Shifting from Seedling Mandarin Trees to Grafted Trees and Controlling Huanglongbing and Viroids: a Biotechnological Revolution in Nepal

Abstract

Poverty in Nepal, largely a rural phenomenon, is widespread, with 30.8% of the population living below the poverty line. Agriculture is the main source of livelihood of the Nepalese people who are living below poverty. Citrus, the first cash crop, is grown in small to very small orchards producing less than 10 tons/ha. More than 90% of the trees are seedlings of a local mandarin and therefore they are essentially free of most graft-transmissible diseases. Huanglongbing (HLB) and the Asian psyllid vector, Diaphorina citri, were reported in Nepal in the mid-1960s and, in the absence of any control measures, have continued to spread ever since. Here we report the information available regarding the presence of HLB in several important citrus-growing areas (Armalakur, Bandipur, Dhankuta/Karmitar, Kathmandu, Lamjung, Paripatle, Pokhara, Sindulimadi and Syangja) and the identification of four citrus viroids (Citrus exocortis viroid, Hop stunt viroid, Citrus viroid-III, and Citrus viroid-V) in the experimental citrus station of Pokhara. Citrus rehabilitation, as part of a program to improve food security for the Nepalese population, was started in 2004, and is based on (I) producing disease-free citrus trees, grafted on adequate rootstocks, in covered, insect-proof nursery facilities, (II) demonstration orchards with grafted trees, (III) control of HLB by trunk applications of systemic insecticides and/or guava interplants, (IV) selection of viroid-free budwood sources, and (V) transfer of technology to the farmers

    Similar works