Farmers' perception and control practices against the invasive red spider mite (Tetranychus evansi Baker & Pritchard) in Benin

Tetranychus evansi (Acari: Tetranychidae), is an important pest of solanaceous plants in Benin where it damages tomato (Solanum lycopersicum L.; Solanaceae), African eggplant (S. macrocarpon L.; Solanaceae), purple amaranth (Amaranthus cruentus L.; Amaranthaceae). The objective of the present study was to evaluate the intensity of T. evansi damage and impact of farmers' control practices in Benin. Two surveys were conducted between 2013 and 2016. The first survey revealed Tetranychus evansi as the only mite, causing production losses of 65% for African eggplant, 56% for tomato and 25% for purple amaranth. To protect the infested crops, growers sprayed various synthetic pesticides at high frequencies according to species cycle: 3, 6 and 12 times per month on purple amaranth, African eggplant and on tomato, respectively. Farmers reported that these compounds were largely ineffective against T. evansi. The second survey found 47 predatory mites of the family Phytoseiidae. The Amblyseiinae were the only group found in this study. An initial identification revealed Neoseiulus barkeri Hughes (Mesostigmata: Phytoseiidae) (77%), Neoseiulus sp. (19%) and Amblyseius swirskii Athias Henriot (4%).