Frequently Asked Questions
Q. Tomatoes – What is causing the dark brown irregular spots with target rings and yellow haloes? They are developing on leaves, stems and fruit; spots on fruit are often at stem end and are sunken.
A. This could be either Early Blight or Phoma Rot. Both are fungal diseases. Use resistant varieties; use registered fungicide; remove old plant debris.
Q. What is causing the dark brown, leathery spot on the blossom end of the tomatoes?
A. This is blossom end rot, caused by a calcium deficiency to developing tomatoes during dry periods. Calcium deficiency is a problem when fruits receive uneven moisture during early development; supply water; apply calcium foliar sprays; mulch.
Q. What is causing large portions of my boxwoods to turn brown?
A. This could be caused by several things. It may be a winter injury and is a common problem with very cold winters, or it could be Volutella blight, a fungal disease. Prune out the dead branches.
A. It could also be Phytophthora root rot, a fungal disease. Check for brown discoloration in roots; improve drainage; plant in another area.
A. If it is an English Boxwood it may be English Boxwood Decline. Submit sample to Virginia Cooperative Extension office for diagnosis.
A. It may be root-feeding nematodes. Submit soil samples to Virginia Cooperative Extension office for diagnosis.
Q. Why are the leaves on several branches of my crab apple tree wilting, curling and turning black, but are still clinging to the twigs? There are black cankers on the young twigs as well as on larger branches and the trunk.
A. This is probably Fire Blight which is a bacterial disease. Prune out affected branches; in late summer remove young suckers as they appear since they are very susceptible to fire blight; do not plant apples near pears which are highly susceptible.
Q. What is the cause of the spots on my dogwood tree leaves?
A. This could be caused by one of several fungal leaf spots. The most common ones are Spot Anthracnose, Discula Anthracnose and Septoria Leaf Spot. Submit sample to Virginia Cooperative Extension office for diagnosis and recommended treatment.
Q: Why are my blueberry bushes decreasing production year by year? Is there a reason why not all new planted varieties do well?
Answer: Blueberries are very demanding in soil and moisture requirements but require very little protection from insect and disease pest. Blueberries should be planted where they have full sun, at least six hours of full sunlight per day. Since they have a shallow root system, they must be irrigated or heavily mulched, and should be planted away from roots of trees to avoid competition for moisture and nutrients. They grow best in a porous, moist, sandy soil high in organic matter with a pH range of 4.2 to 5.5. Adequate cross pollination should be provided by planting two or more varieties which increases the chances for a good crop of fruit. You should take a soil sample to determine whether or not you have the correct pH and proper nutrients for your plants. A list of varieties of blueberries which do best in our area can be obtained at the Virginia Cooperative Extension website.
Q: When should I prune my azaleas?
Answer: It is best to prune azaleas soon after they bloom. Pruning after July should be avoided since flower buds may not have time to form for the next year.
Q: When should I prune my boxwoods?
Answer: For most evergreen shrubs, thinning is the most desirable procedure. This allows air to circulate through the shrub. Boxwoods can be pruned or even sheared when a stiff formal appearance is desired. Boxwoods should be pruned in late winter before new growth starts. Late season pruning may stimulate new growth which may not have time to adequately acclimate to cold winter temperatures, resulting in plant injury.
Q: What is causing the spots on my tomato leaves?
Answer: If the spots are uniformly small (1/8 inch) chocolate brown spots or dark spots with tan centers which began on leaves from the bottom of the plant to top but does not appear on the fruit then it could be Septoria leaf spot which is a fungal disease.
If the spots are dark brown irregular spots with target rings and yellow haloes which appear not only on the leaves, but also on the stem and the fruit, then it most likely is early blight (fungal disease). If the spots are light tan on the upper leaf surfaces with dense olive green moldy growth on the undersurface of the spots, this may be Gray leaf mold (fungal disease) and is caused by plants being exposed to high humidity and adequate ventilation needs to be provided. Be sure to remove all old plant debris and either burn it or put in the trash, If you are not sure, you should bring a portion of the diseased plant to the local Virginia Cooperative Extension office.
Q: What are the brown spots in my lawn grass?
Answer: Brown spots in lawns is referred to as snow mold, which is a fungal disease. This fungal disease is most common when the ground does not freeze in the winter. The damage caused by these molds is seldom serious. The affected areas should be gently raked to encourage drying and prevent further fungal growth. Avoid excessive applications of nitrogen fertilizer in the fall and rake up leaves in the fall. Fungicides are usually not recommended.