We know that Phomopsis is present in California and I've been noticing an explosion in the number of sharpshooter bugs that suck juice from our Mango trees. I've watched them feed and noticed that the area where they feed usually turns dark and sap usually flows out from the wound after several days to a couple weeks and the injury sometimes turns dark and sometimes the injury will heal. I've noticed that in some cases, the entire young stem will die back. I'm actually surprised that nobody else in California is noticing these bugs that scoot from side to side on their trees.
There are already several threads for fungicides but I'm especially interested in a systemic fungicide that someone can recommend for California although I am extremely interested in opinions from Florida and other areas as to why I might want to use something else.
Previous threads mentioned that Azoxystrobin is the best active ingredient to combat Phomopsis here in California and products like Abound, Quadris and Prestine are perhaps the best of the best.
I try to grow all my plants with no pesticides and fungicides but I would like to perform a few experiments where I treat several young trees with a systemic fungicide to see if preventive applications of fungicide, even before I see any signs of disease, could increase the rate of growth of mangos. I will not allow these trees to hold fruit for at least 3-4 years and I intend to stop the use of the systemic fungicide 1 year before I intend to allow the trees to hold fruit.
I believe that sharpshooters are the primary vectors for disease here in California and the diseases that they can spread, mainly Phomopsis, can greatly inhibit the growth of young, unestablished Mango trees here. By using a systemic and preventing disease before the tree is infected, I hope to greatly accelerate the establishment of young trees.
All three of these systemic fungicides are extremely expensive, is there something cheaper that may work as well? Are there smaller sizes available? I've searched the web but I can't find small size bottles? Perhaps there is a generic that works equally well?
If there are other solutions that may work, I'd love to hear your ideas and suggestions. Thanks in advance!
Simon