POTENTIAL INFLUENCES OF MULTIPURPOSE TREE CHOICE IN THE DEVELOPMENT OF DISEASES OF ASSOCIATED CROPS IN AGROFORESTRY SYSTEMS: WHAT DO WE KNOW TODAY?

Abstract

This paper is an attempt to put in perspective how a multipurpose tree can influence plant disease dynamics in associated perennials and annual crops. All trends discussed are based on observations made in various parts of the world and are not exclusive to any single species. Any combination of components in agroforestry systems can have beneficial or detrimental influences on plant disease dynamics. The objective of this paper is to bring awareness of potential beneficial or detrimental interactions, mainly how agro-forestry cropping systems can create suitable conditions for what is known as collateral infection on some major components of agroforestry systems. In this respect, the most important aspects to consider when deciding on the appropriate association (tree-crop) is the host-range of any pathogen to either of the components. In some cases, what may pass as only a minor disease to the less important component of the system may be detrimental to the more income generating component. In addition, the potential of multipurpose trees as breeding support for disease vectors, insects or nematodes, should be taken into consideration.