June 27, 2009
Posted: June 27, 2009
Strawberry Pests and Diseases
Strawberries seldom encounter disease problems in Colorado. If your strawberry crop declines, you should first consider environmental or mechanical factors. Insects could be the culprit, but strawberries in Colorado are relatively free from insect pests as well.
If your crop is confronted with crown borers, leaf hoppers, aphids, earwigs, slugs or tarnished plant bug, fight back with a good insecticide. Malathion is effective against aphids, leaf hoppers, and quite a few other sucking and chewing insects. Use Sevin to control earwigs and beetles. Slugs may be controlled with a commercially prepared bait. Protect beneficial pollinating insects by not spraying during bloom.
If a disease is suspected, the cause is likely to be a fungus or virus. Bacterial diseases are uncommon in Colorado.
Diseases in a strawberry Garden most often are controlled by removing an affected plant or plant part. If the disease is systemic — that is, it occurs throughout the entire plant — remove the plant.
If a systemic disease occurs, it is likely to be caused by a virus or vascular fungal pathogen. In this case, you will want to avoid planting strawberries for three to five years. Such pathogens survive in the soil only for that length of time without a host.
If a fungus causes a leaf spot on your strawberry plants, and leaf removal has been ineffective or isn’t an option, spray the plants with a fungicide such as Captan. Always follow label instructions when applying pesticides.
Nuisance Bees and Wasps
Wasps and bees can cause concern for homeowners. Very few bees cause problems. They are beneficial pollinators and control for them is discouraged. Honeybees and bumblebees are working blooming flowers and may cross paths with people. Typically bees are not aggressive unless an unwary gardener grasps them.
Yellow jackets are a yellow and black striped, ground-dwelling wasp that is very aggressive in the late summer and fall. They are scavengers and will eat caterpillars, many types of sugars and meats at picnics. May is an ideal time for setting out wasp traps baited with sugar solution to reduce populations.
The Polistes or European paper wasp is also yellow with black stripes. It is often confused with the yellow jacket. This wasp is a predator that builds paper nests in the eaves of buildings and in small cavities. As a predator, the Polistes wasp is not a problem for outdoor dining. Their nesting habit in numerous locations around homes leads to many stings. This wasp will not be attracted to traps because it hunts for live prey.
Hunting wasps, such as mud daubers, cause concern when they blunder into homes looking for prey. Several species occur in Colorado but in general they are harmless to humans.
If wasp nests are too close to the house or children’s play area, use permethrin or other pyrethrin insecticides to kill the insects still living in the nest.
Source: Planttalk Colorado