Botrytis the blight of Greenhouse Crops

Botrytis cinerea is one of the most common fungal disease of greenhouse crops. The disease is often referred to as grey mould because it produces a crop of grey fuzzy-appearing spores on the surface of infected tissues. This fungus can affect virtually every greenhouse crop.

Germination of spores and infection of the host is dependent on a film of moisture for 8 to 12 hours over the spores, relative humidity 93% or greater, and temperatures between 12- 24 deg C

Keep dry ? no standing water on plant material. Ventilate to keep humidity down and to keep temp down.

Or given the 8 – 12 hour slot, water as much as you can, but then get the ventilation going, be it vents, doors or fans to dry the plants.

Or ensure you only water the ground and not the plants.

Try to water when its cool, ie first thing in the morning, so as the temp rises it evaporates the water off the plants quickly. DO NOT water last thing at night, as you end up with standing water.

Ensure plants are not tightly packed together, so there is good air flow.

Chemical control is a bit iffy, as fungicide resistance is already a common problem with fungicides from some chemical groups. Try a copper based one, but read the label as to which plants can be sprayed.

In my experience in the domestic situation chemical control is not as effective as just ‘ventilation’.