Integrated Pest Management in Tropical Agroforestry

Abstract

Agroforestry systems most often harbor more pests than monocrop systems. Parasitism is increased by management practices that increase light availability in agroforestry systems, together with connectivity between these agroforestry systems and the forest. In cocoa farms, the trees used to provide shade also host the fungus Phytophthora megakarya, which causes brown rot in cocoa plants. In Malawi, some insects such as Brachyplatys testudonigro, Mesoplatys ochroptera, Exosoma sp. and Ootheca sp. feed on the sap of Sesbania sesban, and are associated with other agroforestry species. Four types of caterpillar that defoliate Ricinodendron heudelotii were identified in the Democratic Republic of Congo, namely Lobobunaea phaedusa, Imbrasia petiveri, Imbrasia epimethea, Imbrasia obscura and probably Imbrasia melanops. Parasitism in agroforestry systems is also due to the integration of germplasms from species with high nutritional and commercial value in local agroforests, and that germsplasms’ integration can be problematic if the genetic base of the species being domesticated is reduced. The integration of trees in agricultural landscapes can also contribute to pest control. Trees can serve as a barrier to insect movement, thereby reducing crop infestation. Integrated pest management in agroforestry can be achieved by: (i) the identification and use of host plants that are resistant to pests and pathogens, (ii) crop rotation between host plants and plants that do not harbor pests, (iii) the biological control of pest abundance, and (iv) the use of farming practices that do not increase light intensity in agroforestry systems.