Focus on... Plant Disease

Fungi, bacteria, viruses, nematodes, and phytoplasmas are the cause of a wide range of major diseases, affecting the world's most important food crops. New diseases, as well as changes in existing pathogens, continue to threaten the livelihoods of farmers worldwide. Controlling diseases has invariably relied on cultural control and, where farmers can afford it and have available inputs, chemicals or disease-resistant varieties are used. But development of new and innovative ways to control plant diseases remains a constant challenge for plant scientists, particularly as disease-causing organisms have an aptitude for spreading to new areas and even new hosts.

In this edition of New Agriculturist we focus on some of the latest approaches to controlling plant disease, from understanding plant genetics to providing the basic principles of plant pathology to help extension advisors give better advice to farmers.

Uganda's war on wilt

Four years after it was first reported in Uganda's Mukono district, Banana Bacterial Wilt (BBW) has now been identified in 32 of the country's 54 districts. Having also been identified in a remote region of neighbouring Democratic Republic of Congo, the disease is becoming of wider regional concern...

Information: key in the fight against blight

As late blight continues to hamper potato production around the world, exchange of knowledge and information is an important weapon in the fight against the disease...

The plant detectives: a clinical approach to plant disease

Recognising and interpreting plant disease symptoms is something in which extension officers rarely have much training. While a two-day course cannot produce a team of plant pathologists, it can instil the basic skills needed to be a plant detective...

Cassava mosaic: a new threat to Burundi's emerging peace

Whilst peace has been restored in Burundi after the success of recent multi-party elections, a new danger in the form of cassava mosaic disease threatens the livelihoods of farmers around Bujumbura...

CMD: a blessing in disguise for Nigeria?

Nigeria is dependent as a vital subsistence crop for smallholder farmers in the south and central regions of the country. So the threat of a highly virulent form of cassava mosaic disease (CMD), spreading westwards from Uganda and resulting in severe crop losses, has been taken extremely seriously...

Grass stunt draws a crowd

With the rapid expansion of zero-grazing in East Africa, cultivation of Napier grass has dramatically increased. But in the last few years, the fodder crop has been affected by disease...

Taking out the blast

Rice blast fungus is the most deadly pathogen of rice. This devastating disease infects both upland and lowland varieties of rice in more than 85 countries, reducing yields by up to 75 per cent. However, efforts to control rice blast fungus have led scientists to discover the biochemical pathways that could prevent blast infestation...

Disease recognition and control in DRC

In a makeshift laboratory in a hotel room in North Kivu, two scientists peer intently at collected samples of blackened roots and shrivelled leaves of cinchona. They strongly believe that the culprit is Phytophthora. Research may in time identify resistant varieties of cinchona but action is needed now...