Japanese Beetle Tree Risks and Removal Methods
There are certain destructive pests that appear in cycles over many years, and a good example in Utah and several other states is the Japanese beetle. Thought to be fully or mostly eradicated for many years in the state, Japanese beetles have seen a resurgence in recent years, including prompting an insect emergency infestation declaration by the Utah Department of Agriculture and Food this spring.
At Affordable Tree Care, we’re proud to provide tree spraying and health services from our high-quality arborists, protecting your trees from numerous disease or pest risks, including Japanese beetles. Let’s take a look at some basic information on Japanese beetles and how they threaten trees, plus how to ensure your trees are not at risk this spring.
Basics and History
Japanese beetles first began showing up in the United States as far back as the 1920s, feeding on a variety of plants and trees – over 200 different species, in fact. However, many parts of the country did not begin seeing them until more recent decades, as they were reasonably controlled upon initially entering the country.
Japanese beetles are generally found on trees like lindens, birches, elms, roses, buckthorns and various fruiting trees. They will feed on the leaves and other parts of the tree, though in most cases their feeding will not be enough to kill the tree – they cause major aesthetic issues, though. In cases where trees are young or already dealing with stress, however, Japanese beetles can cause death, and they commonly lead to premature death by stressing a tree over a period of years.
Japanese beetles spend most of their lives as grubs living in soil. In the later spring periods, though, they begin to emerge as adult beetles and feeding on the tops of trees.
In addition, these adult beetles start emitting pheromones as they feed. This attracts other beetles, and eventually the group will move down the tree and “skeletonize” the leaves, leaving only veins in their wake. These leaves then often drop, making it appear as if fall has come early. Beetles will also mate and lay eggs near the soil surface, beginning the cycle for next year, while creating brown patches and other turf issues in many cases.
Treatments for Trees
Luckily, it’s easy enough to control Japanese beetles and limit the damage they pose to trees or other plants. This begins in many cases with a granular insecticide in early spring, which will kill grubs before they can reach adulthood.
In cases where adult beetles have already reached the tree and begun feeding, insecticides will be placed in the soil that are meant to travel up the roots and into leaf tissue. As beetles feed on the leaves in question, they will consume the insecticide and be killed. There is no true repellant format for Japanese beetles once they’ve reached the tree, sadly, and small amounts of damage will take place as they’re killed.