Kanyumbu village is a compact rural farming village in Lilongwe district in Malawi. Farmers in this village mostly produce maize, beans, and mangoes from a few trees scattered in their fields. In 2013, they received a new service from the Department of Agriculture; a plant clinic, with a plant doctor. They were informed that they could present any crop affected by pests and diseases, or that was simply ‘not looking normal’. The plant doctor could examine the crop samples, diagnose the problem and tell them what was ailing their crops. On the spot, the plant doctor could provide advice on how to manage the crop pests and problems.
A new UN report states that it is dangerously misleading to suggest that pesticides are necessary to achieve food security. Instead, the report recommends that farms reduce pesticide use and adopt sustainable practices that protect crops from pests by enhancing biodiversity and natural enemies. This agroecological approach eliminates reliance on, and exposure to, expensive and toxic chemical inputs, but would it really allow farmers to be just as productive?
Proponents term it the long awaited messiah that food-insecure Africa has been yearning for! ‘Farming God’s way’ promises to end fertilizer woes of resource-poor farmers in the continent by providing a cheaper and less labour intensive farming method.
Food security remains the number one major challenge that citizens across the African continent contend with. While the Green Revolution of the 1960s allowed erstwhile food deficient regions of Asia and Latin America to triple crop yields, food production in Sub-Saharan Africa (SSA) has remained stagnant and in many instances it has even declined. According to IFPRI, among the factors fuelling the continent’s low agricultural outputs include poor resource endowments, minimal use of inputs (fertilizer, improved seeds and irrigation) and adverse policies undermining agriculture. Additionally, continuing environmental degradation, crop pests, high population growth and low levels of investment in agricultural infrastructure has further aggravated the resource limitations of agriculture in Africa.
BBSRC (Biotechnology and Biological Sciences Research Council) and Syngenta funded scientists at the University of York and University of Durham have discovered a gene called AmGSTF1 that plays a key role in controlling multiple herbicide resistance in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum). Now the gene that confers resistance has been identified, it is hoped that chemicals that inhibit the gene may be able to be used in future to make herbicides effective against resistant weeds.
Black-grass and rye-grass are widespread weeds which cause problems in cereal and oilseed rape farming. Management using herbicides is becoming increasingly difficult since both black-grass and rye-grass can acquire a single defence mechanism that confers resistance to multiple herbicides- known as multiple herbicide resistance. The genetics of multiple herbicide resistance have been poorly understood until recently, however scientists have now discovered that a gene producing an enzyme called glutathione transferase (GST) is responsible for multiple herbicide resistance. Scientists created transgenic thale cress (Arabidopsis thaliana) plants with the GST producing gene inserted which were resistant. GSTs are known to detoxify herbicides, but project leader Professor Rob Edwards of the Centre for Novel Agricultural Products at the University of York believes that the gene they discovered works as a kind of ‘master switch’ that activates a range of protective mechanisms in the plant. When resistant plants with the GST gene are sprayed with GST inhibiting chemicals, they become susceptible to herbicides. This demonstrates the potential for using GST inhibiting compounds in future herbicide formulations to manage resistant rye-grass and black-grass. These weeds are currently very difficult to manage due to their widespread herbicide resistance.
Vegetable farmers in the Kayunga and Mukono districts of Uganda are reporting crop losses due to black rot disease. One farmer, Twaha Kahooza of Kyampisi village, Kayunga Sub-county, says he had planted four acres of cabbages and was expecting about Shs18m (about £4,500 or US$7,000) from the harvest, however he only managed to get Shs5m (about £1,200 or US$2,000).
Black rot is caused by the bacterium Xanthomonas campestris pv. campestris and is one of the most destructive diseases of cabbage and other crucifers such as broccoli, brussels sprouts, Chinese cabbage, collards, kohlrabi and mustard. The disease is usually most prevalent in low lying areas where plants remain wet for long periods. The disease is characterized by a yellow V-shaped lesion at the leaf margin which turns brown as the leaf area expands. The disease can also affect seedlings and can enter the plant through insect feeding or injury to the plant. Management of black rot in crucifers includes obtaining certified, pathogen free seed, ensuring there is enough space between plants and crop rotation.To read more about black rot and black rot management visit factsheets on the Plantwise Knowledge Bank.
To read a Plantwise Factsheet for Farmers written in Uganda click here.
To find out more about Plantwise plant clinics running in Uganda, click here
This week, the UK Minister of State for Agriculture and Food, David Heath, has announced his support for the use of agroecological farming methods which are seen as the foundation of sustainable agriculture. The International Assessment of Agricultural Knowledge, Science and Technology (IAASTD) define agroecology as “the science and practice of applying ecological concepts and principles to the study, design and management of sustainable agroecosystems”. In practice, this means simulating natural ecosystems and using low inputs to increase productivity.
In 2011 the UN reported that by using agroecological methods, projects carried out in 20 different African countries were able to double crop yields in 3-10 years. The projects also recorded a reduction in the use of pesticides, leading to savings for the farmers. The agroecological approach has multiple benefits, beyond these economic gains. It also takes into account social and environmental issues, including soil fertility, water availability and climate change. Continue reading →