Since Moringa leaves are grown to eat, what can you do to defeat these pests?
They will most likely be affected in the winter when the tree is compromised from lack of sufficient sunlight, cold and adverse conditions. If your leaves are dusty and dry, that encourages mites too. When your trees are outside on the porch, hose them off to remove dust and mites. That is one of the best ways to keep them in check. I have always done that to mine on a regular basis. That is not easily accomplished when the trees are overwintered in the house.
In the Spring and Summer when it is warm and toasty, the plants are healthier so have more immunity to the spider mites.
If the plant is severely infested with the mites and their webs, prune the affected branches and leaves, putting the infected leaves in a bag and then putting them in the trash. Prune the tree back to the original trunk or stem. When you make the cuts use sharp, well oiled, sterile tools so you don't infect other plants. Cut the branches off at an angle, above a leaf node or at the junction of a branch.
There are beneficial insects that destroy spider mites including ladybugs, lacewing larvae and thrips. This would only work if you had the affected plants enclosed in a special room in the house. Use the beneficial insect control before the infestation gets severe.
Spraying the affecting areas every day with a blast of water containing a few drops of dawn dish detergent will sometimes wipe the majority of them out. Take a soft cloth and apply the mixture to the Moringa trunk and branches. Neem oil will also kill them but will affect the taste of the leaves adversely. You will have to spray them often to keep the mites in check.
Neem OilIf the infestation is severe, has been difficult to control using other means, and is affecting your beloved plants, you can apply Neem or other plant-based oil products to quickly wipe out pest numbers. To effectively kill mites, the oil must come into direct contact with the pests, so complete spraying is crucial to reach the undersides of the leaves. It will take weekly applications.
Insecticidal Soaps can also be used against heavy infestations.
Be aware that soaps will affect the taste of the leaves so the leaves must be washed. Even then, it may taint the taste of the leaves. Some of these soaps may burn the leaves, so test the solution on an area first. Do not use more of the soap then specified on the label. Go weaker first to see if it works. Try the other suggestions first above.