If your trees have EAB
As we slowly creep our way into spring, I have been fielding quite a few questions from area residents about Emerald Ash Borer. As many of you probably know, Emerald Ash Borer (EAB) is now in Redwood County and so it is time that this summer we should be looking for this pest in our ash trees.
The problem with ash trees is that there are several diseases that may cause you to think that your tree has EAB. In the spring Ash trees are susceptible to a disease called Ash Anthracnose, which causes them to lose their leaves. This is something that happens when it is particularly wet outside for longer periods of time. We have not seen much of this behavior lately because it has been so dry. It is also natural for woodpeckers to go after other insects and insect larvae that may be underneath bark on trees. Ash trees also tend to be sort of messy trees in that they will lose branches throughout the year rather randomly.
I have been asked what to do since EAB is in the next county over. You can chose to wait and see what happens. Generally speaking, the U of M Extension suggests waiting until EAB is within 15 miles of your property before treating any trees. You can also choose to be proactive and start using an insecticide just in case it has moved this way. We do have insecticides that we can use and it is very, very important to follow the label of these insecticides carefully. Note that these insecticides are not a one-time use and done but rather are labeled for one or two years of effectiveness. Depending on the insect, you may have to treat more than one time as well. If you have a tree that is unhealthy, it might be best to take that tree down instead of spending the money on it and replacing it with another species of tree.
The insecticides will need to be calculated based on how big the tree is and there are a few insecticides that can be used that are applied onto the soil around the base of the tree. Most trees have most of their roots in the top 18 inches of the soil and so the soil-applied drenches are probably the most easiest to use. The companies that make these types of treatments are Bayer, Bonide, Ferti-lome and Ortho.
The ground must not be frozen so it is important to wait until you know for sure that the ground has thawed or you will not only be throwing your treatment away but it could run off into lakes, rivers and streams. The directions will ask that these products should not be used if within 25 feet of water or a storm drain. Don’t apply when it is windy or if rainfall is expected. Don’t apply if the ground is saturated with water. Moreover, remember, more is not better. The excess chemicals can potentially leach into groundwater. If you have an ash tree that is near water including sump pump areas or a wellhead, you may want to consider taking it down rather than risk getting the insecticide into the water.
If you would like to have a great guide on hand to help you answer some of the questions that you may have, go to the following website at https://www.mda.state.mn.us/sites/default/files/inline-files/eabtreatmentguide2_1.pdf
This guide will not only help you to identify the EAB insect it also gives homeowners instructions on treatment options, how to be safe with yourself, pollinators and aquatic life when using these insecticides and how to measure your ash tree in order to make sure you have the proper treatment.
It is important that if you chose to treat a tree to triple rinse the container and apply the rinse water as you would a treatment. The empty, triple rinsed containers are trash. If you end up having insecticide that is left over or for some reason it is unusable such as if it was frozen, it should not be thrown into the garbage (it is illegal to bury or burn insecticides) but brought to the Household Hazardous Waste facility instead for free disposal.
For more information on gardening, you can reach me at firstname.lastname@example.org