So we had so much rain this spring my trees are going to do really well this year, right? Well, yes and no.

Trees that are susceptible to the common diseases will likely see an increase in disease activity this year.

Rain is good for our trees, however, with all the wet weather we had this spring, and with the cool temperatures, fungal diseases are thriving now. When new foliage first emerges from the bud, is is very prone to fungal attack as the leaf is soft and without a protective cuticle layer. At this point it is easy for a fungal spore to penetrate the leaf’s surface and begin an infection.

I have seen many diseases on deciduous trees this spring, including oak and dogwood anthracnose, scab and rust on apples and crabapples, leaf spot on birch, brown rot on cherry, and verticillium wilt on many Norway maples. Many evergreens are pushing out new growth now, and we will likely see lots of diplodia and ploioderma on hard pines, needlecast on spruce and fir, and phomopsis and other tip blights of juniper.

So what can I do now?

It may be too late to begin preventative fungicide treatments on deciduous trees, but treating evergreens now may be beneficial for this year. You should also consider overall tree health- keep the tree as vigorous as possible by treating with bio-stimulants and fertilization. Also, water your trees this summer when it becomes hot and dry to further reduce stress. At Mayer Tree Service, we are here to consult with you and make recommendations to promote the health of your landscape.