Biological Control最新文献

{"title":"Formulation and bio-efficacy of different isolates of Beauveria bassiana against adults and third nymphal instar of desert locust (Schistocerca gregaria Forskål)","authors":"Pamela C Mwikali , Lizzy A. Mwamburi , Simon Peter Musinguzi","doi":"10.1016/j.biocontrol.2024.105642","DOIUrl":"10.1016/j.biocontrol.2024.105642","url":null,"abstract":"<div><div>Recently, the Horn of Africa witnessed a swift increase in the incidence of desert locust (<em>Schistocerca gregaria</em>) invasion. During outbreaks, pesticides are applied through aerial or ground spraying to kill the insects, and/or to prevent their spread to new grounds. However, after decades of extensive use, many drawbacks such as contamination of the environment, toxicity to non-target organisms, harmful residues on food, pest resistance, and bioaccumulation in the food chains emerged. Entomopathogenic fungi offer viable alternatives to chemical pesticides against many insect invasions, but few studies have tested their bio-efficacy in desert locusts. Therefore, the current study aimed at isolating, formulating local isolates 231, 334, 333, 341, 349, 351, 339 of <em>Beauveria bassiana</em>, and testing their bio-efficacy against larval and adult desert locusts. The 21-day experiment was conducted under controlled conditions in a greenhouse. Soil samples were collected from two agroecological zones in Isiolo and Laikipia Counties in Kenya. <em>B. bassiana</em> was isolated from the soil samples using the <em>Galleria</em> bait method and cultivated in Sabouraud Dextrose Agar Yeast (SDAY). The isolates were identified based on molecular techniques (DNA and PCR amplification). The conidia of the isolates were screened and bioassays on 30 locusts was conducted for 14 days. The best isolates eliciting over 90 % mortality during screening were used for formulations using three carrier materials (liquid paraffin, Diatomaceous Earth, and whey) which were again tested against adult and 3rd nymphal instars of the locusts. The stability of the formulations was also tested after 1 and 2 months. All the tested isolates of <em>B. bassiana</em> significantly outperformed the control and thus pathogenic to the adults and 3rd nymphal instars of <em>S. gregaria</em> under laboratory conditions. They caused mortality ranging from 57.8–100 % after 14 days post-incubation. The isolates 341, 231, and, 334 elicited 50 % mortality responses at concentrations 1.1 × 10<sup>5</sup> conidia/ml, 2.5 × 10<sup>5</sup> conidia/ml and 1.7 × 10<sup>6</sup> conidia/ml respectively in adults and 1.1 × 10<sup>5</sup> conidia/ml, 2.5 × 10<sup>5</sup> conidia/ml and, 1.7 × 10<sup>6</sup> conidia/ml respectively in 3rd nymphal instars. Formulations with 341–1, 341–2, and, 334–1 had the highest efficacy (>99 %) against the adult locusts. There was a significant 3-way interaction (<em>P</em> < 0.05) of isolate for the formulation, carrier material and, time in determining the Cfu of the <em>B. bassiana</em> formulations. After 1 month, the best Cfu occurred in formulation with isolates 231 and 341 formulated using Diatomaceous Earth, while the highest Cfu was observed in formulation with isolate 334 formulated with either liquid paraffin or whey. After 2 months, the highest Cfu occurred in formulation with isolates 231, 341, and, 334 formulated using liquid paraff","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105642"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional structure of the natural enemy community of the fall armyworm, Spodoptera frugiperda in the Americas","authors":"Kris A.G. Wyckhuys ,&nbsp;Komivi S. Akutse ,&nbsp;Divina M. Amalin ,&nbsp;Salah-Eddin Araj ,&nbsp;Gloria Barrera ,&nbsp;Marie Joy B. Beltran ,&nbsp;Ibtissem Ben Fekih ,&nbsp;Paul-André Calatayud ,&nbsp;Lizette Cicero ,&nbsp;Marcellin C. Cokola ,&nbsp;Yelitza C. Colmenarez ,&nbsp;Kenza Dessauvages ,&nbsp;Thomas Dubois ,&nbsp;Léna Durocher-Granger ,&nbsp;Carlos Espinel ,&nbsp;José L. Fernández-Triana ,&nbsp;Frederic Francis ,&nbsp;Juliana Gómez ,&nbsp;Khalid Haddi ,&nbsp;Rhett D. Harrison ,&nbsp;Maged Elkahky","doi":"10.1016/j.biocontrol.2024.105640","DOIUrl":"10.1016/j.biocontrol.2024.105640","url":null,"abstract":"<div><div>Ecosystem functions such as biological pest control are mediated by the richness and abundance of service providers i.e., biological control agents (BCAs), relative contributions of individual taxa and community structure. This is especially relevant in the native range of agricultural herbivores, where a speciose community of co-evolved BCAs can prevent them from attaining pest status. Here, we use a powerful graphical approach to assess the functional structure of BCA communities of the fall armyworm (FAW) <em>Spodoptera frugiperda</em> (Lepidoptera: Noctuidae) on maize in the Neotropics. Drawing upon a curated database of all-time field and laboratory studies, we graphed patterns in the functional contribution, abundance and niche breadth for a respective 69, 53 and 3 taxa of resident parasitoids, predators and pathogens. Regardless of varying taxon coverage and rigor of the underlying studies, functional structure follows a saturating relationship in which the first three taxa account for 90–98% of aggregate biological control function. Abundance-functionality matrices prove critically incomplete, as more than 80% of invertebrate taxa miss empirically derived efficiency metrics while associated FAW infestation data are scarce. Despite its methodological shortfalls and data gaps, our work pinpoints <em>Chelonus insularis</em>, several taxa of egg parasitoids, <em>Doru</em> spp. and <em>Orius</em> spp. as taxa with outsized (average) functionality and conservation potential. This is also exemplified by the highly variable aggregate function across studies, with dispersion indices of 1.52 and 2.14 for invertebrate BCAs. Our work underlines the critical importance of functional ecology research, networked trials and standardized methodologies in advancing conservation biological control globally.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105640"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mesoamerican milpa system: Traditional practices, sustainability, biodiversity, and pest control","authors":"Betty Benrey ,&nbsp;Carlos Bustos-Segura ,&nbsp;Patrick Grof-Tisza","doi":"10.1016/j.biocontrol.2024.105637","DOIUrl":"10.1016/j.biocontrol.2024.105637","url":null,"abstract":"<div><div>The milpa system, an ancient Mesoamerican agricultural practice of intercropping, has sustained communities for centuries, providing food security and preserving biodiversity. Despite its agricultural significance, there exists a notable gap in understanding how this system preserves arthropod biodiversity and facilitates trophic interactions within the milpa community. This review aims to explore the milpa system, examining its historical significance, cultural importance, and ecological benefits and interactions, with a particular emphasis on conservation biological control. With a primary focus on Mexico, supplemented by examples from other countries in the Mesoamerican region, we cover the region that stands as the birthplace and cradle of milpa crop domestication. The review delves into the diversity of arthropods associated with common milpa crops, their roles in ecosystem functioning, and the implications for crop productivity and resilience. It also examines the potential of integrating traditional farming practices into modern agriculture to enhance beneficial interactions and mitigate potential pest pressures. By synthesizing current knowledge on arthropod ecology in the milpa system, this review provides insights that can help to promote sustainable agricultural practices rooted in indigenous knowledge and ecological principles.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105637"},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prioritizing weeds for biological control development in the western USA: Results from the adaptation of the biological control target selection system","authors":"Rachel L. Winston ,&nbsp;Mark Schwarzländer ,&nbsp;Hariet L. Hinz ,&nbsp;Julia Rushton ,&nbsp;Paul D. Pratt","doi":"10.1016/j.biocontrol.2024.105634","DOIUrl":"10.1016/j.biocontrol.2024.105634","url":null,"abstract":"<div><div>Nonnative invasive plants (weeds) negatively impact native ecosystems, and their effects are likely to increase with continuing global trade. Biological weed control has been employed as a cost-effective and sustainable management option for weeds in the USA since 1902. Biological control programs require careful prioritization of target weeds to ensure the most appropriate targets are selected to obtain the greatest beneficial outcomes with available resources. The Biological Control Target Selection (BCTS) system was developed by researchers in South Africa as an objective, transparent approach to prioritizing new weed biological control targets. The BCTS system was recently modified and applied to 295 state-regulated weeds in the western USA for which no biological control agents have yet been released. This paper presents the results of that application, identifying the most suitable candidates for new biological control programs as well as problematic weeds for which the likelihood of successful biological control is low.</div><div>Top-ranked species in the western USA are biennial or perennial weeds that occur in stable habitats, are established in more than one state, have traits deemed difficult to control with conventional methods, have large negative impacts and no conflicts of interest outside of the horticultural industry, and have substantial information available on potential biocontrol agents. Fifteen of the 20 top-ranked species are already targets of ongoing biological control programs in the USA. When species with current programs are excluded from the analysis, the next 20 top-ranked species largely differ by having less information available on potential biological control agents and having native or economically important congeners in the USA. Results from this framework provide valuable insights to the prioritization of current and future biocontrol research programs in the western USA.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105634"},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amino acids promote the rejuvenation of degenerated Metarhizium anisopliae","authors":"Hua Yang,&nbsp;Hua-Long Qiu,&nbsp;Long-Yan Tian,&nbsp;Li-Na Xiao,&nbsp;Si-Quan Ling,&nbsp;Chang-Sheng Qin,&nbsp;Jin-Zhu Xu","doi":"10.1016/j.biocontrol.2024.105639","DOIUrl":"10.1016/j.biocontrol.2024.105639","url":null,"abstract":"<div><div><em>Metarhizium anisopliae</em>, an entomopathogenic fungus widely employed in agricultural and forestry pest control, faces challenges related to colony growth degradation and sporulation decline during industrial production and germplasm preservation. In this study, liquid chromatography-mass spectrometry (LC-MS) was used to detect the metabolomics of the normal strain and degenerated strain, enabling a comparison and analysis of their metabolic profiles. The results revealed significant differences in metabolic phenotypes among different strains of <em>M.anisopliae</em>, with amino acids playing a crucial role in spore production. Through single factor and response surface tests, optimal amino acid concentrations for sporulation media were determined as follows: lysine at 25.00 mg/L, β-alanine at 140.00 mg/L, arginine at 22.5 mg/L, glutamic acid at 155.00 mg/L. Cultivating degenerated <em>M.anisopliae</em> using this optimized amino acid medium resulted in approximately fivefold increase in sporulation without significantly affecting LT₅₀ values; thus indicating that the formulation promotes <em>M.anisopliae</em>’s sporulation without compromising its virulence.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105639"},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Infection with pathogenic fungi is a major threat to the mass production of the parasitoid wasp Habrobracon hebetor: 20 generations under surveillance","authors":"Fatima Badran ,&nbsp;Abdoolnabi Bagheri ,&nbsp;Azadeh Goudarzi ,&nbsp;Mohammadreza Attaran ,&nbsp;Aïda Jalloul ,&nbsp;Yaghoub Fathipour","doi":"10.1016/j.biocontrol.2024.105638","DOIUrl":"10.1016/j.biocontrol.2024.105638","url":null,"abstract":"<div><div>Pathogen infection is one of the most important challenges threatening the success of mass rearing of natural enemies either in insectaries or in augmentative biological control programs. In this investigation, we studied the biological and population growth parameters of a naturally infected colony of the parasitoid wasp <em>Habrobracon hebetor</em> (Say) (Hymenoptera: Braconidae) over 20 generations (G1_inf − G20_inf) of rearing on <em>Ephestia kuehniella</em> (Zeller) (Pyralidae: Lepidoptera) under laboratory conditions. Based on morphological characteristics and ITS sequences, two types of fungal colonies were isolated from the diseased females and identified as <em>Thermothielavioides terrestris</em> and <em>Aspergillus flavus</em>. The results showed that although no significant differences were found in the female longevity and fecundity of <em>H. hebetor</em> on <em>E. kuehniella</em> up to G15_inf, the duration of the immature period was extended as the number of generations increased. In addition, the intrinsic rate of increase (<em>r</em>) and finite rate of increase (λ) had no significant differences up to G8_inf. The net reproductive rate (<em>R</em>₀) of G15_inf had no significant differences with G2_inf, G8_inf, and G10_inf. On the other hand, in G15_inf, <em>R</em>₀ was significantly higher than G4_inf, G6_inf, and G20_inf. The findings underscore the negative impact of fungal infection on population growth parameters compared with uninfected population. This study showed that naturally fungal infection of the parasitoid affected the population growth and life table parameters through mass rearing, compared and discussed with the healthy parasitoid.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105638"},"PeriodicalIF":3.7,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The benefits and potential of pre-emptive weed biological control: Three case studies in Queensland, Australia","authors":"M.D. Day,&nbsp;J.T. Callander","doi":"10.1016/j.biocontrol.2024.105635","DOIUrl":"10.1016/j.biocontrol.2024.105635","url":null,"abstract":"<div><div>Invasive weed species can have significant impacts on agriculture, biodiversity and livelihoods. The cost and feasibility of managing these species using conventional means can be prohibitive depending on the size of the infestations or the habitats in which they invade. Under these conditions, biological control is seen as a viable, sustainable means to manage many weeds. However, biological control can take many years and at considerable cost to achieve the desired level of control, due to the numerous steps that are involved, including native range surveys and host-specificity testing of potential agents. Pre-emptive biological control targeting particularly high-risk species prior to their arrival in a country or emerging weeds can be cost-effective, especially if the respective biological control agents have been utilized in other countries. While pre-emptive biological control of arthropods has been investigated previously, there are few examples of pre-emptive biological control of weed species. The invasive weed species, <em>Chromolaena odorata</em>, <em>Mikania micrantha</em> and <em>Coccinia grandis</em> have all been or are currently targets of pre-emptive biological control in Australia. Research on the gall fly <em>Cecidochares connexa</em> was initiated prior to its host, <em>C. odorata</em> being detected in Australia. <em>Cecidochares connexa</em> was eventually released in Australia to control <em>C. odorata</em>, after initial research on the agent found it to be suitably host specific and effective against the target weed. <em>Cecidochares connexa</em> has also been released in numerous other countries in Africa, Asia and the Pacific, where it is providing very good control. Australia funded research on the rust <em>Puccinia spegazzinii</em> as part of a project involving Fiji and Papua New Guinea while the target weed, <em>M. micrantha</em> was a target for eradication in Queensland. The rust was later approved for release in Australia to control <em>M. micrantha</em> following additional host-specificity testing. However, research funded by Australia overseas suggests that the rust may not be able to suppress <em>M. micrantha</em> populations below current levels. Consequently, while <em>P. spegazzinii</em> has been released in numerous countries now, it has not yet been field released in Australia. Biological control research in Australia on <em>C. grandis</em> is relatively new as the weed is relatively minor and not yet declared a target for biological control. Consequently, no biological control agents have yet been released in the country. Pre-emptive biological control of <em>C. odorata</em> and <em>M. micrantha</em> has been particularly cost-effective, not just for Australia, but subsequently for numerous other countries where these weeds were well-established and problematic and the respective biological control agents were later released.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105635"},"PeriodicalIF":3.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying insect predators using camera traps reveal unexpected predator communities in oilseed rape fields","authors":"Gaëtan Seimandi-Corda ,&nbsp;Thomas Hood ,&nbsp;Matthew Hampson ,&nbsp;Todd Jenkins ,&nbsp;Daniel Blumgart ,&nbsp;Jamie Hall ,&nbsp;Kelly Jowett ,&nbsp;Toke Thomas Høye ,&nbsp;Samantha M. Cook","doi":"10.1016/j.biocontrol.2024.105636","DOIUrl":"10.1016/j.biocontrol.2024.105636","url":null,"abstract":"<div><div>Cameras are common tools for ecologists studying species abundance, richness, and interactions. They are mainly used to study large animals but are increasingly used to study invertebrates. Camera traps could be a powerful tool to identify and quantify the natural enemies, such as predators, of specific agricultural pests. This knowledge can then be applied to adapt farming practices to favour the predators identified and improve conservation biocontrol.</div><div>Here, cameras were used to identify predators of two insect pests of oilseed rape (<em>Brassica napus</em>): the pollen beetle (<em>Brassicogethes aeneus</em>) and the brassica pod midge (<em>Dasineura brassicae</em>). These insects are spring pests of oilseed rape and are both susceptible to predation by ground-dwelling arthropods during their development cycle. The objectives of this study were to 1) identify the predators of the pest species, and 2) investigate the hypothesis that the diel activity periods of the predators match the timing of pest larval presence on the ground. Field observations were conducted in two locations over two consecutive years in the UK.</div><div>In contrast to previous reports, our data collected using cameras showed that larval stages of predatory beetles are responsible for most of the predation events and that adult stages were not frequently observed feeding on the prey. Our data also showed that the traditional method, using pitfall traps, failed to detect the presence of large numbers of beetle larvae. Interestingly, the pests dropped to the ground and were therefore most susceptible to predation at the time when predators were most active.</div><div>These results give new insight on the predators of the two most important spring pests of oilseed rape in Europe. This knowledge can be used by practitioners to develop framing practices targeted on enhancing the abundance of the larval stages of these beneficial arthropods to better control the pests in a more sustainable way.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105636"},"PeriodicalIF":3.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PaLAR3 genotype variability for enhanced resistance against Heterobasidion parviporum in Norway spruce: Insights into allelic frequencies, disease response, and the role of mycoviruses","authors":"Muhammad Kashif,&nbsp;Eeva Terhonen,&nbsp;Leena Hamberg,&nbsp;Tuula Piri,&nbsp;Matti Haapanen,&nbsp;Sirkku Pöykkö,&nbsp;Eeva J. Vainio,&nbsp;Jarkko Hantula","doi":"10.1016/j.biocontrol.2024.105633","DOIUrl":"10.1016/j.biocontrol.2024.105633","url":null,"abstract":"<div><div><em>Heterobasidion parviporum</em> is a destructive forest pathogen causing root and stem rot of Norway spruce (<em>Picea abies</em>) in northern hemisphere. Previous research has suggested that a gene form of PaLAR3 that encodes for the leucoanthocyanidin reductase enzyme, may increase resistance to <em>H. parviporum</em> in Norway spruce, whether heterozygous or homozygous. Our experiment was initially focused on testing this assertion with materials from the Finnish Norway spruce breeding program, comprising 52 full-sib families. Additionally, we investigated the influence of mycoviruses on the growth of <em>H. parviporum</em>. The frequencies of the three PaLAR3 genotypes AA, AB, and BB were 64%, 30%, and 6%, respectively. We found no significant differences in the necrotic response to <em>H. parviporum</em> between the homozygous (BB) and heterozygous (AB) genotypes vs. the homozygous (AA) genotype across the two fungal strains tested, suggesting the gene is rather ineffective as a marker for overall <em>H. parviporum</em> resistance. The two <em>H. parviporum</em> strains used in the study showed significantly different necrosis responses from the control. Mycovirus infection in <em>H. parviporum</em> strains led to a significant reduction in lesion width in phloem and sapwood. Furthermore, the growth of the fungus was notably restricted when hyphae hosted mycoviruses, indicating a high potential of mycoviruses to reduce fungal growth and necrosis development.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105633"},"PeriodicalIF":3.7,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application timing affects the efficacy of Bacillus thuringiensis subsp. kurstaki against Tortrix viridana in deciduous oak forests","authors":"Roberto Mannu ,&nbsp;Maurizio Olivieri ,&nbsp;Luca Ruiu ,&nbsp;Giuseppe Serra ,&nbsp;Maria Leonarda Fadda ,&nbsp;Andrea Lentini","doi":"10.1016/j.biocontrol.2024.105631","DOIUrl":"10.1016/j.biocontrol.2024.105631","url":null,"abstract":"<div><div>The green oak leaf roller moth, <em>Tortrix viridana</em>, is one of the main defoliators of deciduous oaks in the Mediterranean region. Although aerial applications of <em>Btk</em>-based insecticides represent the most effective method to control the larval populations of this pest at a large spatial scale, the optimal time window for sprayings has not yet been defined. Accordingly, experimental trials were conducted in a <em>Quercus pubescens</em> forest district in Sardinia (Italy) involving both large-scale aerial treatments and small-scale applications from the ground. The aim of our work was to study how different larval development stages and/or sprouting phenological phases of the host trees affect <em>Btk</em> efficacy. Aerial sprayings were conducted in 2003 and 2004 in two different areas of about 300 ha, selected according to altitude and exposure to simulate three different application timings against different larval instars and sprouting phenological phases. From-the-ground applications were carried out in 2021 in a <em>Q. pubescens</em> forest stand by applying <em>Btk</em>-based insecticides at different timings, and the overall <em>Q. pubescens</em> phenological stage and the distribution of <em>T. viridana</em> larval development stages were assessed accordingly. The effectiveness of <em>Btk</em> applications was evaluated by estimating larval mortality 7, and 14 days after aerial applications, and 7, 14 and 21 days after ground applications. Defoliation due to <em>T. viridana</em> was also evaluated at the end of larval development in all years. In both 2003 and 2004, the average larval mortality due to <em>Btk</em> exceeded 80 % two weeks after aerial applications across all application timings. Damage caused by <em>T. viridana</em> varied with <em>Btk</em> application timing, with the later applications showing a higher defoliation than other timings. In ground application experiments, larval mortality significantly increased when <em>Btk</em> was sprayed against a larval population primarily composed of IV instars, which were feeding on sprouts with leaves that were spread out and had not fully developed internodes, thus resulting in a significative reduction of insect damage. Our findings indicate that, in accordance with the strict synchrony between the larval development and the oak flushing, the optimal timing for <em>Btk</em> application against <em>T. viridana</em> can be defined based on the bud burst phenological phase. In particular, the prevalence of sprout with expanding leaf surface allowing insecticidal droplet interception and the simultaneous presence of susceptible larval instars (within the IV), resulted in an increased treatment efficacy.</div></div>","PeriodicalId":8880,"journal":{"name":"Biological Control","volume":"198 ","pages":"Article 105631"},"PeriodicalIF":3.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}