Caplan’s June Newsletter

Japanese Maple Scale

Japanese maple scales (JMS) attack a wide variety of trees and shrubs. They are common on dogwood, elms, flowering fruit trees, maples, magnolias, lilac, and roses. Heavy infestations can kill tree branches. Unlike the closely related soft scales, these insects will be dry and not coated with sticky liquid excrement.

This scale is very difficult to control during the growing season because the susceptible stage of crawlers is present throughout most of the summer. There are two generations a year in Indiana with crawlers being found from early May through June an again from mid August through September. The prolonged crawler period makes this insect particularly difficult to control with insecticides.

Homeowners can apply horticultural oil in early or late June. Professionals can apply pyriproxifen, buprofizen, or azadirachtin at this time and may get better results. Each of these produces will kill crawlers but not natural enemies. Repeat in August if scales are still alive. The easiest method of control is to apply horticultural oil during the dormant season.

More information on JMS can be found here:

Jumping Worm Prevention

Jumping worm (a.k.a. snake worms, crazy worms, Amynthas spp.) is an invasive species that dramatically alters the ecosystems where they are introduced. Unlike the earthworms we are familiar with which live deeper in the soil, jumping worms feed primarily on the topsoil. They rapidly consume nearly all of the organic matter in the topsoil. Plants have a hard time growing and establishing a sturdy root system in this soil. Additionally, jumping worms generally leave castings on the top layer of the soil which makes them more likely to get washed away in the rain. This further decreases the soil quality by removing even more organic matter.

There are several visual traits you can use to tell the difference between jumping worm and common earth worms, but the easiest way to identify them is by their behavior. Jumping worms wiggle more than other worms and have been described as jumping, thrashing, and moving like a snake. You can also identify jumping worm based on changes in soil quality. Soil invaded by jumping worm has a grainy, “coffee ground” texture and little or no organic material in it.

Jumping worm can spread through soil, compost, and other similar organic material. You can reduce the risk of spreading it between job sites or to your home by:

Cleaning equipment and tires between locations. Pay particular attention to large clumps of dirt that might be caught in tire treads.
Clean dirt off your boots between locations. Jumping worms and other invasive species only need a little soil to move from one place to another.
Whenever possible, remove soil from new potted plants intended for outdoor planting. You can do this by removing the soil from the plants and throwing it in the trash then either planting it directly into the ground or repotting if with sterile or local soil. If you use local soil, make sure it’s from the place you intend to put the new plants. Jumping worm populations can be patchy so soil from one place may be clean while soil from a few blocks away may be infested.
Avoid walking through or using equipment in areas with jumping worm. If you have to enter these areas, thoroughly clean any soil off yourself and your tools before leaving.

Other prevention measures:

Seal unused fishing bait and dispose of it in the trash.
Check fishing bait before you buy it when possible. If the worms thrash strongly, don’t buy them. They could be jumping worms.
Check any worms bought for composting before putting them in your compost pile. If you suspect they might be jumping worm, don’t risk it. Dispose of them by putting the in a tightly sealed container and throwing them in the trash.

Oak Leaf Miner

I’ve been receiving calls from people concerned about white spots on their oak leaves. After examining a few of these leaves, I believe that most of what we are seeing is caused by an insect called the oak leaf miner.

Leaf miners are insects whose larvae live inside the leaf. They feed on the cells between the upper and lower surfaces. Different species of leaf miners attached different species of plants. For example, if you grow columbines, I can almost guarantee you’ve had columbine leaf miner.

Often, you will see a little zigzag track of feeding damage as the insect grows inside the leaf. While unsightly, the feeding damage by the leaf miners causes little or no permanent damage to the plant. Usually, control is not warranted especially on blooming plants.

Diagnosis Services

There are hundreds of insects and diseases that can attack your landscape plants. There are thousands of non-infectious causes of plant problems, such as root damage, drainage problems, and nutrient deficiencies. The first and most important step in controlling these plant problems is properly identifying what the cause of the plant problem is.

My specialty, derived over decades of work experience, is to examine plants, examine the symptoms, and determine what the cause of the plant problem is. In many cases, changes in the way you manage your landscape can fix these problems. In some cases, pesticides may be required. And in other cases, the only recommendation is to remove the plant.

I do not apply pesticides to landscape plants. This is choice I made in setting up my business. I want you, my customer, to know that I am being 100% honest with you in my diagnosis. I do not want my customers wondering if I am making a recommendation because it puts money in my pocket. If I say a plant needs to be chemically treated, or pruned, or removed…it’s because that’s what’s best for the plant, and your landscape.

If you see something unusual going on in your landscape or garden, call me as soon as possible. The earlier we start working on a plant problem, the better the chance we can save the plant.