Insect pests, such as the Sweet Potato Weevil (Cylas spp.) and various defoliators, pose a major constraint to sweet potato (Ipomoea batatas (L.) Lam.) production in Nigeria, with losses often exceeding 40%. This study investigated the efficacy of Neem Leaf Extract (NLE) as an organic biopesticide in managing insect pests of the Danchina sweet potato variety in Kano State during the 2024 rainy season. The field experiment utilized a Randomized Complete Block Design (RCBD) comparing three NLE concentrations (33.3%, 25%, and 20% weight-to-volume ratio), a Cypermethrin check, and an untreated control. NLE was prepared by soaking fresh leaves for 72 hours and was applied four times, starting at 6 Weeks After Planting (WAP) at two-week intervals. Data analysis using ANOVA showed significant reductions in the total insect pest population across all NLE treatments compared to the untreated control (F-value < 0.05). The 33.3% NLE achieved the most sustained insect control among the botanical treatments, closely approaching the suppression level of the chemical check. Phytochemical analysis confirmed the presence of alkaloids, flavonoids, and phenols. Physical analysis revealed a non-linear viscosity relationship, with the 25% NLE extract exhibiting the highest viscosity (930 cP}). This formulation's superior physical property is hypothesized to enhance adherence, contributing to its strong performance, which was often statistically comparable to the 33.3% concentration. Antimicrobial tests further confirmed the extract's dual role, exhibiting dose-dependent inhibitory activity against key bacterial (S. aureus, E. coli) and fungal (C. albicans) pathogens. In conclusion, NLE, particularly at the 33.3% concentration, is a highly effective, multifunctional, and eco-friendly alternative for sweet potato pest anagement. It is strongly recommended for integration into Integrated Pest Management (IPM) programs for smallholder farmers. However, acknowledging the single-season constraint, further trials across multiple agro-ecological zones are recommended to generalize its optimal use.

• Star anise and long pepper nanoemulsions controlled sweet potato weevil. • High adult mortality and reduced oviposition in the field applications. • No major effects on soil health or non-target arthropods. • Botanical nanoemulsions as eco-friendly insecticide alternatives. • Support IPM adoption in smallholder sweet potato farming. This study investigated the effectiveness of two nanoemulsion-based plant hexane extract formulations, S4L0 and S3L1, for managing sweet potato weevils (SPW) under field conditions. The formulations, derived from star anise and long pepper hexane extracts, were tested alongside a synthetic insecticide (imidacloprid) and an untreated control using a randomized complete block design (RCBD) on farmer plots in Sa Kaeo Province, Thailand. Key determination parameters included SPW infestation levels, crop yield, pesticide residue levels, diversity of non-target soil arthropods, and soil physicochemical properties. Field applications of S4L0 and S3L1 reduced SPW infestations to 3.6 ± 4.3 and 11.1 ± 5.0 insects per plant, respectively, significantly lower than in untreated plots (33.9 ± 11.8 insects/plant). No detectable imidacloprid residues were found in tubers treated with S4L0 or S3L1, whereas imidacloprid-treated tubers retained residues of 0.335 and 0.144 ppm at 5 and 7 days after application. Sweet potato yields ranged from 310 to 440 g/plant, with no significant differences among treatments. The untreated plots supported greater diversity and abundance of non-target soil arthropods, while the imidacloprid-treated plots showed the lowest diversity. Soil properties, including bulk density, pH, electrical conductivity, and organic matter content, remained stable across treatments. Overall, S4L0 and S3L1 demonstrated effective pest suppression and minimal environmental impact, highlighting their potential as sustainable alternatives to synthetic insecticides for integrated pest management in sweet potato production.

Cylas formicarius is a significant quarantine pest worldwide, causing year-round outbreaks in tropical and subtropical regions. This pest is characterized by a highly cryptic nature, a high reproduction rate, and broad environmental adaptability, which makes it difficult to control. Frequent use of pesticides is not cost-effective, as it brings the accompanying effects of pesticide residues and environmental pollution. With the rapid development of green agriculture, biological control has become an important component in an integrated green management system for C. formicarius. Therefore, this paper critically reviews the research progress in insect pathogenic microorganisms, plant-based pesticides, natural enemy insects, insect sex pheromones, transgenic technology, as well as the screening, identification, and breeding of insect-resistant varieties. The aim is to provide theoretical references for the research and application of sustainable management of C. formicarius.

Background: The sweetpotato weevil and sweetpotato virus disease (SPVD) are major biotic constraints that completely devastate sweetpotato fields and cause 50 – 100 % yield losses. Management includes cultural practices, tolerant varieties, chemical pesticides and integrated management strategies. Botanicals are gaining popularity in Integrated Pest and Disease Management strategies. Their insecticidal and fungicidal activities, biodegradability and safety increase their probability as alternatives to chemical pesticides. Urtica spp. are known for their insecticidal properties, but their efficacy in the management of the sweetpotato weevil and SPVD has not been documented. Objective: A field trial was conducted to assess the efficacy of Urtica spp. (Adamfo Pa) against sweetpotato pests and diseases in the forest and savannah transition agroecological zones of Ghana in 2025. Method: A Split-plot design with three replications was used. Three different rates of the extract, reference fungicide (Mancozeb WP) and biopesticide (Bypel), plus a control, were tested on Cylas sp. and SPVD susceptible sweetpotato variety. Results: No disease incidence was recorded. The test product at the application rate of 500 ml/100 L of water per week was effective in reducing pest infestation and damage on the leaves and storage roots. It was also found to be efficacious in minimising sweetpotato storage root damage and increasing yield. Conclusion: The study confirms that Urtica sp. extracts exhibit insecticidal and fungicidal properties that act as insect repellents or growth inhibitors. It is certified for use on carrots, beans, potatoes and strawberries, and recently extended to sweetpotatoes due to the outcome of this study.

Successful control in the first recapture of the sweet potato weevil Cylas formicarius (Coleoptera: Brentidae) since its eradication from Kume Island, Japan

Cylas formicarius, the sweet potato weevil (SPW), is an important invasive pest of sweet potato crops, causing great economic losses to the production of sweet potatoes worldwide. Despite extensive reviews on C. formicarius, a critical synthesis integrating modern ecological insights (notably genomic adaptation and climate-driven range expansion) into a practical, sustainable management framework remains notably absent. This review addresses this gap by introducing the sustainable green management system (SGMS) as a unifying framework for research and implementation. We first synthesize advances in C. formicarius invasion biology, chemical ecology, and molecular foundations that explain its escalating global pest status. We subsequently critique current management strategies, demonstrating that persistent over-reliance on chemical insecticides is untenable, while biological and ecological approaches remain underexploited. Central to our work is the SGMS framework, which prioritizes biological control and ecological regulation, augmented by real-time monitoring and targeted interventions, reserving chemical methods for emergencies. By transcending tactical listings toward an integrated system, this review provides a definitive roadmap for sustainable, green management of this formidable pest. © 2026 Society of Chemical Industry.

Cylas formicarius (Fabricius) is a major pest of sweet potato in Taiwan, where no microbial control agents are currently available. This study aimed to identify Beauveria bassiana strains with both high virulence and high spore productivity using a rice-based solid-state fermentation (SSF) system. Eleven field isolates were characterized using morphological traits and multilocus sequence analyses (Bloc, RPB1, RPB2, and TEF). Laboratory assays compared conidial production on 1/2 potato dextrose agar (PDA) and rice substrates and evaluated pathogenicity against adult C. formicarius by estimating median lethal time (LT50) and the onset of mortality (t0) based on cumulative mortality data. Substantial variation was observed among isolates in growth performance, sporulation, and virulence. Strain TyEf0054 consistently exhibited high pathogenicity, causing more than 80% mortality with conidia produced from both 1/2 PDA and rice, and showed rapid killing activity, with LT50 values of approximately 5.5–5.9 days and t0 values ranging from 3.55 to 3.99 days. In contrast, some strains exhibited high sporulation and virulence on 1/2 PDA but failed to produce conidia or showed severe clumping during rice-based solid-state fermentation, indicating poor suitability for large-scale production. These results demonstrate that high laboratory virulence alone is insufficient for strain selection and highlight the importance of integrating killing speed, final mortality, and SSF compatibility as joint selection criteria. Overall, TyEf0054 represents a promising locally adapted candidate for the development of commercial mycoinsecticides for sustainable management of sweet potato weevil in Taiwan.

Proper postharvest handling is a critical factor in maintaining the quality of sweet potatoes (Ipomoea batatas L). This research evaluated the effectiveness of neem leaf (Azadirachta indica A. Juss) extract concentration and packaging type in inhibiting sprouting, reducing infestation by the sweet potato weevil (Cylas formicarius), and maintaining weight loss, starch content, and total dissolved solids in Cilembu variety sweet potatoes during storage. This experiment used a Completely Randomized Design with three replications, consisting of neem extract concentrations (0, 10, 20 ml/L) and packaging types (jute sacks, polinet nets, bamboo baskets). Neem leaves contain azadirachtin compounds which can preserve the physiological quality of sweet potatoes from pest attacks. The higher the concentration, the higher the level of effectiveness in maintaining and preserving the physiological quality of sweet potatoes during storage therefore, this study tested neem leaf extract concentrations of (0, 10, 20 ml/L). Results showed that the combination of 10 ml/L and 20 ml/L neem leaf extract with poly-net packaging yielded the best overall quality. This treatment significantly reduced sweet potato weevil infestation by up to 99.4% and suppressed weight loss by up to 33.8%, while maintaining more stable starch content and total soluble solids. The 10 ml/L and 20 ml/L neem leaf extract demonstrated optimal insecticidal properties, while the poly-net packaging provided the best ventilation for releasing respiratory heat and controlling moisture accumulation compared to jute sacks and bamboo baskets. In conclusion, the combination of 10 ml/L and 20 ml/L neem leaf extract with poly-net packaging is effective in maintaining the quality of Cilembu variety sweet potatoes during storage.

Sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), is one of the most devastating pests of sweetpotatoes in tropical and subtropical regions. Furanoterpenoids are produced when sweetpotato weevils feed on storage roots, making them potentially unmarketable and toxic to livestock and humans. However, accumulation of these furanoterpenoids in uninfested parts of weevil-infested storage roots is poorly characterized. Here we identified ipomeamarone and its precursor, dehydroipomeamarone, in weevil-infested sweetpotato storage roots and confirmed the identities of the compounds by LC-MS, LC-MS/MS, and NMR analysis. Ipomeamarone induction was systemic in the roots, with elevated levels detected in healthy parts of the roots 2-5 cm away from the site of infestation. A clear relationship between the presence of furanoterpenoids in the storage root and the behavior of C. formicarius elegantulus was found. When adults were presented with root slices taken at several distances from the point of infestation, the number of eggs laid increased progressively with distance from the point of infestation, peaking at 7 cm from the site of infestation. Both egg-laying and adult feeding were reduced on isolated root slices treated with pure ipomeamarone, underscoring the potential role of this compound as a deterrent against C. formicarius elegantulus. This study contributes to our understanding of host plant selection and could inform integrated pest management strategies against the sweetpotato weevil.

The sweet potato weevil, Cylas formicarius（Fabricius）（Coleoptera: Brentidae）, was detected in October 2022 in Hamamatsu City, Shizuoka Prefecture, Japan, with eradication completed in November 2024 through emergency pest control under the Japanese Plant Protection Act. To determine its origin, we analyzed genetic variation in the mitochondrial cytochrome c oxidase subunit I（mtCOI）gene of 2,024 individuals from 20 countries, including Japan. In total, 158 mtCOI haplotypes were identified worldwide, with 94 detected in 1,729 individuals from 47 geographical populations in Japan. A maximum likelihood phylogenetic tree revealed 11 clades（Clades A–K）, with Japanese haplotypes distributed among three clades: Clades A（Nansei Islands and Taiwan）, C（Ogasawara Islands, China, Hong Kong, Fiji, and Australia）, and J（Minamitorishima Island and the Philippines）. All 24 individuals collected from 10 sites in Hamamatsu City shared the same haplotype within Clade C. These results suggest that the invasive population of C. formicarius, which occurred in Hamamatsu City, originated from a single source, possibly the Ogasawara Islands or another country.

The sweetpotato weevil, Cylas formicarius (Fabricius, 1798) (Coleoptera: Brentidae), is a serious pest of sweet potatoes, damaging crops in the field and duringstorage. Its cryptic nature limits chemical control. Entomopathogenic fungi (EPF) like Metarhizium anisopliae sensu lato (s.l.) (Metschnikoff) Sorokin, 1883 (Ascomycota: Hypocreales) offer eco-friendly alternatives. This study aimed to isolate and characterize a native M. anisopliae s.l. strain from infected C. formicarius using morphological and molecular methods and to evaluate its biocontrol potential against the weevil under in vitro conditions. Morphological characteristics and molecular analyses were used to confirm the identity of the isolate. Virulence was tested at three spore concentrations and compared with the commercial M. anisopliae s.l. strain ARSEF5369. Scanning electron microscopy (SEM) was employed to visualize the infection process. Enzyme activities (chitinase, protease) were quantified to compare virulence between strains. The effects of culture media and temperature on fungal growth and sporulation were investigated to optimize mass production conditions. The native isolate caused higher adult mortality (96.7, 93.3, and 50%) than the commercial strain at 1.2 × 108, 5.5 × 107, and 6.2 × 106 conidia/mL after 7days. The median lethal concentrations 30 (LC30) and LC50 of M. anisopliae s.l. strain Pm04 against C. formicarius were 2.15 × 107 and 3.7 × 107 conidia/mL, respectively, while at 1.2 × 108 conidia/mL, the lethal times 30 (LT30) and LT50 were 2.33 and 2.4days. Fungal infection stages were evident under SEM,and native strain exhibited elevated enzymatic activities relative to the commercial strain. Optimal growth and spore yield occurred at 25 ± 1°C on sabouraud dextrose agar (SDA)medium. These results highlight the potential of the native M. anisopliae s.l. strain as a promising biocontrol agent against C. formicarius, warranting further evaluation under field conditions.

In Indonesia, the yield losses of local sweet potato variety due to sweet potato weevil (SPW) caused by the Cylas formicarius insect could reach 100%. The most useful C. formicarius control technology is to use the resistant varieties. This study aims to evaluate the level of resistance of six sweet potato clones to SPW. The field test was conducted in dry season (May - October 2024) in two locations in Lumajang Regency, East Java Province namely Karanganom Village, Pasrujambe District, and Sarikemuning Village, Senduro District. Randomized Block Design with four was used replications. Each sweet potato genotype was planted on a plot of 5 m x 5 m, plant distance of 100 cm x 25 cm (1 steck per hole). The clones were tested in the field and in the laboratory. Observation of tuber borer pest attacks on tested clones Laboratory resistant aims to prove and ensure the tolerance level of candidate sweet potato varieties to tuber borer pests. The sweet potato harvest from the field is then cleaned from the soil using water, then healthy tubers (free from C. formicarius) with uniform sizes are selected. Furthermore, the tubers are put into plastic mylar with a height of 20 cm and a diameter of 8 cm. The resistance test method used were choice and without (no)-choice. Results of the trials showed that sweet potato Gatotkoco has a level of resistance to sweet potato weevil equivalent to the check variety Sari which is classified as a resistant, while Bima Pasru has a level of resistance equivalent to the check variety Beta 2 which is classified as an intermediate resistant. These two local varieties of Lumajang (Gatotkoco and Bima Pasru) could be developed to overcome the problem of sweet potato weevil in the field.

IntroductionSweetpotato (Ipomoea batatas [L.] Lam.) is a critical global food crop that suffers devastating yield losses from the sweetpotato weevil (Cylas formicarius), especially in tropical regions where chemical control is often impractical. Breeding for stable resistance has been hindered by an insufficient characterization of reliable phenotypic markers across diverse genetic backgrounds.MethodsWe evaluated 731 accessions from Cuba’s national sweetpotato collection, enriched with global varieties, to identify morphological traits associated with natural resistance to C. formicarius. Resistance and susceptibility were assessed through combined field and laboratory bioassays.ResultsOnly 6.5% of the accessions demonstrated resistance (<10% infestation), while 80% were highly susceptible. Weak to moderate correlations linked resistance to smoother root surfaces (r = 0.31) and lighter flesh pigmentation (r = -0.38). The strongest correlation was observed with deeper tuberization (r = -0.72). Six Cuban genotypes combined agronomic viability (yield >10 t ha⁻¹) with resistance. Five of these employed deep tuberization as a physical escape mechanism, while one genotype, INIVIT B-25, exhibited shallow tuberization (mean depth 4.53 cm) yet maintained resistance, suggesting a biochemical defense strategy. Under controlled infestation, INIVIT B-2022 demonstrated the strongest antibiosis effect, suppressing adult emergence to just two individuals.DiscussionOur study decodes key phenotypic signatures of weevil resistance, providing immediately actionable morphological traits for use in Caribbean breeding programs. The discovery of a resistant genotype with shallow roots indicates the presence of a non-escape, potentially biochemical resistance mechanism. This highlights the critical need for subsequent molecular studies to uncover the complementary genetic and biochemical bases of these defenses.

In Africa, sweet potato is a key crop for food security and nutrition, especially for poor and vulnerable populations. However, its production faces several challenges that limit its development. This study aimed to contribute to improving production and conservation practices of this tuber. A survey was conducted in 35 villages across 15 communes with 335 producers in the southern and central zones of Benin. Informations’ collected were on production management, constraints, control methods, storage, conservation, and marketing strategies. Data were gathered with KoboCollect, processed in Excel 2016, and analyzed with R4.5.0. Results show that sweet potato production is overwhelmingly male-dominated (97.17%), with producers averaging 45 years of age and 16.8 years of experience. Most belong to the Fon, Nagot, and Adja ethnic groups, while 56.5% are illiterate. Agriculture is the main activity (87.83%), and land is accessed primarily through rental (44.35%) or inheritance (32.17%). Production is largely market-oriented (94.78%), sold wholesale and measured by basin. Major constraints include post-harvest storage, scarcity of cuttings, and pests such as Cylas formicarius, Bedellia somnulentella, and Agrius cingulata. Tubers are mainly stored in the field (94.82%), while planting material is self-produced (88.70%) through cuttings or natural regrowth. The absence of professional organizations limits producers’ access to credit and structured markets. These findings highlight both the importance of sweet potato in local livelihoods and the urgent need for improved conservation methods, pest control, and organizational structures to support sustainable production.

An indigenous Metarhizium sp. strain amended in compost enhances sweetpotato growing system and management of Cylas formicarius (Coleoptera: Curculionidae)

Evaluation of insecticides against the sweetpotato weevil, Cylas spp. (Insecta; Coleoptera) in Ethiopia

Ubi jalar (Ipomoea batatas) merupakan salah satu komoditas pangan penting di Indonesia, namun rentan mengalami penurunan produktivitas akibat serangan hama penggerek umbi Cylas formicarius. Selama ini, pengendalian hama lebih banyak dilakukan dengan insektisida kimiawi yang berdampak negatif terhadap lingkungan, kesehatan manusia, dan musuh alami. Oleh karena itu, diperlukan alternatif pengendalian yang ramah lingkungan dan berkelanjutan. Artikel ini bertujuan untuk mengkaji potensi dan efektivitas cendawan entomopatogen Beauveria bassiana sebagai agen hayati dalam mengendalikan hama C. formicarius pada tanaman ubi jalar. Penulisan dilakukan melalui metode studi literatur dengan menelaah berbagai sumber ilmiah yang relevan, termasuk jurnal, prosiding, dan laporan penelitian. Hasil kajian menunjukkan bahwa B. bassiana mampu menginfeksi serangga target melalui proses penetrasi dan produksi toksin yang mematikan, serta efektif diterapkan di lapangan dengan menyemprotkan suspensi cendawan pada batang, pangkal daun, dan area sekitar akar. Keunggulan lainnya adalah kisaran inang yang luas, aman terhadap lingkungan, dan tidak mengganggu predator alami. Namun, efektivitas aplikasi dipengaruhi oleh kondisi lingkungan, frekuensi aplikasi, serta konsentrasi konidia. Dengan pengelolaan yang tepat, B. bassiana berpotensi besar menjadi bagian dari strategi pengendalian hama terpadu dalam budidaya ubi jalar yang berkelanjutan.

This study analyzed the genetic progress of sweet potato (Ipomoea batatas) breeding in Cuba over the past 50 years by field trials comparing traditional and improved varieties. Improved varieties significantly outperformed traditional ones in tuberous root yield, with an accumulated genetic gain of 0.20-0.37 t ha-1 per year, translating to a 256% yield increase. Improved genotypes also exhibited enhanced pest tolerance: lower weevil (Cylas formicarius) infestation and reduced nematode (Meloidogyne incognita) reproduction rates. For viral diseases, 60% of improved varieties showed incidence rates below 10%, compared with 90% of traditional varieties exceeding this threshold. Under drought conditions, improved varieties showed tolerance, with Stress Susceptibility Indices (SSIs) of less than 0.8, while the traditional varieties were more susceptible (SSI > 1). Phenotypic stability analysis via GGE biplot confirmed the superior yield and adaptability of improved varieties across environments. These advances underscore the critical role of sweet potatoes breeding in Cuba, with improvements in yield, quality and resistance to biotic and abiotic stress, contributing to strengthening climate resilience and food security.

This study aims to evaluate the potential of the entomopathogenic fungus Metarhizium anisopliae as a biological control agent against sweet potato weevil. Sweet potato weevil (Cylas formicarius) is a major pest of sweet potato crops, causing severe economic losses due to its ability to infest both storage roots and vines. Concerns regarding the ecological health risks posed by chemical insecticides in sweet potato farming, a natural approach were tested as an alternative method for controlling this pest. This study evaluates the potential of the entomopathogenic fungus Metarhizium anisopliae as a biological control agent against sweet potato weevil. Laboratory experiments were conducted to compare the effectiveness of different strains of M. anisopliae and other entomopathogens, using two application techniques: "dipping" and "ingestion." Results demonstrated that M. anisopliae significantly increased Sweet potato weevil (SPW) mortality, with the "ingestion" method rather than "dipping" method across all treatments. Among the tested strains, M. anisopliae (MR) showed the highest mortality rate (62.47%) when applied through ingestion. The findings highlight that both the choice of fungal strain and application technique are critical for optimizing pest control outcomes. The study also underscores the advantages of M. anisopliae as an eco-friendly alternative to chemical pesticides, with potential to reduce environmental impact while maintaining effective pest management. Furthermore, the results emphasize the importance of integrating biological control agents with precise application methods to enhance pest control efficacy. This research contributes to sustainable agriculture by promoting the use of entomopathogenic fungi as part of integrated pest management strategies. Further research is suggested to assess the field-level use of M. anisopliae under varying environmental conditions, aiming to establish its effectiveness in large-scale sweet potato cultivation in order to reduce reliance on chemical pesticides. However, field studies are needed to reach a good conclusions and practical applications.

Sweet potato farmers in Nigeria faced the challenge of heightened infestation of the roots by C. puncticollis particularly in the dry season. During this season, soil cracks facilitate the weevil entry, which tunnels into the roots and decreases its quality and market value. Mulch contributes to pest suppression in crops by producing volatile compounds, making pest accessibility challenging. In this study, the potentials of four organic mulches were explored in the management of C. puncticollis. The experimental design was completely randomized with two blocks (covered and uncovered) each comprising four categories and a control. Manures (poultry and cow dung), wooden materials (sawdust and wood chips), plant materials, (Ocimum gratissimum and Lantana camara), and plant wastes (oil palm bunch refuse and oil palm fiber) were screened in a multi-choice mesocosms against C. puncticollis. In the uncovered experiment, the potato roots were left exposed to simulate cracked field soil. For the covered experiment, the roots were covered with 2 cm of soil, mimicking field conditions where soil remains over developing storage roots. Results showed that for the covered-manure mulch, feeding punctures counted on poultry manure (1.5) and cow dung (2.0) treated roots were significantly lower than the control (3.8). For the uncovered-manure mulch, a significantly lower number of feeding punctures (7.1 and 7.7) were observed on poultry manure and cow dung-treated roots compared to the control (11.5). Overall, lower numbers of feeding punctures and weevils were observed in the mulch-treated roots compared with the control. It is recommended that mulching with organic materials can be an effective strategy in the integrated management of sweet potato weevil, particularly during dry periods when soil cracking can facilitate pest access to the storage roots.