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Ficusmicrocarpa L. and F. racemosa L. are often extensively damaged by the defoliating pest Phauda flammans Walker (Lepidoptera: Zygaenidae). The structure, morphology, abundance, and distribution of the antennal sensilla of P. flammans were studied using scanning electron microscopy. Six types and eight subtypes of sensilla were observed on the filiform antennae of both sexes, including trichodea (subtypes I and II), basiconica (subtypes I and II), coeloconica, styloconica, chaetica, and Böhm bristles. The most numerous sensilla were the trichodea on the antennae of both sexes. Sexual dimorphism was observed, with the male antennae having more sensilla trichodea than the female antennae. This information is essential for understanding the electrophysiological and behavioral aspects of chemical communication in P. flammans.
We determined the effects of microwave radiation and static magnetic field on the gene activity in Drosophila by measuring the dimensions of puffing the salivary gland polytene chromosomes of Drosophila melanogaster Meigen following exposure of eggs to the radiation and magnetic field. Drosophila eggs were exposed to either microwave radiation of 36.64 GHz frequency and 1 W/m2 intensity for 30 s, a static magnetic field of 25 mT for 5 min, or both. The diameter of puffs was measured in squashed salivary gland preparations extracted from larvae from those eggs as they entered the prepupal stage. The puffs measured were 50CD, 63F, 71CE, 72CD (chromosome 3L) and 82EF, 83E, 93D (chromosome 3R). Results demonstrated that (a) microwave radiation exposure decreased puffing activity in puffs 63F, 71CE, and 82 EF but had no effect on puffing at 72CD, 93D and 50CD; (b) exposure to magnetic fields only did not change puff activity, but magnetic field exposure appeared to enhance the impact of microwave radiation exposure at locus 83F by decreasing puff activity; (c) puffs 63F, 71CE, and 82EF were smaller when exposed to microwave radiation and magnetic field combined than with microwave radiation alone, and; (d) no apparent changes were observed at the 93D puff after exposure to microwave radiation and the combined treatments.
Bagradahilaris (Burmeister) (Hemiptera: Pentatomidae) is a stink bug species that preferentially attacks cruciferous crops. Because organic growers have limited insecticide tools for combating B. hilaris, the lethal and sublethal effects of organically approved insecticide products and their selected combinations against B. hilaris were examined in laboratory and field settings. In a topical spray assay, spinosad, either alone or in combination with pyrethrins, azadirachtin, and potassium salts, resulted in >95% mortality relative to the water-only treatment 48 h postapplication; whereas, stand-alone pyrethrins and azadirachtin failed to cause similar mortality rates. When adults were exposed to treated broccoli (Brassica oleracea var. italica Blenck) seedlings for 48 h after 0, 1, and 7 d of application, the number of feeding injury sites was significantly lower with the combined treatment of spinosad, pyrethrins, and azadirachtin than those on seedlings treated with water alone at 0 and 1 d postapplication. However, when adults were exposed to seedlings at 7 d postapplication, only the combined treatment with pyrethrins and azadirachtin reduced the number of feeding sites compared with the water control. When the locomotor activity of adults was evaluated after exposure to dried residues for 20 min and 2 h, adults were found to be more active when exposed to combined treatment with spinosad, pyrethrins, and azadirachtin than the individual treatments. In the field trials, although most of the insecticide products and their combinations failed to provide persistent B. hilaris control, the combined treatment of pyrethrins and potassium salts reduced the number of feeding sites compared with the nontreated control.
Flonicamid is a systemic pesticide that inhibits the feeding of certain greenhouse pests and certain hemipteran pests of agricultural crops. In a laboratory study directed at the common bed bug (Cimex lectularius L.), flonicamid (as Aria®) was evaluated for its ability to either kill or inhibit the feeding of this blood-sucking pest. After flonicamid was applied topically (by spray), as a residual (to bed bug harborages), or fed directly to bed bugs by incorporating the insecticide into the bloodmeal, mortality assessments were made and surviving bed bugs were given the opportunity to feed on untreated blood. At the recommended label rates and at rates that approached the solubility limits of the product in water, it was concluded that this insecticide would be ineffective in a bed bug control program.
Several isolates of the recently described bacterial species Chromobacterium sphagni Blackburn et al. were obtained from water collected from Sphagnum bogs in West Virginia and Maine. Bacterial isolates were cultured in a liquid medium and applied to artificial insect diets in the laboratory. The new isolates were toxic to larvae of the gypsy moth, Lymantria dispar (L.), and the diamondback moth, Plutella xylostella (L.), but were not toxic to larvae of the seedcorn maggot, Delia platura (Meigen), or adults of the red flour beetle, Tribolium castaneum (Herbst).
New Chromobacterium sp. strains were isolated from water collected from several localities in the eastern United States and were subsequently identified as the species Chromobacterium vaccinii Soby et al. Bacteria were cultured in a liquid medium and applied to artificial insect diets in the laboratory. All of the recently discovered C. vaccinii isolates tested were toxic to larvae of the seedcorn maggot, Delia platura (Meigen), but had little activity against larvae of the diamondback moth, Plutella xylostella (L.). None of the new isolates of C. vaccinii were toxic to adults of the red flour beetle, Tribolium castaneum (Herbst).
We compared bottle traps to 4-unit multiple-funnel traps (both baited with ethanol and conophthorin) for relative efficacy in catching ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) at four locations in the eastern United States. Our results were geographically inconsistent for three target species. Catches of Xylosandrus germanus (Blandford) in Ohio were greater in bottle traps than in funnel traps while the opposite occurred in Virginia, with no difference in Indiana. Catches of Xyleborinus saxesenii (Ratzeburg) were greater in funnel traps than in bottle traps in Georgia, Indiana, and Virginia but no different in Ohio. Similarly, catches of Xylosandrus crassiusculus (Motschulsky) were greater in funnel traps than in bottle traps in Georgia and Virginia but not in Indiana. Bottle traps caught more Anisandrus maiche Stark in Ohio and Anisandrus sayi (Hopkins) in Indiana whereas more of the following species were caught in funnel traps: Ambrosiophilus atratus (Eichhoff) in Virginia, Cyclorhipidion bodoanum (Reitter) and Dryoxylon onoharaense (Murayama) in Georgia, Euwallacea validus (Eichhoff) in Ohio, and Cyclorhipidion pelliculosum (Eichhoff) and Monarthrum fasciatum (Say) in Indiana. Catches of Cnestus mutilatus (Blandford) in Georgia and Monarthrum mali (Fitch) in Indiana were unaffected by trap type. Differences in trap height, bottle size, and forest composition may have contributed to between-site variability in trap type preferences, thereby requiring further research to resolve these issues.
Pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), is a key pest of pear and is a vector of “Candidatus Phytoplasma pyri”, the pathogen associated with pear decline disease. Although commercial pear trees are grafted to Phytoplasma-resistant rootstock, a recent report indicated that many C. pyricola in Washington and Oregon harbor this bacterium. Using fluorescence in situ hybridization, we confirmed that Phytoplasma invades internal tissues of C. pyricola, suggesting the pathogen is persistently transmitted. Because many persistently transmitted plant pathogens alter the flight behavior of their insect vectors, we examined the effects of Phytoplasma infection on dispersal of C. pyricola. Flight behavior was investigated using greenhouse bioassays, which demonstrated that Phytoplasma-infected psylla were less likely than uninfected psylla to emigrate from trees and become captured on yellow traps. Pear psylla occurs as two seasonal morphotypes—summerform and winterform—and the effects of Phytoplasma were observed for both morphotypes. Results provide direction for future study of C. pyricola ecology and interactions between Phytoplasma and psyllid vectors.
Currently, the rice stink bug complex (Hemiptera: Pentatomidae) attacking Florida rice is the most diversified and unique stink bug complex in United States rice production. This complex includes the common rice stink bug, Oebalus pugnax (F.), and two invasive species, Oebalus ypsilongriseus (DeGeer) and Oebalus insularis (Stal). Insecticidal efficacy for these two invasive species is not known. Insecticidal evaluations of five insecticides were made on adults of both sexes of the three species. Weights of adults were also determined. In all three species, females weighed more than males of the same species. Also, O. pugnax adults were the largest followed by O. ypsilongriseus, with O. insularis being the smallest adults. All five insecticides gave a high degree of control of 93–100% for both sexes of all three species. These data are currently useful to Florida rice growers and may be useful to rice growers in other states if the two invasive species spread to those states. These data also provide baseline data for future studies on development of insecticide resistance of the stink bugs in Florida rice.
Ant abundance and diversity are affected by numerous factors, including competition. Pavement ants (Tetramorium immigrans Santschi) are by far the most dominant species in North American urban areas, and so likely engage in interspecific competition and thus affect the abundance and diversity of other ant species. Ant abundance and diversity were monitored at the level of genus at two field sites in West Lafayette, IN, taking into account temperature, humidity, and habitat as possible factors in ant distribution. Temperature was found to be a significant factor affecting the abundance of ants, while humidity was not. The different habitats at the two locations resulted in the presence of different genera. The number of pavement ants was positively correlated with the number of cornfield ants (Lasius neoniger Emery) in Copper Beech Apartments, but not at Purdue Village. There was also a slightly greater diversity of ants found at Copper Beech Apartments.
Predation is an important interaction for the regulation of population dynamics due to the effect caused by the direct consumption of prey. However, some populations present strategies to detect risk of predation and react to the predator. Our objective was to evaluate the effect of the predation risk of Belostoma dentatum (Mayr), under the behavioral response of the red-eye tetra fish, Moenkhausia sanctaefilomenae (Steindachner), to the availability of refuge and the density of prey. We tested the hypothesis that the distance between prey and predator decreases if there is refuge and if the individual is in a group. We observed the position of M. sanctaefilomenae in relation to the water slide. In the first treatment, we added a predator; in the second, we included refuge; and in the third, we added two more fish. The occupation pattern inside the container was only detected in the presence of the predator. With the addition of the predator, the prey was restricted to the refuge. With the removal of refuges, the distance between predator and prey remained the maximum. On the other hand, when the two new individuals were added, the occupancy pattern was no longer detected, indicating the dilution effect on group behavior. These aspects indicate that in the face of the risk of predation by B. dentatum, the individual M. sanctaefilomenae may adopt different behavioral strategies, suggesting that they are able to perceive the predator and, thus, modify prey behavior. Prey are apparently interpreting environmental cues to increase chances of survival.
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