Loquat plum (Eriobotrya japonica) is native to subtropical to mild-temperate climates in Southeast Asia. The 1- to 2-inch-wide orange, red or yellow loquats are rounded, oval or pear-shaped with downy or smooth skin. Loquat trees have large, dark green leaves that provide shade and give a tropical look to a landscape or garden. They have special problems responding to springtime drops in temperature, and they are subject to attacks by bacteria that cause blight.
Loquat trees will tolerate a low temperature of 12 F, meaning they can be grown in U.S. Department of Agriculture plant hardiness zones 8a through 11. The problem, depending on local springtime weather, is that a temperature drop to 19 F will kill their flower buds and 26 F will kill mature flowers. If loquats have set, a temperature drop to 25 F will kill their seeds and cause them to fall off the tree. Dry, hot winds and summer heat will scorch loquat leaves, and high heat and sun will sunburn the fruit. Varieties with white flesh are better grown in cool coastal areas.
The insects that feed on loquats depend on where they are grown. The green apple aphid (Aphis pomi) and the codling moth (Cydia pomonella) infest loquat trees in California. The Caribbean fruit fly (Anastrepha suspense) is a major problem in Florida. Aphids can curl the leaves and leave a sticky honeydew that can attract fungi but rarely kill plants. They can be washed off with water or insecticidal oils and soaps. The larvae of the codling moth is the worm often found in apples. Growers can protect young loquats by bagging them on the tree or spraying moth caterpillars as they hatch with horticultural oil containing insecticides with the active ingredients spinosad or carbaryl. Fruit fly maggots burrow into loquats, turning them into mush. Pesticides are available to reduce Mediterranean fruit fly populations, but the release of parasitic wasps is also effective, and University of Florida entomologists are experimenting with the introduction of laboratory-produced sterile fruit flies.
Fire blight (Erwinia amylovora), spread by bees, attacks loquat trees in areas of high humidity or that have late spring and summer rain. Fire blight turns young shoots brown and kills their leaves. Preventative bactericides can help control fire blight, but once shoots are infected, they need to be trimmed well into healthy green tissue, and the infected tissue must be bagged and removed or burned. Pear blight (Bacillus amylovorus) also strikes loquat trees in California. Cankers (Pseudomonas eriobotrya) and crown rot (Phytophthora) may occasionally strike trees in California. Leaf spot (Pestalotia sp) may infect trees grown in Florida.
Regular, light application of nitrogen fertilizers are beneficial for loquat trees, but applying too much will reduce their flower and yield of loquats and make them more susceptible to fire blight. Fertilizing recommendations vary. Some authorities say they should be fertilized once a year in mid-winter. For each tree 8 to 10 feet tall, the California Rare Fruit Growers Association recommends applying 1 pound of 6-6-6 fertilizer three times a year when the trees are actively growing.
Your Planting Articles
- Purdue University: Loquat
- California Rare Fruit Growers: Loquat
- Louisiana State University Extension: Growing Loquats in Louisiana
- Texas A&M University Extension: Home Fruit Production – Loquat
- University of Florida Extension: Japanese Plum/Loquat Eriobotrya japonica
- Sonoma County Master Gardeners: Lovely Loquat
- University of California Integrated Pest Management: Aphids
- University of California Integrated Pest Management: Codling Moth
- University of Florida Institute of Food and Agricultural Sciences: Caribbean Fruit Fly
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