© Abaroth 2019. Permission is given to reproduce for non-profit purposes only.

Home   Historic Sites   Models   Heraldry   Puzzles    Garden   Links


Tomato Blight

What is Tomato Blight?

Tomato Blight, also known as Potato Blight or Late Blight is a disease which affects both tomatoes and potatoes in warm, damp conditions. It is caused by a fungus-like organism called phytophthora infestans which spreads rapidly. Tomatoes grown outdoors are especially vulnerable as the wind and rain distribute the spores even faster, but those grown in a greenhouse or polytunnel are by no means immune.
Early Blight of potatoes is a different disease, common in North America but relatively rare in the UK.

What does it look like?

Typically, the disease is first seen on the leaves, which start to exhibit a mosaic pattern before turning grey/brown and furry. If the disease gets into the fruit, the tomatoes will rot quickly starting where they are attached to the truss.

Click thumbnails for larger images

Can it be treated?

There are currently no chemical treatments which are effective against Late Blight.

Indoor plants

In the greenhouse or polytunnel, remove all affected leaflets or leaves and any fruit on affected trusses. Also remove any trusses holding only small fruits or flowers. Fruit on unaffected trusses may still ripen on the plant, even if all the leaves have been removed. Note that the disease spreads quickly, so regular inspection and pruning is essential. If this is not possible it is probably best to cut your losses and remove the plants. When the plants are done, spread the spent compost from the containers or grow-bags in a part of the garden where you won't be growing tomatoes or potatoes for at least four years.

Outdoor plants
Outdoor plants should be dug up and cropped as soon as symptoms appear. Use the fruit as soon as possible after picking. Do not grow tomatoes or potatoes in the same soil for at least four years.

Disposing of the plants.

Do NOT add infected material to the compost heap. It should ideally be burnt or consigned to the green-waste bin. Remove all pruned material from the greenhouse as soon as possible.



Home   Historic Sites   Models   Heraldry   Puzzles    Garden   Links

Contact me with suggestions, comments or questions.

free page counter