Monkey pod trees, also called Pithecellobium saman or raintrees, are fast-growing tropical trees reaching 100 feet in width. The tree likes warm temperatures and humid conditions. Monkey pods do not have many pest or disease problems, but without the proper climatic conditions they can become susceptible to certain illnesses.
Leafspot on the monkey pod occurs when the Phyllosticta pithecolobii fungus attacks the tree. Spots develop on the leaves, eventually causing them to drop off the tree. Most cases do not harm the trees enough to warrant fungicides. Fungicides, however, can control the disease if you catch it before the leaves start dropping.
Three types of caterpillars--Melipotis indomita, Ascalapha odorata, and Polydesma umbricola--invade the monkey pod every year, eating away its leaves. Melipotis indomita causes the most damage. This disease is not life-threatening to the tree, however, as the monkey pod leafs out soon after losing its leaves to the caterpillars. Caterpillar damage does cause stress for a short period of time, increasing the risk of other problems such as borers.
Borers and Ants
Monkey pod roundhead borers, also called Xystrocera globosa, invade stressed trees, making large holes in the wood of the tree. Ants bore into the branches, causing leaf deformation and drop. Control these pests by applying insecticide to the trunk of the tree. Follow the directions on the package for safety and application instructions.
The leaves of the monkey pod plant are highly susceptible to salt spray and herbicide spray. Direct contact burns the leaves, causing injury and sometimes even leaf drop.