Cedar apple rust

Cedar-apple rust completes its life cycle only where the fungal spores can travel back and forth between cedar and apple trees. Spores from cedar trees send spores to infect apple trees, but infections on the apple tree do not spread within the tree they can only send the disease back to infect cedar. 

Pearson, R.C. Szkolnik, M., and Meyer, F.W. 1978. Suppression of cedar apple rust pycnia on apple leaves following postinfection applications of fenarimol and triforine. Phytopathology 68 1805-1809. 

Szkolnik, M. 1974. Unique post-infection control of cedar-apple rust on apple with triforine. Plant Dis. Rep. 58 587-590. 

Cedar-apple rust. 1., Fruit has yellow k- / tepots and -Vnay fall prematurely.,] ... 

Fruit with yellow skin spots that later turn orange. Cause Cedar-apple rust. Infected fruit is small, deformed, and may fall prematurely. For more information see Leaves with pale yel-... 

Branches with large galls. Cause Rust. Cedar-apple rust, cedar-hawthorn rust, and cedar-quince rust are fungal diseases that spend part of their life cycles on junipers, the rest on alternative hosts, such as apples and crab apples. Large galls form and eventually swell to release the spores, especially in warm, moist weather. For an illustration of rust galls on junipers, see below. 

Pests and disease problems on apple trees are covered in the Apple entry beginning on page 21. Crab apples share many of the same problems, including fire blight, cedar-apple rust, powdery mildew, and apple scab. Ibr-tunately, disease-resistant cultivars are available. Some of the best include Adams , with reddish pink flowers Coral Cascade , with white flowers Prarifire , with purplish red flowers and Professor Sprenger , with white flowers. There are also many other resistant cultivars, so check with your local nursery owner or extension agent to learn about the best ones for your area. 

Rusts Rusts are a specific type of fungal disease. Many of them require two different plant species as hosts to complete their life cycles. Typical rust symptoms include a powdery tan to rust-colored coating or soft tentacles. Cedar-apple rust and white pine blister rust are two common rust problems that can appear in home landscapes. 

Symptoms Hard, brown swellings appear on branch tips. These galls do not seriously damage cedar trees, but they can mar the plants appearance. Warm, moist weather in spring causes these galls to swell dramatically, and they produce gelatinous horns that release rust-colored spores. The spores then infect apple trees. For more details about this disease on apples, see Cedar-Apple Rust on page 373. 

Eastern red see Juniperus virginiana) red see Juniperus) Cedar-apple rust... 

For tree fruits such as apples (Table IX), low rates of 2-4 grams active ingredient per 100 liters of spray give near-perfect control of both major diseases, scab and powdery mildew excellent cedar apple rust control is also observed at these rates. Standards for these tests include both sterol inhibitors (fenarimol and bitertanol) and non-systemic protectant fungicides (sulfur and captan). 

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