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Pine Tree Beetles

Ningthoujam Sandhyarani
Beetles are one of the damaging pests that attack nearly all the pine varieties. Some of the commonly observed pine tree beetles are sawyer beetles, bark beetles, and southern beetles.
Pine trees, of the genus Pinus of the family Pinaceae are evergreen coniferous trees with needle-shaped leaves. About 115 species of pine are identified from all over the world. They are distributed widely, especially in cold climatic conditions.
Some species of pines are adapted to extremely cold areas, where there is snowfall for more than six months in a year.The barks of pine trees are usually thick and resinous. In addition to the needle leaves, a mature pine tree exhibits another scale leaves that are brown.
Almost all the varieties exhibit a characteristic shape and/or canopy. Hence, they are usually planted for designing the landscape and other decorative purposes. Commercially, they are also grown for timber, wood pulp, resin and other valuable products.

Pine Tree Problems: Beetles
Though pine trees are harder than other decorative plants, they are susceptible to some diseases and pests. The common diseases are sapsucker damage, needle blight, tip blight, gall rust, fusiform rust, root rot; and damaging pests include beetle, sawfly, scale, spider mite, nematode, moth and weevil. If not controlled soon, the problems can be devastating.

Pine Sawyer Beetle

Pine Sawyer beetles are one of the most damaging pests. These beetles indirectly cause pine wilt by serving as a carrier organism for pinewood nematode, Bursaphelenchus xylophilus.
This nematode blocks the water conducting system of pines, resulting in brown leaves on specific branches or in rare cases, the entire tree. These beetles spread the nematode from infected plants to other healthy trees. Nearly all species of pine are susceptible to this type of beetles.

Pine Bark Beetle

Another harmful pine beetle is of the dendroctonus species, feeding voraciously on the barks of pine trees. Usually, it attacks the middle and upper portion of the trunk. The pine bark beetle burrows into the bark and creates a tunnel to reach the center of the trunk.
Once it reaches the middle of the tree trunk, the adult female lays eggs. The eggs hatch into larvae, which then feed on the barks. The larvae pupate and complete their life cycle in the infested pine tree. Later, they emerge as matured adults from the holes.
Few notable signs of infestation are yellowing or browning of foliage, small holes on tree trunk and accumulation of tube-shaped masses around holes. Since the beetles live under the bark of pine tree, they are not easily spotted. Even a mild infestation with a few beetles can weaken a pine tree. Severe infestation can cause death of the entire tree.

Southern Pine Beetle

Southern pine beetles infest the pine trees independently or in association with engraver and turpentine beetles. Similar to the bark beetle, southern beetles bore through the bark and feed on plant sap. The sign of attack from this species of beetle is the occurrence of pitch tubes or red boring dust on the bark or at the base of the tree.
The female lays eggs, and the larvae, after hatching, continue to feed on the bark and sap. Overall, they affect water and nutrient assimilation, leading to weakening and finally, death of the pine tree. Southern pine beetles have the potential to kill a pine tree within a few days after infestation.
To prevent pine tree beetles, the best method is to keep the trees healthy. Regular pruning is advised to remove the weak and diseased plant parts. Doing so will help control pests and stop the spread of diseases to the remaining parts of the tree. If required, you can spray proper insecticides to the diseased pine tree by consulting a horticulturist.