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The tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an invasive pest that produces significant damage to tomato crops in Senegal. Biological control is one of the options for its control and a large number of natural enemies have been reported in association with the pest. A five-year field survey was conducted in the main tomato-producing area in Senegal (Niayes) to evaluate the parasitoid complex of T. absoluta in tomato crops. Seven parasitoid species were obtained including Apanteles litae, Chelonus sp., Cotesia vestalis and Meteorus laphygmarum belonging to Braconidae family; Diadegma insulare, Pristomerus pallidus (Ichneumonidae) and Elasmus sp. (Eulophidae). The parasitoid Chelonus sp. was largely the most dominant (60.67%). Larval parasitism was very low (1.05%) but greater during the last years of the study (2016 to 2019). Results showed that parasitism was not affected by time of season. However, diversity of parasitoids was variable across year (p < 0.001). This study is a first step toward development of research and extension programs for conservation of natural enemies of T. absoluta in Senegal. [ABSTRACT FROM AUTHOR]

Seed system network analysis can reveal exchange connections between stakeholders and test scenarios such as those of seed systems shocks. We investigated the seed exchange network structure, disease surveillance risk, and gender contribution in Burundi, under two banana disease risk scenarios. Two sites where banana bunchy top disease (BBTD) is endemic in Cibitoke Province were compared with a site free of the disease in Gitega Province. All sites had formal seed interventions using community nurseries. A quantitative survey on seed sharing was done followed by a qualitative evaluation through focus group discussions. Banana seed sourcing options were fewer in the disease-free site, which also had higher cultivar diversity. Most farmers sourced seed informally within a three-kilometer radius. Seed sharing within and between villages was based on social and family linkages, especially for women. The interaction between the formal system and informal seed exchange was more active where new cultivars, or better seed quality was expected. The BBTD endemic region had lower seed quality assessment stringency. Farmers used both direct mother plant assessment and seed source reputation in seed evaluation. The formal banana seed systems are sources of new varieties, and trusted for clean seed but the informal system was still used as a main source of seed, especially local cultivars. Assessing disease surveillance scenarios shows women in a weaker position for healthy seed acquisition. Identifying the roles of individuals in seed systems can support decision processes for seed interventions in vegetatively propagated crops. [ABSTRACT FROM AUTHOR]

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a devastating invasive pest of tomato crops in several areas around the world including Africa. Here, we comprehensively review and discuss the relevant scientific knowledge on its occurrence, biological and ecological aspects, fortuitous insect natural enemies, and potential advantages and constraints of pest management scenarios adopted against this pest in tomato crops in both Northern and Sub-Saharan Africa. We conclude the manuscript with a comprehensive research agenda providing future priorities towards sustainable control of this important tomato pest. [ABSTRACT FROM AUTHOR]

Abstract: Insect pest populations exhibit seasonal dynamics in response to changes in resource availability or other environmental factors such as climatic conditions, natural enemies, and intra‐ or interspecific competition. Understanding such dynamics is critical for developing effective integrated pest management strategies. The objective of the present study was to identify factors driving the seasonal decline of the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in the shifting landscape of a vegetable‐growing area in Senegal. A set of 42 tomato fields was monitored for the number of T. absoluta adults caught in pheromone traps and for the incidence of larvae, during 5 months from June to November 2016 in the Niayes area (Senegal). The surface of solanaceous host crops, climatic conditions, and abundance of natural enemies were also monitored. A drastic decline in T. absoluta abundance was observed during the rainy season. The decrease in resource availability, especially tomato crops, in the surrounding landscape of monitored fields was the main factor affecting the population dynamics during the rainy season. However, alternative host crops such as eggplant and Ethiopian eggplant, can provide ‘reservoirs’ for residual populations of the pest. For applied purpose, it would be interesting to focus the management efforts on residual populations during the rainy season, to make more difficult the reconstitution of populations during the dry season. [ABSTRACT FROM AUTHOR]

The invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae) has become a real threat for the continued production of tomatoes across Sub-Saharan Africa since its first detection in Senegal. However, little is known of its geographical expansion, seasonal population dynamics, and damage to crops. A trapping network was deployed in 2014 and 2015 in Senegal to monitor the dynamics of T. absoluta populations at a regional and nationwide scale. A field network was also implemented in the most infested area to get information on the pest incidence during the 2013-2014 cropping season. In 2014, pheromone traps did not detect the presence of T. absoluta moths in remote areas of Eastern Senegal. In 2015, moths were detected in all the fifteen monitored areas deployed throughout the country. Abundance of trapped moths was greatest in 'Niayes', the main tomato-producing area. Unexpectedly, T. absoluta moths were trapped in some areas with few or no tomato crops, including off-season in the 'Vallée du fleuve', hot drylands ('Matam' and 'Kidira') and urban environments ('Dakar'). This suggests high mobility of moth populations and capacity to survive in harsh environments and to persist on alternative host plants. Field monitoring in the main tomato-producing area showed a very low incidence of T. absoluta over the early dry season (0-2% mined leaves), followed by severe outbreaks during the late dry season (up to 60% mined leaves). Results on the invasive pest occurrence will be helpful to decision-makers with a view to develop alternative strategies such as biological control by indigenous natural enemies or collective management strategies based on the temporal or spatial exclusion of host crops. [ABSTRACT FROM AUTHOR]

Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in augmentative biological control of various insect pests in greenhouse tomato production in Europe, including the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). However, its biocontrol efficacy often relies on the presence of alternative prey. The present study aimed at evaluating the effect of various prey foods (Ephestia kuehniella eggs, Bemisia tabaci nymphs, Tuta absoluta eggs and Macrosiphum euphorbiae nymphs) on some life history traits of M. pygmaeus. Both nymphal development and adult fertility of M. pygmaeus were significantly affected by prey food type, but not survival. Duration of nymphal stage was higher when M. pygmaeus fed on T. absoluta eggs compared to the other prey. Mean fertility of M. pygmaeus females was greatest when fed with B. tabaci nymphs, and was greater when offered M. euphorbiae aphids and E. kuehniella eggs than when offered T. absoluta eggs. Given the low quality of T. absoluta eggs, the efficacy of M. pygmaeus to control T. absoluta may be limited in the absence of other food sources. Experiments for assessing effectiveness of generalist predators should involve the possible impact of prey preference as well as a possible prey switching. [ABSTRACT FROM AUTHOR]