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1.
The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States but little is known concerning its spatiotemporal distribution in corn cropping systems. Therefore, the spatiotemporal distribution of C. hilaris in farmscapes, when corn was adjacent to cotton, peanut, or both, was examined weekly. The spatial patterns of C. hilaris counts were analyzed using Spatial Analysis by Distance Indices methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops in corn–peanut–cotton farmscapes. This stink bug was detected in six of seven corn–cotton farmscapes, four of six corn–peanut farmscapes, and in both corn–peanut–cotton farmscapes. The frequency of C. hilaris in cotton (89.47%) was significantly higher than in peanut (7.02%) or corn (3.51%). This stink bug fed on noncrop hosts that grew in field borders adjacent to crops. The spatial distribution of C. hilaris in crops and the capture of C. hilaris adults and nymphs in pheromone-baited traps near noncrop hosts indicated that these hosts were sources of this stink bug dispersing into crops, primarily cotton. Significant aggregated spatial distributions were detected in cotton on some dates within corn–peanut–cotton farmscapes. Maps of local clustering indices depicted small patches of C. hilaris in cotton or cotton–sorghum at the peanut–cotton interface. Factors affecting the spatiotemporal dynamics of C. hilaris in corn farmscapes are discussed.  相似文献   

2.
Stink bugs (Hemiptera: Pentatomidae) are ubiquitous, cryptic, phytophagous pests that are found in many crops. In agroecosystems, individuals disperse from adjacent noncrop hosts and tend to aggregate or cluster within fields. In this study, we characterized the distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) over 2 yr at three southeastern United States farmscapes. Stink bugs were captured in pheromone-baited traps, and Spatial Analysis by Distance Indices (SADIE) used to identify the location of significant aggregations by habitat type and season. Euschistus servus adults were more likely to be captured in pecan orchards, cotton, other crops, or unmanaged habitats than in woodland habitats. Significant aggregations of E. servus were detected in a variety of habitats including pecan, corn, cotton, peanut, and tobacco, as well as fallow and hay fields, pastures, and hedgerows. Fewer adult E. tristigmus were captured than E. servus adults, and E. tristigmus adults were typically trapped and aggregated in woodland habitats. The resulting data provide an important understanding regarding the seasonal movement and relative abundance levels of stink bug populations, which are critical to the development of integrated pest management strategies.  相似文献   

3.
The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States, but little is known concerning its spatiotemporal distribution in agricultural farmscapes. Therefore, spatiotemporal distribution of C. hilaris in farmscapes where cotton fields adjoined peanut was examined weekly. Spatial patterns of C. hilaris counts were analyzed using SADIE (Spatial Analysis by Distance Indices) methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops. For the six peanut-cotton farmscapes studied, the frequency of C. hilaris in cotton (94.8%) was significantly higher than in peanut (5.2%), and nymphs were rarely detected in peanut, indicating that peanut was not a source of C. hilaris into cotton. Significantly, aggregated spatial distributions were detected in cotton. Maps of local clustering indices depicted patches of C. hilaris in cotton, mainly at field edges including the peanut-to-cotton interface. Black cherry (Prunus serotina Ehrh.) and elderberry (Sambucus nigra subsp. canadensis [L.] R. Bolli) grew in habitats adjacent to crops, C. hilaris were captured in pheromone-baited stink bug traps in these habitats, and in most instances, C. hilaris were observed feeding on black cherry and elderberry in these habitats before colonization of cotton. Spatial distribution of C. hilaris in these farmscapes revealed that C. hilaris colonized cotton field edges near these two noncrop hosts. Altogether, these findings suggest that black cherry and elderberry were sources of C. hilaris into cotton. Factors affecting the spatiotemporal dynamics of C. hilaris in peanut-cotton farmscapes are discussed.  相似文献   

4.
Brown stink bugs, Euschistus servus, are an important early-season pest of field corn in the southeastern United States. Feeding in the early stages of corn development can lead to a number of growth deformities and deficiencies and, ultimately, a reduction in yield. An observational and two experimentally manipulated trials were conducted in 2017 and 2018 to 1) determine optimal timing for assessing brown stink bug damage, 2) assess the level of damage from which yield compensation can occur, and 3) examine the relationship between brown stink bug density and early-season damage and yield. Fields were identified with infestations of brown stink bugs and a damage rating system for early stages of corn was established. Varying rates of brown stink bug densities were introduced using field cages and damage was assessed throughout the season. The density and duration of stink bug infestations were critical factors for damage potential, with each day of active feeding per plant resulting in a loss of ~14 kg/ha in yield. The level of damage in early stages of corn was categorized into easily identifiable groups, with only the most severe damage leading to a reduction in yield. Moderate and minimal feeding damage did not result in yield loss. This study emphasizes the need for early and frequent scouting of corn to determine the risk of damage and yield loss from brown stink bugs. Results from this study can be used to help develop management programs for brown stink bugs in the early vegetative stages of field corn.  相似文献   

5.
Sampling of herbivorous stink bugs in southeastern U.S. cotton remains problematic. Remote sensing was explored to improve sampling of these pests and associated boll injury. Two adjacent 14.5-ha cotton fields were grid sampled in 2011 and 2012 by collecting stink bug adults and bolls every week during the third, fourth, and fifth weeks of bloom. Satellite remote sensing data were collected during the third week of bloom during both years, and normalized difference vegetation index (NDVI) values were calculated. Stink bugs were spatially aggregated on the third week of bloom in 2011. Boll injury from stink bugs was spatially aggregated during the fourth week of bloom in 2012. The NDVI values were aggregated during both years. There was a positive association and correlation between stink bug numbers and NDVI values, as well as injured bolls and NDVI values, during the third week of bloom in 2011. During the third week of bloom in 2012, NDVI values were negatively correlated with stink bug numbers. During the fourth week of bloom in 2011, stink bug numbers and boll injury were both positively associated and correlated with NDVI values. During the fourth week of bloom in 2012, stink bugs were negatively correlated with NDVI values, and boll injury was negatively associated and correlated with NDVI values. This study suggests the potential of remote sensing as a tool to assist with sampling stink bugs in cotton, although more research is needed using NDVI and other plant measurements to predict stink bug injury.  相似文献   

6.
Stink bugs, primarily southern green stink bug, Nezara viridula (Hemiptera: Pentatomidae), are a major pest complex of soybeans (Glycine max) throughout the southern United States. Densities sometimes peak during late R6 and R7 soybean growth stages when soybeans are approaching physiology maturity and the rate of injury from stink bugs is reduced. Field cage trials were conducted from 2005 to 2008 to examine the type and extent of soybean damage caused by southern green stink bugs during the R7 growth stage. The yield response was variable, but overall was not significant. The impact of southern green stink bugs on quality was more consistent. Test weight decreased, and heat damage and total damage increased as stink bug density increased. Based on these data, three economic injury models were developed using different assumptions. The model that assumes no yield loss, does not predict economic injury within the range of stink bug densities tested. However, if the statistically non-significant yield losses are accepted as real, then the models suggest that the southern green stink bug economic injury level and action threshold for soybeans during R7 stage is generally between nine and 15 stink bugs per row m.  相似文献   

7.
Nezara viridula (L.) (Hemiptera: Pentatomidae), commonly known in the U.S. as the southern green stink bug (SGSB), is a cosmopolitan, highly polyphagous feeder that causes severe damage to a wide range of agronomically important crops such as fruit, vegetable, grain, tobacco, and cotton, throughout much of the United States, and is a global pest of considerable ecological, agricultural, and economical interest. During dissection of female Nz. viridula, conspicuous black and brown spots or lesions were observed on various internal organs. To determine the cause of these spots or lesions, tissues of fat body, spermatheca, ovaries, and ovulated eggs were collected from healthy and infected individuals. The gross morphology of the spots was characterized, and the microorganisms associated with the infection were identified by amplicon sequencing of the V4 region of the small subunit rRNA gene. The presence of a microsporidian pathogen Nosema maddoxi, Becnel, Solter, Hajek, Huang, Sanscrainte, & Estep (Microsporidia: Nosematidae) which has been observed on other species of stink bug, was evidenced for the first time. The characterization of the gross morphology of this associated microsporidian may enable more rapid determination of microsporidia infection in stink bug colonies and field populations.  相似文献   

8.
The green belly stink bug, Dichelops furcatus (F.) (Hemiptera: Heteroptera: Pentatomidae) is a pest of corn and soybean in southern Brazil. It also occurs on wheat, but information on its damage to this crop is limited. To determine the need for sustainable IPM programs, the impact of this bug on wheat production should be determined. Studies were conducted in the screenhouse with 1, 2 and 4 bugs caged for 16 days on single plants, cv. ‘BRS Parrudo’. During the vegetative period (plants ca. 25 cm tall), all infestation levels significantly reduced plant height and ear head length, but did not reduce grain yield. Feeding damage caused tissue necrosis on leaves. During the booting stage, grain yield was significantly reduced with 2 and 4 bugs per plant; ear heads were small, discolored and abnormally developed. In 2013 and 2014 field trials, plants were infested for 18 days with 2, 4 and 8 bugs per m2 at vegetative, booting, and milky grain stage. At these infestation levels, there was no significant reduction in grain yield. There was a significant decrease in the number of normal seedlings resulting from seeds exposed to 8 bugs per m2 at the milky grain stage. Results suggest that, in general, there is no need to control D. furcatus on wheat, unless numbers are ≥8 bugs per m2 during reproductive period.  相似文献   

9.
Lethal and sublethal insecticide effects on non-targeted pest species are frequently neglected but have potential consequences for pest management and secondary pest outbreaks. Here, the lethal and demographic effects of four soybean insecticides (chlorantraniliprole, deltamethrin, pyriproxyfen, and spinosad, which are used against caterpillars, whiteflies, and green stink bugs) on the brown stink bug Euschistus heros (F.), the main stink bug species currently attacking Neotropical soybean fields, were assessed. Deltamethrin exhibited drastic acute mortality in adult females of E. heros with a median lethal time (LT50) of 0.6 days, whereas pyriproxyfen treated females exhibited a survival similar to that of water-treated insects (LT50 of 89 and 67 days, respectively). Chlorantraniliprole and spinosad-treated females exhibited intermediate survival with a TL50 of 54 and 47 days, respectively. Further scrutiny of the three most selective insecticides (i.e., chlorantraniliprole, pyriproxyfen, and spinosad) using age-structured matrices to assess the demographic impact of these compounds under earlier exposure indicated that both pyriproxyfen and spinosad significantly reduced the population growth of the pest species by compromising the survival of eggs (<17% hatching) and 1st nymphs (LT50 of 3 and 2 days, respectively) and fertility; these results were unlike those obtained for chlorantraniliprole- and water-treated controls, which exhibited less than 50% mortality during development. However, chlorantraniliprole significantly compromised the fertility of adult insects (>50% reduction compared with water-treated insects) to a greater extent than pyriproxyfen and spinosad, but without impairing insect population growth as much. Therefore, although pyriproxyfen and spinosad, besides deltamethrin, are not used to target the Neotropical brown stink bug, these insecticides adversely affected this pest species at the dose recommended for application on the label, thereby preventing its outbreak under such conditions.  相似文献   

10.
Potato cropping systems in Maine include both continuous potatoes and short-term potato rotations with small grains. Producers recognize the benefits of increased rotations, but the economics of producing a high-valued crop such as potatoes (Solanm tuberosum L.) create incentives for continuous potato production. Research at the USDA-ARS research site in Newport, ME, is evaluating the agronomic and economic impacts of five crops in two-year rotations on potato production and whole-farm profitability. The rotation crops are barley (Hordeum vulgare L.), sweet corn (Zea mays L.) green bean (Phaseolus vulgares L.), soybean (Glycine max L., Mer.), and canola (Brassica napus L.). Enterprise budgets for the five crops were developed. The budgets and historical prices and yields were used as inputs to a Monte Carlo simulation. The simulation was conducted to determine the impact of rotation crops on whole-farm profitability and income risk, as measured by income variability. The net incomes of the five rotation sequences were compared against continuous potatoes. Two rotation crops, sweet corn and green beans, resulted in an increase in net income relative to continuous potatoes. AU of the rotation crops were found to greatly reduce income risk and chance of economic losses. In the case of green beans and sweet corn, the analysis was rerun using data from the research trials on the following potato crop yields. Depending on whether the rotation effect was negative or positive, net income either fell or rose when compared to fist analysis. However, even when the rotation crop led to decreased yields in the following potato crop, income variability and likelihood of economic loss was still superior to the continuous potato rotation. These findings provide support for including rotation crops as a method to improve potato production and sustainability, increase wholefarm profitability, and reduce income risk.  相似文献   

11.
Two artificial diets developed for rearing Lygus spp., a fresh yolk chicken egg based-diet (FYD) and a dry yolk chicken egg based-diet (DYD), were evaluated as an alternative food source for rearing the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae). Survival to adult was 97.3 and 74.67%, respectively, on the fresh and dry yolk diets. Insects fed FYD had 100% survival of nymphs from first through fourth instars. Adult development was significantly shorter on FYD (30.37 ± SE 0.30 d) as compared with DYD (32.77 ± SE 0.16 d). Increased male and female longevity, higher fecundity, and larger egg mass sizes were also observed with N. viridula-fed FYD. However, fertility and hatchability was higher on DYD. A complete cohort life table was constructed to describe the development of N. viridula on both diets.  相似文献   

12.
Harvesting products from plants for conversion into renewable resources is increasing in importance. Determination of nutrition requirements for the applicable crops is necessary, especially in regions where the biofuel feedstock crops have not been historically grown. Sunflower (Helianthus annuus L.), two hybrids and one variety; sweet and grain (milo) sorghums (both Sorghum bicolor L.), one variety each, and sweet corn (Zea mays var. rugosa Bonaf.), four cultivars, were provided the recommended and twice the recommended rate of fertilizer. Biomass, expressed liquid volumes and sugar contents of sweet sorghum and sweet corn were determined. Grain yields of milo and sunflower and oil content of sunflower were determined. Sweet corn stalk sugar levels were below what is expected from field corn (maize), and were not affected by fertilizer rate. Sweet sorghum biomass and sugar content were within expected ranges and not affected by fertilizer rate. Milo grain yields were higher with increased fertilizer. Seed yield in Sunflower, which was below expected levels, was inconsistently affected by fertilizer rate, years or varieties. Overall crops year and cultivar/variety had more effect on results than did fertilizer. There does not appear to be a reason to provide fertilizer above recommended rates in production of these crops.  相似文献   

13.
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14.
The most destructive enemy of the lychee, Litchi chinensis Sonn. (Sapindales: Sapindaceae), in India is a stink bug, Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae). The population of T. papillosa on lychee trees varied from 1.43 ± 0.501 to 9.85 ± 3.924 insects per branch in this study. An increase in the temperature and a decrease in the relative humidity during summer months (April to July) favor the population buildup of T. papillosa. A forecasting model to predict T. papillosa incidences in lychee orchards was developed using the autoregressive integrated moving average (ARIMA) model of time-series analysis. The best-fit model for the T. papillosa incidence was ARIMA (1,1), where the P-value was significant at 0.01. The highest T. papillosa incidences were predicted for April in 2010, January in 2011, May in 2012, and February in 2013. A model based on time series offers longer-term forecasting. The forecasting model, ARIMA (1,1), developed in this study will predict T. papillosa incidences in advance, thus providing functional guidelines for effective planning of timely prevention and control measures.  相似文献   

15.
A 12-yr. (2000–2011) study was conducted in Alberta, Canada to compare the energy use efficiency (EUE) of conventional (CONV) and conservation (CONS) potato (Solanum tuberosum L.) management practices. Potato was grown in 3- to 6-yr. rotations which included dry bean (Phaseolus vulgaris L.), sugar beet (Beta vulgaris L.), soft wheat (Triticum aestivum L.), oat (Avena sativa L.), and timothy (Phleum pratense L.). CONS included compost application, reduced tillage, cover crops, and solid-seeded bean. Findings suggested that potato in 5-yr. CONS produced the highest EUE compared to the other CONS or CONV rotations. CONS can be used as a means of reducing the reliance on non-renewable energy inputs and improving overall EUE of potato production when less than 21% of the N content of compost applied was counted toward energy input use of potato production. At more than 21%, potato in the 4-yr. CONV became more favorable compared to potato in other rotations.  相似文献   

16.
Two trials of winter wheat, embracing 17 varieties and 4 breeding lines, harvested in 2003 from locations in the semi-arid eastern part of Austria, were severely infested by naturally occurring bugs (Eurygaster sp.). In these trials bug damage was determined by selecting and weighing the infested kernels. Glutenin degradation was determined by the addition of meal from bug-infested kernels to meal from sound kernels from the same trials to reach sample mixtures representing a degree of bug attack of 6%. These mixtures and blanks made from sound meal were incubated in buffer solution (pH=8.5) at 37 °C for 45 min. The reduction in glutenin content due to the activity of bug proteinases was measured by RP-HPLC analysis of the glutenin fraction and comparison of the results of damaged and sound samples. The results showed good correlations between the degree of bug attack and the digestibility of glutenin (location 1: R2=0.69, P<0.01; location 2: R2=0.36, P<0.01). Both parameters seem to be variety specific. The determination of digestibility of glutenins was repeated in material from a trial harvested in 2005 in another location in eastern Austria, with eight varieties being the same as used in the 2003 trials. A correlation with the degree of bug attack in location 1 from the 2003 harvest was found again (R2=0.61, P<0.01).  相似文献   

17.
A molecular gut analysis technique is described to identify predators of Lygus hesperus (Knight), a significant pest of many crops. The technique is unique because it can pinpoint which life stage of the pest was consumed. Sentinel egg masses designed to mimic the endophytic egg-laying behavior of L. hesperus were marked with rabbit serum, while third instar and adult L. hesperus were marked with chicken and rat sera, respectively. Then, the variously labeled L. hesperus life stages were introduced into field cages that enclosed the native arthropod population inhabiting an individual cotton plant. After a 6-h exposure period, the predator assemblage, including the introduced and native L. hesperus population, in each cage were counted and had their gut contents examined for the presence of the variously marked L. hesperus life stages by a suite of serum-specific enzyme-linked immunosorbent assays (ELISA). The whole-plant sampling scheme revealed that Geocoris punticpes (Say) and Geocoris pallens Stal (Hemiptera: Geocoridae) and members of the spider complex were the numerically dominant predator taxa in the cotton field. The gut content analyses also showed that these two taxa appeared to be the most prolific predators of the L. hesperus nymph stage. Other key findings include that Collops vittatus (Say) (Coleoptera: Melyridae) and Solenopsis xyloni McCook (Hymenoptera: Formicidae) appear to be adept at finding and feeding on the cryptic L. hesperus egg stage, and that L. hesperus, albeit at low frequencies, engaged in cannibalism. The methods described here could be adapted for studying life stage-specific feeding preferences for a wide variety of arthropod taxa.  相似文献   

18.
Wireworms are the soil inhabiting larvae of click beetles and can cause severe damage to arable crops such as potatoes (Solanum tuberosum, L.). Several strains of the entomopathogenic fungus Metarhizium brunneum (Petch) are pathogenic to wireworms. In this study, three European strains of M. brunneum were tested in the laboratory against the most damaging wireworm species in Europe, Agriotes lineatus (L.), Agriotes obscurus (L.) and Agriotes sputator (L.). A Swiss strain, isolated from an A. obscurus cadaver, proved to be most effective, killing up to 73% of A. lineatus and 83% A. obscurus individuals, respectively. The median lethal time (LT50) was 21 days post inoculation (dpi) for A. lineatus and 14 dpi for A. obscurus. The strain did not lose virulence through subsequent cultivation on artificial medium and thus seems to be suitable for mass production as a biocontrol agent for wireworm control.  相似文献   

19.
Oilseed and pulse crops have been increasingly used to diversify cereal-based cropping systems in semiarid environments, but little is known about the root characteristics of these broadleaf crops. This study was to characterize the temporal growth patterns of the roots of selected oilseed and pulse crops, and determine the response of root growth patterns to water availability in semiarid environments. Canola (Brassica napus L.), flax (Linum usitatissimum L.), mustard (Brassica juncea L.), chickpea (Cicer arietinum L.), field pea (Pisum sativum L.), lentil (Lens culinaris), and spring wheat (Triticum aestivum L.) were tested under high- (rainfall + irrigation) and low- (rainfall only) water availability conditions in southwest Saskatchewan, in 2006 and 2007. Crops were hand-planted in lysimeters of 15 cm in diameter and 100 cm in length that were installed in the field prior to seeding. Roots were sampled at the crop stages of seedling, early-flower, late-flower, late-pod, and physiological maturity. On average, root length density, surface area, diameter, and the number of tips at the seedling stage were, respectively, 41, 25, 14, and 110% greater in the drier 2007 than the corresponding values in 2006. Root growth in all crops progressed rapidly from seedling, reached a maximum at late-flower or late-pod stages, and then declined to maturity; this pattern was consistent under both high- and low-water conditions. At the late-flower stage, root growth was most sensitive to water availability, and the magnitude of the response differed between crop species. Increased water availability increased canola root length density by 70%, root surface area by 67%, and root tips by 79% compared with canola grown under low-water conditions. Water availability had a marginal influence on the root growth of flax and mustard, and had no effect on pulse crops. Wheat and two Brassica oilseeds had greater root length density, surface area and root tips throughout the entire growth period than flax and three pulses, while pulse crops had thicker roots with larger diameters than the other species. Sampling roots at the late-flower stage will allow researchers to capture best information on root morphology in oilseed and pulse crops. The different root morphological characteristics of oilseeds, pulses, and wheat may serve as a science basis upon which diversified cropping systems are developed for semiarid environments.  相似文献   

20.
The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is a serious pest of sugarcane (Saccharum spp.), sorghum (Sorghum bicolor (L.) Moench), corn (Zea mays L.), rice (Oryza sativa L.), and related graminaceous bioenergy crops. A two-year field study was conducted in Jefferson County, TX to examine the impact of nitrogen (N) fertilization on E. loftini infestations and subsequent yields in cultivars of high-biomass and sweet sorghum. In 2013, percentage of bored internodes and number of adult emergence holes per stalk increased with higher N rates; however, only the percentage of bored internodes was impacted by N in 2014. Yields from both years indicated that N rate was positively associated with increases in stalk weight and ethanol productivity, but not sucrose concentration. Because higher N rates were associated with increased yields despite having greater levels of E. loftini injury, our data suggest that increases in yield from additional N outweigh decreases from additional E. loftini injury. Fertilization rates maintained between the recommended 45 and 90 kg N/ha minimize risks of negative area-wide impacts from increased production of E. loftini adults, while still allowing for optimum yields.  相似文献   

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