June is a month of problems.
Some readers will find lacebugs on azaleas, others will find scale on shrubs. Lawns are witnessing the return of sod webworms and chinch bugs, and the dog tick population seems to be the worst in years. Beyond this, black rot is threatening to destroy the grape arbor and the traditional "June drop" of apples, pears, peaches and plums is in progress. Roses are under siege from Japanese beetles, and many leaves already show the tell-tale signs of black spot.
But not everything is bad news. The lawn is perking along nicely, in spite of the moths flying about in the night. The moths are female sod webworms depositing eggs in the soil with each descent.
Where did they come from? If you applied Oftanol to the lawn in April, you killed the webworms, in which case the flying moths may be from your neighbor's untreated lawn. For now, do nothing aside from observing the moth population flying at night. When there are no more moths, that means the first generation of webworm eggs have been laid; the eggs will hatch within 10 days. You should treat the lawn for webworms after the last moths have been seen.
Thankfully, not everyone has lacebugs on azaleas. Over the past five years, I have had to routinely fight them, but there are many readers with hundreds of azaleas that have never been victimized by lacebugs.
Lacebugs are seldom seen on azaleas, but they leave behind unmistakable evidence. Ever see an azalea with foliage that has turned light red by fall? Lacebugs rob the leaves of sugar and nutrients, the foliage turns a pale red, then gray-white and drops from the plant. By Thanksgiving, the azalea has no leaves.
Solid evidence of lacebugs can be found by checking the underside of leaves. Look for a rusty-brown spot about the size of a dot made by a pencil. This is the exudate from the lacebug after it has siphoned sugar from the leaf tissue. In June, single spots will be found on some leaves, but by late summer you may find multiple spots.
In the Balt-i imore-Washington-Fredericksburg corridor, there are three generations of azalea lacebugs: early June, late July and mid-September.
Make a random check of leaves. If no spots are found, count your blessings. If the spots are there, spray with liquid Cygon (four teaspoons per gallon of water) in a hand-pump sprayer; spray in the evening or early morning when air temperatures are below 80 and there is no risk of rain in the next 24 hours. Use Orthene (1 1/2 tablespoons per gallon) in late July, reverting to Cygon for the September spray. Cygon and Orthene are systemic, therefore you need not spray every leaf to stop lacebugs.
A similar inspection is called for on a host of shrubs that are now under attack by scale (bark scale, Fletcher scale, lecanium scale and San Jose scale). Scale was launched last September, with the female depositing hundreds of tiny eggs clusters on woody branches and trunks of shrubs; on dwarf evergreens, pine needle scale may also be found on some needles. The color of the egg deposits varies from brown to gray-white.
Now that scales have left their protective shells, they are feeding on leaves and needles of shrubs. The major host plants for scale are arborvitae, azalea, barberry, boxwood, cotoneaster, euonymus, hemlock, juniper, lilac, mountain laurel, pine, privet, rhododendron, spruce and taxus. Ivy and pachysandra also come under scale attack.
Check shrubs for signs of egg clusters (brown or gray oyster shells) or inspect leaves for signs of crawlers (white or brown). If you applied superior oil in March, that ended the scale threat for the year. If you didn't spray, do it now and in early July. Spray in the evening when temperatures have moderated. Candidates are liquid Dursban (four teaspoons per gallon of water), powdered Sevin (two tablespoons), liquid Diazinon (two teaspoons) and liquid Orthene (three tablespoons).
June is pythium time on well-managed lawns. Conditions favoring an outbreak of pythium are well-fertilized turf, daytime temperatures over 85, high humidity, overwatered lawns and a lack of calcium in the grass tissue. Most often, pythium is caused by overwatering, specifically when the soil is saturated with water and the surplus water begins to flow over the lawn.
How can you tell if you have pythium? First, grass dies in small circles about the size of a softball, then the patches expand. Check early in the morning when the lawn is under a cover of dew. Go just beyond the dead circle of grass and look for white cotton-like webs on the still-green blades of grass. These webs will disappear later in the morning as the moisture evaporates, but can be easily seen in the early morning.
Note: Brown patch, another disease similar to pythium, will show the same white webs on healthy grass just beyond the circle of dead grass, but will also show a blue-purple ring on the still healthy grass.
If pythium develops, eliminate one of the causes of the disease. The obvious answer would be to stop watering. As long as the soil doesn't reach its capacity to hold water, you will have eliminated the primary cause for pythium.
A viable alternative would be to apply a soil surfactant to increase water drainage where the disease usually breaks out. Golf course superintendents respond to this problem by applying Aqua-Gro to the troubled area, then watering. Aqua-Gro is a granular material applied with a lawn spreader. As it's washed into the soil, it coats soil particles to repel water, thereby increasing percolation of water into the soil and eliminating the surplus water problem that triggered pythium in the first place.
At the same time, you should apply a fungicide to the diseased area to stop the disease. The best one is Subdue 2E; one treatment usually suffices.
To clear up any questions on turfgrass disease, most of them display webbed rings on grass blades in the early morning. White webs signify dollar spot, pythium, brown patch or fusarium blight. Brown webs are signs of leaf spot and fading out. Finally, red webs translate to red thread.
Reminders:Dog ticks abound in most gardens. For control, mow tall grass and weeds around the house where pets travel. When walking pets, stay out of weedy, shrubby areas where ticks congregate. Check pets daily, specifically around their collar and ears (inside, too). Consider replacing your pet's bedding. Use your best vacuum cleaner on rugs and carpets where pets sleep; dispose of vacuum bags often for the next month or so. Dogs may be treated with carbaryl, rotenone or d-Limonene, cats only with the last two products; check your veterinarian for specifics.
Outdoors, spraying liquid Dursban or Diazinon in the garden will curb the tick population. Use a hose-end sprayer, add 5 tablespoons of either product to the jar, fill to the gallon mark and spray over a 1,000-square-foot area; focus along paths, walks, shrubs and groundcovers. For personal protection, spray garden clothes, socks and cuffs with Permanone or any insect repellent containing Deet (Off, Metadelphene, MGK, Detamide, etc.). If you come on a tick imbedded in the skin, cover the area with petroleum jelly; with the oxygen cut off, the tick will exit the skin, and you can destroy it. Boxelder bugs continue to swarm on female boxelder maples. Use a tree-shrub hose-end sprayer that can send a stream of water to a height of 25 feet. Use Thiodan (four teaspoons per gallon of water) or Orthene (one tablespoon) to stop as many boxelder bugs on the foliage as possible.
Jack Eden hosts "Over the Garden Fence" Sundays from 10 a.m. to 1 p.m. on WTOP Radio (1500AM).