Spring brings caterpillars and tree disease

This spring will see two plagues of nature sweeping through Cold Lake.

Residents are likely to remember the wiggling masses of Tent Caterpillars that swarmed the area last spring. Considering the caterpillars are currently in the peak of their seven-year cycle, numbers are expected to decrease over the next couple of years until they are virtually unnoticeable in quantity.

City of Cold Lake staff are taking a mechanical approach to controlling the caterpillar population before they hatch, opposed to chemical. There has also been an increased sighting of house flies, which are one of the natural predators of the Tent Caterpillar. A sudden increase in the black fly population signals an end to the caterpillar cycle.

Residents can also take some control on their property. Before they hatch, be on the lookout for Tent Caterpillar egg masses. These can be pruned off the tree and disposed of with regular household waste. Once the caterpillars have started, a homemade solution of dish soap, water, and vegetable oil can be sprayed onto the newly emerged caterpillars. Once sprayed directly onto the caterpillars, the mixture prevents oxygen intake through the skin. It is best to do this in the early morning when the caterpillars are grouped together.

Another issue plaguing Cold Lake this spring is Black Knot.

Black Knot is a fungal disease that affects Prunus tree species, such as Maydays and choke cherries. The fungus causes brown and black knot-like swelling on the branches of the trees, which if left untreated, will eventually kill the tree and potentially spread to others.

Residents are asked to keep watch for Black Knot this spring and summer, and if spotted, to cut off infected branches. Remove the branch a minimum of eight inches away from the infected area, and be sure to sterilize any pruning tools with a bleach solution in between cuts to prevent spread of spores to other areas of the tree. Removed branches must be disposed of immediately – the fungus can continue to produce and spread up to four months after removal. Do not compost these clippings.

This year, the City of Cold Lake will be providing a burn bin at the Cold Lake Transfer Station for residents to dispose of their Black Knot tree clippings. These branches can be dropped off free of charge, and will be disposed of safely by city staff in a controlled burning container.