Predictions Revealed: Diagnostic Forecast for 2017
Written by: Tony Arnoldi, Board Certified Master Arborist WI-0102B
Spring is nearly here, and as I write this in mid-February, it is 60 degrees outside! If this weather pattern holds, it could be a similar start like we had in 2012. In that year we had a warm, early spring and the summer was exceptionally hot, with below normal precipitation. If this turns out to be the case, the timetables for treating most insect and disease issues will be moved up (be earlier). This is because the accumulation of heat in spring coincides with the development (growth) of trees, shrubs, perennials and also the timing of the insect and disease issues that attack them. Using the trajectories of pest problems seen last year can help us understand what to expect this year:
Ips Bark Beetles – that attack conifers had been on the decline because the recent wet springs relieved some tree stress. Stressed trees are what the Ips Beetles need for successful infestation. If the heat gets turned up and moisture is limiting, we could see a rise in Ips beetles.
Conifer fungal diseases like Diplodia tip blight, Dothistroma needlecast (pines) and Rhizosphaera needlecast (spruces) need the wet springs to get spores to successfully germinate on the fresh new needles. Since the last 3 springs were indeed sufficiently rainy, the amount of these fungal diseases has increased.
Fireblight – on crabapples, apples, pears and serviceberries is a bacterial infection that has also increased with the wet weather. Once a tree has developed fireblight, more infections can manifest in subsequent years from bacteria that have been moved to new parts of the tree from rain splash, etc. Careful pruning and treatment can help to stop this progression.
Armillaria root rot – a common oak (and other tree) problem, was observed on numerous oaks in 2016. Alternating wet and dry periods favor many types of root rot. Look for this to continue being an issue for many oaks.
Viburnum Leaf Beetle – is a new insect for our area. It started about 3 years ago in Fox Point and has quickly spread out from there. It has exploded in pockets here and there to defoliate many species of viburnum (shrubs). This happens rapidly in early May – look for numerous holes in the leaves which eventually multiply to become shredded leaves. It would be advisable to take inventory and monitor the viburnums in your yard to keep track of their leaf condition. If many holes appear, a quick treatment can halt it for the year.
Gypsy Moth – some good news here – the wet springs have been beneficial in promoting good fungal and virus diseases of the caterpillars that has killed them before getting much of a start in recent years. I suspect it will take a series of years with dry springs to encourage a rise in their numbers. But vigilance is always prudent…
Emerald Ash Borer – I really needed to include this as the grand finale. Yes they are increasing, and most ash have at least some ongoing infestation at this point. The observations indicate that this could be the last year or so to be able to choose any ash that look good yet to attempt to save them. My interactions with the public indicate that it is not perceived to be all that bad yet, but the damage will accumulate rapidly to give us many dead ash in a relatively short period of time. Action is needed now…
As always, your Wachtel Certified Arborist is ready to help you with these or any other tree concern you may have. Call us for a review of your property.