Spruce and pine trees are found throughout our MN landscapes. They can add great beauty to your land if they are properly maintained. However, stress to the trees can lead to fungal infections and/or insect problems. PTP has created some general maintenance programs to keep your evergreens looking their best.
Spring: Two foliar spray applications are applied in the spring or early summer a few weeks apart. The spray consists of a particular mixture of fungicides and insecticides that we have chosen to specifically target the pests affecting your trees.
Fall: A fertilizer that is specifically blended for trees is applied 10”-15” below the soil’s surface. This allows the targeted tree to take up the majority of the nutrients. Half of the nitrogen in this blend is immediately available to the tree; the other half is slowly broken down in the soil by microbes and will be available to the tree the entire next growing season. There are also a number of vital micronutrients in the blend that are essential to trees in small amounts.
Special Cases: In some circumstances it is necessary to add a systemic insecticide to the fertilizer being applied in the fall. This systemic insecticide is taken up through the tree’s vascular tissue. It protects against many common insects for an entire growing season and is highly effective.
Common Evergreen Insect and Disease Problems:
Rhizosphaera Needle Cast: Inner needles first turn purplish, then orange, then fall off.
Cytospora Canker: Cankers form on branches leading to death of entire branch.
Sawflies: Larvae about 1/3” long feed on healthy needles completely removing them from the branch Needle Scales: Armored scales attach to needle and feed by sucking sap
Spruce Gall: An abnormal growth is found on the branch. Once the gall has formed it is too late to do anything except prepare for the next season.
Fungal – Brown Spot and Dothistroma Needle Blight: Needles become infected and cause death from the infection point outwards.
Tip Blight: Branch shoots my curl or turn brown and die.
Sawflies: Larvae about ½” long feed on healthy needles completely removing them from the branch.
Needle Scales: Armored scales attach to needle and feed by sucking sapDownload PDF
Useful links:U of M: Diseases and Insect Pests of Conifers U of M: Fertilizing Evergreens