Mealy bugs are white, waxy-looking insects that often appear as a cottony mass on catalpa, flowering trees with large, heart-shaped leaves. Mealy bugs enjoy nestling in the many nooks and crannies catalpa offers, making the insects difficult to target and kill. Keep an eye out for mealy bugs at all times so you can catch the infestation while it's fresh. This will increase your chances of being able to use natural insecticides to kill them.
Soak a cotton ball with rubbing alcohol and dab any visible mealy bugs (and their eggs). This natural way to kill mealy bugs works best when the infestation is new, as you do need to target each bug individually for it to work. The alcohol breaks down the mealy bugs' waxy protective shell and kills them.
Cut away infected branches with pruning shears. Trimming the catalpa tree will only work if the infestation is mild and fairly isolated.
Pour 2 tsp. of liquid dish soap into a gallon-sized bucket and fill the bucket the rest of the way with warm water. Soak a paper towel in the solution and use it to wipe away any patches of mealy bugs on the catalpa. This method is most effective when the trees are young and fairly small.
Purchase a container of live ladybugs from a garden center and release them in the catalpa tree. Ladybugs are natural predators of mealy bugs but will not harm the tree. This natural mealy bug remedy is your best bet when the infestation is severe and the catalpa tree is large.