Trisetacus mite, Trisetacus ehmanni
       

Fig. 42  Shortened, twisted needles due to trisetacus mite damage.

Distribution:  Most likely throughout the host range in B.C. 

Tree Species Attacked: Young lodgepole and ponderosa pine are susceptible.

Description & Damage Symptoms: This tiny mite feeds within the needle sheath on the current year's needles. The result is a twisting and shortening of the needles, which then turn yellow and drop prematurely. On repeatedly attacked trees, the twigs may become twisted. The pattern of attack is usually scattered, single trees throughout a stand.

Damage:  Damage is restricted to distortion and loss of the current year's needles. This can result in growth loss.

Similar Damage: Nutrient deficiencies or abiotic damage such as frost can sometimes appear similar, but abiotic damage is usually more extensive than with the trisetacus mite.

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BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated March 04, 2002