Secondary Pests Research Articles

USING TRAP TREES FOR MONITORING AND CONTROL OF BARK BEETLE PITYOGENES CHALCOGRAPHUS (L.) ON MOUNTAIN ZVIJEZDA

UDK: 595.768.1:582.475(234.422 Zvijezda)
 Bark beetles are the most important pests of the coniferous forests. Although they are considered to be a secondary pest, they are becoming the primary pests that attack healthy trees. One of the important spruce bark beetle is the Pityogenes chalcographus (L.) - a small spruce beetle. The research was conducted in the municipality of Vareš, on three locations: Ponikva, Pobrin Han, Doli. The active period of the bark beetle for development began in the last decade of April. P. chalcographus in the field of research had two generations. For the development of generations it took between 12 and 13 weeks. Weather conditions in the object of research did not allow the completion of the second generation. The activity of the bark beetle ends in mid-September. When we talk about the characteristics of wood material which prefers small bark beetle of spruce, we can say that he prefers to inhabit thinner parts of trunk with thin and smooth rind. In the object of research for monitoring of population of bark beetle P. chalcographus was used trap trees. As a measure to combat the small spruce bark beetles are strongly advised in due time, autumn and winter, remove the dried trees and trees with drilled bark beetles. Maintenance and establishment of forest order to reduce the amount of wood material suitable for the settlement of bark beetles.

What Happened to Nezara viridula (L.) in the Americas? Possible Reasons to Explain Populations Decline.

Once abundant in the Americas, the southern green stink bug Nezara viridula (L.) has gradually declined in numbers. Until the 1990s, it was considered the main pest of major crops such as soybean, Glycine max (L.) Merrill, particularly in southern Brazil and southern USA, as well as Argentina, Uruguay, and other countries. In the past 15+ years, a dramatic population decrease was observed to the point of now being considered a secondary pest in these referred countries. In this article, we list and discuss possible reasons which explain the decline in N. viridula population in the Americas. These factors include the following: (1) the steady increase of herbicides used in no-tillage/multiple cropping systems affecting potential hosts such as weeds in crop fields and nearby natural vegetation; (2) the change in cultivation systems, mostly in the Neotropics, favoring other species more adapted to exploit crops in modern day agriculture; (3) competition among several species of stink bugs that colonize major crops; (4) the growing impact of several species of egg parasitoids, some of them laboratory reared and released in crop fields, and other natural enemies (parasitoids and predators); and (5) the impact of global climate change affecting its distribution and biology.

Spatial and temporal dynamics of Siberian silk moth large-scale outbreak in dark-needle coniferous tree stands in Altai

The spatial and temporal dynamics of fir stands damage caused by a large-scale outbreak of the Siberian silk moth (Dendrolimus sibiricus Tschetv.) in the Altai Mountains has been studied using remote sensing and GIS methods. It is ascertained that forest damages are dissimilar relative to the surface features. The pest outbreak initially occurred on the southwest slopes with mean values of 10° and elevation of 400 m asl. The damages further extended both upward and downward, involving slopes of high steepness and the eastern exposure. The total area of the dead stands comprised 6000 ha, 45% of which were lost due to secondary pest (xylophagous insects) attacks. It is indicated that the use of remote sensing made it possible to determine the beginning of a pest outbreak with one-decade precision. The Siberian silk moth large-scale outbreak occurred against an increase in air temperatures, a decrease in precipitation, and a reduction in late frosts. The tree plants weakened by the Siberian silk moth and water stress were affected by xylophagous insect attacks. The observed and predicted warming and climate aridity increase will facilitate Siberian silk moth outbreaks both within its range and northward of the current margins of the range.

Pathogen-induced defoliation of Pinus sylvestris leads to tree decline and death from secondary biotic factors

The contribution of non-lethal pathogenic attacks to tree death is still unclear. Manion’s theory of the spiral of decline predicts that tree decline and death occurs because of a sequence of predisposing, inciting and contributing events. To understand whether pathogens can act as predisposing or inciting factors, we tested whether a sequence of non-lethal pathogen attacks causing crown defoliation could lead to a chronic decline in tree health and predispose trees to die. Scots pine (Pinus sylvestris) trees predisposed or escaping (non-predisposed) a first outbreak by the pathogen Gremmeniella abietina (predisposing event) were compared in terms of survival and susceptibility to secondary pests (contributing event) after a second G. abietina outbreak (inciting event). Four years after the inciting event, mortality among predisposed trees was up to five times higher than among trees escaping the first epidemic. Predisposed trees were twice as susceptible to secondary attacks by the common pine shoot beetle (Tomicus piniperda). Ten years after the inciting event, severely predisposed trees had not been able to restore their crowns and still showed stagnated growth. This study showed that pathogen-induced defoliation can act as predisposing and inciting factors for tree death, reducing the capacity of trees to survive short- or long-term stressing events, such as bark beetle attacks. We also showed that tree decline can result from a combination of predisposing and inciting events caused by pathogens.

Comparative soil distribution and dissipation of phoxim and thiamethoxam and their efficacy in controlling Bradysia odoriphaga Yang and Zhang in Chinese chive ecosystems

Bradysia odoriphaga Yang and Zhang (the chive gnat) is the major insect pest affecting Chinese chives (Allium tuberosum Rottl. ex Spreng.) in Northern China. Only three insecticide products are registered for its control. In the present study, we compared the persistence and distribution of thiamethoxam and phoxim in soil and determined their long-acting control effects against B. odoriphaga and two other secondary pests, Thrips alliorum Priesner and the Asiatic onion leaf miner Acrolepia alliella Semenov and Kuznetsov (Lepidoptera: Acrolepiidae), after a single soil application using the directional spray-washing method during the early Chinese chive root-rearing period. Under the same applied dosage, the rhizosphere soil at a depth of 4.0–10.0 cm had concentrations of thiamethoxam and phoxim ranging from 2.21 to 7.44 mg/kg and 0.09–0.44 mg/kg, respectively, at the 7th day after application. The half-lives of thiamethoxam and phoxim in the soil were 27.5 and 6.7 days, respectively. Thiamethoxam persisted for 210 days, whereas phoxim only persisted for 45 days in the soil and plants. In addition, thiamethoxam applied at 6.0 kg a.i./ha maintained a low population density of B. odoriphaga, T. alliorum and A. alliella for nine months longer than phoxim. In conclusion, thiamethoxam may help farmers more effectively manage B. odoriphaga and other secondary pests on Chinese chive and reduce the costs of insecticide use while sustaining protection.

Primary and secondary pest management in agriculture: balancing pesticides and natural enemies in potato production

Natural enemies (NEs) provide an important ecosystem service by preying on variety of pests in agricultural crop production systems. Current management practices of both primary and secondary pests in agricultural production principally rely on the use of pesticides with associated negative social and environmental consequences/externalities. Excessive use of pesticides against primary pets can remove NEs from the agro-ecosystem and amplify susceptibility of the system to outbreaks of secondary pests. The combined effect of NEs on primary and secondary pests has received limited attention. This study uses an intraseasonal bioeconomic model to explicitly take into account biological interactions among primary pests, secondary pests, and NEs assuming decision makers’ profit maximizing behavior. The model explicitly captures the opportunity cost of injury to NE in terms of both primary and secondary pest suppression by NE. The results show that in the context of the green peach aphid (primary pest) and two-spotted spider mite (secondary pest) in potato production, inclusion of NE into pest mitigation strategy can increase returns by 2%.

Effect of temperature on the reproductive success, developmental rate and brood characteristics of Ips sexdentatus (Boern.)

Abstract Global warming is predicted to enhance the development rate and increase the number of generations in multivoltine insects. For secondary forest pests, such as the pine bark beetle Ips sexdentatus, the resulting increase in population level could trigger more frequent outbreaks. However, this positive effect could be outweighed by a temperature‐dependent decrease in offspring quality. To test these hypotheses, we carried out a laboratory rearing experiment with maritime pine logs at six temperature regimes reproducing hourly fluctuations and averaging 12–25.5 °C. We estimated the thermal requirements for a complete development of the beetle and the number of offspring per female. The offspring quality was estimated using three traits: dry body weight, elytra length and lipid content. The minimum and maximum developmental threshold were estimated at 10.9 and 36 °C, respectively, and the thermal requirements for complete development were estimated at 517 degree‐days. We predicted a mean of two generations per year in southwestern France, although an additional generation could occur during warmer years. The number of offspring increased exponentially with temperature, although we observed a curvilinear response of offspring traits to temperature, with optima at 15–18 °C. This suggests that there are trade‐offs between productivity and quality of offspring. Global warming is therefore likely to result in higher number of generations of I. sexdentatus per year, with larger broods but of reduced fitness at high temperatures.

The Sustainability of the Farm‐level Impact of Bt Cotton in China

AbstractThe short‐run impact of Bt cotton adoption has been well documented; however, the sustainability of the impact remains unclear. In particular, pest resistance build‐up and secondary pest outbreaks have caused concern regarding the sustainability of this benefit. This paper analyses the effects and impact dynamics of Bt cotton adoption in China. Using six unique waves of panel data collected between 1999 and 2007, we show that the benefits of Bt cotton continue 10 years after it has been commercialised, albeit with evidence of a decline in the benefit since the early adoption period. Importantly, we also show that the benefit has been shared by both Bt and non‐Bt cotton adopters.

Perceived Effectiveness of Indigenous Technological Knowledge (ITK) of Insect and Vertebrate Pests Management in Eastern Uttar Pradesh, India

Indigenous technological knowledge is considered as a traditional knowledge that inherited from their ancestors, unique to a culture, society and environment. In this article we documented uses of such local knowledge used by the local farmers of seven villages form Varanasi, Deoria and Mirzapur districts of eastern Uttar Pradesh, India for their crop protection. Data were collected from 140 respondents (twenty from each village) and 60 respondents who had visited the institute from these three districts during farmers’ fair and farmers’ training and whole making a total of 200 respondents. The farmers in the study developed notable innovations to control major pests of agricultural and horticultural crops such as use of ashes to control vegetable insect pests; use of onion/garlic bulbs, neem leaves, salt crystals, wheat straw, brick kiln powder etc. to prevent store grain pests of cereals; ash and kerosene mixture to repel the sucking pests of rice at milky stage; well-rotted fish scales against Nilgai (Boselaphus tragocamelus); red chilli pods against bruchids in pulses; salt and turmeric powder mixture against ants; use of neem cake to repel termite and other soil insects etc. The local farmers were following these practices because of easy availability, eco-friendly, easy to handle, do not leave any harmful residue, pose any threat to develop resistance and resurgence of secondary pests, easy to apply and compatible with other pest management techniques and socio-cultural situation of the farmers.

Capturing the economic value of biological control in western tree fruit

The economic value of biological control in apple in central Washington and pear in northern Oregon was estimated by comparing pest management programs following practices thought to reduce negative impacts on natural enemies to programs following traditional practices. Pest management costs in three apple orchards that had transitioned to the use of codling moth mating disruption (CMMD) plus reduced-risk or organophosphate-alternative pesticides were compared with four orchards that had not adopted these practices. Pest management costs in five pear orchards using CMMD were compared to four orchards not using CMMD. In both cropping systems the impact of pest management programs on biological control was determined by the need to use pesticides to control secondary pests, aphids and spider mites in apple and spider mites and pear psylla in pear. The disruptive nature of pesticides was categorized into four levels from none (0) to high (4) based on data presented by Mills et al. (2016) and Beers et al. (2016), as well as other published information. Some reduced-risk and OP-alternative pesticides proved detrimental to natural enemies and disruptive of biological control in apple and pear. In apple, the use of pesticides with low risk to natural enemies reduced the need to apply controls for secondary pests. In pear, the use of CMMD reduced the need to control secondary pests, spider mites and pear psylla, in summer. The use of pesticides with a high risk to natural enemies increased the cost of secondary pest control by about 50% in apple and pear. A stepwise increase in natural enemy risk values increased total pest management costs by $46/ha in natural enemy unfavorable apple orchards and by $44/ha in pear orchards not using codling moth mating disruption.

Semiochemical Strategies for Tortricid Moth Control in Apple Orchards and Vineyards in Italy.

- This review summarizes work done in Italy in taking semiochemical-based management of orchard and vineyard pests from the research and development stage to successful commercial deployment. Mating disruption (MD) of codling moth Cydia pomonella (CM) was originally introduced into the Trentino-South Tyrol areas to address the development of CM resistance to insecticides, particularly insect growth regulators (IGRs), and to mitigate the conflict at the rural/urban interface related to the extensive use of insecticides. Although the mountainous terrain of the area was not optimal for the efficacy of MD, commitment and determination led to the rapid adoption of MD technology throughout the region. Grower cooperatives and their field consultants were strongly influential in convincing growers to accept MD technology. Public research institutions conducted extensive research and education, and provided credible assessments of various MD technologies. By 2016, the deployment of MD in effective area-wide strategies in apple (22,100 ha) and grapes (10,450ha), has resulted in better control of tortricid moth pests and a substantial decrease in insecticide use. Collaboration between the research community and the pheromone industry has resulted in the development of increasingly effective single-species dispensers, as well as multi-species dispensers for the control of both target and secondary pests. Over the last 20years, hand-applied reservoir dispensers have shown excellent efficacy in both apple and grapes. Recently, aerosol dispensing systems have been shown to be effective in apple orchards. Further research is needed on the efficacy of aerosols in vineyards before the technology can be widely adopted. The successful implementation of MD in apple and grape production in Trentino-South Tyrol is expediting adoption of the technology in other Italian fruit production regions.

Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton.

The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly.

Managing maize under pest species competition: Is Bt (Bacillus thuringiensis) maize the solution?

AbstractTransgenic crops that contain Cry genes from Bt (Bacillus thuringiensis) have been adopted by farmers over the last 17 yr. Unlike traditional broad‐spectrum chemical insecticides, Bt's toxicity spectrum is relatively narrow and selective, which may indirectly benefit secondary insects that may become important pests. The economic damage caused by the rise of secondary pests could offset some or all of the benefits associated with the use of Bt varieties. We develop a bioeconomic model to analyze the interactions between primary and secondary insect populations and the impact of different management options on insecticide use and economic impact over time. Results indicate that some of the benefits associated with the adoption of genetically engineered insect resistant crops may be eroded when taking into account ecological dynamics. It is suggested that secondary pests could easily become key insect pests requiring additional measures, such as insecticide applications or stacked traits, to keep their populations under the economic threshold.

Pesticides used against Cydia pomonella disrupt biological control of secondary pests of apple

The effects of codling moth (Cydia pomonella (Linnaeus)) (Lepidoptera: Tortricidae) management programs on secondary pests of apple were examined from 2008 to 2011 in five replicated large-plot trials. The orchards were chosen for a history of Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) and tetranychid mite outbreaks. Programs covered the first, second, or both generations of C. pomonella, and employed some of the newer insecticides for comparison to older materials. Increased levels of E. lanigerum were consistently associated with the use of spinetoram and novaluron throughout the tests. The mechanism of disruption was not completely clear, but suppression of Forficula auricularia Linnaeus (Dermaptera: Forficulidae) and Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) were associated with the use of these materials. Methoxyfenozide, chlorantraniliprole, and azinphos-methyl did not disrupt biological control of tetranychid mites or aphids, and negative effects on natural enemies were infrequent. Lambda-cyhalothrin provided direct control of aphid species, thus reduced levels of natural enemies could also be ascribed to lack of prey. The effect of some of the insecticide applications made during the first generation were evident for many months after the application in terms of pest and natural enemy populations; however, attempts to mitigate disruptive effects by shifting the use of materials to the second generation of C. pomonella were not successful. The effect on biological control of tetranychid mites was less consistent, although some detrimental effects (increased pest or decreased predatory mite levels) were associated with spinetoram, novaluron, and lambda-cyhalothrin. The difficulties in sampling natural enemies and determining their impact made pest outbreaks the most reliable indicator of pesticide-induced disruption.

Large-plot field studies to assess impacts of newer insecticides on non-target arthropods in Western U.S. orchards

The non-target impacts of two reduced risk insecticides, chlorantraniliprole and spinetoram, were evaluated for two years in Oregon pear and California walnut orchards. Experiments were conducted in large replicated plots (approximately 0.25–0.4ha) to assess the impact of these two insecticides on natural enemies of secondary pests when applied against codling moth, Cydia pomonella. Cumulative insect days (CID) of secondary pests and natural enemies were calculated from leaf samples, plant volatile traps, beat trays or cardboard trunk bands. Ratios of natural enemies and prey were also calculated. Results from these field studies demonstrate that applications of chlorantraniliprole can reduce abundance of predatory Neuroptera and that spinetoram negatively impacts parasitic Hymenoptera. However, these trends did not always occur each year. As a percentage among all trials within a crop, there were more treatment differences for natural enemy/prey ratios (50 and 33% for pears and walnut plots, respectively) than for natural enemy CIDs (25 and 13% for pears and walnut plots, respectively). It is likely that unseasonably cool weather during the two years of this study impacted both pest and natural enemy abundance. The intrinsic value of large-plot field studies is discussed.

Integrated pest management (IPM) in raspberries under subtropical climate in a year round production system

The raspberry crop in Australia is affected by different pests during its growth cycle. The main pests with an economic impact are: Queensland fruit fly (Bactrocera tryoni), two spotted mite (Tetranychus urticae), broadmite (Polyphagotarsonemus latus), grubs (Helicoverpa spp., loopers, cluster caterpillars, etc.), western flower thrip (Frankliniella occidentalis), green stink bug (Plautia affinis) and green vegetable bug (Nezara viridula). As raspberries are harvested daily, the ability to meet the withholding period requirements after each pesticide application becomes a challenge. Also, the use of agrochemicals as the only control method reduces the efficacy of the pest control program in the short and long term. That's why integrated pest management (IPM) should be considered as an essential strategy for the effective pest control in raspberry crops. However, avoidance of broad spectrum pesticides increases the likelihood of secondary pests becoming an issue (e.g., cotton seed bug (Oxycarensus luctuosus), and myrids). In Corindi, New South Wales (NSW), we have been working to establish an IPM program based on biological control agents and selective pesticides with low or no side effects on beneficial insects or mites. We have been testing biological control agents for pests that cannot be controlled by any selective pesticides currently available. As Corindi is located in a subtropical climate and we grow raspberries year round, pest control becomes quite complex and challenging, so we continue to search for new products and control techniques.

Enhancing Integrated Pest Management in GM Cotton Systems Using Host Plant Resistance.

Cotton has lost many ancestral defensive traits against key invertebrate pests. This is suggested by the levels of resistance to some pests found in wild cotton genotypes as well as in cultivated landraces and is a result of domestication and a long history of targeted breeding for yield and fiber quality, along with the capacity to control pests with pesticides. Genetic modification (GM) allowed integration of toxins from a bacteria into cotton to control key Lepidopteran pests. Since the mid-1990s, use of GM cotton cultivars has greatly reduced the amount of pesticides used in many cotton systems. However, pests not controlled by the GM traits have usually emerged as problems, especially the sucking bug complex. Control of this complex with pesticides often causes a reduction in beneficial invertebrate populations, allowing other secondary pests to increase rapidly and require control. Control of both sucking bug complex and secondary pests is problematic due to the cost of pesticides and/or high risk of selecting for pesticide resistance. Deployment of host plant resistance (HPR) provides an opportunity to manage these issues in GM cotton systems. Cotton cultivars resistant to the sucking bug complex and/or secondary pests would require fewer pesticide applications, reducing costs and risks to beneficial invertebrate populations and pesticide resistance. Incorporation of HPR traits into elite cotton cultivars with high yield and fiber quality offers the potential to further reduce pesticide use and increase the durability of pest management in GM cotton systems. We review the challenges that the identification and use of HPR against invertebrate pests brings to cotton breeding. We explore sources of resistance to the sucking bug complex and secondary pests, the mechanisms that control them and the approaches to incorporate these defense traits to commercial cultivars.

Nontarget effects of orchard pesticides on natural enemies: Lessons from the field and laboratory

The nontarget effects of insecticide programs used to control codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), were studied in large-plot field trials in apples, pears, and walnuts in the western United States. We assessed the health of the natural enemy community by sampling the abundance of natural enemies and by monitoring for outbreaks of secondary pests. The insecticides used in the field tests overlapped those tested in laboratory bioassays. Using these parallel lab and field studies, we examined two hypotheses: 1) pesticides found to have negative effects on natural enemy fitness in laboratory bioassays will predict reductions in natural enemy densities in the field, and 2) reductions in natural enemy densities in the field will result in outbreaks of secondary pests. We found only one clear instance, Forficula auricularia (L.) (Dermaptera: Forficulidae), where laboratory results documenting negative effects corresponded to a significant reduction in field studies (apple). This same instance was the only case where a reduction in a natural enemy population was associated with a significantly increased density of a secondary pest, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae). There were several instances where secondary pest outbreaks were associated with unchanged or even increased natural enemy densities. The limited number of field trials, variability in field trial conditions among years and sites, duration of the negative effect relative to sampling interval, sampling efficiency, plot size/inter-plot movement, and compensation by other natural enemies attracted to a large host/prey resource may all have contributed to the poor predictive success. Overall, the laboratory bioassays predicted a far greater negative impact than was found in the field trials.

Life-history parameters of Chrysoperla carnea s.l. fed on spontaneous plant species and insect honeydews: importance for conservation biological control

Chrysoperla carnea s.l. (Stephens) (Neuroptera: Chrysopidae) larvae are generalist predators feeding on many crop pests while adults feed on non-prey food. The knowledge about the nutritional suitability of non-prey food for adults in agroecosystems is crucial to establish conservation biological control strategies and is poorly known in olive groves, where C. carnea s.l. larvae prey on different pests. In this study, the effect of honeydew secreted by two hemipteran olive tree secondary pests and 11 plant species on the life-history parameters (survival, reproduction and development time) of C. carnea s.l. were analyzed. Insect pest honeydew from the olive agroecosystem and several plant species, blooming throughout the year, were found to improve C. carnea s.l. adult survival. Pollen consumption seems to be essential for reproduction. These findings are important for designing and implementing new conservation biological control approaches.

Exclusion of the Brown Marmorated Stink Bug from Organically Grown Peppers Using Barrier Screens

The brown marmorated stink bug (Halyomorpha halys) is a nonnative insect that damages vegetables and other crops in the United States. Because of the current lack of effective control options for organic growers to combat this pest, barrier screens with different mesh sizes were evaluated in their ability to exclude the brown marmorated stink bug, provide entry to beneficial species, and to produce a high percentage of marketable yield. Barrier screens with 1/6-, 1/8-, and 1/25-inch mesh sizes, along with unscreened controls, covered ‘Aristotle’ bell pepper (Capsicum annuum) plants at field sites in Kentucky and Tennessee in 2013–14. In Kentucky, where brown marmorated stink bug pressure was low, overshading decreased the marketable yield under dark, 1/25-inch mesh screens in 2013. Outbreaks of aphids (Aphididae) under light-colored, 1/25-inch mesh plots in 2014 suggest a higher risk of secondary pests proliferating under these screens. In Tennessee, where brown marmorated stink bug pressure was higher and light colored, 1/25-inch mesh screens were tested in 2013–14, the 1/25-inch mesh plots produced the highest yield, due to the general exclusion of insects and protection from sunscald. In areas with small brown marmorated stink bug populations, lighter colored, and/or wider meshes (1/8-inch or 1/6-inch) may be required to allow the entry of sunlight and beneficial species. In areas with higher brown marmorated stink bug pressure, finer meshes (1/25-inch) may be appropriate to exclude larger populations of pests and to protect the crop from sunscald.