Grassy Shoot Disease Control

Symptoms

Look for clumps with many thin, pale white to yellow grassy shoots and excessive tillering, giving a bushy grass like appearance. The leaves are narrow, soft and chlorotic, the canes remain thin and stunted or fail to form, and affected clumps clearly stand out as pale bunches in the field.

Damage

Grassy shoot disease, caused by a phytoplasma and often linked with yellow leaf virus, makes plants tiller excessively into thin pale grassy shoots that never form proper canes. This can cause heavy yield loss in affected clumps. It spreads through infected setts and is also carried by aphid vectors and builds up in successive ratoons.

Organic & cultural control

Use healthy seed from a certified disease free plot, which is the most important measure since the disease is mainly sett borne. Rogue out and destroy grassy affected clumps as soon as they appear. Avoid ratooning affected fields, control aphid vectors with neem based sprays, and follow crop rotation to break the disease cycle.

Chemical control

There is no chemical that cures this phytoplasma disease, so management relies on healthy seed, roguing and vector control. Moist hot air or hot water therapy of seed cane reduces the infection before planting. For aphid vectors, recommended insecticides may be used as advised. Always read and follow the product label, observe the pre-harvest interval, and consult your KVK or a qualified agronomist before applying.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Always plant healthy seed from a certified disease free nursery and consider hot water or moist hot air treated seed. Inspect fields regularly and rogue out grassy clumps early before vectors spread the disease. Avoid ratooning affected fields, control aphid vectors, and follow crop rotation to keep the disease from building up.