A quick look at some common greenhouse diseases:
Angular leaf spot (ALS), or “blackfire,” can overwinter on old tobacco debris and is favored by continuous moisture.
Angular leaf spot is typically treated with streptomycin on a weekly basis.
Anthracnose is a fungal disease that causes small, depressed spots that appear watersoaked in the early stages, becoming larger (up to 3 mm) in diameter and turning gray-white with brownish borders. If you are using outdoor beds, prevent surface drainage water from washing into them to avoid the potential for anthracnose fungus to be introduced.
Damping-off is caused by two different organisms, pythium or rhizoctonia, and is more likely in float systems than plant beds. Damping-off kills young seedlings and can be spotted with the appearance of wilted, yellow, stunted or dead plants among your plant beds.
Target spot, caused by races of rhizoctonia fungi, is a result of different organisms than those that cause damping-off. Target spot is suspected when leaves held up to light display small, circular watersoaked spots with a ringlike appearance. Properly sanitized transplant trays are the best defense against target spot.
Category: Diseases & Pests