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Graham KV, Janasov EG, Paul RL, Scagel CF, Lee JC. Silicon supplementation can reduce infestation by azalea lace bug-(Hemiptera: Tingidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2024:toae164. [PMID: 39028322 DOI: 10.1093/jee/toae164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 06/11/2024] [Accepted: 07/01/2024] [Indexed: 07/20/2024]
Abstract
The azalea lace bug (ALB), Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is a pest of azaleas and rhododendrons. The application of silicon (Si) to plants has been shown to accumulate in other plants and enhance defense to other plant pests. We evaluated whether Si applications decreased ALB infestation on rhododendron leaves and increased Si accumulation in leaves. Potted plants were treated with 4 or 8 weekly applications of calcium silicate and calcium carbonate (calcium control, Ca) via foliar or soil application. In 3 out of 4 choice studies, plants treated with calcium silicate or calcium carbonate had less frass deposition and oviposition by ALB compared to controls, but treated plants did not consistently have fewer ALB adults. Leaf damage was quantified in one study and leaves with more frass as an indicator of feeding had more visible damage. In no-choice studies, there were no differences between treatments in one study, but oviposition was greater on foliar/soil Si-treated plants than controls in another study. Since rhododendron aphids (Illinoia lambersi) appeared in the greenhouse during or after studies, we compared their colonization on previously treated rhododendrons. Infestation of new leaf rosettes or random leaves by I. lambersi was lower on plants sprayed with foliar silicon or calcium applied via soil in 2 studies. Treated rhododendrons did not accumulate extra Si or Ca in leaves compared to controls. In general, silicon or calcium application protected rhododendrons from ALB oviposition and aphid colonization in free-choice conditions, and may be part of an integrated pest management program.
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Affiliation(s)
| | - Eric G Janasov
- USDA-ARS-Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR, USA
| | - Ryan L Paul
- USDA-ARS-Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR, USA
- Department of Horticulture, Oregon State University, Corvallis, OR, USA
| | - Carolyn F Scagel
- USDA ARS Horticultural Crops Plant Genetics and Improvement Research Unit, Corvallis, OR, USA
| | - Jana C Lee
- USDA-ARS-Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR, USA
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2
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Guo B, Chen L, Luo S, Wang C, Feng Y, Li X, Cao C, Zhang L, Yang Q, Zhang X, Yang X. A Potential Multitarget Insect Growth Regulator Candidate: Design, Synthesis, and Biological Activity of Novel Acetamido Derivatives Containing Hexacyclic Pyrazole Carboxamides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10271-10281. [PMID: 38655868 DOI: 10.1021/acs.jafc.4c00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Insect growth regulators (IGRs) are important green insecticides that disrupt normal growth and development in insects to reduce the harm caused by pests to crops. The ecdysone receptor (EcR) and three chitinases OfChtI, OfChtII, and OfChi-h are closely associated with the molting stage of insects. Thus, they are considered promising targets for the development of novel insecticides such as IGRs. Our previous work identified a dual-target compound 6j, which could act simultaneously on both EcR and OfChtI. In the present study, 6j was first found to have inhibitory activities against OfChtII and OfChi-h, too. Subsequently, taking 6j as a lead compound, 19 novel acetamido derivatives were rationally designed and synthesized by introducing an acetamido moiety into the amide bridge based on the flexibility of the binding cavities of 6j with EcR and three chitinases. Then, their insecticidal activities against Plutella xylostella (P. xylostella), Ostrinia furnacalis (O. furnacalis), and Spodoptera frugiperda (S. frugiperda) were carried out. The bioassay results revealed that most of these acetamido derivatives possessed moderate to good larvicidal activities against three lepidopteran pests. Especially, compound I-17 displayed excellent insecticidal activities against P. xylostella (LC50, 93.32 mg/L), O. furnacalis (LC50, 114.79 mg/L), and S. frugiperda (86.1% mortality at 500 mg/L), significantly better than that of 6j. In addition, further protein validation and molecular docking demonstrated that I-17 could act simultaneously on EcR (17.7% binding activity at 8 mg/L), OfChtI (69.2% inhibitory rate at 50 μM), OfChtII (71.5% inhibitory rate at 50 μM), and OfChi-h (73.9% inhibitory rate at 50 μM), indicating that I-17 is a potential lead candidate for novel multitarget IGRs. This work provides a promising starting point for the development of novel types of IGRs as pest management agents.
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Affiliation(s)
- Bingbo Guo
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Lei Chen
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, No 97 Buxin Road, Shenzhen 518120, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shihui Luo
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Chunying Wang
- Engineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Yanjiao Feng
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Xiaoyang Li
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Congwang Cao
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Li Zhang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Qing Yang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, No 97 Buxin Road, Shenzhen 518120, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoming Zhang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Xinling Yang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
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Encerrado-Manriquez AM, Pouv AK, Fine JD, Nicklisch SCT. Enhancing knowledge of chemical exposures and fate in honey bee hives: Insights from colony structure and interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170193. [PMID: 38278225 DOI: 10.1016/j.scitotenv.2024.170193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/13/2024] [Accepted: 01/13/2024] [Indexed: 01/28/2024]
Abstract
Honey bees are unintentionally exposed to a wide range of chemicals through various routes in their natural environment, yet research on the cumulative effects of multi-chemical and sublethal exposures on important caste members, including the queen bee and brood, is still in its infancy. The hive's social structure and food-sharing (trophallaxis) practices are important aspects to consider when identifying primary and secondary exposure pathways for residential hive members and possible chemical reservoirs within the colony. Secondary exposures may also occur through chemical transfer (maternal offloading) to the brood and by contact through possible chemical diffusion from wax cells to all hive members. The lack of research on peer-to-peer exposures to contaminants and their metabolites may be in part due to the limitations in sensitive analytical techniques for monitoring chemical fate and dispersion. Combined application of automated honey bee monitoring and modern chemical trace analysis techniques could offer rapid progress in quantifying chemical transfer and accumulation within the hive environment and developing effective mitigation strategies for toxic chemical co-exposures. To enhance the understanding of chemical fate and toxicity within the entire colony, it is crucial to consider both the intricate interactions among hive members and the potential synergistic effects arising from combinations of chemical and their metabolites.
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Affiliation(s)
| | - Amara K Pouv
- Department of Environmental Toxicology, University of California-Davis, Davis, CA 95616, USA; Department of Fisheries, Animal, and Veterinary Science, University of Rhode Island, Kingston, RI 02881, USA
| | - Julia D Fine
- Invasive Species and Pollinator Health Research Unit, USDA-ARS, 3026 Bee Biology Rd., Davis, CA 95616, USA
| | - Sascha C T Nicklisch
- Department of Environmental Toxicology, University of California-Davis, Davis, CA 95616, USA.
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Ataide LMS, Vargas G, Velazquez-Hernandez Y, Reyes-Arauz I, Villamarin P, Canon MA, Yang X, Riley SS, Revynthi AM. Efficacy of Conventional and Biorational Insecticides against the Invasive Pest Thrips parvispinus (Thysanoptera: Thripidae) under Containment Conditions. INSECTS 2024; 15:48. [PMID: 38249054 PMCID: PMC10816096 DOI: 10.3390/insects15010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024]
Abstract
In 2020, the invasive Thrips parvispinus (Karny) was first detected in Florida, United States. In response to the implemented regulatory restrictions, we conducted laboratory experiments under containment conditions. Thrips larvae and adults were exposed to 32 products (conventional and biorational insecticides) either directly or indirectly. Direct exposure was performed using a Spray Potter Tower, while indirect exposure was conducted by evaluating residue toxicity against the thrips. Water served as a control. We assessed mortality and leaf-feeding damage 48 h post-treatment. Among the conventional insecticides, chlorfenapyr, sulfoxaflor-spinetoram, and spinosad caused high mortality across all stages in both direct and residue toxicity assays. Pyridalyl, acetamiprid, tolfenpyrad, cyclaniliprole-flonicamid, acephate, novaluron, abamectin, cyantraniliprole, imidacloprid, cyclaniliprole, spirotetramat, and carbaryl displayed moderate toxicity, affecting at least two stages in either exposure route. Additionally, chlorfenapyr, spinosad, sulfoxaflor-spinetoram, pyridalyl, acetamiprid, cyclaniliprole, cyclaniliprole-flonicamid, abamectin, and acephate inhibited larvae and adult's leaf-feeding damage in both direct and residue toxicity assays. Regarding biorational insecticides, mineral oil (3%) and sesame oil caused the highest mortality and lowest leaf-feeding damage. Greenhouse evaluations of spinosad, chlorfenapyr, sulfoxaflor-spinetoram, and pyridalyl are recommended. Also, a rotation program incorporating these products, while considering different modes of action, is advised for ornamental growers to avoid resistance and to comply with regulations.
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Affiliation(s)
- Livia M. S. Ataide
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
| | - German Vargas
- New York State Integrated Pest Management Program, Cornell University, Portland, NY 14769, USA;
| | - Yisell Velazquez-Hernandez
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
| | - Isamar Reyes-Arauz
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
| | - Paola Villamarin
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
| | - Maria A. Canon
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
| | - Xiangbing Yang
- United States Department of Agriculture, Agricultural Research Service, Subtropical Horticulture Research Station, Miami, FL 33158, USA;
| | - Simon S. Riley
- Agronomy Department and IFAS Statistical Consulting Unit, University of Florida, Gainesville, FL 32611, USA;
| | - Alexandra M. Revynthi
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA; (Y.V.-H.); (I.R.-A.); (P.V.); (M.A.C.)
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Greene AD, Yang X, Velazquez-Hernandez Y, Vargas G, Kendra PE, Mannion C, Revynthi AM. Lethal and Sublethal Effects of Contact Insecticides and Horticultural Oils on the Hibiscus Bud Weevil, Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae). INSECTS 2023; 14:544. [PMID: 37367360 DOI: 10.3390/insects14060544] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
In 2017, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), was found outside of its native range of Mexico and Texas, infesting hibiscus plants in Florida. Therefore, we selected 21 different insecticide and horticultural oil products to evaluate their effects on the reproductive rate, feeding, and oviposition behavior of the HBW. In laboratory experiments, significant mortality was observed in adult weevils exposed to diflubenzuron-treated hibiscus leaves and buds, and hibiscus buds treated with diflubenzuron contained the fewest number of eggs and feeding/oviposition holes. Among horticultural oil products, significant mortality was only observed in experiments in which adult weevils were directly sprayed (direct experiments). Pyrethrins and spinetoram plus sulfoxaflor reduced the oviposition rate and caused significant mortality in direct experiments. Diflubenzuron, pyrethrins, spinetoram plus sulfoxaflor, and spirotetramat were further tested via contact toxicity experiments and greenhouse experiments. Contact toxicity experiments demonstrated that the tested insecticides (except diflubenzuron) were highly toxic to HBW adults. In greenhouse experiments, only those hibiscus plants treated with pyrethrins had significantly fewer feeding/oviposition holes and larvae within their flower buds when compared to control (water-treated) plants. These results constitute an important first step in the identification of effective chemical control options for the HBW.
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Affiliation(s)
- A Daniel Greene
- Entomology and Nematology Department, Tropical Research and Education Center, University of Florida, 18905 SW 280th St., Homestead, FL 33031, USA
| | - Xiangbing Yang
- Subtropical Horticulture Research Station, United States Department of Agriculture, Agricultural Research Service, Miami, FL 33158, USA
| | - Yisell Velazquez-Hernandez
- Entomology and Nematology Department, Tropical Research and Education Center, University of Florida, 18905 SW 280th St., Homestead, FL 33031, USA
| | - German Vargas
- Entomology and Nematology Department, Tropical Research and Education Center, University of Florida, 18905 SW 280th St., Homestead, FL 33031, USA
| | - Paul E Kendra
- Subtropical Horticulture Research Station, United States Department of Agriculture, Agricultural Research Service, Miami, FL 33158, USA
| | - Catharine Mannion
- Entomology and Nematology Department, Tropical Research and Education Center, University of Florida, 18905 SW 280th St., Homestead, FL 33031, USA
| | - Alexandra M Revynthi
- Entomology and Nematology Department, Tropical Research and Education Center, University of Florida, 18905 SW 280th St., Homestead, FL 33031, USA
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Guo B, Jiang B, Wang C, Jin X, Wang L, Yang Z, Luo S, Yang Q, Zhang L, Yang X. A Potential Lead for Insect Growth Regulator: Design, Synthesis, and Biological Activity Evaluation of Novel Hexacyclic Pyrazolamide Derivatives. Molecules 2023; 28:3741. [PMID: 37175151 PMCID: PMC10179764 DOI: 10.3390/molecules28093741] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Ecdysone receptor (EcR) and chitinase play a critical role in the molting stage of insect pests. Each of them is considered a promising target for the development of novel insect growth regulators (IGRs). In the present paper, a total of 24 (23 novel) hexacyclic pyrazolamide derivatives were designed and synthesized by reducing the heptacycle and inserting small flexible linkers on the basis of the previously discovered dual-target compound D-27 acting simultaneously on EcR and Ostrinia furnacalis chitinase (OfChtI). Their insecticidal activities against Plutella xylostella, Spodoptera frugiperda, and Ostrinia furnacalis larvae were evaluated. The results revealed that the insecticidal activity was not significantly enhanced when the heptacycle on the pyrazole ring was reduced to a hexacycle. However, the insertion of an additional methylene spacer between the substituted phenyl ring and the amide bond can improve the insecticidal activity. Among the derivatives, the most potent compound, 6j, exhibited promising insecticidal activities against P. xylostella and S. frugiperda. Further protein binding assays and molecular docking indicated that 6j could target both EcR and OfChtI, and is a potential lead compound for IGRs. The present work provides valuable clues for the development of new dual-target IGRs.
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Affiliation(s)
- Bingbo Guo
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Biaobiao Jiang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Chunying Wang
- Engineering Research Center of Plant Growth Regulator, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Xiaoyu Jin
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Liuyang Wang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Zhaokai Yang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Shihui Luo
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Qing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Li Zhang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
| | - Xinling Yang
- Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China
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Zhu G, Ding W, Zhao Y, Xue M, Zhao H, Liu S. Biological and physiological responses of two Bradysia pests, Bradysia odoriphaga and Bradysia difformis, to Dinotefuran and Lufenuron. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 190:105338. [PMID: 36740337 DOI: 10.1016/j.pestbp.2023.105338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/19/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Bradysia odoriphaga and Bradysia difformis are destructive root maggots that cause severe losses to vegetables, flowers and edible fungi. Due to the long-term dependence on single pesticides, Bradysia resistance to insecticides has increased, and field control efficacy has decreased obviously. To screen alternative insecticides, and compare the insecticide susceptibility of these two species, we tested the toxicity of eight insecticides to B. odoriphaga and B. difformis, and measured the sublethal effects of Dinotefuran and Lufenuron on life-history parameters and detoxification enzyme activities. Bioassay results indicated that Dinotefuran and Lufenuron had relatively higher toxicity to B. odoriphaga and B. difformis compared to other neonicotinoid and insect growth regulator insecticides, respectively. Significant adverse impacts caused by sublethal concentrations (LC20) of Dinotefuran and Lufenuron on the life-history parameters of F0 and F1 generations of B. odoriphaga and B. difformis were observed. These included reduced survival, prolonged larval development and reduced adult longevity and fecundity. B. odoriphaga had greater resistance and adaptation to insecticides than B. difformis, and an LC20 concentration of Dinotefuran stimulated the reproduction of B. odoriphaga F1 generation and increased the life table parameters. Detoxifying enzymes (CarE and GSTs) and P450 activities fluctuated after a sublethal concentration (Dinotefuran and Lufenuron) treatment, and at the peak value of enzyme activities, the enhancement of detoxifying enzymes of B. odoriphaga was significantly higher than that of B. difformis. These results indicated that Dinotefuran and Lufenuron should be considered as alternatives to other insecticides for control of root maggots. B. odoriphaga exhibited stronger adaptation to insecticides than B. difformis. These data provide guidance for control of root maggots, and the basic information presented here can help reveal the differences in adaptive mechanisms between B. odoriphaga and B. difformis.
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Affiliation(s)
- Guodong Zhu
- College of Agronomy, Liaocheng University, Shandong Province 252000, China; College of Plant Protection, Shandong Agricultural University, Shandong Province 271018, China.
| | - Wenjuan Ding
- College of Plant Protection, Shandong Agricultural University, Shandong Province 271018, China
| | - Yongfei Zhao
- Liaocheng Academy of Agricultural Sciences, Liaocheng 252000, China
| | - Ming Xue
- College of Plant Protection, Shandong Agricultural University, Shandong Province 271018, China.
| | - Haipeng Zhao
- College of Plant Protection, Shandong Agricultural University, Shandong Province 271018, China
| | - Shouzhu Liu
- College of Agronomy, Liaocheng University, Shandong Province 252000, China
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Joseph SV. Insect growth regulators elicit transovarial effects on Teleonemia scrupulosa (Hemiptera: Tingidae). PEST MANAGEMENT SCIENCE 2022; 78:1800-1805. [PMID: 35019229 DOI: 10.1002/ps.6797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/04/2022] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Lantana lace bug, Teleonemia scrupulosa Stål (Hemiptera: Tingidae), is an important insect pest of lantana (Lantana camara L.). The adults and nymphs feed on the leaves, gradually deteriorating the quality of leaf tissue, as the affected leaves appear brown and desiccated. Infestations of T. scrupulosa reduce the market value of container plants in nurseries and the aesthetic value of ornamental landscapes. Because T. scrupulosa typically is managed using neonicotinoids and concerns related to the nontargeted effects of neonicotinoids on pollinators are mounting, practitioners are seeking alternative options to manage T. scrupulosa infestations. Insect growth regulators (IGRs) elicit transovarial activity, where adults exposed to IGRs produce nonviable eggs, but this effect has not been documented for T. scrupulosa. RESULTS A significantly lower number of T. scrupulosa nymphs was produced when adults were sprayed topically with novaluron and pyriproxyfen than nontreated adults. The number of T. scrupulosa nymphs produced was not significantly different when adults were exposed to a lower dose (0.125×) and a maximum dose (1.0×) of novaluron. CONCLUSION Novaluron and pyriproxyfen elicited transovarial effects on T. scrupulosa when adults were exposed to these IGRs. Evidence of transovarial effects was demonstrated when T. scrupulosa adults were exposed to lower doses (≤0.125×) than the maximum label dose, as densities of nymphs were similar between the lower doses and the maximum label dose of novaluron.
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Affiliation(s)
- Shimat V Joseph
- Department of Entomology, University of Georgia, Griffin, GA, USA
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Martínez LC, Plata-Rueda A, Serrão JE. Effect of Benzoylphenyl Ureas on Survival and Reproduction of the Lace Bug, Leptopharsa gibbicarina. INSECTS 2021; 12:insects12010034. [PMID: 33418851 PMCID: PMC7824969 DOI: 10.3390/insects12010034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/31/2020] [Accepted: 01/03/2021] [Indexed: 11/18/2022]
Abstract
Simple Summary Pestalotiopsis fungal complex is a disease that causes damages in oil palm (Elaeis guineensis), and the lace bug, Leptopharsa gibbicarina is the main insect pest that spread this disease. Application of neurotoxic insecticides has been a common method used to control L. gibbicarina for decades in Colombia and Venezuela. The effects of four benzoylphenyl ureas (BPUs) (lufenuron, novaluron, teflubenzuron, and triflumuron) were assessed against L. gibbicarina for toxicity, survival, and reproduction. Overall, the results show that novaluron, teflubenzuron, and triflumuron cause high mortality and reduce survival time, fecundity, and fertility. Thus, BPUs exhibit detrimental effects on L. gibbicarina and can be used as alternatives to other chemical insecticides. Abstract The lace bug, Leptopharsa gibbicarina is a vector of Pestalotiopsis fungal complex in oil palm crops in the Americas. The effects of four benzoylphenyl ureas (BPUs) (lufenuron, novaluron, teflubenzuron, and triflumuron) were evaluated against L. gibbicarina for toxicity, survival, reproduction, and mortality in semi-field conditions. Concentration-mortality bioassays demonstrated that novaluron (LC50 = 0.33 ppm), teflubenzuron (LC50 = 0.24 ppm), lufenuron (LC50 = 0.17 ppm), and triflumuron (LC50 = 0.42 ppm) are toxic to L. gibbicarina nymphs. The survival rate was 99% in control nymphs, decreasing to 50% in nymphs exposed to LC50 of triflumuron, 47% in nymphs treated with lufenuron, 43% in nymphs treated with teflubenzuron, and 43% in those treated with novaluron. Sublethal concentrations of BPUs showed detrimental effects on the adult emergence, longevity, fecundity, and fertility of this insect. The mortality of nymphs caused by these insecticides was similar in both laboratory and semi-field conditions. Our results suggest that novaluron, teflubenzuron, and triflumuron are highly effective against L. gibbicarina, and therefore, have potential applications for this oil palm pest.
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Affiliation(s)
- Luis Carlos Martínez
- Department of General Biology, Federal University of Viçosa, Viçosa 36570-000, Brazil;
- Correspondence: ; Tel.: +55-31-3899-4012
| | - Angelica Plata-Rueda
- Department de Entomology, Federal University of Viçosa, Viçosa 36570-000, Brazil;
| | - José Eduardo Serrão
- Department of General Biology, Federal University of Viçosa, Viçosa 36570-000, Brazil;
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Graham KV, Choi MY, Lee JC. Attracting Chrysopidae With Plant Volatiles for Lace Bug (Hemiptera: Tingidae) Control in Rhododendrons and Azaleas. JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:5900007. [PMID: 32869852 PMCID: PMC7459699 DOI: 10.1093/jisesa/ieaa078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Indexed: 05/19/2023]
Abstract
The azalea lace bug (Stephanitis pyrioides Scott) (Hemiptera: Tingidae) is an invasive pest of rhododendrons and azaleas (Ericaceae: Rhododendron), which feeds on the underside of leaves causing chlorosis, reduced photosynthesis, and even plant death. While insecticides can control this pest, growers, landscape managers, and homeowners have requested softer alternatives. Augmentative release of predatory green lacewing Chrysoperla sp. (Neuroptera: Chrysopidae) eggs and larvae has reduced S. pyrioides, but large-scale implementation may not be practical nor cost-effective. Attracting naturally occurring Chrysopidae with plant volatiles may be an economical and convenient option. In this study, we tested whether volatile blends 1) attracted Chrysoperla sp., and 2) controlled S. pyrioides populations on Rhododendron spp. in farm or urban landscapes. Experimental plots contained different multicomponent lures placed aboveground next to infested plants. Adult Chrysoperla sp., other natural enemies, and S. pyrioides from egg to adult stages were monitored in both farm and urban landscapes for two summers. Overall, two out of three volatile blends consistently attracted Chrysoperla sp. to sticky traps near baited plants. Methyl salicylate + acetic acid + 2-phenylethanol (methyl salicylate blend) and acetophenone + acetic acid + 2-phenylethanol (acetophenone blend) captured more adult Chrysoperla sp. than control traps in farm landscapes. However, only the acetophenone blend was associated with a slight reduction of S. pyrioides. Additional research is needed to determine whether the phenology of the first generation of both species are synchronized for effective season biological control in the Pacific Northwest.
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Affiliation(s)
- Katerina Velasco Graham
- Department of Horticulture, Oregon State University, Corvallis, OR
- Corresponding author, e-mail:
| | - Man-Yeon Choi
- USDA-ARS-Horticulture Crops Research Unit, Corvallis, OR
| | - Jana C Lee
- USDA-ARS-Horticulture Crops Research Unit, Corvallis, OR
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V Joseph S. Ingestion of Novaluron Elicits Transovarial Activity in Stephanitis pyrioides (Hemiptera: Tingidae). INSECTS 2020; 11:insects11040216. [PMID: 32244642 PMCID: PMC7240697 DOI: 10.3390/insects11040216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/20/2020] [Accepted: 03/27/2020] [Indexed: 11/17/2022]
Abstract
Azaleas (Rhododendron L. spp.) are widely grown ornamental plants in eastern and western regions of the USA. The azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is an important insect pest of azaleas. Adults and nymphs of S. pyrioides consume chlorophyll in azalea foliage, and severely affected plants appear bleached. Neonicotinoid insecticides are effective and widely used for S. pyrioides control; however, nursery growers and landscape professionals are concerned about nontarget effects on beneficial insects and demand neonicotinoid-free plants. There is clearly a need to develop reduced-risk control strategies for S. pyrioides. The insect growth regulator (IGR) novaluron elicits transovarial activity when adult S. pyrioides are exposed to it. However, it is not certain whether transovarial effects can be observed when S. pyrioides adults that colonize the abaxial leaf surface ingest novaluron residues deposited on the adaxial leaf surface. Experiments were conducted to assess transovarial activity upon exposure to various application rates of novaluron alone and novaluron with various adjuvants. The numbers of nymphs were significantly lower when the full rate of novaluron was applied on the adaxial surface of leaves compared to the number of nymphs on non-treated leaves. The densities of nymphs were not significantly different between the half and full rates of novaluron treatment. When novaluron with various adjuvants was applied to the adaxial surface of the leaves, the densities of nymphs were significantly lower under the novaluron treatments compared to the non-treated leaves, regardless of the type of adjuvant added. There was no significant difference between treatment with novaluron alone and the treatments of novaluron with adjuvants. These data show that transovarial activity was elicited in adults of S. pyrioides when novaluron was applied on the adaxial leaf surface.
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Affiliation(s)
- Shimat V Joseph
- Department of Entomology, University of Georgia, UGA Griffin Campus, 1109 Experiment Street, Griffin, GA 30223, USA
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Influence of Insect Growth Regulators on Stephanitis pyrioides (Hemiptera: Tingidae) Eggs and Nymphs. INSECTS 2019; 10:insects10070189. [PMID: 31261681 PMCID: PMC6681392 DOI: 10.3390/insects10070189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/24/2019] [Accepted: 06/26/2019] [Indexed: 11/23/2022]
Abstract
The azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is an important insect pest of azaleas (Rhododendron L. spp.) in the USA. Stephanitis pyrioides feeds on azalea foliage and causes extensive chlorosis, which reduces the aesthetic value and marketability of these plants. Because the use of neonicotinoid insecticides has been dramatically reduced or discontinued, growers and landscape managers are seeking alternative tools or strategies to control this insect. Although insect growth regulators (IGRs) are known for their activity against immature insect stages, their activity against egg hatching has not been addressed thoroughly, specifically against S. pyrioides. Thus, a series of experiments was conducted to understand the ovicidal activity of IGRs using novaluron, azadirachtin, pyriproxyfen, and buprofezin against S. pyrioides. The number of newly emerged young instars was significantly lower when leaves implanted with eggs were sprayed on both sides with novaluron, azadirachtin, and buprofezin compared to nontreated and pyriproxyfen treatments. When IGRs plus adjuvant were applied to the adaxial surface of the leaves, the densities of the newly emerged nymphs were significantly lower under the novaluron treatment compared to the nontreated leaves. However, there was no significant difference in the number of nymphs that emerged in the absence of adjuvant. Furthermore, close monitoring revealed reduced levels of egg hatching in the presence of adjuvant with novaluron compared to its absence. The data show that the survival of S. pyrioides first instars was not affected by exposure to dried IGR residues.
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