![]() Infected tissue turns brown to black, shrivels and droops, but remains attached to the tree. The infection moves from blossoms to young fruit and then to adjacent leaves. The bacterium enters the plant through blossoms, wounds, and natural openings (such as stomata, hydathodes, lenticels, and nectaries). In spring when the bacterium becomes active, wind-blown rain or insects spread it from oozing cankers to blossoms. During periods of high humidity, infected tissue may produce a characteristic ooze. Fire blight can infect blossoms, fruit, stems, leaves, and woody branches. The characteristic symptom of fire blight is that affected plant parts (most notably the branch terminals) appear to have been scorched by fire (fig 1). Other hosts include rose, quince, hawthorn, loquat, almond, apricot, plum, cherry, chokecherry, mountain ash, raspberry, blackberry, and strawberry. In New Mexico, the disease is most common on apple, pear, crabapple, pyracantha, photinia, and cotoneaster. Within this plant family, the bacterium infects at least 39 different genera. It affects only plants in the rose family (Rosaceae). In commercial orchards, spray with bactericide.įire blight, caused by the bacterium Erwinia amylovora, is one of the oldest known bacterial diseases of plants.Sign: Watery ooze produced from infected plant tissue. Key symptom: Branch tips turn black as if scorched by fire. Hosts: Plants in the rosaceae family, notably apple, pear, pyracantha, cotoneaster, and photinia. This publication is scheduled to be updated and reissued 2/04.Ĭausal agent: Erwinia amylovora, a bacterium. Goldberg, Extension Plant PathologistĬollege of Agricultural, Consumer and Environmental Sciences New Mexico State University. Ripens early and keeps about one month in the refrigerator.Natalie P. The medium-sized, bright red fruit is sweet and crisp. Pair with other mid- and late-blooming cultivars. ![]() Redfree. Field immune to apple scab and cedar apple rust, moderately resistant to fire blight and powdery mildew, Redfree blooms in midseason. The large, yellow fruit is tart and crisp. It blooms early pair with Liberty, Pristine, William's Pride, Redfree or Jonafree. Pristine. This cultivar is field immune to apple scab, resistant to cedar apple rust, highly resistant to powdery mildew, and moderately resistant to fire blight. The fruit is large, yellow, semi-tart, crisp and juicy. It blooms late pair with Enterprise, Gala or Golden Delicious. It's susceptible to cedar-apple rust, however, so choose another variety if you live in an area where cedar-apple rust is common. Goldrush. This variety is field immune to apple scab, highly resistant to fire blight, and moderately resistant to powdery mildew. Pair with Goldrush, Gala and Golden Delicious. It keeps for months under refrigeration, and its flavor improves after the first month. The tree blooms in mid- to late-season and the fruit ripens late. ![]() The large, bright red, glossy apple has a juicy, spicy and crisp flavor it's thick-skinned. USDA Zones 4 to 7.Įnterprise. Resistant or field immune to apple scab, highly resistant to cedar apple rust and fire blight, and variably moderately resistant to susceptible to powdery mildew. It blooms midseason, so pair with other mid- or late-blooming cultivars. A medium-size McIntosh-like fruit that ripens midseason it's sweet, juicy and crisp color is red-stripe-over-greenish-yellow. ![]() It ranges from moderately resistant to susceptible to powdery mildew. One of the best disease-resistant cultivars, Liberty is highly resistant to apple scab and resistant to cedar apple rust and fire blight. Planting varieties like these - or others as recommended by your local extension agent (how well any given cultivar does has everything to do with region) - can drastically cut down on the amount of spraying you have to do. These varieties won't prevent the bugs from coming to your trees, of course, but they'll at least offer a good shot at thwarting whichever diseases tend to plague apple trees in your area. What usually helps the gardener is choosing disease-resistant cultivars. Among the bugs, there are codling moths, plum curculios, mites, aphids, scale and leaf rollers. If the apple is America's favorite fruit, it's also the favorite of several significant diseases and pests.ĭepending on the geographical region and the weather, apple trees can be beset by cedar-apple rust, powdery mildew, fire blight, bitter rot and apple scab. Having a couple of productive, low-maintenance apple trees in the backyard - ones that yield serviceable crops without lots of spraying - sometimes seems like an impossible dream. ![]()
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