August 1, 1996 * Vol . 6, No. 7
SFU tests new controls for potato blight
A strain of the potato blight now threatening crops in eastern Canada is
only a sizeable rainfall away from infecting B.C. potatoes.
Prof. Zamir Punja, director of SFU's centre
for pestology, is currently involved in a three-year study into ways
of fighting the fungus which destroys potatoes and caused the infamous Irish
potato famine of 150 years ago.
Punja says the fungus only needs periods of cool, rainy weather to re-emerge
as a problem in the Fraser Valley or elsewhere in B.C. The fungus is impossible
to eradicate because it is easily spread by the wind, or through transplants.
It also lies dormant in the soil during dry weather, poised to infect nearby
plants with the arrival of the appropriate, wet conditions.
Punja says tomatoes are also under serious threat because both plants are
susceptible to the same strains of fungus. "That's why you can't grow
tomatoes in Pemberton where farmers produce large quantities of seed potatoes,"
he explains.
"In 1993 we had a bad spell where fungus ravaged local potato crops,"
recalls Punja. "It was so bad, some farmers thought they would never
be able to plant potatoes again. But they did and the weather has been co-operating
lately."
Punja says the only weapons that farmers currently have are chemicals, but
the fungus is so virulent in particularly wet conditions that control may
require treatments every few days. Not only is this expensive, but applications
are not always effective for control.
The natural barrier known as the Rocky Mountains means that the fungal strains
currently threatening eastern potato crops are different than those in B.C.
Punja says his research team and others are investigating a number of new
fungicides which look promising for B.C. strains, but no breakthroughs are
expected anytime soon.
© Simon Fraser University, Media and Public Relations