It is that time of year for calls to come in with people wondering why their plant or plants aren’t looking very good right now.
For the most part the answer is usually the weather. While we tend to think of plants as things that can withstand the elements since they are outside all of the time, they don’t like it when our weather patterns are inconsistent. For example, many of our Tulip trees (Liriodendron tulipifera) have leaves that are turning yellow and falling off the tree. Some might think that this is because fall is coming. In actuality it is because our weather has been really hot and for a while really dry.
From the tree’s perspective, it was taking too much extra energy to keep the leaves green and continue to produce food. So, the tree has decided that it is better to start shutting down for the year to save it’s resources for next year. Other trees and shrubs do this, but they are not as noticeable as the Tulip tree.
Other calls have come in about plant leaves and seed pods being eaten. The plant type usually tells me what has been munching on it. If there are milkweed plants that have had their leaves just completely stripped, then either the monarch caterpillars (Danaus plexippus) were feasting on it or the large milkweed bugs (Oncopeltus fasciatus) have been there.
More recently large sections of grass have been devoured overnight. The culprit for this is the fall armyworm (Spodoptera frugiperda). Even though it is called a worm, it is actually a caterpillar. These caterpillars are usually found in hayfields or pastures, but in our area, we have had several outbreaks in lawns. There isn’t a lot we can do because the damage appears overnight, and happens where the grass blades are nice and tender, which is usually newly established lawns. In hayfields and pastures, agriculture producers scout the areas with sweep nets to locate young caterpillars. If fall armyworm presence is caught early then insecticidal treatments can be used, but these treatments may also affect the beneficial insects.
While plants can’t verbally tell us if something is wrong with them, we can check the plant over every couple of weeks for signs and symptoms of problems and then research what is going on to determine what steps if any need to be taken.