|My Anna apple tree has exhibited black rot and I need to know what spray is commercially available to solve this problem|
|Black rot (Botryosphaeria obtusa) is a fungal disease that results in leaf spot, fruit rot and cankers on branches. Trees that are under stress due to environmental factors such as drought are more susceptible to black rot infection than well maintained trees. Many cultural control practices will reduce the severity of this disease.
To control black rot, remove dead material from the try by pruning out dead or diseased branches. Be sure to pick all mummy fruits remaining on the trees, as these are sources of spores for future infections. All infected plant parts should be burned, buried, included it in household trash, or sent to a municipal composting site. Be sure to remove the stumps of any apple trees you cut down, as dead stumps can be a source of spores.
All winter pruning, of healthy or dead tissue, should be completed during cold weather, as the fungus is not active until spring. Pruning cuts made in winter will have dried out and will not be susceptible to the disease by the time black rot spores are available to infect them.
Captan and sulfur products are labeled for control of both scab and black rot, so a scab spray program including these chemicals may help prevent the frog-eye leafspot of black rot, as well as the infection of fruit. Be sure to follow label directions - repeat applications will be necessary.
Good luck with your Anna apple tree.