What are these black spots on the leaves of my apple tree and sugar peas?
I have old apple trees, which have black spots on leaves and fruit, the apples are only small and not good to eat. I planted sugar peas, got a few nice peas off them then they went dormant for a while, but have now produced but with black spots as well. My nectarine tree has the copper disease and gum (sticky)saps over it. What is the best way to treat all this? Is it because of our cold climate?
Unfortunately it sounds like your apple tree has been infected with apple scab. The disease is usually seen on the leaves to being with and then black spots appear on the fruit eventually turning brown and corky in appearance. It is too late to spray now as a copper spray needs to be applied at green tip stage to prevent this fungus from affecting the emerging bud. The spray to use is either Yates Liquid Copper or Yates Leaf Curl Copper Fungicide Spray. What you will need to do now is to pick up any fallen leaves as the fungus will continue to develop in fallen leaves in winter and in spring spores are released to infect the new leaves and flowers. With regard to your nectarine tree, excessive gumming, wilting and dieback can indicate a fungal disease called 'dead arm disease'. It is likely the fungus has gained entry via prunning cuts. You will need to prune off and remove any infected wood so as not to spread any of the spores. Always disinfect your pruning equipment before and during pruning. Peas do suffer with a number of fungal diseases. Fungal spores can be carried by the wind and the problem is worse in damp weather. Liquid Copper fungicide is registered for use on peas. Apply the spray when signs of disease first appear and repeat the spray at 10 - 14 day intervals.
Answered: 23 Nov, 2013