Phytophthora can be deadly for capsicums

This is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops

- By Bill Kerr

Being a devastating soil-borne disease, Phytophthora capsici, like damping off, requires moist, semi-anaerobic conditions in order to flourish. Although resistance has been bred into some varieties of capsicums, the problem is that the causal organisms mutate frequently and develop resistance to the gene that provides resistance.

In my view, the safest course of action is to provide soil conditions that prevent the disease from developing in the first place. I have noticed that in periods of high rainfall, many farmers would be struck with this disease, yet on my property with its raised beds and 3% to 5% organic matter content, I have never experienced Phytophthora when other farmers in the region would have a problem.

The pathogen is an oomycete, a fungal-like organism with thick-walled, hardy oospores that can remain viable for many years, waiting for the right conditions to become active, which is in a wet, warm, low-oxygen environment.