How to treat yellow rust on thornless raspberries?

fruitbat

My four thornless raspberry canes have yellow rust infection.

I haven't had a crop off them yet but dont want to jeapordise any future crops from spores.

I sprayed them today with Yates liquid copper.  How mant applications are needed to elimiinate the problem?

I am also wondering if I should cut them out and burn them before my next lot of regular canes emerge elsewhere in  the yard. I read that the spores are windborne and atm the underleaf fungal growths are yellow not black.

MitchellMc

Welcome to the Bunnings Workshop community @fruitbat. It's sensational to have you join us, and many thanks for your question about Raspberry care.

Applying Yates liquid copper fungicide is an excellent first step. Typically, you should use the liquid copper every 7 to 10 days throughout the growing season or until the symptoms subside, ensuring complete coverage of all plant surfaces, particularly the undersides of the leaves where spores are commonly found. It is best to apply the fungicide early in the morning or late evening on a clear day to avoid leaf burn and prevent it from being washed off by rain before it takes effect.

If the infection is severe, consider removing and disposing of the infected canes to eliminate the source of spores. Additionally, clean up any fallen leaves and debris around the plants, as they can harbour spores. Regular pruning to improve air circulation can help reduce humidity levels around the plants, making the environment less favourable for rust. After handling infected plants, sanitise your tools to prevent the spread of spores to healthy plants. Monitor new growth closely and apply preventive fungicide treatments as necessary to protect emerging canes.

Look for signs of improvement, such as a reduction in yellow rust spots and healthier foliage. If symptoms persist, continue with regular fungicide applications as needed.

Please let me know if you have any questions.

Mitchell