Almond trees are small, deciduous and flowering. They are one of the earliest trees to bloom after winter, and are popular landscaping trees as well as commercial investments for farmers. Almonds are prone to a few diseases that can destroy crops and eventually the trees as well. The best way to keep your almond trees happy and healthy is to be aware of the signs and symptoms of almond tree diseases.
Shot Hole Disease
Shot hole disease first manifests as small, dark spots on the leaves. If the disease infects the tree late in the season, the nuts may also develop spots, which do not impact taste but do make them less aesthetically appealing. Left alone, the spots will grow in diameter and the centers of the spots will rot out, eventually creating "shot holes" that make the leaves appear to have been peppered with buckshot. You can prevent this infection by watering the trees using a drip hose rather than sprinklers in the early morning. If the infection has already occurred, remove affected foliage with sterile pruning shears and dispose of it in a sealed garbage bag to prevent reinfection. You can treat it with a fungicide, but generally this is not necessary. If you do, do so after the flowers have lost their petals or after the almonds have been harvested.
Brown Rot Blossom and Twig Blight
Blossom and twig blights are caused by the same fungal infection: Monolina fructicola. First almond blossoms wither and fall off the tree, followed by the death of the attacked twigs. In some cases the blossom will remain on the tree, in which case you will be able to spot a brown, slimy mass that is the fungal fruiting body. This fungal infection weakens the tree and can, over time, dramatically decrease crop yield. Remove all affected parts of the tree immediately, since the fungus survives the winter in infected twigs. Use sterile pruning techniques, and also remove all dead debris from beneath the tree. You can also treat the tree using a variety of fungicides, but these will need to be recommended and approved locally to insure legal compliance.
Anthracnose is a fungal infection that spreads during the hard rains of early, cool springs. The disease kills flowers and developing nuts, and causes nuts that survive to be discolored and cosmetically unappealing. Anthracnose also causes entire limbs to defoliate and die. Remove affected foliage and dispose of it in sealed garbage bags or by burning, and remove debris from beneath the almond tree to prevent reinfection. Water the tree with a drip hose in order to prevent additional splashing that could cause reinfection.There are several fungicides that treat anthracnose, but you will need a local, professional recommendation since not all are legal options in all areas of the country.