scelionid egg parasite, Eumicrosoma benefica Gahan, was the only parasite found. Predatory bugs included: 2 lygaeids, Geocoris uliginiosus (Say) and G. bullatus Say; a nabid, Pagasa pallipes Stal.; 2 anthocorids, Xylocoris vicarius (Reuter) and Lasiochilus pallidulus Reuter; and a reduviid, Sinea sp. Other predators included a dermapteran, Labidura riparia Pallas, several ant species, primarily Solenopsis geminata (F.), and a spider, Lycosa sp. A fungus, Beauveria bassiana (Balsomo) Vuillemin, also attacked B. insularis. The biotic control agents that appeared to regulate populations of the southern chinch bug were: E. benefica, G. uliginosus, X. vicarius, and L. riparia.