As we move out of the winter season and into spring, it is important to understand how the changing weather affects your trees and landscape. There are many actions we can take to give our plants the best possible chances for survival, but Mother Nature is the one who is really in charge. Per the Old Farmer’s Almanac, the weather conditions for spring 2017 are predicted to be cool and wet. This forecast, piggybacking off a relatively mild winter, is setting up a season that could be quite favorable for insects and diseases.
Overwintering insects, like boring beetles, gypsy moth, and scale insects, have higher survival rates when winter temperatures remain above extreme cold (extreme cold is defined as temperatures below 20°F for more than 14 days in a row). These insects will overwinter in loose bark, tree cavities, and in the top layer of soil. Our SE Wisconsin winter did not see these kinds of temperature extremes this year which means overwintering insects can be expected to survive in above-normal populations.
Fungal diseases, such as Apple Scab, Rust, and Powdery Mildew, can also survive mild winters better than winters with extreme cold temperatures. Fungal pathogens also spread faster and more vigorously when spring conditions are cool and wet.
Because the 2016-2017 winter season was mild (average temperature: 29.7 °F, National Weather Service), we need to have a good plan for protecting our trees and landscapes for the 2017 growing season. Choosing the right plant for the right location is very important; the plant’s native range, the landscape’s soil conditions, and sunlight availability all affect a plant’s chances of survival. A tree must have adequate water and nutrients as well; fertilization and regular watering practices can help promote tree health. Remember that a healthy tree has a better chance of combating insects and diseases. Routine inspection from an ISA Certified Arborist can help to develop a plant health care program to maintain and improve the health and quality of your landscape. If you have any questions, contact your ISA certified arborist today.
Written by Tony Seidl
ISA Certified Arborist NY 5908-A
Hoppe Tree Service Operations Manager–South Division