Striga (witchweed) is a parasitic weed that seriously constrains the productivity of staples such as maize, sorghum, millet and upland...
Ugandan farmers are faced with the pest and disease burden affecting most banana species grown in the country, ranging from the East African highland banana commonly known as matooke, sukari ndizi, bogoya and gonja. The pests considered “most dangerous” by crop scientists are weevils and nematodes.
The banana weevils, known as Cosmopolites sordidus, are found in all banana growing countries and have existed from the time farmers began growing bananas. They lay eggs at the stems and cause the trunks to rot leading to collapse of the plant.
According to Dr David Talengera, a banana breeder at the National Agricultural Research Laboratories Institute (NARLI) in Kawanda, the weevils destroy the core of the banana stem from the neighbouring infested suckers.
This causes water deficiency in the plant causing stunted growth leading to a 30 to 50 per cent yield loss in most farmers’ fields.
The banana nematodes are a type of roundworm, which inhibit the root system of the crop causing inability to absorb water and reduce the leaves of the plant leading to 50 per cent yield loss.
However the nematode species are very difficult to distinguish; some are parasitic while others are not.
Unlike the banana weevils, which according to the scientists, are hosted in banana plants, nematodes can be found in other crops such as maize and yams.
Many parasitic nematode species cause diseases in plants, animals, and humans while other species are beneficial in attacking insect pests. Few farmers know about banana nematodes because the worms are hard to see with the naked eye.
Farmers are advised to insert a sucker, which has been prepared for planting into hot water at a temperature of 45 degrees Centigrade and apply Furadan pesticide.
The weevils can be trapped especially when the adult insects are seen laying eggs in the stems during harvesting.
“When a farmer is harvesting banana, usually they cut down the stems and split them, if the adult weevils are nearby they usually come to lay eggs on the split stem. A farmer can trap and destroy them there and then. Farmers are also advised to apply pesticides like Furadan,” Dr Talengera said.
Pests tend to infest plantations mainly in the lowlands like central Uganda but highland area like in western Uganda are less affected.
The scientists, apart from developing resistant varieties using conventional means, are also using the biotechnology to come up with transgenic varieties that are expected to be resistant.
But the challenge is having few banana varieties, which are tolerant to the pests. This is not guaranteed to eliminate the infestation rate completely.
Trait of interest
The head of the National Agro-Biotechnology Centre at NARLI, Dr Andrew Kiggundu, said farmers should also take note of the ecological locations they are in.
The pod borer (Maruca vitrata) inflicts severe damage to cowpea leading to yield losses of between 70–80% in severe infestations....
Banana bacterial wilt disease threatens production of banana in the Great Lakes region, leading to a 50% decline in household incomes from banana...
Drought is the most important constraint of African agriculture severely affecting maize, the most important African staple food crop. The WEMA...
Mycotoxins are produced by fungal moulds that contaminate various agricultural commodities either before, during or after harvest.
At the turn of this century, biotechnology emerged as a powerful tool that has contributed to increased agricultural productivity in many...
Cassava is an important food crop both for urban and rural consumers in Sub-Saharan Africa.
Sub-Saharan Africa has for the last two decades been experiencing a continuous increase in rice consumption driven mostly by a shift in consumer...
Rice consumption is increasing at about 8 percent a year in many Sub-Saharan African countries. However, the increase in yield per year is less...