A list of common avocado tree diseases were listed in a previous post.Â If you do not see the problems on this list, here are some suggestions.
If you bought your avocado tree just a few months ago from a nursery, take it back to the nursery. If they are a reliable nursery, they will give you a replacement tree or refund your money. Or perhaps the nursery people will tell you the problem your tree is having and if their avocado trees had suffered from the same problems, they will tell you their solution.
If this avocado tree was a gift from someone, ask that person if they are having similar problems with their trees- you may have planted an unhealthy tree that is not worth saving. If their trees are not having problems, see if they will give you a replacement. Plant this replacement in another location to be sure there are no diseases in the soil that may have been in the tree’s present location. Planting instructions are presented in the video above.
If neither of the above suggestions are applicable and you still want to find out what the problem is, then take your entire tree (I imagine it is not large) or a sizable portion of the tree showing both the unhealthy parts and the healthy parts of the tree to your local Master Gardener office or your Agricultural Extension office to see if there is a volunteer avocado tree expert who can ID the problem. This is a free service. But if no one at these places can ID the problem and you still want the problem ID’d so you will then know how to treat it (and have the time, energy and money), the Master Gardeners or the people at the Ag. Extension office will probably recommend that you send the diseased parts of the tree to the Agricultural Dept Lab to be ID’d. The people you speak to will tell you how to send it and will probably sell you a kit to mail it to the labs. It WILL cost money to have the Agricultural Dept Labs find the problem. If they do ID the problem they will tell you whether the avocado plant can be saved or not. If the plant can be saved, and it is worth saving, they will also tell what to use on the plant and will give you directions on what to do/how to apply chemicals if needed.
And while you are at it, you should take a sample of the soil where you want to plant your avocado. Soil kits will tell if your soil has the nutrient needs of the avocado tree. You can get the soil kit to test your soil at your Master Gardener office or Ag. Extension office and they will tell you how to amend your soil if needed.
As much as this GardenLady loves plants, because I am not a commercial planter, I know when to compost a dying plant or throw it in the trash if it has a really bad disease. Many times it is easier and cheaper to get a new healthy plant. This GardenLady tries to keep her garden healthy before plants get sick by using compost in the soil, buying healthy plants, seeing that plants get enough water in dry weather, using horse, chicken or cow manure and mulching. I am not a plant hospital and have enough work weeding and caring for healthy plants to waste time nursing sick/diseased plants.
TheGardenLady thinks it is NEVER advisable to use chemical sprays without knowing what the problem is. Some sprays can be toxic to the person spraying and some sprays, as you found, do not help the problem and may add unnecessary chemicals to your soil. Read this.