Bagworm. Scouting: January - Look for overwintering bags.
Cultural Control: Pick off and destroy bags in the fall and winter. Bags can be destroyed by dropping them in a can of kerosene or burying them at least 6" deep.
Chemical Control: It is important to treat in mid-June when the larvae are small and susceptible to insecticides. Larger larvae with bags are not easily controlled. See the most recent Virginia Pest Management Guide for insecticides labeled for control of bagworms.
Biological Control: Spraying with Bacillus thuringiensis (B.t., Dipel, Thuricide, etc.) in early to mid June should give satisfactory control.
Pine Tortoise Scale. Scouting: Look for darkened patches or branches on the side or top of the tree. Check the twigs and needles for the presence of the scale insects. High populations will cause browned dead shoots. The presence of honeydew (clear sticky droplets) will also indicate scales, but may also be from aphids, so it is important to identify the source. Ants, bees and wasps will feed on the honeydew and their activity may lead you to a scale infestation.
Threshold for Christmas Tree Farms and Forestry Plantations: No known threshold but the presence coupled with objectionable damage will warrant treatment. Many trees will support low non-damaging populations. The pine needle scale is heavily fed upon by predators and parasites which control it most years.
Mechanical Control: Remove infested branches or trees and burn. Works best if the infestation is localized.
Cultural Control: If chronic problems with this scale are not resolved by chemical or mechanical control it is best to switch to non-susceptible hosts such as spruces, firs, hemlock, or white pine.
Chemical Control: February or March - Treat with dormant oil. June - For severe cases two sprays 10-14 days apart are recommended during crawler emergence early in June.
Remarks: Check wind break trees for infestation as scales may spread from these trees as new seedlings are set nearby.
Nantucket Pine Tip Moth. Scouting: March - Look for small copper-colored moths flying from trees when you shake the branches or walk by the tree. At the same time assess the tree for damage from last year.
Cultural Control: July - For light infestations, simply shear off the damaged tips containing the insects. Ground beetles, ants and other scavengers should consume the tip moths once on the ground.
Chemical Control: Late April - Treat with a residual insecticide such as Cygon, cover all lateral branches and the leader. Additional spray dates: Late-June and Late-August - Treat again with Cygon if damage is heavy. See Fact Sheet 444-238 for more details.
Pine Needle Scale. Scouting: Look for the white scales in the fall and winter and note which rows or blocks need treatment. In early May and early July wrap electrical tape, sticky side up, around twigs with high populations of scale. Treat one week after the first reddish- purple crawler is found. This will usually be about mid May and mid to late July.
Threshold for Christmas Tree Farms and Forestry Plantations: Treat only if stunted growth, yellowing, or unsightly populations of scales are present.
Cultural Control: Promote vigorous growth, as scales tend to cause more damage in poorly growing trees.
Chemical Control: Apply a 2% dormant oil in late March when temperatures are above 45 degrees F. The dormant oil may remove the waxy bloom on the needles and give the trees a dull appearance but this is temporary and will be hidden by the summer's flush of growth. It would be advisable to avoid dormant oils on the year of harvest. Dormant oil is also sold as superior oil or horticultural oil. Malathion or diazinon can be applied one week after the first crawler is found on the tape or in mid May and late July. Sevin or Cygon can be used just as the eggs start to hatch which is indicated at the date of first crawler find on the tape. It is thought that applications timed for the summer generation are the most effective.
Remarks: Crawlers are blown about by wind and carried inadvertently by birds. Adult scales do not have wings and this is the only way they are moved about.
Sawflies. Scouting and Thresholds: All Sawflies: Check the upper sections of pine tree for colonies of sawflies on the tips of lateral branches or on the leader. Spot treat where you find them or treat the whole block if more then 5% of the trees are infested.
Mechanical Control: Cut off and destroy infested branches. Dip sawflies in kerosene or bury 6" deep.
Cultural Control: Avoid susceptible hosts, replant with spruce or white pine which are less frequently attacked by sawflies.
Chemical Control: Spot spray as you find colonies feeding. One method is to carry a small sprayer on the mower and stop and spray as you find the sawflies. Be sure to avoid having the tractor exhaust discharging on a nearby tree as you spray as it may burn a spot. If a whole block needs treatment, a mist blower or back-pack sprayer will work well.
Pine Spittle Bug. Scouting and Thresholds: In May through early July look for spittle masses on shoots and trunk and for dead and yellow twigs. From mid-June look for oval- shaped adults which will not have a spittle mass. Check trees of all ages in May and June. A small number of spittle masses indicate low population and little threat. If there are a large number of masses check the plantation again in the fall for dead shoots. If dead shoots are present in the fall plan to treat the next season.
Cultural Control: Maintain trees in the best possible growing condition. Avoid planting the wrong tree in the wrong spot. Consult guides or enlist help from your local county forester on which trees are best suited for your farm or site. Vigorously growing trees rarely suffer damage from spittlebugs. Plant trees that are resistant to Diplodia tip blight. Two- and three-needle pines, such as Austrian pine, tend to have more problems with Diplodia.
Chemical Control: Control spittlebugs by spraying for the adults about mid-July. To determine the best timing, check spittle masses once a week starting in late June. When 95% are empty, usually in mid-July, treat with a registered insecticide. Treat the entire plantation.
Remarks: Consult the fact sheet if you suspect you have the Saratoga spittlebug, although most growers will have the pine spittle bug.