Efficacy of insect nets for cabbage production and pest management depending on the net removal frequency and microclimate

Abstract

In Africa, synthetic pesticide applications are overly frequent and above labelled rates. We assessed the efficacy of an insect net physical control system on field cabbage (Brassica oleracea var. capitata) production in France and Benin. Various mesh sizes and netting removal frequencies were compared under contrasting climatic conditions. Studies under Mediterranean climatic conditions (spring season) compared two mesh sizes (0.73 mm and 1.6 mm). Studies under subequatorial climatic conditions (cool and hot seasons) tested nets of mesh size 0.4 mm and 0.9 mm used either as permanent cover, removed daily, or 3 days per week. The results showed that a fine mesh did not improve the netting efficacy against pests but had a major impact on the microclimate. In Mediterranean climatic conditions, the netting efficacy and beneficial microclimate improved crop yields. In subequatorial conditions, crop yields were lowest with permanent net protection due to high temperatures under the nets and poor aphid and Spodoptera littoralis control. Removing the nets 3 days per week was a good technical/economic trade-off, ensuring acceptable efficacy with minimal effects on the microclimate. (Résumé d'auteur

Pesticide use practices among smallholder vegetable farmers in Ethiopian Central Rift Valley

“…Like in many African countries, also in Ethiopia, different studies conducted on knowledge, attitude and perception (KAP) among smallholders (Mekonnen and Agonafir 2002;Amera and Abate 2008;Mengistie et al 2014;Damte and Tabor 2015) have shown that farmers have low knowledge, attitude and perception on pesticides use. Other interesting studies done in sub-Saharan Africa (Gogo et al 2014;Faustin et al 2015;Simon et al 2014) can be seen as an attempt to combine some elements of the system of provision into an integrated strategy, emphasizing the need to provide low or nontoxic insecticides (i.e. spinosad, indoxacarb, metarhizium) and netting technology (eco-friendly nets).…”

Consumers’ Willingness to Pay for Cabbage with Minimized Pesticide Residues in Southern Benin

“…In tropical Benin both fine mesh nets (0.4 mm) and larger mesh (0.9 mm) are used to protect cabbage from major lepidopteran pests (Plutella xylostella, Hellula undalis, Helicoverpa armigera and Spodoptera littoralis) and aphids (Lipaphis erysimi). EFNs are usually removed during daylight hours, when pests specializing in cabbage are inactive, to enable regulation of aphids populations by their natural enemies (predators and parasitoids) and to prevent overheating and excessive shade [11,52,53,55,56]. While nets should be removed every day, most farmers remove them just three times a week to minimize labor costs [56].…”

Farmers' control practices against the invasive red spider mite, Tetranychus evansi Baker & Pritchard in Benin

“…Pahou is located in the district of Ouidah, one of Benin city. Southern Benin is subject to a bimodal climate pattern with two rainy and two dry seasons, with maximum temperatures ranging between 30 and 39 C, and minimum around 23 C (Simon et al, 2014). The monthly relative humidity ranges from a minimum of 44e76% to a maximum of 99%.…”