The tomato leaf miner Phthorimaea (syn. Tuta) absoluta Meyrick (Lepidoptera: Gelechiidae) is invasive in many agricultural regions. Its larvae feed inside leaf mines or tomato fruits and are difficult to reach with plant protection products. In contrast, entomopathogenic nematodes (EPNs) are highly virulent and can search for larvae. The challenge is to formulate EPNs to remain protected on a sprayed leaf surface until they enter the mines. We tested 11 formulations, including 2 oils, 4 gels or thickeners, 2 surfactants, 2 UV protectants, water, and combinations with and without the EPN Steinernema carpocapsae (Weiser) RW14-G-R3a-2 (Rhabditida: Steinernematidae), under non-closed low-humidity conditions. Six tomato leaf experiments with 1000 EPNs sprayed per leaf showed that EPNs in 0.25 to 0.5% canola oil or in 5% alkyl polyglycoside surfactant were the most effective (26 to 37%). Other formulations and an insecticide had less or no effect. Seven other bioassays showed that most formulations did not adversely affect EPN survival or pathogenicity. We assume that formulations of EPNs can be further improved, such as with other flowable gels or combinations, and encourage investment in the development of practical and economic protective sprayable formulations of EPNs against leaf miners to reduce reliance on chemical insecticides.

Sarocladium and Fusarium species are commonly identified as causal agents of rice sheath rot disease worldwide. However, limited knowledge exists about their genetic, pathogenic, and toxigenic diversity in sub-Saharan African (SSA) countries, where an increasing incidence of this disease has been observed. This study aimed at identifying, characterizing, as well as assessing the genetic, pathogenic, and toxigenic diversity of the pathogens associated with rice sheath rot disease in Mali, Nigeria, and Rwanda. In this study seventy fungal isolates were obtained from rice plants displaying disease symptoms on research and farmer’s fields in Mali, Nigeria, and Rwanda. Thus, an extensive comparative analysis was conducted to assess their genetic, pathogenic, and toxigenic diversity. The Fusarium spp. were characterized using the translation elongation factor (EF-1α) region, while a concatenation of Internal Transcribed Spacer (ITS) and Actin-encoding regions were used to resolve Sarocladium species. Phylogenetic analysis revealed four Fusarium species complexes. The dominant complex in Nigeria was the Fusarium incarnatum-equiseti species complex (FIESC), comprising F. hainanense, F. sulawesiense, F. pernambucatum, and F. tanahbumbuense, while F. incarnatum was found in Rwanda. The Fusarium fujikuroi species complex (FFSC) was predominant in Rwanda and Mali, with species such as F. andiyazi, F. madaense, and F. casha in Rwanda, and F. annulatum and F. nygamai in Mali. F. marum was found in Nigeria. Furthermore, Fusarium oxysporum species complex (FOSC) members, F. callistephi and F. triseptatum, were found in Rwanda and Mali, respectively. Two isolates of F. acasiae-mearnsii, belonging to the Fusarium sambucinum species complex (FSAMSC) were obtained in Rwanda. Isolates of Sarocladium which were previously classified in three phylogenetic groups were resolved into three species which are: attenuatum, oryzae and sparsum. S. attenuatum was dominant in Rwanda, while S. oryzae and S. sparsum were found in Nigeria. Also, the susceptibility of FARO44, a rice cultivar released by Africa Rice Centre (AfricaRice) was tested against isolates from the four Fusarium species complexes and the three Sarocladium species. All isolates evaluated could induce typical sheath rot symptoms albeit with varying disease development levels. In addition, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine variation in the in vitro mycotoxins of the Fusarium species. Regional differences were observed in the in vitro mycotoxins profiling. Out of the forty-six isolates tested, nineteen were able to produce one to four mycotoxins. Notably, very high zearalenone (ZEN) production was specific to the two F. hainanense isolates from Ibadan-Nigeria, while Fusarium nygamai isolates from Mali produced high amounts of fumonisins. To the best of our knowledge, it seems this study is the first to elucidate genetic, pathogenic, and toxigenic diversity of Fusarium species associated with the rice sheath rot disease complex in selected countries in SSA.

Introduction: Potato ( Solanum tuberosum L. ) production in Rwanda is limited by pests and diseases, resulting in significant yield losses and increased use of synthetic pesticides. Despite growing interest in sustainable agriculture, few studies provide empirical evidence on farmers’ knowledge of agroecological pest management practices and precision agriculture in Rwanda. This study assessed farmers’ management practices, awareness and perceptions of agroecological practices and precision agriculture technologies, as well as factors that may influence the willingness to adopt precision agriculture tools in smallholder potato systems. Methods: A farm household survey using a semi-structured questionnaire was conducted among 223 potato farmers in three districts of Rwanda (i.e., Rubavu, Gicumbi, and Nyamagabe) in July 2025. Descriptive statistics, Chi square tests, and Fisher’s exact tests were used to analyze farmers’ practices and perceptions. A Firth-penalized logistic regression model, constructed based on a purposeful selection of covariates strategy, was used to identify factors associated with farmers’ willingness to adopt precision agriculture technologies. Results: Findings revealed that pests and diseases were the main production constraints, with bacterial wilt, viruses, late blight, and whiteflies being the most frequently cited. Farmers primarily used synthetic pesticides to manage aerial pests and foliar diseases, while preventive agronomic practices were used to manage soil-borne pests and diseases. The use of biopesticides remained extremely limited and farmers were aware of the negative impacts of pesticide misuse and expressed a strong willingness to adopt better pest management practices. Knowledge of precision agriculture technologies was mainly limited (79%). Farmers associated precision agriculture primarily with mechanization, whereas awareness of drones, sensors and digital decision-support tools was limited. They demonstrated highly positive perceptions toward precision agriculture (90%) and a strong willingness to learn more (87%). The results of the logistic regression showed that mobile phone usage (OR = 20.58, p < 0.01) and the willingness to adopt agroecological practices (OR = 67.73, p < 0.001) were associated with a higher likelihood of expressing willingness to adopt precision agriculture technologies. Discussion: These results highlight the opportunity to integrate precision agroecology approaches in Rwanda. Mobile-based advisory systems and low-cost digital technologies could serve as effective entry points for promoting sustainable potato production systems among smallholder farmers.