Common and Japanese persimmon trees (Diospyros virginiana, Diospyros kaki) have a tendency to admire. Fragrant, white or pink spring flowers, shiny green foliage changing to brilliant orange, red or yellow in autumn and deliciously sweet yellow or orange fruit make them desirable additions to ornamental or kitchen gardens. Suitable for U.S. Department of Agriculture plant hardiness zones 4 and 7 through 9, respectively, they’re largely resistant to pests and diseases. When a persimmon’s leaves start to curl, the cause is probably one of two pests.
If your persimmon’s curly leaves have blistered tops and dimpled, orange- or yellow-spotted undersides, microscopic eriophyid mites have penetrated them to drain their mobile tissue. Female blister mites overwinter in cracks on the invading or beneath bud scales. They appear in spring to lay eggs. Their offspring mature and reproduce quickly, so mite populations can explode in a limited moment. Wind disperses the tiny pests, and confining an infestation is difficult. Luckily, their harm is mainly cosmetic.
Blister Mite Control
The very best alternative for managing blister-mite damage would be to prune the most badly damaged leaves and dispose of them in sealed plastic bags. To avoid spreading the mites, rinse your pruning tools between cuts in a solution of 1 part household bleach to 9 parts water. If the infestation is severe, spraying your tree using ready-to-use insecticidal soap in early spring may kill sufficient overwintering adults to lessen the damage. Spray on a peaceful day when no direct sun is about the tree and no rain is in the prediction. Direct the soap to the bark ridge in which the mites shelter, and spray until the twigs drip. Treat your tree one week to 10 days before the buds break and the moment they emerge. Dress in protective clothing, closed-toe shoes, waterproof gloves, safety goggles and a hat and follow the label’s application directions when spraying.
Orange Tortrix Leafroller
Persimmons growing in cool, coastal areas face infestations of orange tortrix moths and their leaf-rolling caterpillars. The 1/2-inch, tan or orange female moths deposit clusters of pale-green eggs on persimmons’ new leaves and twigs. Their brown-headed caterpillars have tan, yellowish-white, green or gray bodies. The caterpillars pull on the borders of the leaves over themselves and stitch them closed with white webbing. They feed inside the leaves for about six weeks before turning cocoons and pupating in their own shelters. In Mediterranean climates, orange tortrix moths and their caterpillars may infest persimmons all through the year.
Leafroller infestations on persimmons seldom require chemical pesticide control. An effective and enjoyable means to limit their harm would be to encourage braconid wasps to your garden. These miniature, black-and-yellow insects do not hurt people, but their larvae are voracious leafroller predators. During their egg-laying period, the adult wasps feed on shallow-faced, nectar- and pollen-rich blossoms. Attract them with vibrant annual zinnias (Zinnia elegans) or with common yarrow (Achillea millefolium), perennial in USDA zones 3 through 9. If it’s not invasive in your region, another good alternative is another annual, daisy-flowering cosmos (Cosmos bipinnatus).