2020

LVM Calls for Timely Prevention of the Spread of European Spruce Bark Beetles

Although the spring of 2020 has been relatively cold and windy and the flying period of the most dangerous pest for spruce stands – the European spruce bark beetle (Ips typographus) – is still expected, JSC “Latvia's State Forests” (LVM) calls on forest owners to be attentive and report to the State Forest Service any damage caused by spruce bark beetles by filling in a special questionnaire and to prevent their spread.

“The bark beetle is among the most dangerous pests in the world and the most dangerous pest in Latvia. The bark beetle is able to cause more damage to Latvia's forests than all other pests taken together. Therefore, this problem should be addressed very seriously,” tells Agnis Šmits, Leading Researcher at the Latvian State Forest Research Institute “Silava”, pointing out that the bark beetle population increased more than twice in 2019 as compared to 2018.

The largest increase in spruce bark beetle population has been recorded in the north-eastern part of Latvia – in the territory of Gauja National Park around Cēsis and in the vicinity of Lubāna, where spruce stands suffered heavily in the floods of 2017, and were infested by spruce bark beetles in 2018.

In areas where spruce stands have been damaged by winds in the previous autumn and winter period, it is necessary to develop these stands before the beginning of the spruce bark beetle flying season, because this pest first develops in weakened spruces.

“When the air temperature reaches +20 ⁰C, bark beetles look for weakened spruces to develop. However, if the number of flying beetles is large, then the choice falls in favour of the largest and thickest spruce grown. About 3 000 to 5 000 beetles are enough to destroy one medium-thick spruce. If any wind-dropped, broken spruces are not removed from the forest in a timely manner, then up to 70 000 beetles can multiply in each cubic metre of wood left in the forest – thus destroying up to 20 healthy trees,” says Agnis Smits.

The researcher reminds that the European spruce bark beetle was, is and will be widely spread both in Latvia and in the world, therefore it is crucially important to take timely measures to control it. During the summer months, the spruce stands on the property should be inspected regularly to check for any bark damage. About 1 mm large holes (run-ins) in trees indicate an infestation of bark beetles. The attack of bark beetles is also characterised by brown bark flour, which accumulates at the root collar or a small resin funnel at a run-in.