Tarnished Plant Bug Research Articles

Enhancing Biological Control Efficacy: Insights into the Feeding Behavior and Fitness of the Omnivorous Pest Lygus lineolaris.

Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), a true omnivorous insect, poses a significant threat to agriculture in the Neartic region. Understanding the feeding behavior of L. lineolaris is crucial for developing integrated pest management strategies. This study aimed to evaluate the effects of different diets on the fitness of L. lineolaris, with a focus on the diet source, feeding regime (phytophagy, zoophagy, and phytozoophagy), and number of diet items. The experimental design in the laboratory investigated the impacts of strawberry, canola and buckwheat flowers, as well as spider mites and aphids to explore relationships found in a conventional strawberry field. Results reveal that diet source, feeding regime, and the number of diet items influence L. lineolaris performance (i.e., survivorship rate, developmental time, and adult weight and length). Improvements in fitness are indicated by higher nymphal survival, shorter developmental time, and larger adults. Immature stages of L. lineolaris show improved fitness when provided with diets rich in canola compared to strawberry flowers and spider mites. Furthermore, the inclusion of multiple diet items in phytozoophagous regimes enhances insect performance. The findings emphasize the significance of understanding L. lineolaris' nutritional requirements and the biodiversity of target ecosystems for modeling energy flows and designing effective IPM strategies against this pest. This research contributes to the knowledge base for biological control programs targeting L. lineolaris in agricultural systems.

Role of Endophytic Entomopathogenic Fungi in Mediating Host Selection, Biology, Behavior, and Management of Tarnished Plant Bug, Lygus lineolaris (Hemiptera: Miridae).

Non-insecticidal control strategies using entomopathogens, nematodes, and endophytes provide sustainable and safer alternatives for managing crop pests. This study investigated the potential of different fungal endophytes, specifically Beauveria bassiana strains, in colonizing cotton plants and their efficacy against tarnished plant bug, Lygus lineolaris. The effect of endophytes on plant growth parameters and cotton yield were measured during different plant growth stages. The entomopathogenicity of these fungi was studied in diet cup bioassays using L. lineolaris adults. The behavior of adult males and females toward endophytic cotton squares was analyzed using olfactometer assays. The experiments showed that the fungal endophytes colonized the plant structures of cotton plants, which resulted in an increase in the number of cotton squares, plant height, and weight compared to control plants. B. bassiana strains/isolates such as GHA, NI-8, and JG-1 caused significant mortality in Lygus adults compared to controls. Also, male and female Lygus adults exhibited repellence behavior towards endophytic cotton squares containing JG-1 isolate of B. bassiana and to other B. bassiana strains such as NI-8, GHA, and SPE-120. No differences were observed in the survival and development of L. lineolaris second-instar nymphs on endophytic cotton, and no yield differences were observed in the field experiments.

Herbivore and pollinator body size effects on strawberry fruit quality.

Land use change affects both pollinator and herbivore populations with consequences for crop production. Recent evidence also shows that land use change affects insect traits, with intraspecific body size of pollinators changing across landscape gradients. However, the consequences on crop production of trait changes in different plant interactors have not been well-studied. We hypothesized that changes in body size of key species can be enough to affect crop productivity, and therefore looked at how the field-realistic variation in body size of both an important pollinator, Bombus impatiens (Cresson), and a key pest herbivore, Lygus lineolaris (Palisot), can affect fruit size and damage in strawberry. First, we determined if pests vary in body size along land use gradients as prior studies have documented for pollinators; and second, we tested under controlled conditions how the individual and combined changes in size of an important pollinator and a key herbivore pest affect strawberry fruit production. The key herbivore pest was smaller in landscapes with more natural and semi-natural habitat, confirming that herbivore functional traits can vary along a land use gradient. Additionally, herbivore size, and not pollinator size, marginally affected fruit production-with plants exposed to larger pests producing smaller fruits. Our findings suggest that land use changes at the landscape level affect crop production not just through changes in the species diversity of insect communities that interact with the plant, but also through changes in body size traits.

Impact of alfalfa perimeter strips on Lygus lineolaris and beneficial arthropods in June-bearing strawberry fields

Impact of alfalfa perimeter strips on Lygus lineolaris and beneficial arthropods in June-bearing strawberry fields

Effectiveness and residual activity of four common insecticides used in the Mississippi Delta to control tarnished plant bugs in cotton.

The tarnished plant bug, (TPB) Lygus lineolaris Palisot de Beauvois (Hemiptera: Miridae) is a key pest of cotton in the midsouth region and some areas of the eastern United States. Its control methods have been solely based on chemical insecticides which has contributed to insecticidal resistance and shortened residual periods for control of this insect pest. This study was conducted over a two-year period and examined the efficacy and residual effect of four commercial insecticides including lambda-cyhalothrin (pyrethroid), acephate (organophosphate), imidacloprid (neonicotinoid), and sulfoxaflor (sulfoxamine). The effectiveness and residual effects of these insecticides were determined by application on cotton field plots on four different dates during each season using three different concentrations (high: highest labeled commercial dose (CD), medium: 1/10 of the CD, low: 1/100 of the CD) on field cotton plots. Four groups of cotton leaves were randomly pulled from each treated plot and control 0-, 2-, 4-, 7-, and 9-days post treatment (DPT) and exposed to a lab colony of TPB adults. One extra leaf sample/ plot/ spray /DPT interval (0-2-4-7-9-11) during 2016 was randomly collected from the high concentration plots and sent to Mississippi State Chemical Laboratory for residual analysis. Mortality of TPB adults was greatest for those placed on leaves sprayed with the organophosphate insecticide with mortalities (%) of 81.7±23.4 and 63.3±28.8 (SE) 1-day after exposure (DAE) on leaves 0-DPT with the high concentration for 2016 and 2017, respectively, reaching 94.5±9.5 and 95.4±7.6 6-DAE each year. Mortality to all insecticides continued until 9 and 4-DPT for high and medium concentrations, respectively. However, organophosphate (39.4±28.6) and pyrethroid (24.4±9.9) exhibited higher mortality than sulfoxamine (10.6±6.6) and the neonicotinoid (4.0±1.5) 7-DAE on 9-DPT leaves with the high concentration. Based on our results using the current assay procedure, TPB adults were significantly more susceptible to contact than systemic insecticides and due to its residual effect, organophosphate could kill over 80% of the TPB population 7-DPT.

Influence of Lygus-Traited Cotton Technology on Performance of Commonly Used Inecticides for Tarnished Plant Bug Management Prior to Bloom

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is the most economically damaging insect pest of cotton, Gossypium hirsutum L., production in the Mid-South region of the U.S. In Mississippi alone, tarnished plant bug caused approximately $270 in losses per hectare and accounted for nearly 70,000 lost bales per annum during 2021 and 2022. Insecticide use is the foundation of integrated pest management strategies for control of tarnished plant bug in the Mid-South. Prior to bloom, acephate, imidacloprid, and sulfoxaflor are commonly used insecticides for tarnished plant bug management. Research was conducted in the Mississippi Delta region with commonly used insecticides prior to bloom to evaluate their performance in non-ThryvOnTM and ThryvOn cotton varieties. Research suggests that imidacloprid has a limited fit in non-ThryvOn cotton production. However, these data indicate that the additional mode of action provided by ThryvOn cotton could extend the longevity of imidacloprid, along with other commonly used insecticides in Mid-South cotton production.

Assessing the Efficacy of Sodium Alginate and Polyacrylamide as Spray Adjuvants Combined with Bifenthrin and Imidacloprid against Lygus lineolaris and Piezodorus guildinii

The tarnished plant bug, Lygus lineolaris, and the red-banded stink bug, Piezodorus guildinii, pose significant economic threats to cotton and soybean crops in the mid-southern USA. However, the efficacy of insecticide spraying is comparatively low, and adjuvants play a crucial role in optimizing insecticide performance. This study evaluated the impact of two adjuvants, sodium alginate (SA) and polyacrylamide (PAM), on enhancing the efficacy of bifenthrin and imidacloprid via laboratory spray bioassays. Both SA and PAM demonstrated insignificant variation in LC50 values with formulated bifenthrin and imidacloprid. However, SA and PAM exhibited synergistic effects with two technical-grade insecticides. High concentrations of PAM increased the efficacy of bifenthrin by 1.50- and 1.70-fold for L. lineolaris and P. guildinii, respectively. Conversely, no enhancement effect was observed for the SA–technical-grade bifenthrin combination against either insect pests. Additionally, both SA and PAM enhanced the effectiveness of imidacloprid in P. guildinii by up to 2.68- and 2.73-fold, respectively. While a high concentration of PAM had a 1.45-fold synergistic effect on technical-grade imidacloprid, no enhancement effect was observed for the SA/imidacloprid combination in L. lineolaris. This study explored the synergistic impact of SA and PAM on the efficacy of technical-grade and formulated bifenthrin and imidacloprid, providing valuable insights into optimizing pest control strategies in agriculture.

Field Evaluation of Biological and Conventional Insecticides for Managing Multiple Insect Pests in Cotton

Abstract Cotton, Gossypium hirsutum (L.), is an economically important crop in the United States that is plagued by a complex of insect pests. Two key pests of cotton in the midsouthern United States are the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae). A suite of highly effective synthetic insecticides is typically used for control of these pests. However, it is unclear how the combined management of these two insect pests with biological insecticides impacts the economics of cotton production. To address this shortcoming, we conducted a field experiment in the Mississippi Delta over 2 yr to study the effects of synthetic and biological insecticides for control of the tarnished plant bug and bollworm on cotton yield. The results indicated the control of tarnished plant bug with synthetic insecticides had the most significant impact on cotton yield and net returns. The conventional tarnished plant bug treatment also significantly increased bollworm density and damage, but these increases did not significantly alter yield or net return in non–Bacillus thuringiensis (Bt) or Bt cottons. The economic benefit of a conventional approach to tarnished plant bug control with synthetic insecticides was US$438.07/ha in non-Bt and $700.88/ha in Bt cotton relative to those treated with a biological insecticide. The biological insecticides used for this study were ineffective at significantly altering yield or net return. However, for insect management in cotton to be sustainable, alternatives must be found to complement conventional synthetic insecticides.

Leveraging satellite observations to reveal ecological drivers of pest densities across landscapes

Landscape ecologists have long suggested that pest abundances increase in simplified, monoculture landscapes. However, tests of this theory often fail to predict pest population sizes in real-world agricultural fields. These failures may arise not only from variation in pest ecology, but also from the widespread use of categorical land-use maps that do not adequately characterize habitat-availability for pests. We used 1163 field-year observations of Lygus hesperus (Western Tarnished Plant Bug) densities in California cotton fields to determine whether integrating remotely-sensed metrics of vegetation productivity and phenology into pest models could improve pest abundance analysis and prediction. Because L. hesperus often overwinters in non-crop vegetation, we predicted that pest abundances would peak on farms surrounded by more non-crop vegetation, especially when the non-crop vegetation is initially productive but then dries down early in the year, causing the pest to disperse into cotton fields. We found that the effect of non-crop habitat on pest densities varied across latitudes, with a positive relationship in the north and a negative one in the south. Aligning with our hypotheses, models predicted that L. hesperus densities were 35 times higher on farms surrounded by high versus low productivity non-crop vegetation (EVI area 350 vs. 50) and 2.8 times higher when dormancy occurred earlier versus later in the year (May 15 vs. June 30). Despite these strong and significant effects, we found that integrating these remote-sensing variables into land-use models only marginally improved pest density predictions in cotton compared to models with categorical land cover metrics alone. Together, our work suggests that the remote sensing variables analyzed here can advance our understanding of pest ecology, but not yet substantively increase the accuracy of pest abundance predictions.

Host plant preference of Lygus hesperus (Hemiptera: Miridae) in 4 field crops: potato, alfalfa, carrot, and pea.

The western tarnished plant bug, Lygus hesperus (Knight), has emerged as a pest of potatoes (Solanum tuberosum L.) in the Lower Columbia Basin of Oregon and Washington. This species is generally found infesting several other field-grown crops in the region; however, their host preference is poorly understood. Thus, greenhouse cage experiments were conducted to evaluate L. hesperus host preference by simultaneously presenting adults with 4 host plants: potato, alfalfa, Medicago sativa L., carrot, Daucus carota L., and pea, Pisum sativum L. In addition, an oviposition test was conducted. The results indicated that L. hesperus actively chose as a host and as an oviposition substrate among the 4 host plants. We found a significantly higher number of adults on alfalfa and potato plants over carrot or pea plants at 6 h, 24 h, and 48 h after adults were released into the cage. However, 96 h after release, more L. hesperus were found in alfalfa. In addition, female L. hesperus strongly preferred potato and alfalfa plants as an oviposition substrate over carrot and pea plants at 96 h after release.

Microarray and Functional Pathway Analyses Revealed Significantly Elevated Gene Expressions Associated with Metabolic Resistance to Oxamyl (Vydate) in Lygus lineolaris.

The tarnished plant bug (TPB, Lygus lineolaris) remains a major pest for a variety of crops. Frequent sprays on row crops, especially cotton, prompted resistance development in field populations. To maintain chemical control as an effective tool against the pest, knowledge of global gene regulations is desirable for better understanding and managing the resistance. Novel microarray expressions of 6688 genes showed 685 significantly upregulated and 1382 significantly downregulated genes in oxamyl-selected TPBs (Vyd1515FF[R]) from a cotton field. Among the 685 upregulated genes (participated in 470 pathways), 176 genes code 30 different enzymes, and 7 of the 30 participate in 24 metabolic pathways. Six important detoxification pathways were controlled by 20 genes, coding 11 esterases, two P450s, two oxidases, and three pathway-associated enzymes (synthases, reductase, and dehydrogenase). Functional analyses showed substantially enhanced biological processes and molecular functions, with hydrolase activity as the most upregulated molecular function (controlled by 166 genes). Eleven esterases belong to the acting on ester bond subclass of the 166 hydrolases. Surprisingly, only one GST showed significant upregulation, but it was not involved in any detoxification pathway. Therefore, this research reports a set of 20 genes coding 6 enzyme classes to detoxify a carbamate insecticide oxamyl in Vyd1515FF. Together with three previous reports, we have obtained the best knowledge of resistance mechanisms to all four conventional insecticide classes in the economically important crop pest. This valuable finding will greatly facilitate the development of molecular tools to monitor and manage the resistance and to minimize risk to environment.

Doublesex is essential for masculinization but not feminization in Lygus hesperus

In most holometabolous insects, sex differentiation occurs via a hierarchical cascade of transcription factors, with doublesex (dsx) regulating genes that control sex-specific traits. Although less is known in hemimetabolous insects, early evidence suggests that substantial differences exist from more evolutionarily advanced insects. Here, we identified and characterized dsx in Lygus hesperus (western tarnished plant bug), a hemipteran pest of many agricultural crops in western North America. The full-length transcript for L. hesperus dsx (Lhdsx) and several variants encode proteins with conserved DNA binding and oligomerization domains. Transcript profiling revealed that Lhdsx is ubiquitously expressed, likely undergoes alternative pre-mRNA splicing, and, unlike several model insects, is sex-biased rather than sex-specific. Embryonic RNA interference (RNAi) of Lhdsx only impacted sex development in adult males, which lacked both internal reproductive organs and external genitalia. No discernible impacts on adult female development or reproductivity were observed. RNAi knockdown of Lhdsx in nymphs likewise only affected adult males, which lacked the characteristic dimorphic coloration but had dramatically elevated vitellogenin transcripts. Gene knockout of Lhdsx by CRISPR/Cas9 editing yielded only females in G0 and strongly biased heterozygous G1 offspring to females with the few surviving males showing severely impaired genital development. These results indicate that L. hesperus male development requires Lhdsx, whereas female development proceeds via a basal pathway that functions independently of dsx. A fundamental understanding of sex differentiation in L. hesperus could be important for future gene-based management strategies of this important agricultural pest.

Registration of Arkot 1202, Arkot 1207, Arkot 1208, and Arkot 1214 cotton germplasm lines

AbstractArkot 1202 (Reg. no. GP‐1143, PI 702793), Arkot 1207 (Reg. no. GP‐1144, PI 702794), Arkot 1208 (Reg. no. GP‐1145, PI 702795), and ‘Arkot 1214’ (Reg. no. GP‐1146, PI 702796) are conventional cotton (Gossypium hirsutum L.) germplasm lines released by the Arkansas Agricultural Experiment Station in June 2023. Arkot 1202, Arkot 1207, and Arkot 1208 lines share ‘UA48’ (PVP 201100041) as a common parent. The second parent for Arkot 1202 and Arkot 1207 was MD25‐87Y and ‘Columbia’, respectively. The second parent for Arkot 1208 was the F1 of a double cross of F1 (Ark 0219‐15 crossed with LA063071653) and F1 (Arkot 0222 crossed with Ark 0203‐11). Arkot 1214 was derived from a four‐way cross of two double crosses: F1 (MD25‐26ne crossed with Arkot 0113) and F1 (Arkot 0114 crossed with ‘UA222’). In replicated field tests at four Arkansas sites over 5 years, the four lines produced more lint yield than UA48 and UA222. Wide adaptation of the lines was indicated by high lint yields of lines in 2020 regional tests. All four lines displayed high resistance to bacterial blight and Fusarium wilt race 1. Plant (leaf, stem, and bract) trichomes and tarnished plant bug response of Arkot 1202 and Arkot 1214 were equal to UA48, but Arkot 1207 and Arkot 1208 were equal to UA222. Yield component values of the four lines were equal to or better than UA222. The maturity and fiber quality of Arkot 1202 approached that of UA48 while the other three were similar to UA222.

Efficacy of selected insecticides on tarnished plant bug in cotton, 2023

Efficacy of selected insecticides on tarnished plant bug in cotton, 2023

Evaluation of selected insecticides for tarnished plant bug management in cotton, 2023

Evaluation of selected insecticides for tarnished plant bug management in cotton, 2023

Evaluation of selected insecticides on tarnished plant bug management in cotton (Test 2), 2023

Evaluation of selected insecticides on tarnished plant bug management in cotton (Test 2), 2023

Diyarbakır ili pamuk alanlarındaki Lygus (Hemiptera: Miridae) türleri, yayılış alanları ve popülasyon gelişimi

Many insect pests infest cotton (Gossypium hirsutum L.) crop, resulting in significant economic losses. The tarnished plant bugs (Lygus species) greatly damage the cotton crop during all growth stages. This study determined Lygus species infesting cotton in Diyarbakır province, their distribution, and population dynamics during 2020 and 2021. Lygus species samples were collected from 244 fields in 7 districts of the province by using either D-vac or sweep net based on the phenological period of cotton. Population dynamics of the species were monitored weekly by using sweep net and D-vac from two fields situated in the Sur (Gencan village) and Çınar (Şükürlü village) districts of the province during both years. Two species including Lygus gemellatus (Herrich-Schäffer) and L. pratensis (Linnaeus) were identified during the study. Lygus gemellatus was the most common and abundant species observed in 91.2% and 74.7% of the surveyed fields during 2020 and 2021, respectively. The species were recorded at the end of May (before flowering) during both years, and their populations increased afterward. The peak population of both species was observed during the boll maturation period. The D-vac trapped a statistically higher number of Lygus bugs than the sweep net at Gencan (p

When the aggressiveness degree modifies the intraguild predation magnitude

In agroecosystems, intraguild predation (IGP) is an ecological interaction that can reduce the effectiveness of biological control programs. Since aggressiveness is correlated with a higher attack rate, it is suspected to influence IGP occurrence. To understand the consequences of increased aggressiveness on the IGP, we used two artificially selected lines of the generalist predator, Nabis americoferus (one aggressive and one docile). We hypothesized that IGP is positively correlated to aggressiveness. Individuals of N. americoferus were tested individually with an intraguild prey (IGPrey), Orius insidiosus, and in the absence or presence of an extraguild prey (XGPrey), third instars of Lygus lineolaris. Firstly, the attack rate of N. americoferus on O. insidiosus was recorded for 15 min and then the IGP after a period of 24 h. We found that aggressive individuals performed a higher attack rate and IGP than docile ones even with the presence of XGPrey. Whereas docile individuals did not display a strong IGP in the absence of XGPrey, it increased significantly when they were introduced. Our results suggest that IGP is positively correlated to a high aggressiveness. Additionally, it seems that docile individuals are more prone to adjust their behavior according to environmental conditions. Finally, the implications of aggressiveness degree for the predator–prey dynamic is discussed.

Resistance risk assessment of six pyrethroids and acephate toward the resistant adult tarnished plant bug, Lygus lineolaris.

Due to rapidly developed resistance, pest management relies less on pyrethroids to control economically damaging infestations of the tarnished plant bug (TPB), Lygus lineolaris (Palisot de Beauvois) in cotton fields of Mississippi. Yet, pyrethroid resistance remains prevalent in TPB populations. This study assessed the resistance levels in adult TPB to six common pyrethroids and acephate. Resistant TBPs were collected from wild host plants in late October after harvest in the Mississippi Delta region of the United States. Based on LC50 values, the field-resistant TPBs displayed higher resistance to permethrin, esfenvalerate, and bifenthrin (approximately 30 fold) and moderate resistance to λ-cyhalothrin, β-cyfluthrin, ζ-cypermethrin, and acephate (approximately 15 fold). Further investigations showed that the inhibitors of three detoxification enzyme, triphenyl phosphate (TPP), diethyl maleate (DEM), and piperonyl butoxide (PBO) had synergistic effects on permethrin, λ-cyhalothrin, and bifenthrin in resistant TPBs. Furthermore, elevated esterase, GST, and P450 activities were significantly expressed in field-resistant TPBs. Additionally, GST and esterase were reduced after 48 h exposure to certain pyrethroids at LC50 dose. The synergistic and biochemical assays consistently indicated that P450 and esterase were involved in pyrethroid detoxification in TPBs. This study provides valuable information for the continued use of pyrethroids and acephate in controlling TPBs in cotton fields in the Mississippi Delta region of the United States.

Biochemical and molecular characterization of neonicotinoids resistance in the tarnished plant bug, Lygus lineolaris

In the southern United States, neonicotinoids are commonly applied as foliar insecticides to control sucking insect pests, such as the tarnished plant bug (TPB, Lygus lineolaris). In this study, spraying bioassays were conducted to determine the toxicity of five neonicotinoids and sulfoxaflor to susceptible and late fall field-collected TPB adults from Mississippi Delta region. Compared to a susceptible population, the field-collected TPBs exhibited the highest resistance to imidacloprid (up to 19.5-fold), a moderate resistance to acetamiprid (9.43-fold), clothianidin (13.68-fold), thiamethoxam (7.88-fold) and the least resistance to thiacloprid (4.61-fold) and sulfoxaflor (1.82-fold), respectively. A synergist study demonstrated that piperonyl butoxide (PBO) significantly increased the toxicity of imidacloprid and thiamethoxam by 22.2- and 15.3-fold, respectively, while triphenyl phosphate (TPP) and diethyl maleate (DEM) only showed 2–3-fold synergism to both neonicotinoids. In the field-collected TPBs, activities of the three detoxification enzymes esterase, glutathione S-transferase (GST) and CYP450 monooxygenase (P450) were significantly increased by 3.43-, 1.48- and 2.70-fold, respectively, when compared to the susceptible population. Additionally, after 48 h exposure to imidacloprid or thiamethoxam, resistant TPB adults exhibited elevated esterase activities, decreased GST activities, and no significant changes in P450 activities. Further examinations revealed that the expression of certain esterase and P450 detoxification genes were significantly elevated in resistant TPBs. Overall, these results suggest that elevated esterase and P450s expression and enzyme activity are key mechanisms for metabolic resistance in TPBs to neonicotinoids. Our findings also provide valuable information for selection and adoption of neonicotinoid insecticides for resistance management of TPBs and minimizing toxic risk to foraging bees.