Most damage caused by insects and fungi is manageable and mainly aesthetic; it is mostly when pest populations become unbalanced (usually caused by unusual weather conditions or previous human "interventions") that a healthy tree is in danger of dying from pests.
-Observe your plants for signs of stress - a stressed tree will not fight off insects and disease as well. Stress usually shows up first in the leaves through discolouration or shape distortion. Contact us or use reputable pest identification resources if you suspect your tree is struggling
-If a pest has been identified, look for organic solution or cultural control. Sometimes all a plant needs is some proper pruning or correct amounts of irrigation.
-Never spray pesticides preventatively - pesticides disrupt the balance of insect or fungal populations which include a host of insect or fungal allies; preventative use tends to set up worse infestations in the future by reducing the predator populations in your local area. Always identify which pest is becoming a problem before choosing a remedy: some treatments will not be as effective, especially if an insecticide is sprayed on a fungal issue, or vice-versa. The best prevention is ensuring the plant has healthy soil, a preferred environmental location, and adequate moisture and nutrients.
-Timing is essential with almost every intervention, and there is no point in wasting money on ineffective treatments. Care must also be taken to follow all labels. If a pesticide like malathion must be used to control outbreaks of insects like curculio on fruit trees, it should be applied precisely.
-Fungal diseases usually show up as powdery substances or mushroom-like protrusions, or spots, blotches, and/or discolourations on branches and leaves. Weather conditions are the top contributor - different fungi prefer different temperatures, but the worst tend to spread at 25-30C with humidity. Harmful diseases like fireblight will kill branches from the tips of branches inward toward the stem. Watch out for entire leaves losing their green colour, or dying branches, especially if the new growth is curled over like a shepherd's crook.
-Irrigate the roots, not the leaves: many fungal issues are caused by leaves staying wet overnight - if you can't avoid overhead irrigation, water in the early morning.
-Remove diseased leaves in fall - don't compost diseased leaves or branches; particularly deadly diseases like fireblight. At the same time, it is very useful to compost healthy branch clippings and leaves near your woody plants to encourage beneficial soil organisms. These beneficial fungi and bacteria increase the health of the soil and will allow the tree to fight off pest diseases easier.
-Copper or sulphur sprays can be effective against fungal or bacterial issues - always read the labels to make sure the product will treat the current disease. Avoid over-applying these fungicides on the leaves since they may get into the soil. The more often they are applied, the more reliant a tree or shrub becomes on human intervention. Tolerating minor aesthetic infections may save costly future interventions.
-Watch out for small holes chewed out of the leaves, or leaf skeletonization. Soft-bodied worms or bugs tend to be the worst culprits in Manitoba, whereas a lot of their predators tend to be hard-shelled. Get to know your insect allies like Ladybugs, Minute Pirate Bugs, Ground and Rove Beetles, Stinkbugs, Lacewings, and Damsel Bugs. Plant a wide variety of shrubs and flowers to encourage healthy insect populations that keep the pests in check.
-In a heavy outbreak, Diatomaceous Earth (D.E.) or horticultural oils are useful solutions for leaf-eating pests. D.E. can be found at local agriculture supply stores. When applying D.E., wear a mask because the powder can be harmful to your lungs, or mix it with water and spray on the leaves and soil - just avoid spraying flowers. D.E. and oils must be re-applied after rainfall.
-If an insect like plum curculio on fruit trees has been present in previous years causing high percentage of fruit damage, use insecticides like malathion just after all the flowers have dropped, and then re-apply a week later. The timing is critical, and it cannot be sprayed while pollinators are flying. Traps can also be set up to target specific pests.
-When in doubt, we can help you identify your plant stresses and recommend sustainable approaches to pest management.