Timely Tips from Over the Garden Fence
You can catch George Wedel on Over the Garden Fence, 9:05 am Saturdays on AM 590 WKZO.
And return here each week at www.wedels.com for the latest in Wedel's timely tips.
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OVER THE GARDEN FENCE MAY 25, 2002 Even though April and May were cold, many insect and diseases continued to be active. Look for and take action to prevent further damage from these pests. Pins sawfly larvae are merrily munching on scotch, mugho, and red pine trees. Severe defoliation can occur. If present, spray Sevin or Pyrethrin to kill pine sawfly larvae. Tent caterpillars are very active now on crab and cherry trees. Control tent caterpillars with Sevin or Pyrethrin also. Plants inclined to anthracnose and scab diseases are most likely to be infected because of the recent damp weather. To prevent further leaf infection and leaf drop, begin a spray program now. Sycamore, crab, oak, maple, mountain ash, serviceberry, rose bushes, and many others need to be sprayed now. Use Benomyl or Thiophanate to help suppress anthracnose and scab leaf diseases. Cancer worms are very active on many trees, including maple, crabapple, birch, beech, and linden. These little green worms are often called inchworms, but they consume great quantities of foliage. Inchworms can be controlled with BT or Sevin. Cutworms are very numerous in most gardens now. They make their presence known by eating the foliage of almost any plant and cutting off new transplants at soil level. Control cutworms with Diazinon granules sprinkled on the soil. Euonymus oyster shell scale and juniper scale is active; control measures should be taken now. Apply Horticultural Spray Oil mixed with Malathion. Apply Bayer Systemic Insect Control on soil at the base of plants to control later scale infections. Feed infected plants yearly with Espoma Tree Tone. We don’t have to look very far to see aphid damage on shrubs, trees, and perennials. Curled and deformed leaves on the ends of branches are the tell-tale signs. Control aphids on ornamental plants with Isotox, Orthene, Malathion or Pyrethrin. If gypsy moth caterpillars are to be controlled with BT spray, it must be applied now. After this week, use Sevin to kill the caterpillars. Gypsy moth caterpillars can also be controlled with sticky band traps wrapped around the trunks of affected trees. Strawberries are at various stages of bloom and fruit formation. To prevent gray mold, stem end rot, and leaf spots, spray strawberries with Captan. Due to the moist conditions of late, slug damage has become epidemic in many gardens. Slugs are attracted to young spring foliage in annual and perennial gardens. Slugs are very fond of hosta leaves. Control slugs with Bug-Geta Plus pellets. Scatter Bug-Geta pellets around susceptible plants for overnight results. Two weeks ago, I warned our “Over the Garden Fence” listeners about the threat of the invading garlic mustard plant. This is no joke. Last week’s MSU Landscape Alert ran a full page on this problem plant. Garlic mustard is a non-native invasive plant that poses a threat to our Michigan woodlands, wildlife, roadside beauty, parks, and gardens. I would again like to review the garlic mustard problem. Many wildflowers that complete their life cycles in the springtime such as spring beauty, wild ginger, bloodroot, Dutchman’s breeches, hepatica, toothworts, and trilliums, occur in the same habitat as garlic mustard. Once introduced to an area, garlic mustard out-competes native plants by aggressively monopolizing light, moisture, nutrients, soil, and space. Wildlife species that depend on these early plants for their foliage, pollen, nectar, fruits, seeds, and roots, are deprived of these essential food sources when garlic mustard replaces them. We are also deprived of the vibrant display of beautiful spring wildflowers. Garlic mustard is a cool season biennial in the mustard family with heart-shaped, toothed leaves that give off an odor of garlic when crushed. First year plants appear as a rosette of green leaves close to the ground. Rosettes remain green through the winter and develop into mature flowering plants the following spring. Flowering garlic mustard plants reach from 2 to 3 ½ feet in height and produce button-like clusters of small white flowers, which are currently in bloom. Garlic mustard frequently occurs in moist, shaded soil in areas that are most susceptible to rapid invasion and dominance. After spending the first half of its two-year life cycle as a rosette of leaves, garlic mustard plants develop rapidly the following spring into mature plants that flower, produce seed, and die by late June. A single plant can produce thousands of seeds, which scatter as much as several feet from the parent plant. Additionally, because white-tailed deer prefer native plants to garlic mustard, large deer populations may help to expand it by removing competing native plants and exposing the soil and seedbed through trampling. Due to the long life of its seeds in the soil, which may be five years or more, effective management of garlic mustard requires a long-term commitment. The goal is to prevent seed production until the stored seed is exhausted. Hand removal of plants is possible for light infestations and when desirable native species co-occur. Care must be taken to remove the plant with its entire root system because new plants can sprout from root fragments. This is best achieved while plants are small and the soil is moist, by grasping the base of the plant firmly and tugging slowly and gently until the main root loosens from the soil and the entire plant pulls out. Pulled plants can be left onsite or removed. For heavy infestations, application of the systemic herbicide Round-up is effective. Round-up may be applied at any time of year as long as the temperature is above 50 degrees. Care must be taken not to get Round-up on desirable plants as the product is non-selective. It is very important for everyone to become familiar with garlic mustard and destroy all visible plants. We all need to work together to help protect our Michigan landscape from this pest. George Wedel |
Timely Tips
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07/27/02 |