Canola extracts curb potato nematodes

Irish potatoes in the market, Coast Weekly.JPG

Potatoes in bags ready for sale. Canola and broccoli extracts have been found to be effective in controlling potato cyst nematodes that are threatening  the crop. Photo by Coast Weekly.

As the potato cyst nematodes (PCN) threaten to wipe out potato production in the country, research has shown that extracts of canola can reduce the infestation given that there is no commercial product for the treatment of the pest in Kenya.

Some regions in Kenya have reported 100 per cent infestation of the pests, with the effect on production being more than 80 per cent for the crops that survive the attack, according to a recent Food and Agriculture Organisation  (FAO) commissioned research in 20 counties in Kenya.

One hundred per cent infestation was reported in West Pokot, Taita-Taveta and Trans-Nzoia.

In Nyandarua County, 91 per cent of the crops analysed were affected followed by Nakuru and Narok, both with 88 per cent. Elgeyo Marakwet County follows in with 87 per cent.

A United Kingdom university research has shown that extracts of the rape seed that is also called canola inhibit the growth and multiplication of this pest, which can stay in the soil for 30 years after establishment.

The Harper Adams University established that that the active ingredient in the Brasssica juicea species of canola – glucosinolate - reduced the population of the PCN at harvesting. The crops withstood the effects of the pests to harvesting stage in the B. juicea treated plots.

Glucosinolate inhibits growth and multiplication of fungi and oomycetes, according to another research published in the Plant Production Science.

The journal, however, notes that the content in the canola may inhibit growth of other crops in the following season.

Leaves and roots of the rapeseed herb have significant levels of this active ingredient.    

The cyst, also known as Globodera rostochiensis or Globoder pallida is highly infectious to potatoes and quarantine is usually recommended to control its spread in addition to crop rotation.

The PCN germ was first identified in 2014 by a Chuka University Masters student, James Mwangi, during field work in Nyandarua County. The

G. pallida, is a best controlled by quarantine, to mean marketing of the tubers for propagation of consumption aggravated the spread.

A different study published in the American Journal of Potato Research found that chemicals, 2-propenyl and 2-phenethyl – in broccoli extracts can suppress the PCN by 50 per cent. 

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At least 99 per cent of potato farmers rely on seeds from peer suppliers. But the FAO study found that even the seeds at the Kenya Agricultural and Livestock Research Organisation bore the pest.

Canola is grown in Kenya, and its seeds and flour are consumed by health enthusiasts for various medicinal purposes.

People who want to control weight consume the seeds to reduce the frequency of eating. The oils in the seeds take long to be digested; the stomach feels full during this period.

Apart from being Kenya’s most staple food after maize, potato farming earns income to more than 80,000 households in the country.

Harper Adams University recommends the inclusion of the rape seeds in the integrated pest management practices.