Farmers who depend on the land for a living can’t afford to lose an entire crop to unknown pests or disease.

That’s why Plantwise – a program developed by the Centre for Agriculture and Bioscience in the U.K. – trains agricultural extension workers to diagnose problems before crops are lost.

Extension workers began holding unofficial, free plant clinics in Mukono, Uganda in 2006. Since then, they have spread to 45 of Uganda’s local government districts, according to a report in All Africa.

Since 2010, Plantwise has trained 1,000 agents – unofficially called “plant doctors” – and set up clinics in 24 countries, including three in West Africa, nine in East Africa and 13 in Zambia.

The Centre for Agriculture estimates that 40 percent of the value of crops is lost to pests and disease. To combat those statistics, the plant doctors hold free clinics which anyone can attend. Farmers travel miles, crops in hand, to have their crops diagnosed by the “doctors,” who write their “prescriptions” for the cure – a different pesticide, perhaps, or planting another crop nearby that’s known to repel a particular pest.

“Clinic data reveal the farmers present problems on over 30 crops, and plant doctors have to consider over 60 different pests and diseases,” said crop scientist Eric Boa, who pioneered the Plantwise program.

Prior to establishing the Plantwise clinic-based program model, agricultural extension workers visited individual farms. Having the farmers gather in one location enables far more to be seen and more problems to be solved, the report said.

“More farmers are seen in a session, if good mobilization is done, than an extension officer can look at in an entire month,” said Joseph Mulema, who coordinates the clinics in Uganda and Zambia. “Even if the clinic only runs twice a month, with good mobilization you can see hundreds of farmers.”

Add to that the word-of-mouth effect, whereby farmers who attended the clinics go back to their villages and relay the information to other farmers, and the benefit is magnified.

Researchers who analyzed the effectiveness of the clinics noted that plant doctors didn’t often consider factors such as soil fertility or recommend biological remedies. They point out, however, that the “doctors” had only received three days of study by Plantwise before being sent out to hold clinics.

The goal of Plantwise is to expand to 31 countries by 2014.