Strawberry Plant Diseases and Your First Line of Defense

It's bad enough to have to worry about all of the insects that might attack your strawberry plants, but the strawberry plant aficionado must also understand and recognize many diseases that can affect the strawberry plant.

The list is lengthy, but it is not intended to discourage anyone who wants to grow strawberries. Just like when you have children, you need to know about childhood diseases, so that you can recognize when you need outside help to treat them -- the same is true in gardening. Know your strawberry plant enemies is the first rule of a successful crop.

Like with humans, there are a lot of things that can go wrong with strawberry plants. They can get bacterial diseases. Strawberry plants can get fungal diseases. They can get root rot diseases. Strawberry plants can get nematodes and parasitic diseases. Finally, strawberries can also get virus and virus like diseases.

Take heart and know thy enemies, but don't dwell on them. Once you have ill strawberries, take action and wage an aggressive war until you eliminate the problem from your property or plants! Remember:

"As to diseases, make a habit of two things, to help, or at least do no harm."

There are three main bacterial diseases of strawberries, they are:

• Angular Leaf Spot
• Bacterial Wilt
• Cauliflower Disease

Fungal diseases of strawberries are numerous, here are some common fungal diseases, likely to attack your strawberry plants:

• Alternaria fruit rot - Caused by excessive rain induced cracking leading to fungal infection.
• Anthracnose and anthracnose fruit rot - Characterized by sunken, dark, well-defined lesions of rotting on fruit. Known to come from the soil or plant debris.
• Armillaria crown and root rot (shoestring crown and root rot) - Attacks root system and can remain in the soil for years.
• Black leaf spot - The most common and widespread fungal disease found in strawberries. Causes the death of the leaves and can extend to the seeds of the strawberries.
• Cercospora leaf spot - Common and minor fungal problem. Starts out as small round purple spots, then as it spreads the center of the spots become tan or gray.
• Charcoal rot - This is a hard to diagnose fruit rot emerges with first showing sings of water stress and then total collapse.
• Common leaf spot - Purplish red spots on upper leaf, and later getting grey in center that causes leaf death and later loss of plants.
• Leaf scorch- Similar to the cerospora leaf spot, only the centers do not become light colored and the outside edges are more irregular.
• Leather rot - This is a big problem in southern states where the weather is hot and humid. Once the soil is infected, all it takes is standing water touching the plant. Then, the fruit clusters turn grayish, become mushy, and once they dry out become leather like.
• Powdery mildew - A white powdery growth on turned up leaves underside and fruit, usually a spring and early summer problem.
• Phytophthora crown and root rot - Newest leaves rot first, then the whole plant once soil is infected.
• Fruit rots - One of the biggest strawberry crop problems. At first, a small brown spot shows up, the crown rapidly turns brown and rots. Spreads in moisture and water.

Root rot disases of strawberries are another concern of the strawberry grower. There are a large number of root rot diseases that can affect strawberries.

Here are a few of them to watch out for:

• Black Root Rot - Serious and common problem in strawberries, shows up in first year decline, that upon root examination shows the normally whitish roots, turning black.
• Botrytis (Grey Mold) Crown Rot - Largest losses of strawberry harvests are a result of this disease. Blighted flowers and stems, leading to lesions on the fruit, rapidly giving way to grey mold.
• Red stele - This winters in the soil and typically attacks the second year strawberry plant. Once infected, the fungus will be in the soil for years. It is particularly a problem in heavy or poorly drained soils. Roots turn red, plant is stunted, and little or no fruit appears.
• Verticillium wilt - Outer and older leaves droop, wilt, and turn brown and dry. New leaves, if any, will be stunted.

Just like we get colds, strawberries get viruses, here are the twenty-one different ones that can strike your strawberry garden and by what method they are transmitted:

• Strawberry chlorotic fleck - Aphid transmitted
• Strawberry crinkle - Aphid transmitted
• Strawberry latent C virus in Fragaria - Aphid transmitted
• Strawberry mild yellow-edge - Aphid transmitted
• Strawberry mottle - Aphid transmitted
• Strawberry pseudo mild yellow-edge - Aphid transmitted
• Strawberry vein banding - Aphid transmitted
• Aster yellows MLO -Leafhopper transmitted
• Maladie du bord jaune - Leafhopper transmitted
• Strawberry green petal Leafhopper transmitted -
• Strawberry lethal decline - Leafhopper transmitted
• Strawberry multiplier plant -Leafhopper transmitted
• Strawberry mycoplasma yellows disease - Leafhopper transmitted
• Strawberry rickettsia yellows disease - Leafhopper transmitted -
• Strawberry witches'-broom -Leafhopper transmitted
• Arabis mosaic virus - Nematode transmitted
• Raspberry ringspot virus - Nematode-transmitted
• Strawberry latent ringspot virus -Nematode -transmitted
• Tomato black ring virus - Nematode transmitted
• Tomato ringspot virus - Nematode transmitted
• Tobacco necrosis virus in Fragaria vesca - Fungus transmitted
• Strawberry pallidosis - Pollen transmitted
• Necrotic shock - Vectors unknown
• Strawberry leafroll - Vectors unknown
• Strawberry feather-leaf - Vectors unknown
• Strawberry June yellows - Genetically transmitted

There are a number of strawberry nematodes and parasitic diseases that strawberries are prone to.

Some of them are: (1) Bulb and stem; (2) Dagger; (3) Lesion; (4) Spring dwarf (crimp); and (5) Sting. Two others, more common throughout the United States, are:

• Root knot - Plant looks stunted, not producing, and galls/knots appear on the roots, causing black and rotted roots and secondary smaller roots.
• Summer dwarf (crimp) - Severely stunted summer and early fall plants, mature leaves seem darker and slimy, new leaves are too small and crimped.

• January - Order new plants
• February - Fertilize old strawberry beds, apply mulch
• March - Plant new plants and frost protect
• April - Remove mulch covering, water, frost protect, control pests
• May - Water if dry, netting, harvest frequently, removal of blossoms 1st year, training runners, weeding.
• June - Harvest, training runners, pest control, water if dry, reclaim old beds if done fruiting.
• July - Pest control, water, fertilizer, cultivate
• August - Pest control, water if necessary, fertilize, check for mites
• September - Fertilize, pest control, deep soak water, weed, thin plants, check for nematodes
• October - Water if dry, ready next strawberry field, order new plants
• November - Order mulch
• December - Mulch after ground is frozen

What to Do About Strawberry Plant Diseases

Obviously, strawberry plant diseases, fungi, parasitic diseases, nematodes and the like, are troublesome to say the least. Unless you are a seasoned strawberry grower, you first line of defense upon discovering you have a potential diseased plant is to get expert advice, at least in terms of properly diagnosing what is wrong with your strawberry plants. Unlike humans, this medical care is absolutely free and easily found at your local county agricultural extension agent's office.

They will help you not only get a proper diagnosis, but also steer you in the right direction in terms of how to win the war of strawberry plant disease. They will help you determine what biological, cultural, mechanical, physical, organic, or chemical is a right fit for your situation.