The pine root collar weevil can infest many types of pine trees including Scotch, Austrian, red, and mugho. The adults measure around ½ inch in length and are reddish-brown in color. Eggs are primarily laid during the spring, but may continue throughout the summer season.
The larvae of the pine root collar weevil feed in the inner bark of the root collar of the tree – where the trunk and roots meet at the soil line. Feeding may also take place in large roots below the soil line. The larval feeding may girdle trees at the soil line, killing them and even causing them to fall over!
Young, smaller pine trees growing amidst open land are most susceptible to attack from the pine root collar weevil. Pay attention to trees that are leaning or off-center. The soil around infected trees will show dark resin oozing from the tree’s bark and is a tell-tale sign of infection.
Control of the pine root collar weevil is difficult because the larvae reside either under the soil or under the bark of the tree. Treatment sprays can be used to control the population of the weevil, but the best outcomes from treatment come from early detection. Inspect your trees for signs of disease regularly and in nurseries and Christmas tree farms, random inspections should be completed annually in May and early August to help detect infestations.
If you are considering planting new trees on your property, susceptible pine trees should be planted at least ½ mile away from weevil infested trees to minimize the risk of spread. Planting resistant varieties of Scotch pine trees can also help to lower risk of disease. If your trees are currently battling an infestation or you are considering planting new trees, call or text Eric for a free consultation.