Yellow Sticky Cards Research Articles

Spatial and temporal patterns of Frankliniella fusca (Thysanoptera: Thripidae) in wheat agroecosystems

AbstractFrankliniella fusca Hinds (Thysanoptera: Thripidae) is an economically important pest of many cultivated crops including cotton, tomatoes, peppers and tobacco. Previous research has focused on the importance of non‐crop weeds for F. fusca populations when estimating crop infestation risk in the spring. Although weeds play an integral role in population development, early‐season cultivated hosts (e.g. wheat and sage) may also contribute and augment overall populations. Few studies have examined the role of early‐season crops as a source habitat for sensitive host crops later in the season. The goal of this study was to investigate the abiotic conditions and landscape components that are associated with F. fusca populations in winter wheat (Triticum aestivum L.). Exploring these relationships will provide insight into early‐season drivers of F. fusca. To do this, we conducted a 2 year study documenting F. fusca populations during an 8 weeks period each spring. We sampled immature thrips abundance on wheat heads while concurrently monitoring adult dispersal from the field using yellow sticky cards. Across both years, we found that immature thrips sampled during the milk and dough development stages best‐predicted adult dispersal 2 weeks later. Cumulative precipitation and the number of precipitation events beginning in the autumn of the prior year were the most important abiotic predictors of F. fusca abundance. At the landscape scale, adult F. fusca density was negatively related to the area of row crop agriculture, grasslands and amount of landscape fragmentation. Results of our study provide a basis to assess larval thrips and forecast dispersal of this pest from wheat using a head sampling method. At a landscape scale, we show that specific combinations of abiotic and landscape variables influence population abundance of F. fusca in North Carolina row crop agroecosystems.

The vertical distribution and temporal occurrence of three types of rice planthoppers in Shanghai

AbstractIn this study, we investigated the dynamic occurrence and vertical distribution of three types of rice planthoppers (Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus) in Shanghai, China. Our results showed that S. furcifera and L. striatellus infested the lower part of rice plants in the early development stage, S. furcifera and L. striatellus inhabited every part of rice in the middle development stage, and L. striatellus and N. lugens formicated in the upper part of the rice plant in the posterior development stage. The populations of rice planthoppers were larger in July and September, Where more than 600 adult and nymphal planthoppers, per a hundred hills of rice, were found in late July, and out of the 600, the majority were the nymphs of S. furcifera and L. striatellus. S. furcifera was mainly found from July to October, L. striatellus during the rice development, and N. lugens after September, during which their maximal individual number, per a hundred hills of rice, was 480, 220, less than 50, respectively. In addition, our results showed that adult rice planthoppers were mostly observed from late August to mid‐October with the highest population being found during mid to late September. The adult S. furcifera, L. striatellus, and N. lugens were mostly observed in August and September, from August to October, and past mid‐September, respectively. Moreover, the number of adult L. striatellus that were sticking to yellow sticky card was significantly higher than that of S. furcifera and N. lugens.

Overwintering of Anthonomus eugenii (Coleoptera: Curculionidae) in Southern Georgia

Overwintering of <i>Anthonomus eugenii</i> (Coleoptera: Curculionidae) in Southern Georgia

Survey of Florida Olive Groves during Olive Fruit Development: Monitoring for Stink Bugs and Olive Fruit Flies

Olives, Olea europaea L. (Oleaceae), are an emerging commercial crop in Florida; however, potential arthropod threats during olive tree establishment and fruit development remain uncharacterized. Two potential pests that may threaten olive fruit production directly are native and invasive pentatomid stink bugs, which are important pest species of many crops in the southeast, and the invasive olive fruit fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae),which is not known to be established in Florida. Monitoring for stink bugs during fruit maturation was done using dual funnel tube traps baited with stink bug lures. Yellow sticky card traps baited with food and pheromone lures were used to monitor for the olive fruit fly. Both trap types were placed in tree canopies in 4 North Central Florida olive groves during the anticipated fruit development period for 2 growing seasons. Whereas neither of the invasive species targeted (Halyomorpha halys Stål [Hemiptera: Pentatomidae] or B. oleae) were detected, several other potential pests were identified including brown stink bugs (Euschistus spp.; Hemiptera: Pentatomidae), glassy winged sharpshooters, Homalodisca vitripennis Germar (Hemiptera: Cicadellidae), and grasshoppers. No fruit damage attributable to arthropod pests was detected although fruit production was very low with limited samples. These results contribute to awareness of potential pests that may jeopardize olive fruit production and aid in the future studies to develop effective monitoring activities for Florida growers.

Comparison of Yellow and Blue Sticky Cards for Detection and Monitoring Parasitoid Wasps of the Invasive Halyomorpha halys (Hemiptera: Pentatomidae).

The invasive Halyomorpha halys (Stål) is a significant agricultural and urban nuisance pest in many parts of the world. In North America, biological control of H. halys by parasitoid wasps in the families Scelionidae and Eupelmidae has shown promise. An effective technique for detection and monitoring native and exotic parasitoids is the deployment of yellow sticky cards; however, yellow cards also attract nontarget arthropods, reducing efficiency and accuracy of parasitoid screening. This study sought to identify an alternative yet effective trapping technique by comparing the number of target parasitoid wasps [Anastatus spp. Motschulsky (Hymenoptera: Eupelmidae), Telenomus spp. Haliday (Hymenoptera: Scelionidae), and Trissolcus spp. Ashmead (Hymenoptera: Scelionidae)] and arthropod bycatch on yellow and blue sticky cards deployed in urban, orchard, and vegetable landscapes in northern Utah from late May to early October in 2019 and 2020. Yellow sticky cards captured 54–72% more target parasitoids than blue cards from June through August in all three landscape types in both years; however, a positive correlation in parasitoid capture indicated blue cards detect target parasitoids, just in fewer numbers. Both card colors detected adventive Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) in initial findings of 2019, and in expanded locations of 2020. Furthermore, blue cards captured 31–48% less Diptera and nontarget Hymenoptera than yellow cards in both years across all three landscapes, translating to reduced card processing time and impacts to beneficial insect populations. Our results suggest that blue vs yellow sticky cards offer an alternative monitoring technique to survey for H. halys parasitoids.

Could Broccoli and Cauliflower Influence the Dispersal Dynamics of Western Flower Thrips (Thysanoptera: Thripidae) to Lettuce in the Salinas Valley of California?

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important, worldwide vector of two tospoviruses (Family Bunyaviridae; Genus Tospovirus), Impatiens necrotic spot virus (INSV) and Tomato spotted wilt virus (TSWV). In the Salinas Valley of California, INSV causes severe necrosis, stunting, and crop losses to lettuce (Lactuca sativa L.). Because broccoli (Brassica oleracea var. italica L.) and cauliflower (Brassica oleracea var. botrytis L.) are major rotation crops with lettuce in the Salinas Valley, it is critical to understand if these Brassicas influence the dispersal dynamics of F. occidentalis. In 2013 and 2014, surveys were conducted evaluating yellow sticky cards and plant samples in lettuce, broccoli, and cauliflower fields in three regions of the Salinas Valley. F. occidentalis were collected on sticky cards from April to November and on foliage in all three regions. Two-choice oviposition assays as well as no-choice and two-choice feeding assays were conducted where F. occidentalis adults were exposed to leaves of lettuce, broccoli, and cauliflower. A significantly greater number of eggs was found on lettuce than on broccoli or cauliflower leaves in the choice assay, whereas for the broccoli and cauliflower choice assay, the number of eggs retrieved was low and not significantly different between hosts. The number of F. occidentalis feeding spots and leaf area injury ratings were similar on broccoli and lettuce leaves but were significantly lower on cauliflower than on lettuce and broccoli leaves. The implications of these results on thrips and plant virus management are discussed.

Survey for Adventive Populations of the Samurai Wasp, Trissolcus japonicus (Hymenoptera: Scelionidae) in Pennsylvania at Commercial Fruit Orchards and the Surrounding Forest.

Simple SummaryInvasive species that are freed of associated natural predators increase in population and disrupt the management plans of growers. The brown marmorated stink bug, Halyomorpha halys, is an invasive species that originated in Asia. A promising management tactic for the species is to release an associated parasitoid, the samurai wasp, Trissolcus japonicus. Populations of the samurai wasp have begun to adventively establish in several regions, including Pennsylvania. In order to monitor and use the species as an alternative management strategy to insecticides, it is imperative to understand the baseline populations during the early establishment phase. The aims of this study were to determine if the samurai wasp is already present in commercial orchards in Pennsylvania, where the brown marmorated stink bug has been present in high numbers since approximately 2010. Native Trissolcus wasps were also identified. This study found the samurai wasp in eight counties in Pennsylvania with several orchards containing populations of the species within orchard blocks. These baseline data provide a starting point for controlling H. halys naturally, which was previously controlled only with broad-spectrum insecticides.The samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), is an egg parasitoid associated with the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Trissolcus japonicus is a candidate for classical biological control of H. halys populations. Since 2014, adventive populations of T. japonicus have been detected in 14 US states, in the Canadian provinces of British Columbia and Ontario, and in two European countries, Switzerland and Italy. Establishing baseline information about populations of T. japonicus is important, as this species is not host specific to H. halys and the potential ecological effects of the accidental introductions are not fully known. In this study, yellow sticky cards were deployed at commercial fruit orchards in nine counties in Pennsylvania separated by more than 400 km. Trissolcus japonicus was detected on cards in eight counties, and in two habitats, in the orchard and at the forest border. Other native species of Scelionidae known to attack the eggs of H. halys were also identified, including Trissolcus euschisti (Ashmead), Trissolcus brochymenae (Ashmead), and Telenomus podisi Ashmead (Hymenoptera: Scelionidae). These results are important baseline ecological knowledge for both T. japonicus, which appears to be established in orchards throughout Pennsylvania, and other native Scelionidae.

Community science data suggests that urbanization and forest habitat loss threaten aphidophagous native lady beetles.

Community scientists have illustrated rapid declines of several aphidophagous lady beetle (Coccinellidae) species. These declines coincide with the establishment of alien coccinellids. We established the Buckeye Lady Beetle Blitz program to measure the seasonal occupancy of coccinellids within gardens across a wide range of landscape contexts. Following the Habitat Compression Hypothesis, we predicted that gardens within agricultural landscapes would be alien‐dominated, whereas captures of natives would be higher within landscapes encompassing a high concentration of natural habitat.Within the state of Ohio, USA, community scientists collected lady beetles for a 7‐day period across 4 years in June and August using yellow sticky card traps. All identifications were verified by professional scientists and beetles were classified by three traits: status (alien or native), mean body length, and primary diet. We compared the relative abundance and diversity of coccinellids seasonally and determined if the distribution of beetles by size, status, and diet was related to landscape features.Alien species dominated the aphidophagous fauna. Native aphidophagous coccinellid abundance was positively correlated with forest habitat while alien species were more common when gardens were embedded within agricultural landscapes. Urbanization was negatively associated with both aphidophagous alien and native coccinellids. Synthesis and Applications: Our census of native coccinellid species within residential gardens—a widespread and understudied habitat—was enabled by volunteers. These data will serve as an important baseline to track future changes within coccinellid communities within this region. We found that native coccinellid species richness and native aphidophagous coccinellid abundance in gardens were positively associated with forest habitat at a landscape scale of 2 km. However, our understanding of when and why (overwintering, summer foraging, or both) forest habitats are important remains unclear. Our findings highlight the need to understand how declining aphidophagous native species utilize forest habitats as a conservation priority.

Are Yellow Sticky Cards and Light Traps Effective on Tea Green Leafhoppers and Their Predators in Chinese Tea Plantations?

Simple SummaryLeafhoppers are serious insect pests in agriculture across the world. Both nymphs and adults suck the sap of plant shoots and leaves with their piercing–sucking mouthparts causing damage called “hopperburn”. The tea green leafhopper, Empoasca onukii, is one of most damaging pests in tea plantations in Asia. In China, yellow sticky cards and light traps are increasingly used to control leafhoppers in tea plantations, especially the tea green leafhopper. Visually, several leafhoppers appear to be captured and killed, however, the real control efficiency and the damage to natural enemies remains unclear. In our study, a 16-week open field experiment with daily weather monitoring was designed to test the responses of tea green leafhopper, parasitoids and spiders to yellow sticky cards and light traps (cover with sticky cards) that used different light colours. An exclosure experiment was also designed to further test the influence of the three light systems (without sticky card) on the same groups of species. The results suggested that light, especially green and white, can be useful as a way to control leafhopper populations without affecting parasitoids and spiders too much.In Chinese tea plantations, yellow sticky cards and light traps are increasingly used to control insect pests, especially the tea green leafhopper Empoasca onukii. In this study, a 16-week open-field experiment with daily weather monitoring was designed to test the responses of tea green leafhopper, parasitoids and spiders to yellow sticky cards and three light traps with different wavelengths (covered with sticky cards). An exclosure experiment was also designed to further test the influence of the three light systems (without sticky card) on the same species. The results showed that all three light emitting diode (LED) light traps (white, green and yellow) and yellow sticky cards attracted many more E. onukii male adults than females during the course of the open field experiment, with less than 25% of trapped adults being females. Parasitoids and spiders were also attracted by these systems. Weather variables, especially rainfall, influenced the trapping efficiency. In the exclosure experiment, the population of leafhoppers in the yellow sticky card treatment did not decline significantly, but the number of spiders significantly decreased. The green and white light treatments without sticky cards showed a significant control of E. onukii and no obvious harm to spiders. These results suggest that yellow sticky cards and light traps have limited capacity to control tea green leafhoppers. However, light, especially green light, may be a promising population control measure for tea green leafhoppers, not as killing agents in the traps, but rather as a behavioral control system.

A Multimodal Attract-and-Kill Device for the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae).

Simple SummaryControl of Asian citrus psyllid (Diaphorina citri), a vector of Candidatus liberibacter asiaticus (CLas), contributes to management of citrus greening disease (huanglongbing). We developed two prototypes of a multimodal attract-and-kill (AK) device with specific elements of color, attractant, phagostimulant, ultraviolet (UV) reflectant, and toxicant. Key sensory stimuli comprising the AK ingredients were identified in our current and previous research studies and incorporated into a yellow, slow-release wax matrix (SPLAT). This formulation was applied directly to the surface of yellow cylinders, or to corrugated plastic cards housed within perforated cylinders. Psyllids landing on the devices attempted to feed from the wax matrix, became intoxicated, died, and fell from device surfaces. Our laboratory and field experiments showed that AK devices attracted and killed significantly more adult D. citri than ordinary yellow sticky cards and remained fully active over a period of 12 weeks. Effective use of attract-and-kill for management of D. citri could reduce need for broad-spectrum insecticide sprays and encourage biological control as part of an integrated approach to huanglongbing (HLB) management in citrus.Phytophagous insects, including Asian citrus psyllids (Diaphorina citri Kuwayama), use multiple sensory modalities (vision, olfaction, and gustation,) to locate and accept host plants. We explored incorporation of several sensory cues into a multi-modal attract-and-kill device (AK device) using a three-dimensional shape to increase visibility, as well as elements of color, attractant, phagostimulant, UV reflectant, and toxicant. Attraction of adult D. citri to the device was mediated by a combination of a highly reflective yellow cylinder, a UV reflectant compound (magnesium oxide), and an odorant blend as a short-range attractant. The device surface was coated with a slow-release wax matrix (SPLAT™) augmented with a phagostimulant consisting of a 3-component blend (formic acid, acetic acid, and para-cymene) and an insecticide (β-cyfluthrin). Psyllids landing on the device attempted to feed from the wax matrix, became intoxicated, died, and fell from the device. The device remained fully active over a period of 12 weeks partly because dead psyllids or nontargets did not adhere to the surface as occurs on adhesive yellow sticky cards, the industry standard. Laboratory and field assays showed that the device attracted and killed significantly more adult D. citri than ordinary yellow sticky cards. This device or a future iteration based on the design elements of this device is expected to contribute to sustainable and environmentally appropriate management of D. citri by exploiting the psyllid’s innate behavioral responses to visual, olfactory, and gustatory stimuli.

Vertical Distribution of Insect Pests Using Insect Towers Placed Near Potato Fields in the Lower Columbia Basin.

This study was conducted at the Oregon State University Hermiston Agricultural Research and Extension Center, Hermiston, Umatilla County, OR, during the 2016 and 2017 potato, Solanum tuberosum L. (Solanales: Solanaceae), growing seasons. The objective was to determine the vertical distribution of hemipteran (Bactericera cockerelli Šulc, Circulifer tenellus Baker, Myzus persicae Sulzer, Macrosiphum euphorbiae Thomas, and Lygus spp.) and thysanopteran (Frankliniella occidentalis Pergande and Thrips tabaci Lindeman) potato pests using insect towers placed near potato fields. Towers were 8 m tall and secured to the ground with metal cables. In each tower, yellow sticky cards were mounted at 1.5 m intervals up to 7.6 m aboveground. Data were collected at 7-d intervals from mid-April until mid or end of August. This study showed that B. cockerelli, C. tenellus, M. persicae, Lygus spp., and both species of thrips were captured on sticky cards placed closest to the ground; in both years, as sticky card height increased, abundances decreased. In contrast, trapped M. euphorbiae numbers were not affected by sticky card height. To our knowledge, this is the first study in the lower Columbia Basin of Oregon that evaluated the vertical distribution of major potato pests.

Molecular Gut-Content Analysis of Adult Ground Beetles (Coleoptera: Carabidae) Provides No Evidence of Predation of Western Corn Rootworm (Coleoptera: Chrysomelidae) in a Nebraska Corn Agroecosystem

Abstract This study was conducted to characterize the ground beetle (Coleoptera: Carabidae) community in Nebraska continuous cornfields and investigate the potential for predation of the western corn rootworm, Diabrotica virgifera virgifera LeConte, a key root-feeding insect pest that is an annual management challenge in this system. Seven collection dates were conducted at five commercial cornfields in west central Nebraska during the growing season of 2014. In each field, carabids were sampled using five 24-h pitfall traps. Carabid specimens were placed in 95% ethanol in the field and stored at –20°C to preserve DNA. After identification to the species level, DNA was extracted and polymerase chain reaction was conducted for gut-content analysis using D. v. virgifera-specific primers. Data from single-plant emergence cages and yellow sticky cards showed high abundance of D. v. virgifera prey in three of the five fields sampled. Sixteen genera and 36 carabid species were found in pitfall traps. Of the total 235 carabid specimens tested in this study, zero tested positive for D. v. virgifera DNA. The lack of positive results for the presence of D. v. virgifera DNA in the gut-contents of carabids, despite abundant pest populations, indicates that, in this system, ground beetles may not be a strong mortality agent of D. v. virgifera. However, results presented here contribute to our knowledge of carabid diversity in agroecosystems and indicate that future D. v. virgifera biological control efforts in this region should focus on other natural enemies and/or other life stages of carabids, such as larvae.

Overwintering, Host-Plant Selection, and Insecticide Susceptibility of Systena frontalis (Coleoptera: Chrysomelidae): A Major Insect Pest of Nursery Production Systems.

Systena frontalis (F.) is a major insect pest of nursery production systems in the Midwest and Northeastern regions of the United States with the adults feeding on plant leaves, which reduces salability. However, there is conflicting information on overwintering, and no information on host-plant selection or insecticide susceptibility of S. frontalis adults. Therefore, we conducted a series of experiments under greenhouse, laboratory, and field conditions from 2015 to 2019. The overwintering experiment was isolated in a greenhouse to assess adult emergence from growing medium of containerized plants collected from a wholesale nursery. We found that S. frontalis overwinters in growing medium based on adults captured on yellow sticky cards and the presence of adults on new plant growth. Host-plant selection experiments were conducted at the wholesale nursery and under laboratory conditions to determine feeding selection based on S. frontalis adult feeding damage on whole plants using a foliar damage ranking scale for different cultivars of Itea virginica L., Hydrangea paniculata Siebold, Weigela florida (Bunge), and Cornus sericea L., plants. We found that S. frontalis adults exhibited no preference for the leaves of the plant species or cultivars tested in the field or laboratory. Insecticide efficacy experiments were conducted under field and laboratory conditions. In the field experiments, the insecticides acetamiprid, dinotefuran, and Isaria fumosorosea (Wize) (Hypocreales: Clavicipitaceae) provided better protection of plants from S. frontalis adult feeding than the untreated check. In the laboratory experiments, the acetamiprid and pyrethrins with canola oil treatments provided the highest percent S. frontalis adult mortality.

Biological control of Halymorpha halys (Stål) (Hemiptera: Pentatomidae) in apple orchards versus corn fields and their adjacent woody habitats: High versus low pesticide-input agroecosystems

Halymorpha halys is an invasive pest in the USA that inflicts damage to specialty crops, and conventional growers have increased use of broad-spectrum insecticides to manage this pest. The impacts of pest management programs on natural enemies of H. halys were examined in high vs. low intensity insecticide input agroecosystems in western North Carolina (USA). Apple orchards and corn fields, with their adjacent wooded habitats, served as the high and low-input environments, respectively. Sentinel egg masses and yellow sticky cards were deployed in these agroecosystems to compare predation and parasitism on H. halys eggs, and presence, abundance, and richness of natural enemies. A total of approximately 85% of all sentinel eggs deployed in apple orchards in both 2018 and 2019 produced a healthy stink bug nymph, higher than all other habitats. A total of 26.6% and 32.9% of eggs deployed in wooded habitats bordering corn exhibited mortality due to natural enemy attack in 2018 and 2019, respectively. Comparatively, eggs deployed in apple borders had 10.0% and 17.8% of total eggs killed by natural enemies, in 2018 and 2019, respectively. Corn agroecosystems generally had greater predation and parasitism of sentinel eggs, and greater richness and abundance of predators detected on yellow sticky cards compared to apple agroecosystems. Wooded habitats bordering crops serve as population reservoirs for H. halys, allowing for egg laying and dispersal into crops. If these areas are protected as refuge areas free from insecticide drift, such as from apple orchards, they can also harbor thriving natural enemy populations that could reduce populations of H. halys. Wooded areas free from harsh broad-spectrum insecticides are an important component for successful conservation and augmentative biological control in neighboring crops.

Development of an IPM Strategy for Thrips and Tomato spotted wilt virus in Processing Tomatoes in the Central Valley of California.

Tomato spotted wilt virus (TSWV; species Tomato spotted wilt orthotospovirus; genus Orthotospovirus; family Tospoviridae) is a thrips-transmitted virus that can cause substantial economic losses to many crops, including tomato (Solanum lycopersicum). Since 2005, TSWV emerged as an economically important virus of processing tomatoes in the Central Valley of California, in part due to increased populations of the primary thrips vector, western flower thrips (WFT; Frankliniella occidentalis). To develop an understanding of the epidemiology of TSWV in this region, population densities of WFT and incidence of TSWV were monitored in California’s processing tomato transplant-producing greenhouses and associated open fields from 2007 to 2013. Thrips were monitored with yellow sticky cards and in tomato flowers, whereas TSWV incidence was assessed with indicator plants and field surveys for virus symptoms. All thrips identified from processing tomato fields were WFT, and females were three-fold more abundant on sticky cards than males. Symptoms of TSWV infection were observed in all monitored processing tomato fields. Incidences of TSWV ranged from 1 to 20%, with highest incidence found in late-planted fields. There was no single primary inoculum source, and inoculum sources for thrips/TSWV varied depending on the production region. These results allowed us to develop a model for TSWV infection of processing tomatoes in the Central Valley of California. The model predicts that low levels of primary TSWV inoculum are amplified in early-planted tomatoes and other susceptible crops leading to highest levels of infection in later-planted fields, especially those with high thrips populations. Based upon these findings, an integrated pest management (IPM) strategy for TSWV in processing tomatoes in California was devised. This IPM strategy focuses on strategic field placement (identification of high-risk situations), planting TSWV- and thrips-free transplants, planting resistant varieties, monitoring for TSWV symptoms and thrips, roguing infected plants, thrips management targeting early generations, extensive sanitation after harvest, and strategic cropping to avoid overlap with winter bridge crops.

Effect of Plant-growing Media on Western Flower Thrips, Frankliniella occidentalis, Pupae and Fungus Gnat, Bradysia sp. nr. coprophila, Larvae under Laboratory Conditions

Western flower thrips, Frankliniella occidentalis, and fungus gnats (Bradysia spp.) are major insect pests of greenhouse production systems. Both insect pests have life stages that reside in the soil or plant-growing medium: prepupae and pupae of western flower thrips and fungus gnat larvae. There are unsubstantiated allegations made by a manufacturer that certain plant-growing media that contain a bacterium, Bacillus pumilus, and arbuscular mycorrhizal fungus, Glomus intraradices, negatively affect the survival of western flower thrips pupae and fungus gnat larvae. Therefore, we conducted a study involving laboratory experiments replicated over time (2019 and 2020) to investigate the influence of the plant-growing media Pro-Mix BX + Mycorrhizae and Pro-Mix BX + Biofungicide + Mycorrhizae on western flower thrips pupae and fungus gnat larvae. All experiments involved placing western flower thrips pupae or fungus gnat larvae (second and third instar) into 473-mL deli containers with the different treatments (plant-growing media). A 5 × 4-cm section of a yellow sticky card was affixed to the lid of each deli container. After 21 days, the number of western flower thrips or fungus gnat adults that emerged from the growing media and were captured on the yellow sticky cards was recorded. The use of the yellow sticky card was an indirect assessment of western flower thrips pupal or fungus gnat larval mortality. We found none of the plant-growing media tested that contained a bacterium and/or arbuscular mycorrhizal fungus affected the survival of western flower thrips pupae or fungus gnat larvae. Therefore, greenhouse producers should be leery of information provided by manufacturers that does not contain valid, scientifically based data.

Predation Efficacy of Rove Beetle (Coleoptera: Staphylinidae) Adults in Response to Western Flower Thrips (Thysanoptera: Thripidae) Pupal Stage, Predator–Prey Ratio, and Searchable Area

AbstractThe rove beetle, Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae), is a soil-dwelling predator that preys upon insect pests residing in growing media. Minimal information exists addressing its predation on western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), below-ground life stages. Two laboratory experiments were conducted to assess the effects of western flower thrips pupal stage, predator–prey ratio, and searchable area on predation efficacy of rove beetle adults. In Experiment 1, predation was recorded in response to two thrips pupal stages (prepupae and pupae); three predator–prey ratios (1:5, 1:10, 1:15) and predator–prey ratios that were 2, 3, and 4 times greater. Experiment 2 was designed to assess predation in response to those predator–prey ratios along with searchable areas in 15.2- and 11.5-cm-diameter containers. Response was measured by capturing thrips adults on yellow sticky cards (YSC) as they emerged from pupation. The estimated mean probability of thrips adults captured on the cards was significantly higher for the 1:5 (61.1%) than for the 1:10 (39%) and 1:15 (34.7%) predator–prey ratios. The estimated mean probability of thrips adults captured on the cards for 2 times the predator–prey ratio (57%) was significantly higher than 3 times (37.2%) and 4 times (40.6%) the ratios. A significantly higher estimated mean probability of thrips adults was captured on the cards in the 15.2-cm-diameter containers than in the 11.5-cm-diameter containers. We conclude that a predator–prey ratio of 1:15 would result in fewer rove beetle adults needed to reduce western flower thrips prepupae/pupae stages and subsequent adult populations.

Survey of Thysanoptera Using Colored Sticky Card Traps in Florida, USA, Olive Groves

Olives are a potential emerging crop for the state of Florida, USA, and the pest arthropods in commercial groves in the state are under-studied. Thrips (order Thysanoptera) are an almost ubiquitous concern among specialty crop growers in Florida. Yellow and blue sticky card traps were used to survey the canopies of trees in 4 North Central Florida olive groves to determine thrips abundance and distribution over 2 growing seasons. Of the 16 species of thrips identified, most were Frankliniella spp., with Florida flower thrips, Frankliniella bispinosa (Morgan) (Thysanoptera: Thripidae), being the most abundant species for both yr. Yellow traps were more effective for most species of thrips, although several species were more abundant on blue traps. No consistent differences between yr existed. Although overall abundance of flower feeding thrips species coincided with flowering events in the olive orchards, there was insufficient flowering to make statistical correlations between the peak of thrips abundance and flowering events in the olive groves. The results of this study will be useful in informing future economic threshold analyses of Thysanoptera in Florida olive groves. Resumen Las aceitunas son un cultivo potencial emergente para el Estado de la Florida, EE. UU., y los artropodos plagas en los bosques comerciales del estado estan poco estudiados. Los trips (orden Thysanoptera) son una preocupacion casi omnipresente entre los productores de cultivos especializados en la Florida. Se usaron trampas adhesivas amarillas y azules para examinar las copas de los arboles en 4 olivares del norte central de la Florida para determinar la abundancia y distribucion de trips durante 2 temporadas de crecimiento. De las 16 especies de trips identificadas, la mayoria fueron Frankliniella spp., con el trips de flores de la Florida, Frankliniella bispinosa (Morgan) (Thysanoptera: Thripidae), siendo la especie mas abundante para ambos anos. Las trampas amarillas fueron mas efectivas para la mayoria de las especies de trips, aunque varias especies fueron mas abundantes en las trampas azules. No existieron diferencias consistentes entre los anos. Aunque la abundancia general de especies de trips que se alimentan de las flores coincidio con los eventos de floracion en los huertos de olivos, no hubo suficiente floracion para hacer correlaciones estadisticas entre el pico de abundancia de trips y los eventos de floracion en los olivares. Los resultados de este estudio seran utiles para informar futuros analisis de umbral economico de los Thysanoptera en los olivares de la Florida. Key Words: thrips; flower pest; Frankliniella bispinosa; Homalodisca vitripennis; olives; Olea europaea View this article in BioOne

Impact of buckwheat and methyl salicylate lures on natural enemy abundance for early season management of Melanaphis sacchari (Hemiptera: Aphididae) in sweet sorghum

Early in the growing season when pest densities are low, crop environments are often unattractive to natural enemies. A combination of flowering plants providing food and alternate prey and herbivore induced plant volatiles (HIPV) may attract and retain natural enemies in crops. Melanaphis sacchari Zehntner (Hemiptera: Aphididae), a new pest of sweet sorghum (Sorghum bicolor L.), causes significant yield loss if left unmanaged. In a three-year field study, we tested the extent to which buckwheat (Fagopyrum esculentum Moench) border strips and lures containing the HIPV methyl salicylate attracted natural enemies prior to and during M. sacchari establishment in sweet sorghum plots. Natural enemies were surveyed weekly within the sweet sorghum (visual counts and yellow sticky cards) and in buckwheat border strips outside the plots (vacuum sampling). M. sacchari visual counts and natural enemy surveys were performed until harvest. Within buckwheat border strips, natural enemies were more abundant relative to non-buckwheat border strips. However, the increase in buckwheat borders did not increase natural enemies within sweet sorghum plots. In addition, the most abundant natural enemies within sweet sorghum (Coccinellidae) were uncommon in buckwheat strips. Methyl salicylate did not impact natural enemies in sweet sorghum border strips. M. sacchari populations and sweet sorghum yields were not affected by treatments. Other methods of increasing natural enemies will need to be explored to enhance early season management of M. sacchari in sweet sorghum fields.

Attractiveness of Different Coloured Sticky Traps to the South African Citrus Thrips (Scirtothrips aurantii Faure) in Avocado, KwaZulu-Natal, South Africa

The South African citrus thrips, Scirtothrips aurantii, is a recently confirmed economic pest in South African avocado. Scarring damage by thrips results in corky tissue development, making the fruit unsuitable for export and potentially costing the country in lost export revenue. Thrips management is complicated by the multiple and protracted flowering patterns of susceptible cultivars. In addition, widespread pesticide resistance of thrips and the negative environmental effects along with minimum residue levels for export fruit limit the application of pesticides for thrips control. Monitoring an insect pest's presence and abundance is the first step in thrips management. This study aimed to investigate S. aurantii's colour preferences, establish the distribution of thrips in the orchard and population dynamics from flowering to fruit establishment. Attractiveness followed the order yellow > blue, white, clear > red, black, purple and orange. Thrips were evenly distributed throughout the orchard, with the highest populations occurring during flowering (August), declining sharply and picking up in the summer months starting December. Yellow sticky cards are recommended as a monitoring tool.