Information in this report is based largely on observations made by Forest Resource Protection personnel, including some spot-checks of key plantations. This was again an excellent growing season for Christmas trees, similar to the past three years, and again many growers reported that their trees had few insect and disease problems.
Insects
Balsam Gall Midge, populations continue to increase, with noticeable damage to balsam fir visible in more and more Christmas tree plantations throughout the region. Damage was moderate to heavy in scattered locations. Some growers have had difficulty in controlling the larval stage of this insect with applications of chlorpyrifos at the recommended shoot length of 1.5 to 2 inches but have reported good success by applying bifenthrin (OnyxPro) at budbreak to target adults. One such grower in Walden cooperated by leaving a group of trees untreated to compare with treated trees. Trees were sprayed on May 15 with 6 oz. per acre of OnyxPro applied at about 70% budbreak using a tractor-mounted mistblower. Evaluations on August 29 showed a reduction in number of galled needles of 94% on treated trees compared to untreated trees. There is also some evidence that repeated applications of chlorpyrifos in the past in plantations such as this one have kept populations artificially high by killing the good midge that is the primary biological control agent, while not providing adequate control of P. tumifex.
Gall midge damage was observed on edge trees in some balsam plantations that have remained free of this pest in the past so careful monitoring by growers is recommended to control this pest before it becomes a larger problem.
Balsam Shootboring Sawfly population levels were heavier than in 2007, this being an even numbered year, but damage in most fir plantations was light, with some spots of moderate damage.
Balsam Twig Aphid damage was mostly light, with a few spots of heavier damage, similar to what was seen in the past three years. It’s surprising that populations have remained so low for four years in a row.
Balsam Woolly Adelgid populations remain visible on wild balsam fir trunks due to recent mild winters but mortality of large trees as mapped by aerial surveys decreased.
Damage was most evident in southern Vermont. This insect was not observed on Christmas trees but has the potential to become a problem if populations continue to build.
Cooley Spruce Gall Adelgid caused heavy damage to scattered blue spruce Christmas trees in Waterbury.
Eastern Spruce Gall Adelgid damage to white spruce remains common, at mostly light to moderate levels.
Root Aphids were associated with the foliar yellowing and stunting of recent Fraser fir transplants in Stannard.
Sawyer Beetle adults were sometimes seen but damage was infrequent.
White Pine Weevil damage to pine and spruce trees remained common throughout the state but damage remained mostly at light levels in Christmas tree plantations.
Diseases
Armillaria Root Rot continues to be a problem associated with tree mortality in more and more plantations. This is particularly true for sites that are beyond their second rotation and plantations where trees are inter-planted near old stumps. Some Armillaria caused mortality was again found on the majority of such plantations visited in northern Vermont this year. Fraser fir is much more susceptible to this root rot than balsam fir, while balsam-Fraser crosses appear to be intermediate in susceptibility. Growers who are converting to Fraser fir by planting them between mature balsam Christmas trees may be inviting a greater risk of loss due to Armillaria in the future.
Brown Spot Needle Blight was widespread and often heavy on white, red and Scots pines again this year. Infected needles turn brown from the tips back and develop small black fruiting bodies.
Cyclaneusma Needlecast of Scots pine remains very common but mostly at light levels.
Delphinella Shoot Blight was less commonly observed on balsam fir this year.
Fir-Fern Rust was widespread again this year at light to moderate levels. Needle loss was similar to or slightly less than what was seen in 2007. Although it was very noticeable on balsam fir nearly everywhere during the growing season, it was rarely heavy enough to impact marketability.
Lirula Needlecast remains common but infection levels were down this year compared to 2007. One grower reported that heavy Lirula damage in his plantation was restricted to one particular seed source. Needles killed by this fungus maintain their orientation on the stems, with retention of dead two and three year needles. Mature trees that are crowded or partially shaded are most likely to be infected. Look for long narrow black fruiting bodies down the midrib on the upper side of brown previous-year needles.
Phytophthora Root Rot continues to be associated with the death of Fraser fir and occasionally balsam fir growing on poorly or somewhat poorly drained sites in more and more locations. The extremely wet summer is likely to result in increased mortality on such sites. It appears that once the organism gets established during wet years, it persists and becomes more of a problem in years with average precipitation.
Rhizosphaera Needle Blight of fir, caused by Rhizosphaera pini, was increasingly noticeable in Christmas tree plantations this year. Some needle loss from this fungus was observed in nearly every plantation visited. Infected needles tend to bend and hang straight down from the twigs. Close inspection will reveal rows of tiny black fruiting bodies on the undersides of needles, arising from the stomates. Damage was especially heavy on crowded or shaded trees.. Harvesting of crowded trees and low pruning in plantations helps to alleviate the damage.
Rhizosphaera Needlecast of white and blue spruce remains widespread and very common, with some heavy damage to blue spruce again this year.
Scleroderris Canker has not been found in any new towns since 1986.
White Pine Blister Rust damage remains common throughout the state and continues to kill white pines at moderate levels in plantations that have had the problem in the past.
White Pine Needle Blight was observed in one Craftsbury plantation but damage was light.
Woodgate Gall Rust damage to Scots pine is decreasing, as growers remove heavily damaged trees.
Yellow Witches Broom Rust of balsam fir was again very noticeable in scattered locations. Removal of these brooms during shearing is recommended.
Frost Damage was light and was only observed in a few northern locations.
Winter Injury wasnot observed except for light injury to the south sides of some fir trees where the companion tree to the south had been harvested the previous year.
Winter-Related Branch Breakageof Fraser fir occurred in young plantations in Lyndonville and Brookfield. When an icy crust develops on the surface of the snow and then drops due to a thaw, it sometimes rips off all the branches that were covered by the ice layer. This leaves the trees without branches for a lower section of the main stem. Fraser fir must be particularly vulnerable to this type of damage, as it has not been reported for other tree species.
Animal Damage
Moose Damageremains an increasing problem in remote northern plantations, including one in Craftsbury.
Not Observed in 2008
The following pests were not observed on Christmas trees this year:
Insects: Cinara Aphids, Introduced Pine Sawfly, Pine Leaf Adelgid, Pine Needle Midge, Pales Weevil, Pine Root Collar Weevil, Pine Thrips, Spruce Speder Mite and Yellow-Headed Spruce Sawfly.
![Vermont Division of Forestry [photo]](../img/banner_protection.jpg)
Balsam Shootboring Sawfly population levels were heavier than in 2007, this being an even numbered year, but damage in most fir plantations was light, with some spots of moderate damage.
Balsam Twig Aphid damage was mostly light, with a few spots of heavier damage, similar to what was seen in the past three years. It’s surprising that populations have remained so low for four years in a row. 
rly true for sites that are beyond their second rotation and plantations where trees are inter-planted near old stumps. Some Armillaria caused mortality was again found on the majority of such plantations visited in northern Vermont this year. Fraser fir is much more susceptible to this root rot than balsam fir, while balsam-Fraser crosses appear to be intermediate in susceptibility. Growers who are converting to Fraser fir by planting them between mature balsam Christmas trees may be inviting a greater risk of loss due to Armillaria in the future. 
th the death of Fraser fir and occasionally balsam fir growing on poorly or somewhat poorly drained sites in more and more locations. The extremely wet summer is likely to result in increased mortality on such sites. It appears that once the organism gets established during wet years, it persists and becomes more of a problem in years with average precipitation.
Winter Injury was not observed except for light injury to the south sides of some fir trees where the companion tree to the south had been harvested the previous year.