Identification

• Root weevils are often visible and may be easy to see with the naked eye. Sugar pines are susceptible to the pine root collar weevil, which attacks the tree near the base of the trunk. Adult root weevils are about 1 inch in length and dark brown with white-spotted wings and bodies and a down-turned snout. Larvae are also problematic and can be identified by their white bodies and brown heads. You may notice larvae burrowing into the bark of the sugar pine, causing sap to leak out onto the ground. Adults also hide in the sugar pine's loose bark during the day and often come out only at night. Adult and larvae weevils will often remain in the sap left on the ground during winter. Root weevils do not fly and must crawl up the sugar pine to feed on it.
  
  

Root and Trunk Damage

• One of the best ways to detect root weevils is to examine the grafted sugar pine's trunk 1/2-inch under the soil. You may see them gathered there; if you see a sawdust-like substance, larvae have invaded the trunk and caused the base to girdle. Also look for soaked, black pitch near the root collar of the tree. Once larvae start to feed, sap will soak the soil around the tree, often reaching several inches from the trunk. In time, the trunk will break near the ground or be easily pushed over by wind. If you have a small sugar pine that is under 4 inches in diameter, it can be killed within a year by just a few root weevil larvae.
  
  

Foliage and Branch Damage

• The presence of weevils can also be detected by obvious damage to the sugar pine's foliage and branches. Foliage will quickly turn from a vibrant green color to yellow, then red or brown. When adult root weevils feed on branches, branches die and turn red in color. You may notice that a shoot or branch has been gnawed at its base, closest to the sugar pine's trunk. This may also be accompanied by pitch.
  
  

Remedies

• There are various ways you can prevent or get rid of root weevils before they destroy your grafted sugar pine. Planting resistant trees, such as white pine, spruce or fir, around your sugar pine can help deter root weevils. Keeping the base of the tree exposed to sunlight and fresh air by removing branches on the lower foot of the tree can also keep root weevils at bay. Spraying the base of your sugar pine with an insecticide that contains bifenthrin, permethrin or acephate in late spring, around mid-May, can help prevent heavy infestations.