Q What is take-all?
A Take-all is a relatively uncommon disease that attacks the roots of grasses, killing the plants. It is caused by the fungus Gaeumannomyces graminis. This was previously known as Ophiobolus graminis, hence the alternative name, ophiobolus patch.
Caption: Take-all attacks grass roots, causing dead patches in the lawn
Q How do I recognise take-all?
A Irregular dead areas, which may look pale or bronzed, appear and gradually enlarge. Patches often develop in the same place year after year. The dead grass can be pulled away in tufts owing to the lack of roots. Over time, the centre of the patch may be colonised by weed, including annual meadow grass, creating a brown ring with a green centre.
Q Could I mistake take-all for anything else?
A Dead patches in lawns can have many causes. Take-all is only likely to be a problem in lawns with a high percentage of bentgrass species. Its appearance in early summer and the way dead plants are easily pulled up are quite distinctive. Take-all is unlikely to appear on acid soils unless they have been limed.
Q What is the life cycle of take-all?
A Fungal growths are brought into a lawn with plant debris, on shoes or equipment. Once established, it spreads through the soil from root to root. Spore production does not appear to be important to its spread.
Q When do take-all attacks occur?
A Damage tends to start in midsummer, especially where lawns are stressed by drought. The disease is more common on sandy and acid soils. Take-all also affects cereal crops and is the most important disease of wheat in the UK, largely because it is so difficult to control. More cheeringly, it also attacks couch grass.
Q How do I control a take-all attack?
A There are no chemical controls for take-all available to gardeners, so control must be cultural. If left untreated, the effects of take-all gradually lessen through the action of bacteria antagonising the disease. However, this will take several years, during which the patches become increasingly unsightly. So over-seeding with resistant grasses, such as rye or fescue, is a more practical solution.
Q How do I prevent take-all in future?
A Vigorous, deep-rooted lawns, encouraged by good maintenance are less susceptible to take-all. Poor drainage and alkaline conditions favour the disease, so these should be counteracted as far as possible.