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Insect migrations have ecological and economic impacts, particularly in agriculture. However, there is limited knowledge about the migratory movements of pests at the continental scale, which is an important factor influencing the spread of resistance genes. Understanding the migratory patterns of economic pests, like Helicoverpa zea (Boddie), is essential for improving Integrated Pest Management (IPM) and Insect Resistance Management (IRM) strategies. In this study, we used stable hydrogen isotopic ratios in wing tissue as a biogeochemical marker to examine migratory patterns and estimate the native origins of H. zea individuals collected across a wide latitudinal gradient in North America. Samples collected at higher latitudes (Ontario, Canada and Minnesota, USA) exhibited a greater proportion (60%–96%) of nonlocal individuals, with an increased probability of origin from the southeastern United States. Populations from mid-latitudes (Florida, North Carolina, and South Carolina) showed a blend of local and nonlocal (40%–60%) individuals. Finally, 15% of the southernmost population individuals (Puerto Rico) were classified as migratory, with some having a probability of origin at higher latitudes (>30°). Overall, our results provide evidence of a northward spring/summer migration of H. zea in North America and underscore the significance of the southeastern United States as a hub for genetic flow. In addition, based on stable hydrogen isotopic ratios, there is strong evidence of reverse (southward) migration of H. zea from the continental United States to Puerto Rico. Our study highlights the implications for IPM and IRM programs and the need for management strategies that account for both northward and southward migration patterns. [ABSTRACT FROM AUTHOR]

Exclusion netting in some European and North American apple (Malus domestica Borkhausen, Rosaceae, Rosales) orchards has been documented to be an effective method of control for multiple insect pest species. By minimizing reliance on insecticides, these orchards have reduced costs, risks to the environment and non-target species, and reduced the risk of insecticide resistance. This study examined the use of commercially available hail netting (DrapeNet®; Prosser, WA) as a pest exclusion strategy under conditions in Minnesota, USA. In 2021 and 2022, we assessed the efficacy of hail netting as a tool for pest suppression in orchards by monitoring pest species in netted and open plots crossed with and without insecticide applications. Our findings show that both of the major pest species in Minnesota, the codling moth (Cydia pomonella L.; Lepidoptera: Tortricidae) and the apple maggot (Rhagoletis pomonella Walsh; Diptera: Tephritidae), were significantly reduced inside the netting compared to open plots by 94% and 96%, respectively. For a secondary pest, the red-banded leafroller (Argyrotaenia velutinana Walker; Lepidoptera: Tortricidae), moth populations were reduced by 56%. We also found that insecticide application alone did not significantly reduce pest pressure in these species. Additionally, we investigated the subsequent effects of hail netting on fruit quality and yield. The use of hail netting and insecticide application resulted in significantly higher proportions of high-quality fruit at harvest. However, netting did not significantly influence yield. These findings suggest that hail netting can be used to control Midwest apple insect pests with limited insecticide applications while maintaining high fruit quality. [ABSTRACT FROM AUTHOR]

Stink bugs represent an increasing risk to soybean production in the Midwest region of the United States. The current sampling protocol for stink bugs in this region is tailored for population density estimation and thus is more relevant to research purposes. A practical decision-making framework with more efficient sampling effort for management of herbivorous stink bugs is needed. Therefore, a binomial sequential sampling plan was developed for herbivorous stink bugs in the Midwest region. A total of 146 soybean fields were sampled across 11 states using sweep nets in 2016, 2017, and 2018. The binomial sequential sampling plans were developed using combinations of five tally thresholds at two proportion infested action thresholds to identify those that provided the best sampling outcomes. Final assessment of the operating characteristic curves for each plan indicated that a tally threshold of 3 stink bugs per 25 sweeps, and proportion infested action thresholds of 0.75 and 0.95 corresponding to the action thresholds of 5 and 10 stink bugs per 25 sweeps, provided the optimal balance between highest probability of correct decisions (≥ 99%) and lowest probability of incorrect decisions (≤ 1%). In addition, the average sample size for both plans (18 and 12 sets of 25 sweeps, respectively) was lower than that for the other proposed plans. The binomial sequential sampling plan can reduce the number of sample units required to achieve a management decision, which is important because it can potentially reduce risk/cost of management for stink bugs in soybean in this region. [ABSTRACT FROM AUTHOR]

Spotted-wing drosophila, Drosophila suzukii (Matsumura), an economically damaging invasive species of numerous fruit crops, was first detected in Minnesota in 2012. High fecundity, and short generation times facilitated a rapid rise in the global pest status of D. suzukii, particularly in North America and Europe. To date, the majority of crop injury research has focused on fruit crops such as blueberries, raspberries, and cherries. However, little is known regarding the impact of D. suzukii on the wine grape industry in the upper Midwest region of the United States. Field trials were conducted in Minnesota during the summers of 2017–2018 to examine season-long phenology of D. suzukii in wine grape vineyards and wineries, and to assess the efficacy of exclusion netting for control of D. suzukii. Four treatments were evaluated, 1) open plot check (control), 2) open plot treated with an insecticide, 3) exclusion netting, and 4) exclusion netting, with artificial infestations of D. suzukii adults. Exclusion netting was applied at véraison and removed at harvest. On each sample date, 20 berries (10 intact and 10 injured) were collected from each plot for dissection. The number of larvae and adults were recorded for each berry to determine infestation levels. As shown by mean larval infestations and injured berries across treatments, exclusion netting provided a significant reduction in the level of D. suzukii infested berries when compared with the untreated check. These results indicate that exclusion netting could provide an effective alternative management strategy for D. suzukii in wine grapes. [ABSTRACT FROM AUTHOR]

Ventral intermediate thalamic deep brain stimulation is a standard therapy for the treatment of medically refractory essential tremor and tremor-dominant Parkinson's disease. Despite the therapeutic benefits, the mechanisms of action are varied and complex, and the pathophysiology and genesis of tremor remain unsubstantiated. This intraoperative study investigated the effects of high frequency microstimulation on both neuronal firing and tremor suppression simultaneously. In each of nine essential tremor and two Parkinson's disease patients who underwent stereotactic neurosurgery, two closely spaced (600 µm) microelectrodes were advanced into the ventral intermediate nucleus. One microelectrode recorded action potential firing while the adjacent electrode delivered stimulation trains at 100 Hz and 200 Hz (2-5 s, 100 µA, 150 µs). A triaxial accelerometer was used to measure postural tremor of the contralateral hand. At 200 Hz, stimulation led to 68 ± 8% (P < 0.001) inhibition of neuronal firing and a 53 ± 5% (P < 0.001) reduction in tremor, while 100 Hz reduced firing by 26 ± 12% (not significant) with a 17 ± 6% (P < 0.05) tremor reduction. The degree of cell inhibition and tremor suppression were significantly correlated (P < 0.001). We also found that the most ventroposterior stimulation sites, closest to the border of the ventral caudal nucleus, had the best effect on tremor. Finally, prior to the inhibition of neuronal firing, microstimulation caused a transient driving of neuronal activity at stimulus onset (61% of sites), which gave rise to a tremor phase reset (73% of these sites). This was likely due to activation of the excitatory glutamatergic cortical and cerebellar afferents to the ventral intermediate nucleus. Temporal characteristics of the driving responses (duration, number of spikes, and onset latency) significantly differed between 100 Hz and 200 Hz stimulation trains. The subsequent inhibition of neuronal activity was likely due to synaptic fatigue. Thalamic neuronal inhibition seems necessary for tremor reduction and may function in effect as a thalamic filter to uncouple thalamo-cortical from cortico-spinal reflex loops. Additionally, our findings shed light on the gating properties of the ventral intermediate nucleus within the cerebello-thalamo-cortical tremor network, provide insight for the optimization of deep brain stimulation technologies, and may inform controlled clinical studies for assessing optimal target locations for the treatment of tremor. [ABSTRACT FROM AUTHOR]

Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson's disease symptoms. The therapeutic benefits of deep brain stimulation are frequency-dependent, but the underlying physiological mechanisms remain unclear. To advance deep brain stimulation therapy an understanding of fundamental mechanisms is critical. The objectives of this study were to (i) compare the frequency-dependent effects on cell firing in subthalamic nucleus and substantia nigra pars reticulata; (ii) quantify frequency-dependent effects on short-term plasticity in substantia nigra pars reticulata; and (iii) investigate effects of continuous long-train high frequency stimulation (comparable to conventional deep brain stimulation) on synaptic plasticity. Two closely spaced (600 µm) microelectrodes were advanced into the subthalamic nucleus (n = 27) and substantia nigra pars reticulata (n = 14) of 22 patients undergoing deep brain stimulation surgery for Parkinson's disease. Cell firing and evoked field potentials were recorded with one microelectrode during stimulation trains from the adjacent microelectrode across a range of frequencies (1-100 Hz, 100 µA, 0.3 ms, 50-60 pulses). Subthalamic firing attenuated with ≥20 Hz (P < 0.01) stimulation (silenced at 100 Hz), while substantia nigra pars reticulata decreased with ≥3 Hz (P < 0.05) (silenced at 50 Hz). Substantia nigra pars reticulata also exhibited a more prominent increase in transient silent period following stimulation. Patients with longer silent periods after 100 Hz stimulation in the subthalamic nucleus tended to have better clinical outcome after deep brain stimulation. At ≥30 Hz the first evoked field potential of the stimulation train in substantia nigra pars reticulata was potentiated (P < 0.05); however, the average amplitude of the subsequent potentials was rapidly attenuated (P < 0.01). This is suggestive of synaptic facilitation followed by rapid depression. Paired pulse ratios calculated at the beginning of the train revealed that 20 Hz (P < 0.05) was the minimum frequency required to induce synaptic depression. Lastly, the average amplitude of evoked field potentials during 1 Hz pulses showed significant inhibitory synaptic potentiation after long-train high frequency stimulation (P < 0.001) and these increases were coupled with increased durations of neuronal inhibition (P < 0.01). The subthalamic nucleus exhibited a higher frequency threshold for stimulation-induced inhibition than the substantia nigra pars reticulata likely due to differing ratios of GABA:glutamate terminals on the soma and/or the nature of their GABAergic inputs (pallidal versus striatal). We suggest that enhancement of inhibitory synaptic plasticity, and frequency-dependent potentiation and depression are putative mechanisms of deep brain stimulation. Furthermore, we foresee that future closed-loop deep brain stimulation systems (with more frequent off stimulation periods) may benefit from inhibitory synaptic potentiation that occurs after high frequency stimulation. [ABSTRACT FROM AUTHOR]

The use of mixtures of transgenic insecticidal seed and nontransgenic seed to provide an in-field refuge for susceptible insects in insect-resistance-management (IRM) plans has been considered for at least two decades. However, the U.S. Environmental Protection Agency has only recently authorized the practice. This commentary explores issues that regulators, industry, and other stakeholders should consider as the use of biotechnology increases and seed mixtures are implemented as a major tactic for IRM. We discuss how block refuges and seed mixtures in transgenic insecticidal corn, Zea mays L., production will influence integrated pest management (IPM) and the evolution of pest resistance. We conclude that seed mixtures will make pest monitoring more difficult and that seed mixtures may make IBM riskier because of larval behavior and greater adoption of insecticidal corn. Conversely, block refuges present a different suite of risks because of adult pest behavior and the lower compliance with IBM rules expected from farmers. It is likely that secondary pests not targeted by the insecticidal corn as well as natural enemies will respond differently to block refuges and seed mixtures. [ABSTRACT FROM AUTHOR]

Pest risk maps are powerful visual communication tools to describe where invasive alien species might arrive, establish, spread, or cause harmful impacts. These maps inform strategic and tactical pest management decisions, such as potential restrictions on international trade or the design of pest surveys and domestic quarantines. Diverse methods are available to create pest risk maps, and can potentially yield different depictions of risk for the same species. Inherent uncertainties about the biology of the invader, future climate conditions, and species interactions further complicate map interpretation. If multiple maps are available, risk managers must choose how to incorporate the various representations of risk into their decision making process, and may make significant errors if they misunderstand what each map portrays. This article describes the need for pest risk maps, compares pest risk mapping methods, and recommends future research to improve such important decision-support tools. [ABSTRACT FROM AUTHOR]

Postural instability and falls are a major source of disability in patients with advanced Parkinson's disease. These problems are currently not well addressed by either pharmacotherapy nor by subthalamic nucleus deep-brain stimulation surgery. The neuroanatomical substrates of posture and gait are poorly understood but a number of important observations suggest a major role for the pedunculopontine nucleus and adjacent areas in the brainstem. We conducted a double-blinded evaluation of unilateral pedunculopontine nucleus deep-brain stimulation in a pilot study in six advanced Parkinson's disease patients with significant gait and postural abnormalities. There was no significant difference in the double-blinded on versus off stimulation Unified Parkinson's Disease Rating Scale motor scores after 3 or 12 months of continuous stimulation and no improvements in the Unified Parkinson's Disease Rating Scale part III scores compared to baseline. In contrast, patients reported a significant reduction in falls in the on and off medication states both at 3 and 12 months after pedunculopontine nucleus deep-brain stimulation as captured in the Unified Parkinson's Disease Rating Scale part II scores. Our results suggest that pedunculopontine nucleus deep-brain stimulation may be effective in preventing falls in patients with advanced Parkinson's disease but that further evaluation of this procedure is required. [ABSTRACT FROM PUBLISHER]

Grape phylloxera, Daktulosphaira vitifoliae Fitch (Hemiptera: Phylloxeridae), is a growing pest concern in the Midwest United States due to the increased planting of cold-hardy hybrid grape varieties such as 'Frontenac'. Grape phylloxera is native to North America and has been distributed to other viticultural regions of the world. In terms of foliar infestations, grape phylloxera preferentially infests many native Vitis species and hybrid grapes (e.g. V. vinifera × V. riparia) as opposed to V. vinifera. The pest's ability to asexually and sexually reproduce leads to the build-up of large populations and allows for genetic recombination. High humidity, cool temperatures, and long day length favor grape phylloxera establishment on grape foliage. Damage by grape phylloxera on foliage results in a reduction of photosynthesis and variable impacts on fruit yield and juice quality. Economic thresholds have not yet been determined, but severe foliage infestation may lead to secondary infestations by other pests. For effective management, grape growers are to examine vines for signs of galls and take management actions early in the season. Currently, chemical control is the main management method. Insecticides such as spirotetramat and fenpropathrin show the most consistent efficacy. Recommendations for insecticide use include rotating insecticides with different modes of action and combining chemical controls with cultural management tactics such as field sanitation. Following these guidelines for the use of chemical controls can help alleviate environmental concerns and ensure long-term effectiveness. Research into other management tactics such as breeding for resistant grape varieties and biological control is also needed. [ABSTRACT FROM AUTHOR]

Minnesota was dubbed the 'raspberry consumption capital of America' in 2017 by wholesaler Driscoll's, Inc. Local production of this high-demand fruit, however, is limited by the invasive pest, spotted wing Drosophila (Drosophila suzukii Matsumura, Diptera: Drosophilidae). Recent research to develop integrated pest management (IPM) programs for MN berry crops indicates that raspberry growers are particularly vulnerable to significant spotted wing Drosophila-related yield losses. Spotted wing Drosophila was detected in Minnesota in 2012 across 29 counties. This analysis explores the economic impact of raspberry yield losses associated with spotted wing Drosophila in Minnesota as part of a multifaceted research initiative. An electronic survey of 157 MN berry growers was conducted in November 2017. Eighty-two individual grower surveys were returned (52% response rate). The survey included questions about production acreage, marketing practices, spotted wing Drosophila-related yield losses and future production intentions. The results of the e-survey indicate that raspberry growers have borne the highest levels of infestation among MN fruit growers surveyed. Spotted wing Drosophila-related yield losses for raspberry growers ranged from 2 to 100% of planted acreage.The median yield loss for this group of growers was 20% in 2017. Applying the median yield loss to ex-ante production estimates, we conclude that MN growers lost approximately $2.36 million in raspberry sales during the 1 yr studied. Investing in spotted wing Drosophila control measures will help MN growers reduce some of these losses in the future. [ABSTRACT FROM AUTHOR]

Transgenic corn, expressing the insecticidal S-endotoxin of Bacillusthuringiensis Berliner, provides high levels of control of some lepidopteran pests, particularly the European corn borer, Ostrinia nubilalis (Hiibner). However, resistance to B. thuringiensis has been documented recently in laboratory colonies of agronomically important Lepidoptera, including O. mibilalis. For the past 4 yr, we have selected for CrylAc resistance in a population of O. nubilalis from southeastern Minnesota. Increasing resistance to B. thuringiensis was noted after only 8 generations of selection, with a peak at 162-fold resistance, based on comparisons of LC50s to a nonselected parental strain. This resistance was found to decrease at the same rate in the absence of B. thuringiensis selection, with one selected colony becoming nearly as sensitive to the CrylAc toxin as the nonselected colony after 9 generations without exposure to B. thuringiensis. The most resistant of the colonies, S-I, was only marginally cross-resistant to CrylAb, yet another selected colony, S-IV, did demonstrate a 16-fold cross-resistance. In addition, larvae from the S-IV colony had significantly greater weight gain when feeding on diet incorporated with B. thuringiensis-transgenic corn than did larvae from the nonselected parental colony. These findings emphasize the need for careful deployment of B. thuringiensis corn to preserve this effective pest management technology. [ABSTRACT FROM AUTHOR]

Pink bollworm, Pectinophora gossypiella (Saunders), has failed to establish economically damaging populations on southeastern U.S. cotton(Gossypium spp.). Failure to establish may be the result of prevention and quarantine programs or the physiological tolerances of the species. The objectives of this study were to determine which regions within the southeastern United States might support pink bollworm survival and reproduction and which environmental factors might preclude establishment. Three independent analyses based on logistic regressionof output from climate matching software, Climex, indicate that the probability of establishment was >50% in parts of -Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Virginia, and Tennessee. At least 2 analyses concurred that the probability of establishment was =/>80% in portions of Arkansas, Louisiana, Mississippi, Alabama, Florida, and Georgia. All logistic regression models correctly classified 89-93% of the locations where pink bollworm occurs in the southwestern United States or does not occur outside the United States cotton belt. The models incorrectly classified 13-18% of the cases where successful establishment was predicted and 5-8% of cases where establishment was considered unlikely. Cold winter temperatures, causing direct mortality, or cool summer temperatures, providing inadequate degree-days for development, reduce the probability of establishment in more northern states. Slowed population growth caused by excessive moisture also lessens, but doesnot eliminate, the chances for establishment in certain southeasternstates. These analyses do not indicate the potential severity of infestations. Nevertheless, the risk assessment suggests that monitoringefforts for presence and establishment of pink bollworm in the southeastern United States are warranted. [ABSTRACT FROM AUTHOR]

From 1995 to 1997, data sets (351) were collected from 30 fields in central and southern Minnesota to determine the most efficient, fixed-precision, sequential sampling plan for density estimation of aster leafhopper, Macrosteles quadrilineatus Forbes, in carrot, Daucus carota (L.). Conventional and organic farms were sampled to obtain a range of leafhopper densities likell to be encountered with various management practices. Densities ranged from 0.01 to 6.97 leafhoppers per sweep. Taylor's a and b parameters were estimated from 266 data sets and used in conjunction with 1.5 independent data sets to validate thesampling plan with resampling software. The results showed that, fora density range of 0.01-1.61 leafhoppers per sweep, 20 samples of 10sweeps each must be taken to achieve an average precision level of 0.25 (SE/ mean). In subsequent analyses, results were partitioned intolow (<0.17 leafhoppers per sweep) and high (=/>0.17 leafhoppers per sweep) density data sets. Further analysis, using modified precision levels, showed that either 86 samples of 10 sweeps each (low densities) or 5 samples of 10 sweeps each (high densities) were needed to achieve the desired average precision level of 0.15. Implementation of this plan requires growers to collect a minimum of 5 samples of 10 sweeps each; if the mean density =/>0.17, then mean actual precision approx. 0.25, and no further sampling is necessary. For densities <0.17,an additional 5 samples of 10 sweeps each should be taken, and finaldensity estimated (precision may be >0.25). Final density can be compared with the aster yellows index for control guidelines. [ABSTRACT FROM AUTHOR]

Adult striped cucumber beetles. Acalymma vittatum (F.), were sampledin 20 fields during 1994-1995 in southern Minnesota. Data in both years were collected using a fixed sample unit of 7 consecutive plants within a row and a fixed sample size of 48. Sample units of 1 through7 plants were separated out from each data set, and data sets for each sample unit of 1, 2, 3, . . . 7 plants each, were used for analysis. The sampling plan was analyzed and validated using resampling software, Resampling validation for sampling plans, which uses the Wald sequential probability ratio test to develop a binomial sampling plan. Based on actual a (type J) and A (type 11) error rates derived from the resampling analysis of 32-36 datasets, the optimum sample unit was determined to be 2 consecutive plants. Specifying nominal error rates of a = /3 = 0.10, with a tally threshold = 2 and an action threshold = 0.25, the sample plan required an average of 14, 2-plant sample units per field. Actual a and (3 error rates were 0.05 and 0.08,respectively. Analysis of the average sample number function indicated that a maximum of 29 samples would be required to classify A. vittatum populations near the action threshold of 0.25 proportion of samples infested with a tally threshold = 2. Binomial sampling plans should provide an efficient sampling program for use in managing A. vittatum infestations in cucurbits with minimal sampling costs. [ABSTRACT FROM AUTHOR]

Commercial pheromone lures for monitoring European corn borer, Ostrinia nubilalis (Hubner), captured significantly fewer moths and indicated a delayed peak emergence compared with blacklight traps in Minnesota. Pheromone trap studies were therefore conducted during 1992--1994 ar Rosemount and Le Sueur, MN, to determine the relative attractiveness of different ratios of (Z)- and (E)-11-tetradecenyl acetate isomers to O. nubilalis male moths. Isomer ratios in the pheromone lures tested ranged in percentage of concentration from 99.5:0.5 to 95.0:5.0 (Z:E). In addition to overall catch, the timing of O. nubilalis flights based on pheromone and blacklight traps catches was compared. The variance to mean relationship in pheromone trap catch data was usedto estimate the optimum number of traps needed. Analysis of the proportion of total moths captured indicated that moths were highly attracted to lures with a ratio of isomers near 98:2 (Z:E). A significant decline in attractiveness occurred with lures in the 95:5 (Z:E) isomer range. Although the 1st moth catch in pheromone traps usually coincided with blacklight traps, the timing of 2nd-generation cumulative emergence (e.g., 50% peak catch) was significantly different between pheromone and blacklight traps. Despite an aggregated distribution of moth catches, the expected optimum trap number ranged from 2 to 5 at the 25% precision level. Results of this study confirm the increased response of O. nubilalis males to limited concentrations of (E) isomer (1--3%) in the pheromone blend. To ensure optimum performance of O.nubilalis pheromone lures, a renewed emphasis must be placed on quality control protocols during commercial pheromone lure preparation. [ABSTRACT FROM AUTHOR]

The striped cucumber beetle, Acalymma vittatum (F.), has been identified as one of the most damaging insect pests of vegetables in Minnesota. In an effort to develop practical methods for estimating adult beetle density, beetles were sampled in cucurbit fields throughout central and southern Minnesota during 1994-1995. A. vittatum samples were collected in several cucurbit crops including cucumber, pumpkin, and squash. A sample unit consisted of 7 consecutive plants within a row. Beetle counts were recorded for each of the 7 plants in a sample unit and the sample size consisted of a total of 48 sample units in each field. Counts from individual plants in a sample unit were combined to evaluate progressively larger sample units of 1, 2, . . . 7 consecutive plants. An enumerative fixed-precision sampling plan was developed based on Green's method and the Taylor power law. Performance of the plan was validated using bootstrap (resampling) simulations and9 independent data sets. Final analysis indicated that a sample unitof 2 consecutive plants provided the highest relative net precision (RNP) for estimating A. vittatum adult density. On average, over a range of densities, thirty 2-plant sample units per field were necessary to maintain the desired precision (SEM/x) level of 0.25. This plan should aid further research on A. vittatum population dynamics, the yield-density relationship, or the correlation between density and incidence of bacterial wilt. This plan also can be used in tandem with recently developed economic thresholds for pest management decision making. [ABSTRACT FROM AUTHOR]