News, Uganda

Can Crop Diversity Reduce Pests and Diseases Pressure? The case of common bean in Uganda

July 15th, 2011

Our team in Uganda led by John Mulumba Waswa and Rose Nankya was prepared for interviewing 60 farmers in each of the three sites where beans are the target crop (Nakaseke, Kabwohe, and Rubaya). The team is composed of farmers that are directly involved in the project and were trained to conduct the interviews. The aim is to know how much bean diversity the farmers cultivate, if they were sowing mostly traditional or improved varieties and how much pests and diseases pressure he was experiencing. They also wanted to know if there were differences in resistance to various pests and diseases of the different varieties. The reason why we think that this information is important is because we want to find ways for reducing genetic vulnerability within the farmers’ fields.  Vulnerability is intended here as the probability of crop loss due to a new pest or pathogen infesting farmers’ fields. Our assumption is that this is more likely to occur in an area consisting of one or few varieties that share a very similar resistance structure.

The information they gave was very useful and proved once more how knowledgeable farmers are and how ingenious in finding useful solutions to solve their problems.  As an example, only 22% of the farmers believes that monoculture brings more resistance to pests and diseases than mixtures. This observation is in agreement with several studies showing that this is actually true. Also, farmers consider that landraces do not loose their resistance to pests and diseases over time while improved varieties do so. This is also a good observation considering that landraces are genetically much more heterogeneous than improved varieties. What farmers told us is that they grow different varieties, on average between 2.3 and 2.4 on the different sites, and that these varieties have different resistance to pests and diseases. There is a potential for us to check if there is a direct relationships between the amount of diversity farmers keep in their fields and the pests and diseases pressure. Click here to continue the article.