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Bark beetles

With the return of the rains in most of the state since the last newsletter, the threat of bark beetle damage is reduced. The first generation adults began emerging from logs the week of June 14th in northeastern Minnesota. With the early start of the season, three generations of bark beetles are expected in northern Minnesota instead of the more usual two generations. This along with the usual moisture deficit in mid- to late-summer, means that even though the threat of damage is reduced from earlier this year it should not be ignored. Cutting in pine stands during the growing season is more likely to result in a bark beetle problem than cutting during the fall or winter. If cutting is done in pine stands during the growing season, prompt removal of logs and proper management of slash are recommended. If you have pine trees in or near your yard that died from drought and bark beetles last summer or fall, continue to monitor rainfall levels. If rain does not supply ½ to one inch of water per week, water your trees. Avoid stressing them in other ways also. Don't drive on the root systems, prune, wound or thin trees, etc.


Larch sawfly

On June 10th, adults of the larch sawfly were laying eggs in a stand in S 17- T 52- R 21 in St. Louis County. This stand was completely defoliated in 1997. Some eggs had already hatched and larvae from to ¼ inches long were feeding on the needles. Although a few pockets of defoliation caused by this sawfly are found most years, the population usually collapses after one or two years.