Smallholder farmers indigenous knowledge of maize storage pests and pesticidal plant use: The case of Wards 9 and 10 in Bikita District, Masvingo Province, Zimbabwe

Abstract

Farmers' indigenous knowledge of storage insect pests and management practices in stored grain protection against insect pests are critical for sustainable food security in the smallholder sector in Zimbabwe. A survey was conducted among 48 and 51 maize farmers in wards 9 and 10 Bikita district respectively, to evaluate their knowledge, attitudes and traditional maize storage management practices against storage insect pests. The selected farmers grew maize and a variety of vegetables for subsistence. Problem storage pests listed in order of prevalence were maize weevil (Sitophilus zeamais) 49%, lesser grain borer (Rhizopertha dominica) and maize weevil (Sitophilus zeamais) complex 25.5%, lesser grain borer (Rhizopertha dominica) 17.7% and larger grain borer (Prostephanus truncatus) 7.3%. The commonly used botanical pesticides in the two wards were gumtree (Eucalyptus spp) (24.6%), tamboti (Spirostachys africana) (7.2%), lilac tree (Melia azedarach) (4.1%), sunflower (Helianthus annuus) ash (5.1%), cow dung (3.1%), lemon bush (Lippia javanica) (2%), murwiti (Rapanea melanophloeos) (1%), sweet basil (Ocimum basilicum) (1%) and finger millet (Eleucine coracana) chuff (1%),wood ash (4.1%) and mixtures of the above mentioned botanicals (4.5%). The botanicals are mixed with maize grain before storage either in sealed hessian bags or as loose grain placed in the granary plastered with cow dung. The use of botanicals was more prevalent in Ward 10 (100%) than ward 9 (14.7%). Farmers resort to the use of cheap and locally available botanicals when there is no money to buy synthetic insecticides. There is an urgent need for laboratory evaluation of the efficacy, chemical composition and mode of action in order to come up with dosage guidelines of these ethnobotanicals for the resource poor smallholder farmers.