What scientists are doing to eliminate deadly wheat rust

Tell us something about the award and why is it important for the country?

This award was not only a recognition for our work but for the country’s scientists as well. It recognised my 30-year efforts in fighting the wheat rust disease. The award puts the entire nation on the international research map. We proved that local scientists can solve global problems because the disease is affecting the crop across the world. 

So, what is wheat rust disease and why is it causing such a big concern?

Wheat rust is a fungal disease that attacks the stem and leaf. The disease is of great concern because the pathogen has no respect for geographical borders and has the potential to spread to many parts of the world.

The infectious pores are transmitted by wind and through soil. Two weeks after infection, small red dots begin to form on the leaves and stem. The epidemics of rust diseases has invaded countries in the Middle East, Southern Africa and East Africa.

In Kenya for instance, the production is low and we have a deficit of 650,000 tonnes and this is attributed to wheat rust. 

How prevalent is the disease in the country?

The disease has several variants and they include stem, yellow and leaf rusts. They are a big threat to wheat production, which currently stands at 350,000 metric tonnes (MT) against an annual demand of a million metric tonnes.

The pathogen, which was first reported in Uganda in 1999, has kept on mutating making it difficult to eliminate. It has the potential to spread very fast.

The threat is so serious that our new variety Robin developed some three years ago is now susceptible. The severity of the rust in Kenya’s wheat basket of North Rift, South Rift, Central Rift and Mt Kenya regions remains high with some of the areas recording a high infection of up to 80 per cent. In the last five years, it’s only South Rift which recorded a low infection. 

How can farmers protect their farms against the different strains of wheat rust?

The most economical way is to grow a variety that can resist the diseases and it is, therefore, advisable for the farmers to buy certified seeds from institutions such as KARLO or authorised merchants. However, in the event a farmer is growing a susceptible variety that has succumbed to the disease, he is supposed to spray fungicides on his farm as advised.

We normally advise them to spray the crop when it is two months old and repeat the spraying after two weeks and after another two weeks, the farmer should do the final spraying. When the spraying is done at sprouting and flowering, the farmers are able to control the diseases and reduce the infection rate. 

As a farmer, how do I know my crop has been attacked?

You must monitor the crop on a weekly basis by checking for stem, leaf and yellow rusts and the moment one notices symptoms of rust, which include brownish or reddish substance on the crop, they should spray the wheat. 

Wheat rust disease aside, why is production of wheat dwindling in the country?

We have several other diseases such as Barley Yellow Dwarf, which is the only virus in wheat and although it can be controlled, if not detected early it leads to massive losses. We also have cereal aphids and the most common one is the Russian Wheat Aphids. There are also challenges with the Quelea  wild bird.

Any wheat farmer must know how to scare these birds because they can make one lose their entire harvest. 

A good number of farmers also don’t practice crop rotation, thus, depleting soil fertility. Acidic soils, copper deficiency in some areas, climate change, weeds, lack of water, soil erosion and high cost of farm inputs affects mostly the small-scale farmers.

Low quality seeds; how widespread is the problem in the sector?

The challenge is there as with other seeds, but to attain maximum yields, farmers must ensure they check the seeds for quality by searching for their codes on specific websites or sending details via text messages to a particular code. They can also make inquiries at our Njoro offices. But most importantly they must observe other critical agronomic practices including spraying their farms at appropriate times and using the right chemicals and planting the recommended variety for their areas. 

Most of the new wheat varieties developed in Kenya are becoming susceptible to diseases.  Why is this so?

Wheat rusts such as the UG99 and other related races keep on mutating very fast.  However, that notwithstanding, we as scientists at KARLO are not sleeping. We are constantly screening new germplasm to be able to identify resistance lines and at the same time we keep an eye on the released varieties that farmers grow to monitor their performances in the field in case of infection. We collect infected plants and do a thorough analysis to identify and establish if there are any races of Ug99 and related races that have emerged. 

Shall scientists ever overcome this disease?

All is not lost. KARLO is working closely with other partners such International Maize and Wheat Improvement Centre, International Centre for Agricultural Research on Dry Areas and top scientists from across the globe to develop new wheat varieties that are tolerant to various strains of wheat rust through the Durable Rust Resistance in Wheat  Project and the Borlaug Global Rust Initiative.