Looking for a Silver Bullet for Silver Scurf

Silver scurf is a major concern for potato growers in the Lower Mainland. The fungus infects potatoes before harvest, and once they are harvested and stored, it causes silver lesions on the skin of the tuber, reducing quality and weight.

The BC Potato and Vegetable Growers and E.S. Cropconsult have been working together to evaluate new products to protect potatoes for both organic and conventional potato growers.

“As growers, we need to know if we’re using a product, whether or not it works before we put the money into it,” says Val Fair, director with the BC Potato and Vegetable Growers Association. “The cost [of the product] is one factor, but the cost of the disease if the product is not effective is huge.”

A study evaluated six products – sodium bicarbonate, Actinovate SP, Phostrol, Confine, Rampart and the registered industry standard, Mertect SC. The trials tested application 24 hours and 72 hours after harvest to determine if the timing of the application has an effect.

The stored potatoes were assessed for infection immediately before product application, after three months in storage and after six months in storage.

While the study did not find a silver bullet, results showed Confine, a phosphoric acid-based fungicide, successfully reduced the progress of silver scurf in stored potatoes.

It is now available to growers as a registered control. None of the organic post-harvest solutions tested in this trial were effective.

Funding: $2,000 allocated through the federal Canadian Agriculture Adaptation Program. (SP174)

Improving Soil Quality

Cows give us a lot. Not only do they turn some of what they eat into milk or protein, but even the stuff that passes right on through their four stomachs contains useful nutrients.

It’s certainly not a new idea to use livestock manure to build up soils, but local farmers near Smithers and Houston – where nutrient depleted older pastures are common – wanted to see just how manure would compare with commercial fertilizers at enhancing forage productivity during their short growing season.

“With the high cost of fertilizer, some farmers were asking if they could afford to use it,” says Al Brandsma, a dairy farmer and president of the Smithers Farmers’ Institute, which orchestrated the trials in partnership with regional cattle and horse groups and the Ministry of Agriculture. “We wanted to show the benefits of manure and help people weigh their options.”

Aside from the effect on forage growth, there were other considerations too, from location of nearby water supplies and timing of manure application, to weed management, resulting nutrient levels and environmental factors.

The project ran over three years and compared four fertilizer types commonly used in the region (cattle manure, horse manure and two commercial fertilizers) at two local farms. Each was applied in the spring and fall.

Fall applications of all treatment types appeared to have the greatest impact on forage productivity. Encouragingly, both cattle and horse manure resulted in productivity levels at least the same or greater than the chemically fertilized sites.

“The biggest impact of the trials was to show local producers how well the manure performed when compared directly with the commercial fertilizers,” says Megan D’Arcy, a registered professional biologist who coordinated the trials and field day. “It also showed that soil testing, although expensive, provides critical information necessary for good nutrient management.”

But this doesn’t mean manure is a magic potion.

All sites, whether treated with manure or commercial fertilizers, still ended up very nitrogen deficient. Weather also plays a role.

“You can apply all the fertilizer you want, but if it doesn’t rain, it’s not going to do you a lot of good,” adds Al, who encourages farmers to test their soil.

Funding: $11,203 provided through former federal adaptation programming. (A0579)