Japanese Beetle, Scales, and Summer

Japanese Beetle

Be on the lookout for Japanese beetles! These insects will begin popping up late June and early July. Japanese beetles overwinter as larvae in our soils beneath our trees. In spring the larvae feed on roots and grass and can cause serious turf damage in certain areas. Those larvae then mature and emerge from the soil as adult beetles and feed on the leaves of our favorite landscape trees. Beetles will skeletonize leaves. When feeding, Japanese beetles emit pheromones that will attract other beetles to the area causing the problem to increase with it; if left uncontrolled they are able to defoliate entire trees!. An accumulation of beetles over the years can negatively affect the health and development of trees.


Scale is a broad name for the insects in the superfamily Coccoidea. There are thousands of different species of the insect, however, we commonly treat for lecanium, calico, and magnolia scale in this region. The nymph stage of the insect feeds along the leaf veins ultimately disrupting the phloem vessels in the tree. Most scales mature in Spring, then lay eggs. Those eggs hatch in late spring to early summer and feed throughout the growing season. Honeydew is associated with most scales and is a clear sticky liquid that gets on sidewalks, branches, and cars. Honeydew attracts a black sooty mold, which is not pretty but is also not harmful.

Treatments target the crawler stage and can provide protection for the growing season. Although it infects a wide variety of deciduous tree species, common trees to observe are crabapples, pears, honeylocust, maple, dogwood, and magnolia.

Treatment & Timing

Japanese Beetle: Treatments begin in late May to Mid June and treatment may continue as long as beetles are present. It is important to remember that the beetle produces a pheromone that attracts other beetles. We advise that people do not put out beetle traps as they may contain but also attract others to the area!

Scale: Treatments may begin in mid to late May through August for the crawlers. There are also treatments that can be applied in the Fall for the upcoming year.

Trees in Summer

As trees begin to bloom, blossom and bud in the Spring and leaf out at the beginning of Summer, a lot of things are happening behind the scenes. The root hairs below the surface uptake water and nutrients by osmosis and transport these up the tree through the xylem. This takes an immense amount of pressure to complete the transport of water and nutrients up into the tree. As the leaves are utilizing the water and nutrients along with carbon dioxide they are completing a process known as photosynthesis. This process uses sunlight, water, and carbon dioxide to produce energy (sugars) and oxygen which the tree then releases into the air. The energy or sugars are sent back down throughout the tree in order for the sugars to be turned into complex carbohydrates and stored in the woody parts you see on the tree. A tree also has priorities! A tree will direct its energy to growth, maintenance like repairing wounds, reproduction like seeds or cones, storage of carbohydrates or sugars, and defense against pests or diseases. Many times a tree is not able to complete all of these processes due to poor soils or the location in which they were planted. It is crucial to help maintain the tree during these early months of the year to ensure that we are giving the tree the best chance before heading into the summer with hot temperatures and dry soils. As many landscapers have begun mowing the grass and mulching, it is also important to keep an eye on the amount of mulch that is applied around the base of the tree.

Remember we are trying to ensure that the tree is in the best possible shape entering into the growing season. If you notice that your tree is not leafing out or the leaves are more lime green to yellow that is a sign that the tree is not getting the nutrients it needs. The best route is to complete a soil or foliar test to determine which nutrients should be administered to your tree.