Gardening Articles: Edibles :: Fruit & Nut Trees
Meet the Asian Pears (page 4 of 4)
by Kris Wetherbee
Diseases and Pests
Several bacterial diseases can affect Asian pear trees. The two most common are fire blight (Erwinia amylovora) and bacterial canker (Pseudomonas syringae). The diseases look similar and are easy to spot: the infected branch or twig will look singed with scorched leaves remaining attached. Wet weather promotes both diseases, with fire blight thriving in warm temperatures and bacterial canker in cool ones.
If you live in a disease-prone region, select resistant varieties. Note, however, that disease resistance varies by region, soil conditions, and climate. If your tree is affected, prune infected branches 12 to 15 inches below the infection, and sterilize tools with alcohol or bleach between each cut.
A dormant oil spray will destroy many overwintering insects and even some diseases, but codling moth (Carpocapsa pomonella) requires more control. Careful fruit thinning helps, but the easiest and most effective control I've found is an annual release of parasitic trichogramma wasps. I release them when I see the first moths fluttering in mid-April, and again two to four weeks later. Releasing 5,000 wasps each time is sufficient for two to three trees. Before our release program, up to 30 percent of the fruit suffered codling moth damage. Now less than 5 percent is affected.
Expect a healthy young tree to produce 5 to 15 pounds of fruit, a 5-year-old tree 30 to 50 pounds, and a mature tree, from 100 to 400 pounds. Wait to harvest fruit until its background color has changed but the fruit is still firm, then begin tasting it for peak flavor. If the fruit is picked too soon, the sugars won't develop fully. However, don't wait until the fruit is soft, or it will be overripe and spongy. Never pull fruit off the tree; wait until it lifts off effortlessly. The tender skin also bruises easily, so handle fruit gently.
Asian pears keep up to two weeks at room temperature, and many varieties will retain their quality for up to five months in a cool, humid environment (about 34 degrees F.). The fruits also freeze and dry well. I prefer, however, to enjoy the crisp, juicy fruits in the cool of the morning -- right from the tree.
Kris Wetherbee has more than 100 trees of nine varieties of Asian pears in her Oakland, Oregon orchard. Photography by Michael MacCaskey.