Plant pests and diseases
Transboundary plant pests and diseases affect food crops, causing significant losses to farmers and threatening food security.
The spread of transboundary plant pests and diseases has increased dramatically in recent years. Globalization, trade and climate change, as well as reduced resilience in production systems due to decades of agricultural intensification, have all played a part.
Transboundary plant pests and diseases can easily spread to several countries and reach epidemic proportions. Outbreaks and upsurges can cause huge losses to crops and pastures, threatening the livelihoods of vulnerable farmers and the food and nutrition security of millions at a time.
Locusts, armyworm, fruit flies, banana diseases, cassava diseases and wheat rusts are among the most destructive transboundary plant pests and diseases. Plant pests and diseases spread in three principal ways:
- trade or other human-migrated movement
- environmental forces – weather and windborne
- insect or other vector-borne – pathogens
Cassava virus diseases
Cassava Mosaic and Brown Streak virus diseases continue to affect the main food crop – cassava – throughout the Great Lakes region of Eastern and Southern Africa. In Africa, an estimated 70 million people are dependent on cassava as a primary source of food contributing over 500 kcal per day per person.
Cassava is produced mostly by smallholders on marginal and sub-marginal lands in the humid and semi-humid tropics. It is efficient in carbohydrate production, adapted to a wide range of environments and tolerant to drought and acidic soils.
The FAO strategic programme framework “Cassava diseases in central, eastern and southern Africa” (CaCESA) assists cassava-dependent vulnerable populations through better control and management of pests and diseases in central, eastern and southern regions of Africa. FAO provides technical assistance to national institutions to establish effective surveillance approaches, integrated management procedures, farmer training and capacity building. FAO initiatives promote integrated approaches, strengthening linkages among the stakeholders and promoting regional collaboration.
The Desert Locust migrates in swarms across continents and is a potential threat to the livelihood of one-tenth of the world’s population. This pest is a serious menace to agricultural production in Africa, the Near East and Southwest Asia. A locust can eat its own weight (about 2 grams) in plants every day. That means one million locusts can eat about one tonne of food each day, and the largest swarms can consume over 100 000 tonnes each day, or enough to feed tens of thousands of people for one year.
In 2012, the Desert Locust threat in the Sahel was controlled thanks to timely contributions of USD 8.2 million and a decade of strengthening national capacities and regional coordination in the framework of the FAO Emergency Prevention System (EMPRES), through the FAO Commission for Controlling the Desert Locust in the Western Region (CLCPRO).
FAO's Desert Locust Information Service monitors the locust situation and provides early warning to countries and donors on an on-going basis. Through the FAO Emergency Prevention System (EMPRES) and the three regional locust commissions, national capacities in early warning, early reaction and contingency planning are constantly being strengthened so locust emergencies can be better managed and the frequency and duration of Desert Locust plagues can be reduced.
Wheat rust diseases with continuous evolution of new pathotypes and airborne nature pose a serious threat to wheat production worldwide. Their impact is more pronounced across the major wheat growing regions including East Africa, North Africa, Middle East and Asia. It is estimated that 37% of world's wheat is under risk of potential epidemics of yellow, stem or leaf rust diseases.
FAO promotes and supports global efforts for monitoring and management of wheat rust diseases – as a member of the Borlaug Global Rust Initiative. FAO provides technical support to countries at risk of rust epidemics. FAO assistance includes capacity building, surveillance and monitoring, seed systems, contingency planning, strengthening linkages among institutions and stakeholders, enhancing research–extension–farmer links, training of officers and farmers and emergency responses where necessary.