Pesticides regulator questions Nyandarua potato study

Farmers prepare their potatoes at Kanyiri village in Olkalou Constituency, Nyandarua County. January 19, 2025. [John Githinji, Standard]

A pesticide regulator has raised concerns over the credibility of a recent study that found Nyandarua potatoes to be unsafe for human consumption, further questioning the safety of the products.  

In what appeared to be a dismissal of the research, the Pest Control Products Board (PCPB) pointed out the gaps the survey failed to clarify for Kenyans.  

PCPB Chief Executive Officer Fredrick Muchiri alluded that there might have been some "external forces" behind the study. 

Muchiri was speaking on Tuesday during a presser at the institution's headquarters in Loresho, Nairobi

He said the two insecticides-chlorpyrifos and fenitrothion, that the survey flagged are not approved for use by farmers in growing crops. 

And that, even if applied, he said, the ingredients cannot be translocated from the leaves to other parts of a plant, thus contradicting the findings. 

"What the study has not clarified is if they were applied on the leaves, then the standard is questionable because those two products are not translocated, they are not systemic. They cannot be moved from one part of the plant to another one they will remain where they were applied," he said. 

He added: "Therefore, they would be expected to be found on the leaves, not in the tubers. So that is why questioning whether the science was meant to achieve a particular endpoint or if it was the actual science as it is supposed to be."

The study by researchers from Egerton University and published in The Journal of Food Protection, indicated that chlorpyrifos and fenitrothion were detected at levels exceeding the international safety limits. 

However, PCPB defended itself, saying it has not approved the use of the two insecticides for growing potatoes, and any use of the products contrary to the registered use constitutes an illegality. 

Chlorpyrifos and fenitrothion insecticides are widely linked to serious health issues like brain damage, among other health hazards. 

"Further, we wish to point out that chlorpyrifos is only registered for use in building, construction, and wood treatment and has no approval for agricultural use," said Muchiri. 

At the same time, the study revealed that the majority of the farmers used synthetic fertilizers, with more than 80 per cent of the farmers failing to follow the appropriate instructions on the pesticide labels.

"Farmers who followed the labelled instructions had notably lower or even undetectable residues. PCPB urges farmers to strictly follow label instructions since it is a crucial factor keeping residue levels within acceptable limits," he noted. 

The findings sparked public outrage, with the worrying trend in the use of harmful fertilizers reported to be costing the country billions in exports. 

Muchiri alluded to the rampant misuse of unauthorised fertilizers to a lack of awareness by farmers, exacerbated by the missing link between the pest control agencies and the counties to which the agricultural function was devolved. 

"Farmers are on their own. Extension services are not working because there is little collaboration between the institutions at the national government and the counties," he stated. 

To resolve the challenge, he said, the board will begin educating farmers by July to enhance awareness and knowledge among them on the use of fertilizers. 

"We have enhanced compliance capabilities. By last week, we had inspected 95 per cent of pesticides across the country," he said, assuring Kenyans that they are safe from harmful food products in the market.