Tag: apples

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Rust Diseases – Cedar apple rust and Quince rust

cedar apple rust
Figure 1. Apple rust diseases with cedar apple rust (left) and quince rust (right). Photo courtesy of Penn State University.

Cedar apple rust can infect leaves and fruit of most cultivars in the United States, where the alternate host, Eastern Red Cedar, occurs. A notable exception is ‘Delicious’, which is nearly immune.

The most conspicuous symptoms on apple are bright orange, glistening lesions on the leaves. Lesions which are not inhibited chemically may form small tufts of spore-producing structures (aecia) …

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Sooty blotch and fly speck disease on apple

Sooty blotch and fly speck are caused by a complex of fungal pathogens that commonly appear together as surface blemishes on apple (and pear) in late summer and fall. Although these fungi may shorten the storage life of fruit due to increased water loss, they do not cause decay, and losses are attributed to unacceptable appearance. During wet growing seasons, losses of 25 percent or more are commonly found, even in orchards treated with fungicides. Sooty blotch appears as sooty …

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Fire blight

Fire blight is a destructive bacterial disease of apples and pears that kills blossoms, shoots, limbs, and, sometimes, entire trees. The disease is generally common in most apple-growing regions of the US; although, outbreaks are typically very erratic, causing severe losses in some orchards in some years and little or no significant damage in others. This erratic occurrence is attributed to differences in the availability of overwintering inoculum, the specific requirements governing infection, variations in specific local weather conditions, and …

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Apple Tree Viruses


Virus and Other Graft-Transmissible Diseases and Disorders of Apples

Virus diseases cause economic losses through lower yields and reduced quality of apples and apple products. In general, virus diseases in perennial crop plants, such as apples, are more potentially damaging than in annual crops. Viruses can remain latent, spreading through an orchard and inflicting damage, often without the growers’ knowledge. Latent virus infection can produce small to moderate losses in fruit production. Often growers can maintain the productivity of diseased …

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Apple Rootstock Info: M.7 EMLA

Characteristic Detail Description
Rootstock M.7 EMLA

Formerly known as EM VII. Selected in 1912 from unknown parentage at the East Malling Research station in Maidstone, Kent, England. Trees on M.7 EMLA produce a semi-dwarf tree about 60 to 70% as big as seedling. Trees are moderately precocious and may lean with some cultivars and may require trunk support. Trees tend to produce many rootsuckers. M.7 EMLA has been widely planted since the 1960s with cultivars such as ‘McIntosh’, ‘Empire’, ‘Cortland’,

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Apple Rootstock Info: B.9

Characteristic Detail Description
Rootstock B.9

Resulted from a cross of M.8 x ‘Red Standard’ (Krasnij Standard) from Russia. B.9 has been tested widely and is used commercially in the U.S. In general, B.9 is slightly more dwarfing than M.9 and has slightly higher yield efficiency than M.9. B.9 was selected as a dwarfing cold hardy rootstock and initial inoculation results indicated that it was as susceptible to fire blight as M.9. However, in field trials, trees grafted onto B.9 survived

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A High Density Apple Production System for the Home Garden

Have you ever considered planting a high density orchard at home?  Nearly full production can be achieved within four years, less space will be required, a larger variety of fruit may be planted and the training and pruning is quite simple.  Further, the horticultural techniques learned in training these trees are easily applied to controlling the growth of other plants in the landscape.  Researchers have developed the Tall Spindle System for apple production that may be of interest to gardeners …

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Apple Rootstock Info: Mark

Characteristic Detail Description
Rootstock Mark

An open-pollinated seedling of M.9 and introduced by Michigan state University, USA in 1979. It is a virus-free clone of MAC-9. Mark is a hardy, precocious dwarfing rootstock. It is susceptible to fire blight and fairly resistant to crown and root rots, produces many burr knots and few root suckers. Mark requires tree support. Trees are very precocious and tree vigor may decline earlier than desired when young trees are allowed to produce heavy crops

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Apple Rootstock Info: MM.111 EMLA

Characteristic Detail Description
Rootstock MM.111 EMLA

Introduced in 1952 from a cross of Merton 793 x ‘Northern Spy’ by the John Innes Horticultural Institute and the East Malling Research Station in England. MM.111 EMLA is one of the more vigorous semi-dwarf rootstocks, producing a tree about 85 to 100% the size of seedling. It is resistant to wooly apple aphid and is quite tolerant to fire blight and crown and root rots. It is fairly winter hardy and produces moderate

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Apple Rootstock Info: MM.106 EMLA

Characteristic Detail Description
Rootstock MM.106 EMLA

Selected in 1932 from a cross of M.2 x ‘Northern Spy’ by the John Innes Horticultural Institute and the East Malling Research Station in England. MM.106 EMLA is a semi-dwarf rootstock, producing a tree about 60% the size of seedling. It is quite precocious and productive and usually does not need tree support. It is resistant to wooly apple aphid, but is highly susceptible to crown and root rots, susceptible to fire blight, and

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