Early Blight on King Arthur Peppers


“Mertie,   Could You please look at the photos and tell Me what this is and what I can do to fix it or save some of them I have about 800 Plants not all of them are as bad as others. Please hurry with a answer.

Thanks Duane”

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Hi Duane,

Thank you for the email and photos regarding the problems you have been having with your peppers.  Based on the photos, it looks like you have a pretty severe infestation of early blight.

Early blight(Alternaria solani) is a fungal pathogen that most commonly affects tomato and potato but it will also attack eggplant, pepper, horse nettle, black nightshade, wild cabbage, cucumber, petunia, and zinnia.  It produces a wide range of symptoms at all growth stages which include damping-off, collar rot, stem cankers, leaf blight, and fruit/tuber rot.

Seedlings grown from infested seeds damp off within 48 hours after emergence because large lesions develop at the ground line on stems of transplants or seedlings. Collar rot occurs when the young stem becomes girdled with dark lesions at the soil level.

For plants that grow to full size and/or are producing fruit/tubers, the infection occurs by inoculant in the soil that is splashed onto the leaf or stem by precipitation events.  The infected leaf has circular lesions of about 1.2 cm (1/2 inch) in diameter. Dark, concentric circles (circles with a common center) are found within these lesions. Infection usually begins on the lower, older leaves and progresses up the plant. Infected leaves eventually wilt, die, and fall off. Early blight lesions show a generally dry “bulls-eye” angular pattern that do not usually spread very far and rarely affect petiole tissue, as the progress of the fungus is stopped by the veins of the leaf.

An infected stem has small, dark, slightly sunken areas that enlarge to form circular or elongated spots with lighter-colored centers. Concentric markings, similar to those on leaves, often develop on stem lesions.

Infestation during the flowering stage of tomato causes the blossoms to drop. The fruit stems are spotted with lesions that lead to loss of the young fruits.

An infested pepper fruit will have dark, leathery sunken spots, usually at the point of the stem attachment or towards the bud scar. These spots may enlarge to involve the entire upper portion of the fruit, often showing concentric markings like those on leaves. Affected areas may be covered with velvety black masses of spores. Fruits can also be infected during the green or ripe stage through growth cracks and other wounds. Infected fruits often drop before reaching maturity.

Conditions that favor development:

1.    Infested plants nearby (tomatoes, potatoes, etc.)

2.    Unhealthy plants

3.    Plenty of weeds

4.    Over crowded plants that cause the poor flow of air among the plants

5.    Too much moisture during cool and warm weather

Prevention and control

1.    Proper selection of seeds for sowing/planting. Make sure that these are disease-free and not taken from plants that were previously infested by the early blight disease. (We make sure our seed is disease free)

2.    Plow under all the crop residues after harvest to physically remove the spore source from the topsoil.

3.    Practice crop rotation.  Fields/gardens should not be planted with tomato, potato, pepper, or eggplant for at least 2 cropping seasons so that these hosts are not present for the spores to thrive on.

4.    Remove weeds as these may serve as the alternate hosts.

5.    Practice the recommended plant spacing to promote good air circulation.

I hope this information helps you out.  If you have any other questions, please feel free to ask.

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© Mertie Mae Botanics LLC and Horticulture Talk!, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.

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