Biosecurity Queensland senior inspector Aaron Russell said recent wet conditions were ideal for the spread of yellow Sigatoka and other plant diseases such as speckle disease.

“Sigatoka disease can reduce crop yields and cause premature ripening of fruit on heavily infested banana plants,” he said.

“Leaf spot diseases rely on moisture from rain, heavy dew and wind to spread to other areas.

“Fungal spores can travel up to 30km by air, so it is vital that all banana growers practice good plant hygiene.

“Anybody who owns a banana plant needs to take action now before yellow Sigatoka or speckle disease get out of control.”

Mr Russell said it was illegal within the Northern Pest Quarantine Area, which includes Innisfail, Babinda and Cairns, to have more than 5 per cent of a banana leaf covered in leaf spot disease.

“Biosecurity Queensland will conduct random inspections to ensure commercial and backyard banana growers are observing the leaf disease coverage limits,” he said.

“The disease is easy to manage – just remove all leaves carrying leaf spot from the plants as soon any spots appear.

“This will improve the health of your own plants and reduce the number of airborne spores that can infect other people’s banana plants.”

Banana growers can control leaf spot by:

-Growing bananas well spaced apart in a sunny area where leaves will dry more quickly. Remove old diseased leaves every two weeks.

-Spraying plants every two weeks with fungicides or organic alternatives such as white oil and copper oxychloride (use as per label). Alternate between fungicides with different active ingredients to reduce fungicide resistance.

-Growing Sigatoka-resistant varieties such as Ducasse in residential areas rather than susceptible varieties like Cavendish and Lady Finger. Sigatoka-resistant varieties are available from many retail nurseries in North Queensland.

-Familiarising themselves with the symptoms of exotic leaf diseases such as black Sigatoka and Eumusae leaf spot, and keep an eye out for other exotic pests and diseases such as banana spider mite, banana skipper, Panama (Fusarium wilt), bacterial wilt, bunchy top and bract mosaic diseases.

-Reporting crops with high disease levels or possible exotic diseases to Biosecurity Queensland on 13 25 23.