Features Agronomy Diseases
Heatwave keeps late blight in check but stems sunburn

One Alliston farmer describes the 2.5 inches of rain that fell in the Alliston, Ont. area on July 5, as “a lifesaver” according to Eugenia Banks’ latest potato update. In other potato production areas, growers have been irrigating. 

However, the heatwave has kept late blight in check and no late blight spores were detected by the eight spore traps placed across Ontario. 

The crop in Simcoe-Delhi is described as “pretty good” taking into consideration the heat and humidity, according to Joe Lach, a potato farmer in the Simcoe area. Simcoe has not received a lot of rain so Lach has been irrigating instead. However, Lach has found three inch tubers, and expects cooler temperatures and rain will bring this crop on before the end of the month. 

Some growers of the first eaarly table variety Envol have noticed early senescene, or deterioration, in their crop. The variety does not tolerate heat stress well and tends to go down early when heat waves occur. However, Envols grown in chloropicrin fumigated fields show more tolerance to heat stress and Verticillium. 

Sunburnt stems have been observed in the Envol variety. As the canopy opens up, stems are exposed to the sun. The stems shrink and turn white.