Huge clouds of butterflies combined with the snow

News 15 July, 2017
  • Photo Didier Debusschere
    The investigator Yan Boulanger is studying the movements of the butterflies of the budworm the spruce.

    Hugo Duchaine

    Saturday, 15 July, 2017 08:00

    Saturday, 15 July, 2017 08:00

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    The butterflies of the budworm the spruce, which is ravaging the forests of Quebec, are now so numerous that the weather radars were taken to the snow storms in the east of the province.

    The epidemic of this insect destroyer, which has been raging for more than 10 years in the province, continues to gain ground, to the great fear of the forest producers. Already, more than seven million hectares of forest are infested, that is, 140 times the size of the island of Montreal.

    In the night from Thursday to Friday, the weather radar of the canadian government showed a snow storm that plagued the south of the Côte-Nord and Bas-Saint-Laurent. But the dreaded white flakes were none other than a butterfly in search of places to lay their eggs.

    “There are millions and billions who disperse from one region to the other […] with the winds, they can travel up to 200 km in the space of a night,” says the researcher in forest ecology, Yan Boulanger, who is studying the impact of these trips.

    His research for the canadian forest Service are aimed at determining which moves the epidemic, when more and more regions in Québec are affected.

    After the Côte-Nord, Abitibi and the Saguenay, more and more of moths of the spruce budworm are now observed in the Bas-Saint-Laurent, the Gaspé peninsula, the Laurentides and Centre-du-Québec.

    In search of food

    “Bigger isn’t passed yet, this is only the beginning of the flights of the mass,” observes the researcher. It is still too early to say where direct the butterflies, presumably in search of new food.

    In 2013, these flights-of-mass, had struck the imagination to Rimouski, when the butterflies of moths, which ravaged the North Shore, crossed the St. Lawrence river. The shop windows of shops and cars were completely covered with insects.

    These flights, which occur only during epidemics, occur every year, according to Mr. Baker, but are growing more and more every four or five years, when the trees begin to die within a sector.

    Cuts preventive

    For his part, Yves Laurencelle, owner of a private forest in the south of the Côte-Nord region, where the insect is gaining ground, will be forced to cut its trees this summer if he wants to avoid losing.

    “These are trees that had to wait another 15 years before maturity. I had to cut for my retirement, financially it just thwart my plans “, said the man 45 years of age, who sees his neighbors doing the same thing.

    On the other side of the river, the president of the Syndicat des producteurs de bois de la Côte-du-Sud, Christmas, Dionne, contacts also owners of private forests to make cuts as a preventive measure.

    “This is what we see on the horizon and it has no control,” he says, helpless. “The big question, is whether plants will be able to take it all in “, is concerned, Mr. Dionne.

    An epidemic that worsens every year

    The epidemic of moths of the spruce budworm is like a forest fire which is never extinguished only when everything has burned, described by professor of forest ecology at UQAM, Daniel Kneeshaw.

    “There’s nothing else to do than trying to protect the trees, such as firs baumiers, who are particularly vulnerable. The population of moths is too large to be controlled, ” says the expert.

    “It’s increasing every year, even if the explosion has slowed in the last year,” he said, adding that half a million hectares have been affected.

    If the current outbreak has not yet reached the record acreage of that observed in the 1970s, this is the first time that the northern province is severely affected.

    “It is unheard of, mortality as that observed on the North Shore […] What is intriguing is that this is also the first time that an outbreak starts in the north,” said Mr. Kneeshaw, who estimates that climate change may have played a role in the dispersal and damage in the last 10 years.


    For his part, Christian Hébert, canadian forest Service, points out that, even if the insect begins to defoliate areas of the Laurentians and Mauricie, in the forests of western Quebec are less vulnerable, because they are more diversified.

    Still, it is not less than 10 % of the forest wealth of Quebec is in danger, he noted.

    Watering air

    In order to prevent the trees from dying, the government of Quebec is stepping up its efforts each year with watering air against the budworm the spruce.

    However, Mr. Hébert points out that only an area of 240 000 hectares will be watered, which represents less than 5 % of the affected forest.

    The epidemic will end of itself, ” he said, when the food will be less abundant for the insect and its natural enemies, such as small parasites, will succeed to take over.

    Insect destroyer

    Photo courtesy

    • The insect is the most destructive stands of conifers of North America
    • It consumes mainly the foliage annual of the balsam fir and white spruce
    • At maturity, the caterpillars measure from 20 to 30 millimeters in length
    • The butterfly only has a life span of 10 days, but the female lays up to 200 eggs, which she deposits on the undersides of needles

    Photo courtesy

    Forests decimated

    Photo courtesy

    • Seven million hectares are affected in Quebec, or 140 times the island of Montreal
    • The tree is more vulnerable to the budworm spruce
    • During an outbreak, the trees, the weakest usually die after three or four years of defoliation severe
    • Epidemics occur about every 30 years. In Quebec, epidemics began in 1909, 1938, 1967 and 1992.

    Source : ministry of Forests, Wildlife and Parks

    Butterflies play tricks with the radar

    Photo courtesy

    “The radar is not able to distinguish between snow, hail, or the butterflies,” explains researcher Yan Boulanger.

    The clouds of pale blue on the radar image, especially around the towns of Amqui and Matane, are, in fact, several millions of butterflies that fly to more than 100 meters of altitude.

    M Baker stressed, however, that a cloud of precipitation moves differently than a cloud of millions of tiny butterflies.

    “It has a special signature, a bit like a cloud of smoke. It is much slower than a displacement of the cells of thunderstorms and it is in a lower altitude, ” explains the expert.