Preventing key food crops from diseases has emerged as a big challenge for policymakers, as the country struggles to improve their yields to meet growing domestic demand and to create exportable surplus.

All major food crops i.e. wheat, rice and sugarcane are continually attacked by specific diseases frustrating plans to obtain the required increase in their per-hectare output.

Some progress has, however, been made over the past four years to check the spread of such diseases after devolution of agriculture as a provincial subject in FY10. Meanwhile, the federal ministry of National Food Security and Research and federal organisations like Suparco and PCSIR continue to support provincial initiatives in identifying and attacking food crop diseases. “Suparco’s satellite imagery surveys of crops help in generating early warnings on overall weather impact on crops including its potential impact on proliferation of crop-specific diseases,” says a senior official of Sindh agriculture department.

Planting of wheat seeds dried in the sunlight after soaking them in water saves the crop from black smut

Similarly, PCSIR and other federal and provincial institutions are engaged in experiments to determine the resistance level of food crops against various diseases and pest attacks. This helps in directing the course of disease-control programmes.

“Making wheat crop resistant to leaf rust and yellow rust has always been a challenge for us,” says a senior official of Pakistan Agricultural Research Council, adding that his organisation has so far developed over 100 wheat varieties resistant to twin diseases. Screening of wheat cultivars against Karnal Bunt, a fungal disease, was successfully undertaken two years ago and 80 plus wheat lines, including 10 commercial varieties, were found free of KB.

In a 2009 field survey, four diseases - leaf rust, yellow rust, spot blotch and powdery mildew - were found prevalent in Punjab. Spot blotch was the most prevalent and no wheat variety was found free of it. Such widely used varieties like Bhakkhar-2001, Inqalab-91, Faisalabad-08, Lasani-2008 and Seher-2006 were found seriously affected by spot blotch.

“Following this survey, initiatives were taken at the federal and provincial level to contain the spread of wheat diseases particularly the spot blotch and within next four years the rate of prevalence of these diseases declined to some extent,” says a source in Punjab agriculture department.

Officials of Sindh agriculture department also say wheat crop diseases have been handled effectively in past few years across Pakistan including Sindh. This also reflects in an increase in the national average per-hectare yield, up from a little over 2550kg in 2009-10 to around 2800kg in 2013-14, according to official data.

An official of Sindh Agriculture department told Dawn that solar energy treatment has particularly helped in checking loose smut, a disease in which the ears of wheat plants contain black powder of smut spores instead of grains. Planting of wheat seeds dried in the sunlight after soaking them in water saves the crop from black smut, he explained.

Prevalence of bacterial blight in rice crop has been rampant in both Punjab and Sindh and several field surveys have established that in some districts the entire rice crop affected by the disease. Whereas in other districts at least one-fourth of the crop is affected by it. Bacterial blight causes wilting of seedlings and yellowing and drying of leaves. Since overuse of nitrogen promotes this disease, officials of provincial agriculture departments say they warn paddy farmers to use balanced amounts of fertiliser to prevent it. Proper drainage of paddy fields particularly in times of floods, removal of weeds from nurseries beds, keeping fallow fields dry enough to suppress bacteria producing agents are some other ways that are being adopted to fight bacterial blight.

“Lack of workforce or money for carrying out these exercise, negligence by farmers or scant coordination between them and field officials of provincial agriculture departments make it difficult to effectively check this disease,” admits an official of Ministry of National Food Security and Research.

The fact that total output of rice has been on the rise almost entirely due to expansion in the area under cultivation, and very little due to a substantial increase in the per-hectare yield confirms failure with regard to containing diseases affecting paddy crop. In 2009-10, the per-hectare yield stood at 2387kg which only inched up to 2437kg in 20013-14, officials statistics reveal.

Maize varieties such as Sadaf and Raka Roshi and some of their hybrids have long developed enough resistance against maize-specific diseases thanks to a disease control programme launched a few years ago in Punjab. That is one big reason behind a gradual increase in the per-hectare yield of maize from less than 3500kg in 2009-10 to over 4050kg in 2013-14. Accordingly, maize output has also increased from 3.27m tonnes in 2009-10 to 4.53m tonnes in 2013-14.

Whereas sugarcane crop continues to come under attack of certain diseases despite efforts to counter them, an ongoing campaign for saving cane from diseases-causing insects and pests has gathered pace. Under the sugarcane national uniform yield trial, more than a dozen candidate varieties have been tested and found free from the attack of pests except for termites which was found prevalent in at least three varieties, federal food officials say.

They say that the productivity test of over a dozen new varieties of sugarcane has also been completed and their trial sowing undertaken. Some of these varities are capable of producing up to 90,000 tonnes per hectare against the 2013-14’s average yield of 66,500 tonnes.

Published in Dawn, Economic & Business, July 28th, 2014