How to Identify Strawberry Plant Diseases

Pests

• 1

  Look for small brown insects. Plant bugs are the most common pest found on strawberries. They sucks on the unripened fruit, causing it to become cat-faced. The tip of the strawberry is deformed and indented where seeds become tightly clustered. Bugs can be handpicked. Planting Junebearers as opposed to everbearing strawberries will also reduce fruit deformation because Junebearers fruit earlier than the plant bug's most active growing and feeding time.

• 2

  Identify the condition of the fruit. Slugs cause great damage to the fruit, eating the strawberries and making holes in the fruit. Slug populations increase with rainier weather. Placing broken eggshells around plants prevents slugs from accessing plants, and placing a small container of stale beer at soil level will attract and drown slugs.

• 3

  Determine if the plant has been cut at the root crown, where the stem and the root meet. Cutworms cut the stem at the root crown, killing the plant. A few different varieties of cutworm exist. They range in color from brownish green to gray with black dots and striations. When a plant has been cut by the worm, the worm can often be found by digging around the base of the plant. To prevent cutworm damage, place a 3-inch high cardboard collar around the base of the plant. A cut-up juice or milk carton works.

• 4

  Look for stunted growth and small green insects on the plant. Aphids are tiny sucking insects that stunt plant and fruit growth. Affected plants have smaller, stunted leaves and smaller fruit. To treat, spray a mixture of one part soap to two parts water directly on the plant to smother the insect.

Fungal and Bacterial Diseases

• 5

  Examine the fruit and plant, looking for hairy gray mold or a gray-brown coating of mold on the strawberry. Botrytis gray mold is a fungal disease that affects strawberry plants during particularly wet and rainy weather. It spreads by spores, and handpicking affected fruit and leaves with minimal disturbance to plants is effective. Do this only when the plant is dry because spores spread more under wet conditions. With severe infestations, fungicidal sprays are available to treat plants. Leaving adequate spacing around plants for proper air circulation and mulching under plants with woodchips are two effective preventative measures for gray mold.

• 6

  Look for purple spots on the leaves. Leaf spot is a fungal disease that shows up on leaves. As the spots get larger, the center turns gray or white in older leaves and brown in younger leaves. This fungus spreads during wet weather. Best control for leaf spot is to remove infected leaves and stems, provide proper air circulation around plants and plant in the sunniest location possible. Planting strawberry varieties resistant to leaf diseases is the best option for complete prevention of this fungus.

• 7

  Determine if yield is being reduced and the plant is wilting. Verticillium wilt, a fungal disease, causes severe reduction in strawberry yield and may eventually cause plant death. Strawberry leaves wilt and older leaves turn reddish-purple, eventually drying out and dying. Young leaves, if they develop, are stunted in growth and plants appear flattened. Several verticillium wilt-resistant varieties exist, providing the best defense against this disease.

• 8

  Carefully dig the plant up and look at the root. Red stele can be diagnosed best by looking at the root. The main root will begins to rot from the tip up towards the plant. The white part of the root above the rotting potions will, when sliced open, show a red core. The leaves of a diseased strawberry plant will show reds, yellows and browns and will eventually die in severe infestations. Several varieties resistant to red stele exist and are the best defense against infection.

• 9

  Hold the leaf up to a light source. Angular leaf spot, a bacterial disease, shows up on the leaf as translucent spots, delineated by the leaf's veins. No treatments are commonly available for the home gardener to treat infestations.