Pub Date : 2026-01-14DOI: 10.1016/j.cropro.2026.107543
Nathan S. Little, Ryan T. Paulk, Blake H. Elkins, R. Michelle Mullen, K. Clint Allen
The bollworm (Helicoverpa zea), a persistent pest of U.S. cotton, poses ongoing challenges to producers. Transgenic cotton expressing Bacillus thuringiensis (Bt) insecticidal proteins has revolutionized bollworm control while reducing reliance on broad-spectrum insecticides. However, variability in toxin expression across plant structures and developmental stages may reduce efficacy and contribute to the development of resistance. This study evaluates the relative expression of Cry1Ac, Cry2Ab, and Vip3A proteins in two Bt cotton cultivars throughout the growing season and compares these data with bollworm larval mortality on fruiting structures. Our results show a general decline in Cry1Ac and Cry2Ab levels throughout the growing season, while Vip3A expression remained relatively stable. Bollworm larval mortality was highest in squares, followed by blooms and bolls. Bollgard II cotton exhibited higher early-season Cry1Ac levels than the Bollgard III variety, potentially influencing early-season pest suppression. Vip3A expression was the highest in blooms of Bollgard III cotton, followed by squares and bolls. These findings underscore the importance of mid-to late-season scouting for surviving larvae on blooms and boll damage in Bt cotton. A better understanding of the spatiotemporal expression of Vip3A, coupled with preemptive resistance screening, will be vital for preserving Bt cotton's longevity and maintaining its role in sustainable production systems.
{"title":"Impact of crystalline and vegetative protein expression in dual- and multi-gene transgenic cottons on bollworm larval survival","authors":"Nathan S. Little, Ryan T. Paulk, Blake H. Elkins, R. Michelle Mullen, K. Clint Allen","doi":"10.1016/j.cropro.2026.107543","DOIUrl":"10.1016/j.cropro.2026.107543","url":null,"abstract":"<div><div>The bollworm (<em>Helicoverpa zea</em>), a persistent pest of U.S. cotton, poses ongoing challenges to producers. Transgenic cotton expressing <em>Bacillus thuringiensis</em> (Bt) insecticidal proteins has revolutionized bollworm control while reducing reliance on broad-spectrum insecticides. However, variability in toxin expression across plant structures and developmental stages may reduce efficacy and contribute to the development of resistance. This study evaluates the relative expression of Cry1Ac, Cry2Ab, and Vip3A proteins in two Bt cotton cultivars throughout the growing season and compares these data with bollworm larval mortality on fruiting structures. Our results show a general decline in Cry1Ac and Cry2Ab levels throughout the growing season, while Vip3A expression remained relatively stable. Bollworm larval mortality was highest in squares, followed by blooms and bolls. Bollgard II cotton exhibited higher early-season Cry1Ac levels than the Bollgard III variety, potentially influencing early-season pest suppression. Vip3A expression was the highest in blooms of Bollgard III cotton, followed by squares and bolls. These findings underscore the importance of mid-to late-season scouting for surviving larvae on blooms and boll damage in Bt cotton. A better understanding of the spatiotemporal expression of Vip3A, coupled with preemptive resistance screening, will be vital for preserving Bt cotton's longevity and maintaining its role in sustainable production systems.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107543"},"PeriodicalIF":2.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.cropro.2026.107541
Mingyan Luo, Mengying Liu, Kexin Cheng, Yulan Jiang, Fengquan Liu
Sorghum is a globally grown crop for food and feed,as well as holds a crucial position in brewing industry in China. Anthracnose poses a major threat to both the yield and quality of sorghum. In August 2024, an outbreak of anthracnose affecting 90 % plants was observed in a sorghum cultivation area of Xingyi City, Guizhou Province, China. The typical symptoms started as irregular to oval maroon spots on the leaves, which later developed to wider necrotic lesions and produced a lot of fruiting bodies. To determine the causal agent, the fungus was isolated from the diseased and healthy junctions. Based on integrated evidence from morphological characteristics, multi-locus phylogenetic analyses (ITS, GAPDH, ACT, HIS3, TUB, and CHS-1), and pathogenicity assays, the pathogen was pinpointed as Colletotrichum truncatum. This study provides the first report of C. truncatum as the causative agent of sorghum anthracnose in China.
{"title":"First report of Colletotrichum truncatum causing anthracnose on sorghum (Sorghum bicolor) in China","authors":"Mingyan Luo, Mengying Liu, Kexin Cheng, Yulan Jiang, Fengquan Liu","doi":"10.1016/j.cropro.2026.107541","DOIUrl":"10.1016/j.cropro.2026.107541","url":null,"abstract":"<div><div>Sorghum is a globally grown crop for food and feed,as well as holds a crucial position in brewing industry in China. Anthracnose poses a major threat to both the yield and quality of sorghum. In August 2024, an outbreak of anthracnose affecting 90 % plants was observed in a sorghum cultivation area of Xingyi City, Guizhou Province, China. The typical symptoms started as irregular to oval maroon spots on the leaves, which later developed to wider necrotic lesions and produced a lot of fruiting bodies. To determine the causal agent, the fungus was isolated from the diseased and healthy junctions. Based on integrated evidence from morphological characteristics, multi-locus phylogenetic analyses (ITS, <em>GAPDH</em>, <em>ACT</em>, <em>HIS3</em>, <em>TUB</em>, and <em>CHS-1</em>), and pathogenicity assays, the pathogen was pinpointed as <em>Colletotrichum truncatum</em>. This study provides the first report of <em>C. truncatum</em> as the causative agent of sorghum anthracnose in China.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107541"},"PeriodicalIF":2.5,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.cropro.2026.107539
Fengchao Wang , Jingwei Gao , Lelin Zhao , Jeremiah Joe Kabissa , Haiyan Wang , Yan Jin , Hongyan Wang
Ginger rhizome rot, poses a significant challenge in major ginger growing regions of China, adversely affecting both yield and quality. In this study, we identified three Fusarium species responsible for the disease isolated from infected plants. The pathogens were identified as Fusarium proliferatum, F. oxysporum, and F. solani through morphological and molecular identification. We established the pathogenicity of three target pathogens and evaluated the efficacy of nine antifungal agents against these pathogens using mycelial growth rate assays and spore germination tests. Subsequent safety assessments of the selected antifungal agents on ginger plants and field efficacy trials were conducted to validate practical applicability. Among the tested antifungal agents, pyraclostrobin and tetramycin displayed potent inhibitory effects on both mycelial proliferation and spore germination across all three pathogens species. Specifically, pyraclostrobin demonstrated EC50 values for mycelial inhibition of 1.637, 3.177, and 1.301 mg/L against F. proliferatum LW-FP4, F. oxysporum LW-FO3, and F. solani LW-FS2, respectively, while spore inhibition EC50 values were found to be 0.025, 1.374, and 0.065 mg/L. Tetramycin exhibited mycelial EC50 values of 5.460, 5.649, and 1.436 mg/L, alongside spore inhibition EC50 values of 2.502, 2.431, and 2.015 mg/L for the respective isolates. Notably, no phytotoxicity symptoms were observed on ginger rhizomes treated with 25 % pyraclostrobin SC (Suspension Concentrate) or 0.3 % tetramycin AS (Aqueous Solution). Field trials with 25 % pyraclostrobin at a concentration of 250 mg/L achieved control efficacies of 81.90 % and 86.58 % in Laizhou and Laiwu, respectively. These findings lay the foundation for optimized antifungal agent application and enhanced management strategies for ginger rhizome rot in agricultural practice.
{"title":"Screening of effective agents and field efficacy trials on control ginger rhizome rot caused by Fusarium species","authors":"Fengchao Wang , Jingwei Gao , Lelin Zhao , Jeremiah Joe Kabissa , Haiyan Wang , Yan Jin , Hongyan Wang","doi":"10.1016/j.cropro.2026.107539","DOIUrl":"10.1016/j.cropro.2026.107539","url":null,"abstract":"<div><div>Ginger rhizome rot, poses a significant challenge in major ginger growing regions of China, adversely affecting both yield and quality. In this study, we identified three <em>Fusarium</em> species responsible for the disease isolated from infected plants. The pathogens were identified as <em>Fusarium proliferatum</em>, <em>F. oxysporum</em>, and <em>F. solani</em> through morphological and molecular identification. We established the pathogenicity of three target pathogens and evaluated the efficacy of nine antifungal agents against these pathogens using mycelial growth rate assays and spore germination tests. Subsequent safety assessments of the selected antifungal agents on ginger plants and field efficacy trials were conducted to validate practical applicability. Among the tested antifungal agents, pyraclostrobin and tetramycin displayed potent inhibitory effects on both mycelial proliferation and spore germination across all three pathogens species. Specifically, pyraclostrobin demonstrated EC<sub>50</sub> values for mycelial inhibition of 1.637, 3.177, and 1.301 mg/L against <em>F. proliferatum</em> LW-FP4, <em>F. oxysporum</em> LW-FO3, and <em>F. solani</em> LW-FS2, respectively, while spore inhibition EC<sub>50</sub> values were found to be 0.025, 1.374, and 0.065 mg/L. Tetramycin exhibited mycelial EC<sub>50</sub> values of 5.460, 5.649, and 1.436 mg/L, alongside spore inhibition EC<sub>50</sub> values of 2.502, 2.431, and 2.015 mg/L for the respective isolates. Notably, no phytotoxicity symptoms were observed on ginger rhizomes treated with 25 % pyraclostrobin SC (Suspension Concentrate) or 0.3 % tetramycin AS (Aqueous Solution). Field trials with 25 % pyraclostrobin at a concentration of 250 mg/L achieved control efficacies of 81.90 % and 86.58 % in Laizhou and Laiwu, respectively. These findings lay the foundation for optimized antifungal agent application and enhanced management strategies for ginger rhizome rot in agricultural practice.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107539"},"PeriodicalIF":2.5,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.cropro.2026.107537
Dong Yuhua, Sohail Abbas, Aleena Alam, Bilal Ahmad, Muneer Abbas, Khalid Ali Khan, Hamed A. Ghramh, Gong Xuesong, Jamin Ali, Xiao Han, Li Qiyun, Ri-Zhao Chen
Light spectrum and photoperiod are fundamental environmental cues that regulate insect development, survival, and reproductive performance. However, despite extensive work on photoperiodic regulation of diapause in insects, the combined roles of spectral composition and photoperiod in shaping growth, development, and reproductive traits remain poorly understood in Ostrinia furnacalis (Guenée). In this study, we investigated the independent and interactive effects of five light spectra (blue, purple, green, red, and white) and four photoperiod regimes (LD: 14:10, 10:14, 16:08, and 08:16 h) on the growth, development, and reproductive traits of O. furnacalis. Using controlled laboratory experiments, we quantified key parameters, including larval survival across instars, larval and pupal durations, pupal weight, pupation rate, adult emergence rate, adult survival, and reproductive output. Both spectral quality and photoperiod significantly affected most traits, often interacting to produce spectrum-dependent photoperiodic responses. Short-wavelength light (blue, purple) generally promoted high larval survival and stable development across photoperiods. Green light extended larval and pupal development but enhanced pupal mass and fecundity. Red and white light produced variable effects across traits. These findings suggest that short wavelengths can diminish photoperiod sensitivity, whereas longer wavelengths enhance it. Our results highlight the potential role of spectral composition in shaping pest phenology and reproductive performance, providing a basis for predictive models and the development of sustainable light-based management strategies for O. furnacalis.
{"title":"Light Spectra and Photoperiods Interactively Influence Growth, Development, and Reproductive Traits of Ostrinia furnacalis (Lepidoptera: Crambidae)","authors":"Dong Yuhua, Sohail Abbas, Aleena Alam, Bilal Ahmad, Muneer Abbas, Khalid Ali Khan, Hamed A. Ghramh, Gong Xuesong, Jamin Ali, Xiao Han, Li Qiyun, Ri-Zhao Chen","doi":"10.1016/j.cropro.2026.107537","DOIUrl":"https://doi.org/10.1016/j.cropro.2026.107537","url":null,"abstract":"Light spectrum and photoperiod are fundamental environmental cues that regulate insect development, survival, and reproductive performance. However, despite extensive work on photoperiodic regulation of diapause in insects, the combined roles of spectral composition and photoperiod in shaping growth, development, and reproductive traits remain poorly understood in <ce:italic>Ostrinia furnacalis</ce:italic> (Guenée). In this study, we investigated the independent and interactive effects of five light spectra (blue, purple, green, red, and white) and four photoperiod regimes (LD: 14:10, 10:14, 16:08, and 08:16 h) on the growth, development, and reproductive traits of <ce:italic>O. furnacalis</ce:italic>. Using controlled laboratory experiments, we quantified key parameters, including larval survival across instars, larval and pupal durations, pupal weight, pupation rate, adult emergence rate, adult survival, and reproductive output. Both spectral quality and photoperiod significantly affected most traits, often interacting to produce spectrum-dependent photoperiodic responses. Short-wavelength light (blue, purple) generally promoted high larval survival and stable development across photoperiods. Green light extended larval and pupal development but enhanced pupal mass and fecundity. Red and white light produced variable effects across traits. These findings suggest that short wavelengths can diminish photoperiod sensitivity, whereas longer wavelengths enhance it. Our results highlight the potential role of spectral composition in shaping pest phenology and reproductive performance, providing a basis for predictive models and the development of sustainable light-based management strategies for <ce:italic>O. furnacalis</ce:italic>.","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"21 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.cropro.2026.107538
Min Li , Jinhua Sun , Gengxin Chen , Zhengke Zhang , Yajun Ran , Meijiao Hu
Litchi (Litchi chinensis Sonn.) is an economically important fruit crop in southern China. In May 2024, litchi fruits harvested from Haikou City, China, exhibited anthracnose-like symptoms, with a disease incidence (DI) of 7.6 % at 7 days of storage at 25 °C. Fungal colonies with consistent morphology were isolated from the margins of typical symptomatic pericarp tissues. The pathogen was identified as Colletotrichum gigasporum based on morphological characterization and multi-locus phylogenetic analysis utilizing sequences of the ITS region, GAPDH, ACT, TUB2 and CAL genes Pathogenicity was confirmed by fulfilling Koch's postulates. To our knowledge, this is the first report of C. gigasporum causing postharvest anthracnose on litchi fruit in China.
{"title":"Colletotrichum gigasporum causes postharvest fruit anthracnose on litchi in China","authors":"Min Li , Jinhua Sun , Gengxin Chen , Zhengke Zhang , Yajun Ran , Meijiao Hu","doi":"10.1016/j.cropro.2026.107538","DOIUrl":"10.1016/j.cropro.2026.107538","url":null,"abstract":"<div><div>Litchi (<em>Litchi chinensis</em> Sonn.) is an economically important fruit crop in southern China. In May 2024, litchi fruits harvested from Haikou City, China, exhibited anthracnose-like symptoms, with a disease incidence (DI) of 7.6 % at 7 days of storage at 25 °C. Fungal colonies with consistent morphology were isolated from the margins of typical symptomatic pericarp tissues. The pathogen was identified as <em>Colletotrichum gigasporum</em> based on morphological characterization and multi-locus phylogenetic analysis utilizing sequences of the ITS region, <em>GAPDH</em>, <em>ACT</em>, <em>TUB2</em> and <em>CAL</em> genes Pathogenicity was confirmed by fulfilling Koch's postulates. To our knowledge, this is the first report of <em>C. gigasporum</em> causing postharvest anthracnose on litchi fruit in China.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107538"},"PeriodicalIF":2.5,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-06DOI: 10.1016/j.cropro.2026.107536
Andrea Rilaković , Miloš Zarić , Vamsi Manthena , Ana M. Vélez Arango , Greg R. Kruger , Brian Krienke , Daran R. Rudnick , Julie A. Peterson
Western bean cutworm, Striacosta albicosta Smith (Lepidoptera: Noctuidae), is a significant pest in Midwestern U.S. corn (Zea mays L.) production. In Nebraska, foliar application of insecticides at the tasseling stage of corn is commonly performed via chemigation using overhead irrigation systems (center pivots). However, the efficacy of various chemigation practices for S. albicosta have not been well explored. A two-year field study was conducted to evaluate the efficacy of chlorantraniliprole and bifenthrin, applied at both minimum and maximum label rates for bifenthrin (36.8 and 112.1 g a.i. ha−1) and chlorantraniliprole (52.7 and 75.1 g a.i. ha−1), using two application depths (6.35 mm and 19.05 mm). In 2021, chlorantraniliprole reduced ear feeding injury compared to bifenthrin 28 days after application (DAA). In 2022, no differences were observed between the two insecticides for the ear feeding injury. Throughout both field seasons, no S. albicosta larvae were found in plots treated with chlorantraniliprole during ear assessments at 28 DAA. This was not the case with bifenthrin, which provided moderate control. Application depths of the applied insecticides did not influence ear feeding injury.
Our results indicate that insecticide selection for S. albicosta management is more important than the depth of the application. Chlorantraniliprole provided superior larval control, supporting its use in chemigation-based management strategies for S. albicosta in corn.
西部豆蛾（Striacosta albicosta Smith）（鳞翅目：夜蛾科）是美国中西部玉米生产中的重要害虫。在内布拉斯加州，玉米抽雄期的叶面施用杀虫剂通常是通过使用架空灌溉系统（中心枢纽）进行化学灌溉。然而，各种化学处理方法对白色葡萄球菌的效果尚未得到很好的探讨。为评价氯虫腈和联苯菊酯的效果，开展了一项为期两年的实地研究，采用两种施药深度（6.35 mm和19.05 mm），分别以最小和最大标示剂量（36.8和112.1 g a.i. ha - 1）和氯虫腈（52.7和75.1 g a.i. ha - 1）施用联苯菊酯和联苯菊酯。2021年，与施用后28天的联苯菊酯（DAA）相比，氯虫腈减少了耳朵喂养损伤。2022年，两种杀虫剂对食耳损伤的防治效果无差异。在整个田间季节，在28 DAA的穗期评估中，氯虫腈处理的样地未发现白色葡萄球菌幼虫。联苯菊酯的情况并非如此，它提供了适度的控制。施用杀虫剂的深度对取食损伤无显著影响。结果表明，在白曲曲菌管理中，杀虫剂的选择比施用深度更重要。氯虫腈具有良好的幼虫控制效果，支持其在玉米白曲曲病菌化学防治策略中的应用。
{"title":"Chemigation efficacy of bifenthrin and chlorantraniliprole for Striacosta albicosta (Lepidoptera: Noctuidae) management in corn under different irrigation depths","authors":"Andrea Rilaković , Miloš Zarić , Vamsi Manthena , Ana M. Vélez Arango , Greg R. Kruger , Brian Krienke , Daran R. Rudnick , Julie A. Peterson","doi":"10.1016/j.cropro.2026.107536","DOIUrl":"10.1016/j.cropro.2026.107536","url":null,"abstract":"<div><div>Western bean cutworm, <em>Striacosta albicosta</em> Smith (Lepidoptera: Noctuidae), is a significant pest in Midwestern U.S. corn (<em>Zea mays</em> L.) production. In Nebraska, foliar application of insecticides at the tasseling stage of corn is commonly performed via chemigation using overhead irrigation systems (center pivots). However, the efficacy of various chemigation practices for <em>S. albicosta</em> have not been well explored. A two-year field study was conducted to evaluate the efficacy of chlorantraniliprole and bifenthrin, applied at both minimum and maximum label rates for bifenthrin (36.8 and 112.1 g a.i. ha<sup>−1</sup>) and chlorantraniliprole (52.7 and 75.1 g a.i. ha<sup>−1</sup>), using two application depths (6.35 mm and 19.05 mm). In 2021, chlorantraniliprole reduced ear feeding injury compared to bifenthrin 28 days after application (DAA). In 2022, no differences were observed between the two insecticides for the ear feeding injury. Throughout both field seasons, no <em>S. albicosta</em> larvae were found in plots treated with chlorantraniliprole during ear assessments at 28 DAA. This was not the case with bifenthrin, which provided moderate control. Application depths of the applied insecticides did not influence ear feeding injury.</div><div>Our results indicate that insecticide selection for <em>S. albicosta</em> management is more important than the depth of the application. Chlorantraniliprole provided superior larval control, supporting its use in chemigation-based management strategies for <em>S. albicosta</em> in corn.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107536"},"PeriodicalIF":2.5,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.cropro.2025.107527
Shi-Qi Guo , Chada Norphanphoun , Fatimah Al-Otibi , Kevin D. Hyde , Juan Liu , Hong-Mei Liu , Wen-E Zhang , Yong Wang
Rhododendron is an important ornamental crop in Guizhou Province, China, where intensified cultivation has led to increasing disease problems. In this study, a leaf spot disease was investigated on Rhododendron in the Baili Forest Region. The disease initially appeared as brown, circular to irregular lesions, which gradually enlarged, turned dark brown, and developed lighter margins with visible signs of wilting and decay. Severe infection led to premature leaf death, thereby compromising plant vigor. Field surveys of 200 Rhododendron hybridum leaves revealed 66 symptomatic samples, corresponding to a disease incidence of 33 %, which has caused notable economic losses to local horticultural operations. Morphological examination, together with multi-gene phylogenetic analysis (ITS, tef1-α, and β-tubulin), identified the causal agent as Neopestalotiopsis maddoxii. Pathogenicity was confirmed by artificial inoculation, which reproduced typical symptoms and fulfilled Koch's postulates. This is the first report of N. maddoxii causing leaf spot on Rhododendron in Guizhou Province, providing a basis for future studies on its epidemiology and management.
{"title":"Leaf spot of Rhododendron hybridum caused by Neopestalotiopsis maddoxii in China","authors":"Shi-Qi Guo , Chada Norphanphoun , Fatimah Al-Otibi , Kevin D. Hyde , Juan Liu , Hong-Mei Liu , Wen-E Zhang , Yong Wang","doi":"10.1016/j.cropro.2025.107527","DOIUrl":"10.1016/j.cropro.2025.107527","url":null,"abstract":"<div><div><em>Rhododendron</em> is an important ornamental crop in Guizhou Province, China, where intensified cultivation has led to increasing disease problems. In this study, a leaf spot disease was investigated on <em>Rhododendron</em> in the Baili Forest Region. The disease initially appeared as brown, circular to irregular lesions, which gradually enlarged, turned dark brown, and developed lighter margins with visible signs of wilting and decay. Severe infection led to premature leaf death, thereby compromising plant vigor. Field surveys of 200 <em>Rhododendron hybridum</em> leaves revealed 66 symptomatic samples, corresponding to a disease incidence of 33 %, which has caused notable economic losses to local horticultural operations. Morphological examination, together with multi-gene phylogenetic analysis (ITS, <em>tef1-α</em>, and <em>β-tubulin</em>), identified the causal agent as <em>Neopestalotiopsis maddoxii</em>. Pathogenicity was confirmed by artificial inoculation, which reproduced typical symptoms and fulfilled Koch's postulates. This is the first report of <em>N. maddoxii</em> causing leaf spot on <em>Rhododendron</em> in Guizhou Province, providing a basis for future studies on its epidemiology and management.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107527"},"PeriodicalIF":2.5,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145893700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.cropro.2026.107535
Fernando Semmelroth de Assunção e Amaral , Giovana Moraes de Souza , Rafael Brandão Garcia , Marcelo Pedreira de Miranda , Celso Omoto
In Brazil, control of the Asian citrus psyllid, Diaphorina citri, primarily relies on insecticides. Recently, field failures in controlling D. citri with some insecticides have been reported. This study investigates the susceptibility of five field populations of D. citri from key citrus-producing areas in the State of São Paulo, Brazil, to the three most used insecticides (bifenthrin, imidacloprid, and malathion). Subsequently, to characterize resistance under laboratory conditions, resistant strains were selected from one of the least susceptible field populations of D. citri located in Tabatinga, São Paulo. To provide evidence of field-evolved resistance, the effectiveness of imidacloprid was tested through foliar spray and soil drench applications. Leaf-dip bioassays characterized susceptibility of D. citri to bifenthrin, imidacloprid, and malathion. Resistance ratios among field populations of D. citri ranged from 39.6- to 192.7-fold for bifenthrin, 22.2- to 271.2-fold for imidacloprid, and 6.6- to 37.1-fold for malathion, compared to a susceptible reference strain. Following six generations of laboratory selection pressure in a field population of D. citri, resistance ratios increased to 1037.3-fold for bifenthrin, 790.6-fold for imidacloprid, and 298.9-fold for malathion. Low efficacy of imidacloprid against field populations of D. citri was observed in both application methods. This is the first report of field-evolved resistance of D. citri to bifenthrin, imidacloprid, and malathion insecticides in the citrus belt of São Paulo State, Brazil. Therefore, the evolution of resistance might be one of the reasons for the increased population density of D. citri. This research will help implement Insecticide Resistance Management (IRM) strategies for D. citri in Brazilian citrus groves.
{"title":"Field-evolved resistance of Diaphorina citri (Hemiptera: Psyllidae) to insecticides in Brazil","authors":"Fernando Semmelroth de Assunção e Amaral , Giovana Moraes de Souza , Rafael Brandão Garcia , Marcelo Pedreira de Miranda , Celso Omoto","doi":"10.1016/j.cropro.2026.107535","DOIUrl":"10.1016/j.cropro.2026.107535","url":null,"abstract":"<div><div>In Brazil, control of the Asian citrus psyllid, <em>Diaphorina citri</em>, primarily relies on insecticides. Recently, field failures in controlling <em>D. citri</em> with some insecticides have been reported. This study investigates the susceptibility of five field populations of <em>D. citri</em> from key citrus-producing areas in the State of São Paulo, Brazil, to the three most used insecticides (bifenthrin, imidacloprid, and malathion). Subsequently, to characterize resistance under laboratory conditions, resistant strains were selected from one of the least susceptible field populations of <em>D. citri</em> located in Tabatinga, São Paulo. To provide evidence of field-evolved resistance, the effectiveness of imidacloprid was tested through foliar spray and soil drench applications. Leaf-dip bioassays characterized susceptibility of <em>D. citri</em> to bifenthrin, imidacloprid, and malathion. Resistance ratios among field populations of <em>D. citri</em> ranged from 39.6- to 192.7-fold for bifenthrin, 22.2- to 271.2-fold for imidacloprid, and 6.6- to 37.1-fold for malathion, compared to a susceptible reference strain. Following six generations of laboratory selection pressure in a field population of <em>D. citri</em>, resistance ratios increased to 1037.3-fold for bifenthrin, 790.6-fold for imidacloprid, and 298.9-fold for malathion. Low efficacy of imidacloprid against field populations of <em>D. citri</em> was observed in both application methods. This is the first report of field-evolved resistance of <em>D. citri</em> to bifenthrin, imidacloprid, and malathion insecticides in the citrus belt of São Paulo State, Brazil. Therefore, the evolution of resistance might be one of the reasons for the increased population density of <em>D. citri</em>. This research will help implement Insecticide Resistance Management (IRM) strategies for <em>D. citri</em> in Brazilian citrus groves.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107535"},"PeriodicalIF":2.5,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145893701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.cropro.2025.107533
Ali Kayahan , Betül Kayahan
This study examined the effects of three insecticides—Deltamethrin, Cypermethrin, and Chlorantraniliprole—at different doses (LC30, LC40, and LC50) on the demographic parameters of the green peach aphid Myzus persicae Sulzer, 1776 (Hemiptera: Aphididae). Populations of M. persicae reared on pepper plants (Capsicum sp.) were used in the experiments. The trials were conducted in a climate-controlled chamber (25 ± 1 °C, 60 ± 5 % RH, 16:8 h L:D photoperiod). Lethal concentrations of each insecticide were determined using probit analysis, and subsequent life table analyses were performed at LC30–LC50 levels using the age–stage, two-sex life table approach. Data were processed with TWOSEX-MSChart and TIMING-MSChart software, and statistical differences among treatments were assessed using the bootstrap method. Results showed that increasing insecticide concentrations significantly affected development, longevity, and fecundity traits of M. persicae. The longest nymphal and pre-adult development periods were observed at the LC50 level of Deltamethrin, while the shortest were recorded at LC30 of Chlorantraniliprole. Higher doses led to significant reductions in adult longevity, total lifespan, and reproductive potential. The lowest values of net reproductive rate (R0), intrinsic rate of increase (r), and the finite rate of increase (λ) were found in the Deltamethrin LC50 treatment, while the highest (excluding control) occurred under Chlorantraniliprole LC30. Age–stage survival rate (sxj) and life expectancy (exj) also decreased with insecticide exposure, with marked population reductions observed at higher concentrations. Overall, the results indicate that pyrethroid insecticides—particularly Deltamethrin and Cypermethrin—impede the population growth of M. persicae by prolonging development, reducing fecundity, and shortening lifespan. Considering low lethal effects, Chlorantraniliprole exhibited milder adverse effects at low doses. These findings highlight the importance of considering sublethal effects on population dynamics when designing sustainable and environmentally sound integrated pest management (IPM) programs.
研究了溴氰菊酯、氯氰菊酯和氯虫腈3种杀虫剂不同剂量（LC30、LC40和LC50）对桃蚜种群参数的影响（半翅目：蚜科）。实验采用在辣椒植株上饲养的桃蚜种群。试验在气候控制室（25±1°C, 60±5% RH， 16:8 h L:D光周期）中进行。采用概率分析法确定每种杀虫剂的致死浓度，随后采用年龄阶段、两性生命表法进行LC30-LC50水平的生命表分析。采用TWOSEX-MSChart和TIMING-MSChart软件对数据进行处理，采用自举法评估处理间的统计学差异。结果表明，增加杀虫剂浓度对桃蚜的发育、寿命和繁殖力性状有显著影响。溴氰菊酯LC50时，若虫和成虫前期发育时间最长，氯虫腈LC30时，若虫和成虫前期发育时间最短。较高的剂量导致成人寿命、总寿命和生殖潜力显著降低。净繁殖率（R0）、内在增长率(r)和有限增长率（λ）均以溴氰菊酯LC50处理最低，氯虫腈LC30处理最高（不含对照）。年龄阶段存活率（sxj）和预期寿命（exj）也随着杀虫剂的暴露而下降，在杀虫剂浓度较高时观察到明显的种群减少。综上所述，拟除虫菊酯类杀虫剂（特别是溴氰菊酯和氯氰菊酯）通过延长桃蚜种群发育、降低繁殖力、缩短寿命等方式抑制桃蚜种群的增长。考虑到低致死效应，氯虫腈在低剂量下表现出较轻的不良反应。这些发现强调了在设计可持续和无害环境的害虫综合治理（IPM）方案时考虑种群动态的亚致死效应的重要性。
{"title":"Impact of deltamethrin, cypermethrin, and chlorantraniliprole on the life table traits and demographic parameters of Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae)","authors":"Ali Kayahan , Betül Kayahan","doi":"10.1016/j.cropro.2025.107533","DOIUrl":"10.1016/j.cropro.2025.107533","url":null,"abstract":"<div><div>This study examined the effects of three insecticides—Deltamethrin, Cypermethrin, and Chlorantraniliprole—at different doses (LC<sub>30</sub>, LC<sub>40</sub>, and LC<sub>50</sub>) on the demographic parameters of the green peach aphid <em>Myzus persicae</em> Sulzer, 1776 (Hemiptera: Aphididae). Populations of <em>M. persicae</em> reared on pepper plants (<em>Capsicum</em> sp.) were used in the experiments. The trials were conducted in a climate-controlled chamber (25 ± 1 °C, 60 ± 5 % RH, 16:8 h L:D photoperiod). Lethal concentrations of each insecticide were determined using probit analysis, and subsequent life table analyses were performed at LC<sub>30</sub>–LC<sub>50</sub> levels using the age–stage, two-sex life table approach. Data were processed with TWOSEX-MSChart and TIMING-MSChart software, and statistical differences among treatments were assessed using the bootstrap method. Results showed that increasing insecticide concentrations significantly affected development, longevity, and fecundity traits of <em>M. persicae</em>. The longest nymphal and pre-adult development periods were observed at the LC<sub>50</sub> level of Deltamethrin, while the shortest were recorded at LC<sub>30</sub> of Chlorantraniliprole. Higher doses led to significant reductions in adult longevity, total lifespan, and reproductive potential. The lowest values of net reproductive rate (<em>R</em><sub><em>0</em></sub>), intrinsic rate of increase (<em>r</em>), and the finite rate of increase (<em>λ</em>) were found in the Deltamethrin LC<sub>50</sub> treatment, while the highest (excluding control) occurred under Chlorantraniliprole LC<sub>30</sub>. Age–stage survival rate (<em>s</em><sub><em>xj</em></sub>) and life expectancy (<em>e</em><sub><em>xj</em></sub>) also decreased with insecticide exposure, with marked population reductions observed at higher concentrations. Overall, the results indicate that pyrethroid insecticides—particularly Deltamethrin and Cypermethrin—impede the population growth of <em>M. persicae</em> by prolonging development, reducing fecundity, and shortening lifespan. Considering low lethal effects, Chlorantraniliprole exhibited milder adverse effects at low doses. These findings highlight the importance of considering sublethal effects on population dynamics when designing sustainable and environmentally sound integrated pest management (IPM) programs.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107533"},"PeriodicalIF":2.5,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145893702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.cropro.2025.107534
Pedaveeti Suma , D.N. Kambrekar , P.U. Krishnaraj , Y.P. Arun , V. Naveen , P. Harikrishnan , Suresh R. Jambagi
Lepidopteran pests such as Plutella xylostella, Spodoptera litura, and Spodoptera frugiperda cause severe yield losses worldwide, and their management is increasingly constrained by resistance development and environmental concerns associated with synthetic insecticides. Actinobacteria, particularly Streptomyces spp., are prolific producers of bioactive metabolites, many of which exhibit insecticidal properties. In this study, three actinobacterial isolates—Streptomyces hyderabadiensis, S. racemochromogenes, and S. xiaminensis were characterized for their insecticidal activity against second instar larvae of the above pests under laboratory and greenhouse conditions. Bioassays demonstrated significant larval mortality, ranging from 58 %to 68 % at 48 h post-treatment to 75 %−81 % at 72–96 h, with efficacy comparable to the reference insecticide (spinosad). Molecular identification based on 16S rDNA sequencing confirmed the identity of the isolates with 98–99 % similarity to reference strains. LC-MS analysis identified diverse insecticidal metabolites, including linoleic acid, farnesyl acetate, coumaroyl tyramine, huperzine A, delsemine A, 9-octadecenamide, and organophosphate esters, which act through multiple mechanisms such as acetylcholinesterase inhibition, juvenile hormone agonism, and disruption of cuticular and respiratory functions. All the tested actinobacterial strains showed equal efficacy across all three insect pests tested. These findings highlight the potential of actinobacterial metabolites as eco-friendly alternatives for lepidopteran pest management. Further exploration of their formulation and field applicability could contribute to the development of sustainable microbial biopesticides.
{"title":"Biochemical characterization of actinobacterial metabolites and their potential application in the management of selected lepidopteran pests","authors":"Pedaveeti Suma , D.N. Kambrekar , P.U. Krishnaraj , Y.P. Arun , V. Naveen , P. Harikrishnan , Suresh R. Jambagi","doi":"10.1016/j.cropro.2025.107534","DOIUrl":"10.1016/j.cropro.2025.107534","url":null,"abstract":"<div><div>Lepidopteran pests such as <em>Plutella xylostella</em>, <em>Spodoptera litura</em>, and <em>Spodoptera frugiperda</em> cause severe yield losses worldwide, and their management is increasingly constrained by resistance development and environmental concerns associated with synthetic insecticides. Actinobacteria, particularly <em>Streptomyces</em> spp., are prolific producers of bioactive metabolites, many of which exhibit insecticidal properties. In this study, three actinobacterial isolates—<em>Streptomyces hyderabadiensis</em>, <em>S. racemochromogenes</em>, and <em>S. xiaminensis</em> were characterized for their insecticidal activity against second instar larvae of the above pests under laboratory and greenhouse conditions. Bioassays demonstrated significant larval mortality, ranging from 58 %to 68 % at 48 h post-treatment to 75 %−81 % at 72–96 h, with efficacy comparable to the reference insecticide (spinosad). Molecular identification based on 16S rDNA sequencing confirmed the identity of the isolates with 98–99 % similarity to reference strains. LC-MS analysis identified diverse insecticidal metabolites, including linoleic acid, farnesyl acetate, coumaroyl tyramine, huperzine A, delsemine A, 9-octadecenamide, and organophosphate esters, which act through multiple mechanisms such as acetylcholinesterase inhibition, juvenile hormone agonism, and disruption of cuticular and respiratory functions. All the tested actinobacterial strains showed equal efficacy across all three insect pests tested. These findings highlight the potential of actinobacterial metabolites as eco-friendly alternatives for lepidopteran pest management. Further exploration of their formulation and field applicability could contribute to the development of sustainable microbial biopesticides.</div></div>","PeriodicalId":10785,"journal":{"name":"Crop Protection","volume":"202 ","pages":"Article 107534"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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