White pine weevil

The white pine weevil can seriously impact the growth of young eastern white pine by causing the terminal leader to die back. The weevil can create stem deformation, increase the susceptibility to wood decay organisms, reduce growth andz increase tree mortality. Weevil attacks can reduce tree height growth by 50 percent annually and when the dominant leader is removed, the tree will develop forks or become bushy. Early white pine weevil evidence is apparent in the spring when tiny droplets of resin are exuded from feeding punctures made by the adult insect. Larvae will girdle the leader and cause the needles of the tree to wilt. Eastern white pines infested with the weevil will appear either with brownish needle whirls or may appear completely white as pitch from the tree
crystallizes along branches.

For more information on white pine weevil, visit the following link:

http://www.na.fs.fed.us/spfo/pubs/fidls/wp_weevil/weevil.htm,

Preventing weevil infestation

Trees grown in open spaces that receive full sunlight on the terminal shoots are vulnerable to weevil attack.

• The preferred method of stand protection is finding the balance between shade from crown closure and adequate light to maintain tree growth.

• Stands established under a hardwood canopy have shown lower susceptibility levels for weevil outbreak.

• Maintaining high densities of young white pines until the stand reaches 20 feet in height has also reduced the level of weevil damage.

• There are chemical treatments that have been used, but these should only be considered when more than
  5 percent of the trees are infested and an economic evaluation warrants such a decision.

Pales weevil

Pales weevils are attracted to freshly cut over pinelands where they breed in stumps and old root systems. Seedling mortality may approach 60 percent in areas where pales weevil is dominant. Adults will feed on the aboveground bark tissue of seedlings, causing the resin of the seedling to crystallize and giving a “sugary” appearance to damaged individuals. On older trees, the girdling of twigs and branches will produce poor form and a bushy appearance.

There are two effective measures for preventing weevil-caused mortality of seedlings – chemical spraying or delayed planting. Seedlings can be treated with an insecticide to prevent damage prior to planting. If the cost of chemical dips is high, delayed planting should be the selected option.

For more information, please visit the following link:

www.entomology.umn.edu/cues/Web/175PalesWeevil.pdf