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SHRUB DISEASES
Problems still may occur with good intentions Establishing Plants...
When planting you may run into a number of problems. The site "area", in which you choose, can be unsuitable for the type of plant. Soil-borne plant diseases, such as root rots, wilt diseases, nematode infestations, can cause problems even if the site previously supported plants of the same kind. The transplants are more vulnerable to the effects of the disease. Sometimes plants produce toxins that leach into surrounding soil and disrupts growth of other plants. Walnut trees are well known for this. In these cases, one may have to wait a year or more after the removal of the toxin producer to plant replacements.
Mulch Volcanoes... Mulch is good for your trees and shrubs, but you can over due a good thing. The common problem is creating a Mulch Volcano, or piling too much mulch near the trunk. Having a mulch volcanoes may look pretty, but too much mulch near the trunk can actually suffocate the roots which leads to a damaged tree. Mulch volcanoes and compacted soil will block nutrients from going into the soil. In addition, it can cause cankers (open wounds) on the lower trunk. Once your tree develops cankers, the damage cannot be reversed, and your tree will die within a few seasons. Knowing prevents future complications Tree Decline... is a progressive deterioration in the health of a tree that is attributed to a combination of factors, such as competition among plants, environmental stresses, injuries and diseases like defoliating leaf diseases, root rots, wilt diseases, and nematode infestations in the soil. Although each of these may be unimportant individually, in combination they may cause decline and death of the plant. Avoid unnecessary injury. To avoid stress, know and supply the maintenance needs of the plant. Water deeply during dry periods. Don't induce rapid top growth by applying high nitrogen fertilizers in the root zone. Prevent serious, recurrent defoliating disease with fungicide treatments and treat serious insect and mite infestations. Uncontrollable & Controllable symptoms
Annual needle shed- Older needles inside shrub yellow. Younger needles remain green. May occur in late spring or early summer, or more slowly over the entire season. A normal part of the growth cycle. No control is necessary.
Fall Needle shed - Inner branchlets turn yellow, then brown. Outer foliage remains healthy. Normal part of growth cycle. No control is necessary. Iron chlorosis - Interveinal chlorosis of youngest leaves. Leaves may eventually become yellow, cream colored, or white. Usually caused by reduced availability of iron in high pH soil. Correct site-related conditions such as high soil pH, water logging, and poor aeration. Iron chelate applied to foliage may provide temporary greening, but for long term control, lower the soil pH. Leaf Scorch - is a symptom that can occur any time the leaves need more water than they receive. It may be caused by diseases of the roots, crown and vascular system; cankers; inadequate available water; high air temperatures; damage to the roots from transplanting, "wet feet," soil compaction or excavation or natural gas leaks; chemical injury such as herbicides, excessive fertilizer and road salt; root girdling; "pot boundness" that occurred in containers before planting or following planting if roots fail to extend beyond the planting hole. Be sure soil is moist in the fall. Provide windbreaks around plants. Plant adapted varieties in sheltered locations or erect wind barriers. Spine spot - Small, grayish-brown to dark punctures and scratches on both leaf surfaces in early spring. Spots caused by wounding of leaves by spines of nearby leaves during windy conditions. Plant in sheltered locations or erect wind barriers. Wet feet - Plants turn yellow and brown. Whole plant may die rather rapidly. Usually occurs in spots where moisture has been excessive. Can be complicated by root and crown diseases. Can occur in long established planting if periods of drought alternate with periods of saturated soils. Maintain good drainage. Plant yews in spots that do not get overly wet. Winter injury - Foliage brown and scorched. Twigs die back. Bark splitting. No control is necessary. Protect plant from injury as in frost situations.
Disease or Fungus in your Landscape
Black spot - General and serious. Leaves have black spots with irregular margins. Leaflets yellow and drop off. Collect and remove fallen leaves. Fungicide is necessary in spring as leaves expand. Susceptible varieties must be protected with fungicides before disease is present for good control.
Blight - Phomopsis needle and twig - Serious in wet seasons. Needles, twigs and smaller branches turn brown to reddish-brown; gradually die back. Tiny black dots appear later on infected parts. May be confused with normal fall browning, winter injury, spider mites, etc. Prune or remove blighted plants. Spray fungicide. Cankers - are diseased areas of the bark. Many different kinds of fungi and a few bacteria may cause them. The outer bark may appear abnormal. Inner bark is brown and discolored. In time the bark may fall off. Leaves beyond the canker may yellow, scorch or die. Usually canker-causing pathogens can infect only hosts that have been injured or stressed. Trees in decline often loose branches to cankers. Management of canker disease includes avoiding unnecessary injuries and knowing and supplying the maintenance needs of the host to reduce stress. Prune out diseased branches well below the visible infection. After each cut, disinfect pruning tools with rubbing alcohol or 10 percent household chlorine bleach in water. With Rhizoctonia/Phoma canker or die back stems and leaves may become blackened or blighted. Shoots beyond necrotic area wilt and die. Worst in wet weather. No chemical control. Remove severely affected plants. It may be necessary to increase air circulation by pruning overhanging shrubs and improve drainage by amending soil. Crown gall - General and serious. Euonymous extremely susceptible. Small to large, hard, rough galls on roots, crown, or canes. Use certified and disease-free stock. Rounded galls with irregular rough surfaces on roots and lower stems. Avoid nursery stock with galls. Avoid wounding stems or roots. Prune out and destroy affected plant parts. Use disinfectants on cut surfaces. Destroy severely affected plants. Carefully remove and destroy infected plants or plant parts. Avoid wounding. Use strict sanitation measures. Fire blight - General and serious. New shoots suddenly appear as if scorched by fire. Leaves cling to twigs. Cankers may be present on twigs and branches. Prune blighted parts in dormant season or in late summer or fall when weather is dry. Dip pruning tools in 70 percent alcohol or 10 percent household bleach between cuts. No chemical control suggested. Cultivars vary in susceptibility. Leaf and flower gall - Leaves become thickened or fleshy galls that then turn pale green or white. The entire blossom may become a fleshy gall covered with a whitish bloom. Usually, chemical control is not warranted. Pick off and destroy galled parts, if feasible. If severe infection, you may apply the correct fungicide. Leaf Spots - Leaf spots may be caused by a variety of fungal pathogens and a few bacterial ones. Anthracnose causes brown lesions on the leaves, in which tiny fruiting bodies may be seen with a hand lens. Anthracnose is a term used for a group of loosely related fungal diseases that often cause blotches along leaf veins or leaf spots, and can cause twig blights and cankers. Bacterial leaf spot has small, water soaked circular spots that eventually turn brown to purple. Twigs may become girdled, resulting in a blight. Prune and remove affected parts. Nematodes - Above-ground symptoms depend on the level of infestation. At high levels, there may be stunting, yellowing and an unthrifty appearance. Symptoms may be confused with mineral deficiency, drought, herbicide injury or other soil-borne diseases. Roots have small to large galls and may be excessively branched. Dark brown to black lesions on roots, to overall browning. Roots are usually discolored. Control recommendations depend on species present. Powdery mildew - Powdery white moldy patches on leaves. Remove badly affected shoots. Prune to thin out branches. Spray with fungicide when mildew appears. Phytophthora Dieback - Terminal buds and leaves turn brown. Evergreen leaves roll up and droop as though in a winter condition. Cankers are formed on the stems. If stems are girdled, all parts above will wilt and die. Prune and remove affected branches. Phytophthora root and crown rot - Usually, plants slowly decline in vigor and die. Brownish cortical tissues in the root and crown areas. Often associated with wet feet. Maintain good drainage and vigor. Root Rot - can be caused by a wide number of fungi. Few of these can be controlled in the landscape, especially on large trees. With Phytophthora root rot, the leaves wilt. Growth is stunted. Fine roots decay and cankers may develop at the base of the stem. Fungicides are available, but their use generally is not recommended for established planting. Remove and destroy affected plants. If practical, improve soil drainage and replant with a more tolerant variety. Scab - Serious in wet weather. Dull, olive to black velvety or scurfy spots on leaves. Leaves may yellow and fall off. May also appear on fruit. Varieties vary in susceptibility. Shoot blights - Common and severe in wet springs on shaded or crowded plants. Immature leaves turn black and die. Flower buds may be entirely black. Spots and blotches on leaves. Annually prune for good air circulation. Prune out blighted portions. Disinfect tools between cuts. Avoid over fertilization with nitrogenous materials. Control borers. Verticillium wilt - Leaves become pale, wilt, and fall early, starting at base and spreading upward. Stems show brownish green streaks under bark. Branch die back. Dig up and remove affected plants, roots and all. Avoid replanting in same spot for 5-6 years and/or replant with resistant species.  Acer Palmatum  Black Spot  Black Spot  Crown Gall  Fire Blight  Iron Chlorosis  Phytophthora Root and Crown Rot  Phytophthora Root and Crown Rot  Phytophthora Root and Crown Rot |
