Helping trees grow in Minnesota
Getting ready for winter
Here are some tips for homeowners who want to get ready for winter and plan ahead for early spring.
|Pest or condition||Tree||Fall activity||Spring activity|
|Rodent damage||Young and thin-barked trees||Rake mulch back away 3 to 4" from tree trunk. Wrap lower 12 to 18" with aluminum foil or enclose trunk with cylinder of 1/4 " hardware cloth, extending slightly into the soil.||Remove foil or cylinder.|
|Sun scald||Young and thin-barked trees, recently pruned or transplanted trees||Wrap trunk with commercial tree wrap or plastic tree guards.||Remove all wrappings after the last frost.|
|Winter drying||Conifers||Water throughout the fall. Erect temporary barriers around yews, arbor vitae. Keep de-icing salts away from trees.||After snow melt and prior to budbreak, rinse de-icing salts off.|
|Branch removal||All||Prune live, dying or dead branches. Always cut outside of the branch collar.||Prune dead branches. Always cut outside the branch collar.|
|Anthracnose||Hardwoods||Rake and dispose or burn fallen leaves and twigs.||At budbreak, spray chlorothalonil, mancozeb or zyban.|
|Black knot||Cherry||Prune away infected branches at least 4" below the knot. Apply lime-sulfur as dormant spray following pruning.||At dormant-bud, pink-bud, full bloom and 3 wks. later, apply thiophanate-methyl.|
|Fire blight||Apples, pears and mt. ash||Remove and destroy all infected material.||Apply basic copper sulfate or copper hydroxide as directed on the label.|
|Dutch elm disease||Elms||Remove dead trees and debark wood to be stored for firewood. If you live in a community with access to it, a vibratory plow line should be installed prior to cutting tree(s) down.||Do not prune after April 15th .|
|Oak wilt.||Oaks||Remove dead trees and debark wood to be stored for firewood. If you live in a community with access to it, a vibratory plow line should be installed prior to cutting tree(s) down.||Do not prune after April 15th|
|White pine blister rust||White pine||Prune dying branches anywhere in the crown. Prune lowest whorls of branches to prevent infection.|
|Cytospora canker||Spruces||Prune and destroy infected branches. Disinfect tools between cuts with rubbing alcohol.|
|Rhizosphaera needlecast||Spruces||Prune away lower branches to promote air circulation.||Make 2 applications of chlorothalonil as directed on label.|
|Scab and canker||Willows||Rake and destroy fallen leaves and twigs. Prune out diseased branches. Apply Bordeaux (8-8-100)after leaf drop.||2 or 3 applications of Bordeaux (6-6-100) starting when leaves first visible.|
|Tar spot||Maples||Rake and compost or destroy leaves.|
|Birch leaf miner||Birches||Spray foliage when mines first appear. Use acephate or dimethoate.|
|Bronze birch borer Prune away dead branches.||Birches||Prune away dead branches. Dispose , debark or destroy the wood.||Dispose , debark or destroy the wood.|
|Cankerworms||Many hardwoods||Spray at leaf expansion using Bt or acephate, carbaryl, malathion, diazinon, insecticidal soap, etc.|
|Elm leafminer||Elms||Spray foliage with dimethoate when mines first appear.|
|Mite galls||Maple, elm, ash, hackberry and more.||Spray carbaryl or dicofol at or just prior to budbreak.|
|Two-lined chestnut borer Prune away dead branches.||Oaks||Prune away dead branches. Dispose , debark or destroy the wood.||Dispose , debark or destroy the wood by April 15th.|
|Spruce gall adelgids||Spruces||Clip and destroy galls.||As buds swell, spray acephate, carbaryl or diazinon before galls form.|
|Pine needle scale||Pines, spruces||In late May, apply acephate, carbaryl, chlorpyrifos, cyfluthrin, insecticidal soap or malathion.|
|White pine weevil||Pines||Spray terminals with chlorpyrifos in mid to late April.|
Information in the above table was derived from the following publications:
Ash, C., M. Draper, H. Laney and D. Gallenberg. 1995. Disease Management Recommendations for Trees and Shrubs. Minn. Ext. Serv. Pub. BU-6659-S.
Hahn, J., R. Wawrzynski and V. Krischik. 1996. Insecticide Suggestions to Manage Landscape Trees and Shrub Insects. Minn. Ext. Serv. Pub. FO-0704-B.
Swanson, B. and R. Rideout. 1992. Protecting trees and shrubs against winter damage. Minn. Ext. Serv. Pub. AG-FO-1411-B.