Anthracnose On Blackberries

Question

Hi, The bush had Anthracnose last year, and again this year, after 5 years of heavy production with no problems. What can I spray to eliminate or control this? Thanks for your help! Dave

Answer 1

If your bush is battling anthracnose again after years of healthy yields, it’s time for a two-pronged approach: sanitation and treatment.

Start by removing all infected leaves, twigs, and dropped debris around the base of the plant—anthracnose spores overwinter in this material and re-infect plants in spring. Prune for airflow, especially in the center of the bush, to reduce humidity and allow light to penetrate. Disinfect pruning tools between cuts to avoid spreading spores.

For sprays, choose a fungicide labeled for anthracnose. Copper-based fungicides and biofungicides like neem oil or Bacillus subtilis can work preventively if applied early in the season. For active outbreaks, use something stronger like chlorothalonil or azoxystrobin, following label directions strictly. Rotate modes of action to avoid resistance buildup.

Apply the first treatment in early spring as buds break, and repeat as needed—especially after rain. Long term, consider adding compost or microbial inoculants to strengthen plant immunity. Stay consistent and you should see improvement next season.

https://www.gardeningknowhow.com/plant-problems/disease/anthracnose-disease.htm