Plant health overview
3 December 2019
The year 2020 is the International Year of Plant Health (IYPH). As we prepare to mark this important event, we look back; take stock and celebrate IITA’s contribution to plant health in Africa.
When the International Institute of Tropical agriculture (IITA) was started in 1967, the founders—Ford and Rockefeller Foundations—had one thing in mind: increased yield. And rightly so. If people are going to be well fed, there needs to be a constant supply of food, which can only be done through improving crop productivity. So in the earlier days, research focused on increasing productivity until nature played a nasty trick in 1970.
In 1970 there was an outbreak of maize streak virus (MSV) disease, which could have entirely wiped out the crop. Faced with this crisis, IITA’s research focus turned to plant health but the yield objective was not abandoned. IITA and partners worked tirelessly to combat MSV and by 1985 high yielding MSV cultivars and hybrids with different maturity classes, grain colors, and textures for different zones in Africa were released. To breed these MSV resistant varieties, IITA together with CYMMYT and 36 national partners, got germplasm from Thailand and central and south America. Because of this concerted effort to overcome MSV, in 1986 IITA got its first award and it was in plant health—the CGIAR King Baudouin Award. This award coupled with never-ending plant diseases invigorated the Institute’s commitment to plant health.
Next was cowpea, a food and income security crop that also doubles as animal fodder in the arid and semi-arid parts of Africa, i.e., Central and West Africa. Cowpea is easily devastated by bacterial blight and brown blotch. Breeding efforts focused on those diseases and soon new varieties with multiple resistance to disease were bred and made available. It is through this breeding work that bacterial blight and brown blotch were combated. Again, in recognition of this tremendous work, Bahdur Singh, an IITA breeder was awarded in 2006, the CGIAR Outstanding Senior Scientist Award. Bahdur was recognized for breeding fast maturing “60-day” cowpea cultivars for the tropics as well cultivars with resistance to more than 10 pathogens and drought and heat tolerance in other cultivars.
Up until the 1970s, resistance breeding was the most used method for combating disease and insect pests. However, in the late 1970s, biological control (use of natural enemies) was adopted alongside resistance breeding. Biocontrol was first used in the fight against the cassava mealybug and cassava green mite using Apoanagyrus lopezi, a predator wasp. This wasp, from South America, is a natural enemy to the mealybug and green mite. It controlled the cassava mealybug wherever it was released. This was the first of many successes in biocontrol. In 1990, the CGIAR King Baudouin Award was given to IITA and CIAT teams for Africa-wide cassava mealybug control.
Following the successful use of the biocontrol method, IITA opened a Biological Control Center for Africa in Cotonou, Benin, in the 1980s. This center has grown to become Africa’s leading biocontrol research hub. Scientists from Cotonou have put their expertise to many pest challenges and surmounting them.
Another successful use of natural enemies was in Uganda when weevils were used to control the water hyacinth. IITA in collaboration with the National Biological Control Unit of Uganda managed to tame the hyacinth that was spreading rapidly on Africa’s deepest and largest fresh water body—Lake Victoria.
After 20 years of successes in agricultural research, IITA decided to expand beyond West Africa. In the 1990s, IITA set up its first center in East and South Africa based in Uganda in collaboration with the National Agricultural Research Organisation (NARO). The first agricultural challenge this partnership tackled was cassava mosaic disease. Cassava mosaic, which was pandemic in six districts of Uganda, was controlled thus saving a major food crop for people in those districts. Other than the successful combating of mosaic, the IITA‒NARO partnership was recognized by donors as a good example of collaborative work. James Legg, an IITA virologist, was recognized with the Promising Young Scientist Award for his contribution to this work and partnership.
At the same time, plant health research was going on in the West Africa hub. New yam varieties were bred with resistance to yam anthracnose disease and yam mosaic virus. With these diseases out of the way, farmers experienced increased yield and stability of field performance. Farming cannot be profitable with only high yielding and disease resistant seed; reducing the costs of inputs is important if a farmer is to control expenditure. Thus, with the aim of reducing production costs, yam cultivars were selected for good performance in the absence of fertilizer. The first of such cultivars, Dioscorea rotundata, were released in 2001 in Nigeria.
The year 1994 saw IITA win yet another CGIAR King Baudouin award for breeding of hybrid plantains resistant to black sigatoka disease. These hybrids named PITA14 were disseminated to about 20,000 farmers in Nigeria, Ghana, Cameroon, and Côte D’Ivoire. Thereafter they were disseminated in Uganda, Tanzania, Malawi, Mozambique, and Zambia. Other IITA bred hybrids have been adopted in Latin America and Asia.
Green Muscle®—an insecticide that does not negatively affect human and environmental health. With new knowledge comes new discoveries and soon it was realized that pesticides were doing more harm to both people and the environment. IITA set out to develop an “insecticide with a conscience”; one that could control the pests without harming human health and the environment. In 1989, the Lutte Biologique contre les Locusts et Sauteriaux (LUBILOSA) was set up. On top of securing a 10-year funding commitment from donors, this project released a biopesticide that controls locusts and grasshoppers without harming other insects, the environment, and human life. It was licensed to a South African company for manufacturing. The Food and Agriculture Organization (FAO) listed Green Muscle® among the top insecticides that do not have a negative impact on the environment or human health. It continues to be used by farmers and NGOs in place of synthetic insecticides.
In 1990, the germplasm health unit (GHU) was established. It ensures that planting materials do not have diseases especially viruses. The germplasm health unit protocols for safety are set and popularized around the world. This is especially helpful in enabling the free movement of safe planting materials.
Since the 1990s, IITA has continued to grow in leaps and bounds in plant health research.
Throughout 2020, we shall share our breakthroughs on plant health that have enabled farming in Africa to remain afloat—feeding and nourishing the continent’s ever-growing population.