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Just a little off the top

Kevin Sanderson believes he has the answer to reducing the amount of storage rot in carrots – the Carrot Foliage Trimmer.

Agriculture and Agri-Food Canada research scientist Kevin Sanderson, right, and his research assistant Russ Campbell, left, examine a plot of carrots treated with the Carrot Foliage Trimmer. It’s believed proper management of carrot foliage can help to eliminate the possibility of rot in carrots in storage. Photo by Dan Woolley

Researcher develops carrot-top trimmer to control sclerotinia rot

Kevin Sanderson believes he has the answer to reducing the amount of storage rot in carrots – the Carrot Foliage Trimmer.

A research scientist with Agriculture and Agri-Food Canada and based in Charlottetown, Prince Edward Island, Sanderson designed his trimmer as a means of removing the tops’ leaves in carrot rows.

Development of the trimmer was sparked by research originally performed in Ontario during 1981. Sanderson’s continued development of the trimming technology was funded through federal coffers dedicated to funding technology development aimed at reducing on-farm pesticide use. “What is really interesting and exciting (is) we’re taking it right through from initial research to the final application,” he says.

In typical double-row, commercial-scale production, carrot canopies begin to grow together around mid-August. As the canopy closes, air and sunlight find it more difficult to reach the soil, moisture starts to collect and disease sets in. According to Sanderson, the most devastating of the diseases is sclerotinia, or white mold, which is typically only discovered once the carrots enter storage.

But with the carrot foliage trimmer, the carrot canopy can be cut away, helping to re-open the rows, increasing access of air and sunlight to the soil and ultimately reducing the amount of rot in the carrots.

The prototype trimmer, comprised of a four-row-wide shaft equipped with 28-inch diameter carbide tip saw blades, mounts on the back of a tractor and is powered by the PTO. As the tractor moves through the carrot rows, the saw blades spin on either side, lifting the foliage and trimming it back at the same time. Once cut, the trimmings fall between the rows and dry out, causing any fungi on the leaves to die. The unit operates on a 2:1 ratio; therefore, if the engine speed is 1,180 rpm, the blades spin at 590 rpm.

Sanderson believes carrot foliage trimming is an efficient way to control carrot rot, “a big plus” since there is currently no chemical carrot rot treatment available. The technique does not hurt carrot quality and trimming the rows to two feet wide is not detrimental to crop yield.

Now that his prototype is operational, Sanderson is hopeful an implement manufacturer will show interest in building and marketing it. He has received interest in the machine from the carrot processing industry in Ontario and Quebec. Nova Scotia’s Oxford Frozen Foods has also shown interest in a unit.

Sanderson would like to demonstrate the trimmer next year outside of Prince Edward Island, if he can get the funding. “I would like to see it in operation by the 2008 season.”

Based on the state of production in 2006, the sooner the better. This year proved to be an extremely bad year for carrot production.

“There are fields in Nova Scotia that are completely gone,” Sanderson notes, attributing the high incidence of sclerotinia rot to a wet crop canopy, mucky field conditions and high humidity.