By: Richard Markham and Anne Vézina

The situation created by the bacterial wilt disease attacking bananas in Uganda is both more complex and less intractable than your article suggests (see Uganda 'needs biotech law' to save banana sector).

It is more complicated in the sense that, although all banana varieties tested so far eventually succumb to the disease, these results were obtained by injecting the bacteria directly into the plant.

In farmers' fields, the conditions for the bacteria to enter the plant naturally are not always met, making it possible for some varieties to escape infection.

So far, the worst affected variety is Kayinja, a type of banana used to make juice, beer and alcohol that provides a much needed income for poor farmers in East and Central Africa.

The disease can be controlled by sterilising cutting tools, as mentioned in your article, but also by removing the male inflorescence as soon as the fruits have set.

This prevents insects from transmitting the bacteria to healthy plants.

The insects pick up the bacteria when they visit the inflorescence of sick plants, which exude bacteria-laden ooze through the openings made by the fallen bracts.

Removing the male inflorescence reduces the incidence of new infections almost to zero and is easy to implement.

In southwest Uganda, home to a group of bananas unique to the highlands of East Africa, farmers have been routinely removing the male inflorescence for other reasons.

This simple measure has prevented the disease from getting a foothold in the region, important as the region produces most of the cooking bananas that Ugandans eat at almost every meal.

There is no denying that farmers need resistant bananas, and given that bananas are hard to breed because they don't usually produce seeds, genetic engineering is an obvious avenue to explore.

We at the International Network for the Improvement of Banana and Plantain have also been coordinating a project to genetically engineer varieties of highland bananas with Ugandan scientists.

At present, however, the only genetically modified (GM) bananas ready for field testing are dessert types and plantains that would not help the farmers wrestling with the bacterial disease, even if they were released tomorrow. 

Contrary to the impression given by your article, it is not just any resistant banana that will do the trick. There are some 80 to 100 varieties of East African highland bananas in Uganda alone.

They cannot be replaced by one resistant variety. In the case of bacterial wilt, the variety that most urgently needs engineering is Kayinja, but as far as we know, nobody is working on it.

Biotechnology is one tool among many. Banana farmers should not be scared into accepting GM bananas as the only solution to a problem for which other measures are proving effective, and which Uganda's National Agricultural Research Organisation is also actively promoting, in addition to its work on GM bananas.

It is not worth the risk of creating a backlash against GM bananas, a situation that could jeopardise years of work and the ability of Ugandan scientists to exercise their skills in their home country.