Well, December is finally here and as our cool weather settles in, one of our favorite fruit trees begin to show off their wonderful blooms. Mangoes begin to bloom this time of year and depending on the variety you have your tree could either just be starting to go into bloom or your tree could be in full bloom now. Several of my mango trees are in full bloom but I do have some later blooming varieties that are just showing the first signs of blooming. Today, I would like to discuss a few things that you need to do now to protect your fruit as they develop and to help you maintain a healthy tree for years to come. I also want to cover some diseases that mangoes can have on both the fruit and the leaves so you can properly identify them and control these problems as they occur.
First you should know the mangoes can be grown from seed or purchased in the nursery as a grafted tree. Seedling mangoes are generally inferior to the grafted variety of mangoes purchased at local garden centers. Now that I have made that statement I know some people will say the best mango they have ever eaten was from a tree their grandmother planted from seed. This can and does happen occasionally, and this is how many of the named varieties of mangoes have come into being. Unfortunately, most seedling mango fruit are small in size, stringy, and many have a bad turpentine taste. Grafted mangoes are named varieties of trees which are grafted onto seedling rootstock and will produce fruit earlier than seedling trees. Another benefit is that when you purchase a grafted tree you can pick the type of mango you want. If you have grown your tree from seed and wish to graft it with a named variety of tree, or maybe a tree that you like the flavor of that a neighbor has, you can graft that variety on the seedling you have grown. This is best done in the spring when the plant is actively growing.
If your mangoes are currently in bloom like mine are, you need to protect the blooms from a disease called anthracnose. Anthracnose or Colletotrichum gloeosporoides infects the blossoms as they develop on the tree. Mango blossoms form a pyramid shape on the tip of the leaf stems. These blossoms are very fragrant and if you are standing next to a tree in bloom you will appreciate the sweet scent. Unfortunately, these blossoms can succumb very quickly to anthracnose and if left unchecked, all the blossoms and the fruit they would have produced for you will be aborted. In order to spot this fungus you need to look closely at the individual flower buds, the pedicel, and the main and auxiliary flower stalks. Look for small, pin sized black spots on the individual blossoms as this will be the first signs of infection. As the disease progresses, the spots will enlarge and coalesce eventually covering the entire flower cluster which will turn black and dry out.
Control of this disease is easy if caught early. I prefer to start spraying for this disease as the tree first starts sending up its bloom stalks. Apply copper hydroxide to the blossoms every seven to ten days with a pump up sprayer. You need to be sure you coat the entire bloom stalk and spray from several angles to be sure the entire bloom stalk is covered. Be sure to agitate the product in the pump up sprayer by shaking the sprayer vigorously during each application. You can pick up the copper hydroxide at any local garden center. Mix the product according to the product label and spray the blossoms to the point of run-off. One you have finished spraying the flower blossoms, wash out the sprayer with clean water so the sprayer will be ready for your next application in about ten days. As the young fruit begin to appear, repeat applications until the fruit are the size of a small marble or new leaf growth is initiated. After you stop your spray applications you will still want to monitor the fruit and new leaves for other problems.
As the young fruit develop, the same fungus which affected the blossoms can also cause problems on the fruit. Look for dark lesions on the fruit or blackened areas at the fruit tip. These black areas are caused by the fungal spores which first attacked the blossoms and were carried onto the developing fruit from rainfall. Tear-staining or russeting of the fruit can occur anytime and appears as corky or slightly raised pin-sized lesions on the fruit. When you notice these problems you will need to spray the fruit with mancozeb, chlorothalonil, or benomyl. Copper fungicides have also shown some degree of control of this fungal pathogen. I like to alternate applications of the products I listed above to help eradicate this fungus.
Do not forget to pay close attention to the leaves of your mango trees. Anthracnose, Grey Leaf Spot, and Stigmina leaf spot fungus can also harm your trees. These fungal pathogens start as small pin sized spots on the leaves which coalesce during times of high humidity. Sometimes these spots will form tiny yellow halos around the small spots or one way to see these spots more clearly is to pick off a suspected leaf and hold the leaf up to a light source and as you look through the leaf the “Halo” will become visible. The same fungicides I mentioned above for the fruit disease can be applied to the leaves in order to correct this situation.
One final point I would like to make is the importance of a regular fertilizer program. I like to fertilize my trees every two months with a granular 8-10-10 fertilizer at the rate of one half pound of fertilizer per inch of trunk diameter. I will also apply a citrus minor essential element spray to the tree twice per year. I do one application in the spring and one application in the summer. These applications add nutrients to the tree by the means of foliar absorption. Sometimes tree root systems are unable to pick up these materials even if they are present in the soil because of high soil pH.
Mangoes are one of the most consumed fruits in the world. You can grow mangoes relatively easy in our area if you pay attention to what the tree is telling you. This does involve regular inspections of your trees to inspect for diseases of the fruit or the leaves. Not everyone will have problems I have mentioned here with their tree but I want you to know several of the problems that I have had to deal with in the past. I hope this information will help you grow bigger and better mangoes for your table. Keep growing as many fruits and vegetables from your own garden as possible and remember, without plants we would not be here!