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STINKBUGS, POPULATION dynamics, RICE, PEST control, and PADDY fields

The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is one of the most harmful insects for Brazilian rice fields. Aiming to define the most appropriate time and place for pest management measures in commercial paddy fields, we adjusted regression models (Poisson, Zero Inflated Poisson, reparametrized Zero Inflated Poisson, Negative Binomial and Zero Inflated Negative Binomial) for modeling the population variation of T. limbativentris along the phenological cycle of the flooded rice cultivation. We hypothesize that the rice stem stink bug population's size is influenced by the rice cycle (time) and geographical positions within the crop. It was possible to predict the occurrence of the rice stem stink bug in the commercial flooded rice crop. The population of the rice stem stink bug increased significantly with the time or phenological evolution of rice. Our results indicated that the start of T. limbativentris monitoring should occur up to 45 d After Plant Emergence (DAE), from the regions along the edges of the rice paddies, which are the points of entry and higher concentration of the insect. In addition, 45 and 60 DAE were considered the crucial times for T. limbativentris control decision making in flooded rice paddies. [ABSTRACT FROM AUTHOR]

PLANT phenology, STINKBUGS, SOYBEAN farming, SOYBEAN diseases & pests, and HEMIPTERA

Stink bugs (Hemiptera: Pentatomidae) are an increasing threat to soybean (Fabales: Fabaceae) production in the North Central Region of the United States, which accounts for 80% of the country's total soybean production. Characterization of the stink bug community is essential for development of management programs for these pests. However, the composition of the stink bug community in the region is not well defined. This study aimed to address this gap with a 2-yr, 9-state survey. Specifically, we characterized the relative abundance, richness, and diversity of taxa in this community, and assessed phenological differences in abundance of herbivorous and predatory stink bugs. Overall, the stink bug community was dominated by Euschistus spp. (Hemiptera: Pentatomidae) and Chinavia hilaris (Say) (Hemiptera: Pentatomidae). Euschistus variolarius (Palisot de Beauvois) (Hemiptera: Pentatomidae), C. hilaris and Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) were more abundant in the northwestern, southeastern and eastern parts, respectively, of the North Central Region of the United States. Economically significant infestations of herbivorous species occurred in fields in southern parts of the region. Species richness differed across states, while diversity was the same across the region. Herbivorous and predatory species were more abundant during later soybean growth stages. Our results represent the first regional characterization of the stink bug community in soybean fields and will be fundamental for the development of state- and region-specific management programs for these pests in the North Central Region of the United States. [ABSTRACT FROM AUTHOR]

FOSFOMYCIN, INFECTION, ESCHERICHIA coli, EPIDEMIOLOGY, and TEST methods

Objectives Fosfomycin susceptibility testing is complicated and prone to error. Before using fosfomycin widely in patients with serious infections, acquisition of WT distribution data and reliable susceptibility testing methods are crucial. In this study, the performance of five methods for fosfomycin testing in the routine laboratory against the reference method was evaluated. Methods Ten laboratories collected up to 100 ESBL-producing isolates each (80 Escherichia coli and 20 Klebsiella pneumoniae). Isolates were tested using Etest, MIC test strip (MTS), Vitek2, Phoenix and disc diffusion. Agar dilution was performed as the reference method in a central laboratory. Epidemiological cut-off values (ECOFFs) were determined for each species and susceptibility and error rates were calculated. Results In total, 775 E. coli and 201  K. pneumoniae isolates were tested by agar dilution. The ECOFF was 2 mg/L for E. coli and 64 mg/L for K. pneumoniae. Susceptibility rates based on the EUCAST breakpoint of ≤32 mg/L were 95.9% for E. coli and 87.6% for K. pneumoniae. Despite high categorical agreement rates for all methods, notably in E. coli, none of the alternative antimicrobial susceptibility testing methods performed satisfactorily. Due to poor detection of resistant isolates, very high error rates of 23.3% (Etest), 18.5% (MTS), 18.8% (Vitek2), 12.5% (Phoenix) and 12.9% (disc diffusion) for E. coli and 22.7% (Etest and MTS), 16.0% (Vitek2) and 12% (Phoenix) for K. pneumoniae were found. None of the methods adequately differentiated between WT and non-WT populations. Conclusions Overall, it was concluded that none of the test methods is suitable as an alternative to agar dilution in the routine laboratory. [ABSTRACT FROM AUTHOR]

BROWN marmorated stink bug, STINKBUGS, HEMIPTERA, ORNAMENTAL trees, and FARM produce

The brown marmorated stink bug, Halyomorpha halys (Stål), is a polyphagous pest that feeds on a wide variety of agricultural commodities including tree fruits, berries, vegetables, field crops, and ornamental trees and shrubs. Accurate knowledge of where H. halys lays eggs is critical to optimize the potential release of Trissolcus japonicus (Ashmead), a scelionid egg parasitoid native to the same host region as H. halys. Ideally, parasitoids should be released in and around areas with high host density. In southwestern Virginia in 2017 and 2018, we searched trees for egg masses in an urban environment and nonmanaged wooded border environment. We also evaluated the effects of a commercial aggregation lure on the number of eggs being deposited. This aggregation lure, when combined with methyl (E , E , Z)-2,4,6-decatrienoate (MDT), has been shown to attract both adult and nymph H. halys and its effects on egg laying were not known. Results of this study showed no difference between the number of eggs laid on trees with and without lures. Catalpa trees, Catalpa bignonioides Walter, had the most egg masses throughout the course of the study; however, the redbud, Cercis canadensis L., had similar numbers in the late July and August. There was an overall trend with more eggs masses found on trees with fruiting structures present. This information can provide insight on where and when to make augmentative releases of egg parasitoids for H. halys. [ABSTRACT FROM AUTHOR]

BROWN marmorated stink bug, PODISUS, and INSECT pest control

Stink bugs (Hemiptera: Heteroptera: Pentatomidae) are an emerging threat to soybean and corn production in the midwestern United States. An invasive species, the brown marmorated stink bug, Halyomorpha halys (Stål), is spreading through the region. However, little is known about the complex of stink bug species associated with corn and soybean in the midwestern United States. In this region, particularly in the more northern states, stink bugs have historically caused only infrequent impacts to these crops. To prepare growers and agricultural professionals to contend with this new threat, we provide a review of stink bugs associated with soybean and corn in the midwestern United States. Descriptions and images of common stink bug species are provided as a diagnostic aid. The biologies and impacts of stink bugs to crops are discussed, with particular attention to differences among species. Based primarily on information from southern states, scouting, thresholds, and insecticide-based management of these pests are discussed. It is hoped that this review will provide stakeholders sufficient information for management of these pests, until more region-specific research can be performed on stink bugs in soybean and corn in the midwestern United States. [ABSTRACT FROM AUTHOR]

SOYBEAN diseases & pests, BROWN marmorated stink bug, and STINKBUGS

Sampling soybean fields for the brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), can be challenging. Both adults and nymphs have a "startle response" and drop to the ground with even the slightest disturbance. This behavior could reduce the effectiveness of the traditional sweep net and ground cloth sampling methods. In 2013 and 2014, in Virginia, Delaware, and Maryland, we evaluated a visual plant inspection method that consisted of counting the number of brown marmorated stink bug nymphs and adults seen on soybean plants in a 2-min inspection period while walking carefully between two rows. After a 30-min interval, which allowed the stink bugs to reposition in the canopy, the area was resampled using 15 sweeps with a 38-cm-diameter sweep net. In total, 76 soybean fields and 2,042 paired comparisons were used to determine a strong linear relationship between sampling methods (y = 0.984x + 0.4359, R2 = 0.6934, where y = brown marmorated stink bugs/2-min visual count and x = brown marmorated stink bugs/15 sweeps). An average visual count of 5.4 brown marmorated stink bugs in 2 min was estimated as being equivalent to the current economic threshold of 5 stink bugs per 15 sweeps. Visual inspection appears to be an effective method for assessing brown marmorated stink bug populations in soybeans. [ABSTRACT FROM AUTHOR]

SWEET corn, STINKBUGS, PEST control, POPULATION density, and CORN

The brown marmorated stink bug, Halyomorpha halys (Stål), is an Asian species that now dominates the stink bug complex in many cultivated crops throughout the mid-Atlantic United States. Sweet corn (Zea mays L.) is a preferred host of H. halys, and the bug can cause kernel injury on developing ears. Currently, there is limited information available on which plant growth stages are most sensitive to H. halys feeding or density of bugs required to cause yield and quality reductions on processing and fresh market sweet corn ears. In 2011 and 2012, sweet corn ears were infested at three different corn growth stages: silking (R1), blister (R2), and milk (R3) at densities of zero, one, three, and five H. halys adults per ear for 7d. At harvest, four yield measurements were assessed and ears were inspected for quality reductions. The greatest yield loss from H. halys occurred when infestations were initiated during early stages of ear development, and the greatest quality reductions (damaged kernels) occurred during later stages of ear development. A density of one H. halys per ear resulted in levels of kernel damage great enough to cause significant quality reductions. This study highlights the ability of H. halys to cause sub-stantial economic losses in both fresh market and processing sweet corn in a relatively short period of time at low population densities. Therefore, infestations by this insect in sweet corn must be considered when making pest management decisions in regions where it has become established. [ABSTRACT FROM AUTHOR]

EXITIANUS, CORN diseases, LEAFHOPPERS, and INSECTS

"Corn stunt" caused by the mollicute Spiroplasma kunkelii (Whitcomb) is potentially one of the most severe diseases affecting the corn (Zea mays L.) crop in the Americas, and the leafhopper Dalbulus maidis (DeLong & Wolcott) is considered its most important vector. However, other insects seen quite frequently in corn crops might well be its vectors in Argentina. To identify any leafhoppers species other than D. maidis that can transmit S. kunkelii, transmission assays were conducted, using individuals of Exitianus obscurinervis (Stål) collected in field and reared under controlled conditions. S. kunkelii was transmitted to corn plants by E. obscurirwrvis. The pathogen was transmitted to seven of the 11 plants, which showed characteristic corn stunt symptoms, and the presence of the pathogen was confirmed by DAS-ELISA. The presence of S. kunkelii in the E. obscurinervis individuals used in transmission experiments was confirmed by polymerase chain reaction and electron microscopy. The current study shows the existence of a new experimental vector of S. kunkelii, the leafhopper E. obscurinervis, which acquired spiroplasmas from infected plants and inoculated it to healthy plants. [ABSTRACT FROM AUTHOR]

HEMIPTERA, COREIDAE, INSECT development, OPUNTIA, and FEROCACTUS

Narnia femorata Stål (Hemiptera: Heteroptera: Coreidae) is a leaffooted bug commonly found on Opuntia and Ferocactus cacti (Cactaceae) in southern New Mexico. Although general information has been published on the biology of this species, detailed studies are limited, particularly in America north of Mexico. Therefore, we conducted a study of this bug's life history in southern New Mexico from August 2010 to May 2012, reared the bug in the laboratory, and described the immature stages. Six prickly pear cactus plants, Opuntia phaeacantlut Engelmann, and four barrel cactus plants, Ferocactus wislizeni (Engelmann) Britton & Rose, were examined weekly to record numbers of the various life stages, adult sex ratios, and behavioral activities. Adults of this apparently bivoltine species overwintered in plant debris at the bases of their host plants. They emerged in late February to deposit eggs in rows along the underside of cactus spines. Nymphs were found from late February through late December. Nymphs of the first generation were most abundant April through June on and around developing flowers of O. phaeacantha. Those of the second generation were most abundant during August and September on maturing fruit of O. phaeacantha and developing flowers and maturing fruit of F. wislizeni. The bug also was reared from egg to adult under controlled laboratory conditions on fruit and pads of O. phaeacantha at 25 ± 0.01°C under a photoperiod of 14:10 (L:D) h. The incubation period averaged 12.70 d. The five stadia averaged 3.84, 11.00, 12.12, 17.06, and 22.94 d, respectively. Instars can be distinguished readily by differences in several morphological features in addition to body size and coloration. [ABSTRACT FROM AUTHOR]

ANIMAL classification, ANIMAL species, IDENTIFICATION of animals, HEMIPTERA, and INSECTS

Copyright of Annals of the Entomological Society of America is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

POPULATION dynamics and INSECTICIDES

NEEM, CERCOPIDAE, PLANT products, PESTICIDES, PLANT fibers, NYMPHS (Insects), PEST control, HOMOPTERA, and AGRICULTURAL chemicals

Copyright of Journal of Economic Entomology is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

COWPEA, LEGUMES, DEFOLIATION, PLANT canopies, SEED disinfection, EFFECT of temperature on plants, and PHYSIOLOGICAL effects of temperature

Pottedcowpea, Vigna unguiculata (L.) Walp., plants were used to determine the effects of defoliation and pod position relative to the leaf canopy on infestation and damage by the coreid pod-bugs Clavigralla tomentosicollis Stål and Anoplocnemis curvipes (F.). Temperature measurements were taken within and outside the canopy to determine whether there was a correlation to seed damage. Seed damage decreased significantly with increasing defoliation in plants infested with C. tomentosicollis; an inverse trend was observed with A. curvipes. Temperatures within the canopy increased as the number of leaves decreased. As observed in the defoliation experiment, C. tomentosicollis and A. curvipes reacted differently in a free-choice situation between pods located outside or within the canopy. Significantly higher numbers of C. tomentosicollis concealed themselves within the canopy, where they caused more severe damage to seeds, in comparison with numbers and damage outside the canopy. These trends were reversed for A. curvipes. There was a significant negative correlation between percentage of seed damage and temperature with C. tomentosicollis, and a significant positive correlation with A. curvipes, both in defoliated plants and those with pods distributed outside and within the canopy. Overall, plants with less dense canopy, and long peduncles holding pods outside the canopy showed some resistance to C. tomentosicollis, which is the most damaging pod bug on cowpea. Because such cowpea plants harbor fewer C. tomentosicollis, they are likely to suffer less overall damage from infestation by the complex of pod bugs that occur concurrently in cowpea fields. [ABSTRACT FROM AUTHOR]

BIOLOGICAL pest control agents and MODELING (Sculpture)

Canatoxin is a toxic protein isolated from the jackbean, Canavalia ensiformis. The toxin injected intraperitoneally is lethal for mice and rats, however, it is inactive if given orally. In this study, Mandura sexta (L.) (Lepidoptera), Schistocerca americana (Drury) (Orthoptera), Drosophila melanogaster (L.) (Diptera), Aedes aegypti (L.) (Diptera), Rhodnius prolixus (Stal) (Hemiptera), and Callosobruchus maculatus (F.) (Coleoptera) were fed on canatoxin-containing diets. No effects were seen in M. sexta, S. anericana, D. melanogaster or A. aegypti. No traces of canatoxin were found in their feces, suggesting that the protein was digested completely by these insects, which characteristically have a trypsin-based digestion. In contrast, canatoxin was lethal for insects displaying cathepsin-based digestion. Thus, for C.maculatus, a diet containing 0.25% wt:wt canatoxin caused complete inhibition of larval growth. When R. prolixus were fed on canatoxin, 2effects were seen: impairment of water excretion and increased lethality 48--96 h after feeding. The lethal effect of canatoxin in R. prolixus was blocked partially or completely when the digestion of the toxin by R. prolixus midgut enzymes was impaired. The data showed thatcanatoxin is highly toxic when ingested by some species of insects but not affecting others, probably in correlation with the characteristics of the digestive process of the insect. [ABSTRACT FROM AUTHOR]