Tanzania: experts warn on pesticides use

There are concerns over alleged excessive use of pesticides on the extensive onion farms in Karatu District, with experts warning of harmful effects on people.

A survey conducted in the area recently indicated that there was a rampant use of agrochemicals by people who have little knowledge on how to handle them.

As the suppliers of such chemicals make brisk business, the sprayers and farmers are at the risk of suffering from long term after effects, the experts contend.

Rampant and consistent application of the chemicals also posed a danger of introducing pests which are resistant to pesticides, thereby complicating the situation.

"There is a lot of spraying going on there. Ignorant farmers are at the mercy of pesticide dealers," lamented Dr Vera Ngowi, a team leader of the researchers just back from the area.

She told The Citizen in an exclusive interview that it was unfortunate that the lucrative onion farming at Mang'ola basin, on the shores of Lake Eyasi, had attracted excessive use of agrochemicals.

The chemicals have not only increased the cost of onion production on the farmers but also posed risks to their health and the environment.

The study conducted under the heading: ' Community/Farmers Self Assessment to Prevent Pesticide Hazards' was sponsored by the Tanzania Association of Public Occupational and Environment Health Experts (Tapohe).

Dr Ngowi, a senior lecturer at the Muhimbili University of Health and Allied Sciences (Muhas), said excessive use of agrochemicals in the area could have long-term effects to the people and the environment.

It also endangered the multi-billion shilling onion cultivation sector because substantial amount of the produce is exported to as far as the European Union (EU) markets where chemical traces could lead to their rejection.

Mr Thomas Mbise, a collaborating scientist with Tahope, concurred that there was "too much" spraying at the Mang'ola onion fields which involves improper pesticides.

He cited as an example onion thrips, common pests which attack onion crops, whose control does not need insecticides but instead require acaricides. He added that there was no justification for the use of some chemicals.

Impacts of excessive use of chemicals would not only consolidate resistance by some pests but in turn increase use of chemicals and killing of beneficiary organisms, he observed.

He was concerned that many farmers who were interviewed were ignorant of the pesticides and their harmful effects on human beings and called on the government to invest in research to assist them.

Onion farming on irrigated fields on the shores of Lake Eyasi has attracted more than 10,000 farmers in an area covering over 5,131 hectares in several villages, especially in the last 10 years.

Statistics from the Karatu district commissioner's office indicate that the farmers could be raking up to Sh2.7 billion from onion sales which has lately found a ready market in Kenya.

No statistics were given on the amount of chemicals used there, but the survey found that dealers were making money amid fears that more pesticides would be needed because of a likelihood of pest resistance.

Commenting on the problem, the Karatu district commissioner, Mr Mathew Sedoyeka, challenged the Agriculture ministry to send experts to assess the gravity of the matter.

He underscored the need to train farmers on safety measures and the proper use of agrochemicals that are not harmful to them.