It is a busy time at the extension office this month. Puzzled gardeners have called and some have brought in their sickly plants, just as a concerned parent will take their child to the doctor hoping for a remedy.
Some commonly asked questions from home gardeners lately have been about fungal and bacterial disease in ornamental trees and shrubs, and vegetable disease and pest problems.
Ornamental trees and shrubs have particularly been affected with a bacterial disease called fireblight, which attacks blossoms, leaves, shoots, branches, fruit and roots of a plant.
The disease often enters through natural openings through wounds in the spring. It is spread by rain, wind and pruning.
Many gardeners have come in with infected branches and leaves. Branches and young twigs appear to die from the terminal end and have a burned appearance. Dead leaves and fruit remain on the branches. This bacterium overwinters in sunken cankers on infected branches.
Spraying plants in early spring with a fungicide containing basic copper sulfate (Kocide) when plants are flowering and leaf emergence begins is an effective preventive measure. The only measure now is to prune out infected branches about 8 inches below the damage and make sure to dip your pruning tools in rubbing alcohol or a 10 percent bleach solution between each cut.
And now on to the vegetables ...
Common vegetable insect problems include beetles, aphids, whiteflies and worms. First, identify the culprit; the Extension can give you recommendations on how to control them. Sprays containing malathion or sevin can be useful. Worm infestation can be treated with a product called Bt, and horticultural oils and insecticidal soaps sprayed every 7 to 10 days can be useful.
Fungus such as early blight and late blight also can damage vegetables. These diseases result from wet, cool springs and alternating periods of wet and dry hot, humid weather. Fungal spores are spread just as on ornamental plants — rain, wind and insects. Try treatment with a spray containing captan in every 7 to 10 days. Do not water overhead and mulch well. Clean out any dieback you see and destroy the infected debris.
Wanda Cannon is a Master Gardener trained through the Hall County program and also serves as Master Gardener coordinator and horticulture assistant for the Hall County Extension office. Phone: 770-535-8293.