Tag: apple

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Powdery Mildew

Powdery mildew can be a persistent disease of susceptible apple cultivars throughout the United States. It is one of the most predominant diseases in the more arid apple growing areas. It is the only fungal apple disease that is capable of causing infection without wetting from rain or dew.

Powdery mildew causes whitish lesions on curled or longitudinally folded leaves, stunted whitish-gray twig growth evident on dormant shoots, and fruit russeting. Economic damage occurs in the form of aborted blossoms, …

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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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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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What apple rootstocks are commercially available?

There are currently at least 23 different apple rootstocks available from rootstock nurseries. Most fruit tree nurseries propagate apple cultivars on about 7 to 10 different rootstocks. The most common dwarfing rootstocks offered by nurseries include several clones of the dwarfing rootstocks M.9 (T-337, NIC 29, Pajam 2 and M-9 EMLA), Bud 9, and EMLA 26. Common semi-dwarf rootstocks include EMLA 7, EMLA 106 and EMLA 111. …

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Apple Tree Propagation: Grafting

 

Cleft grafting: placing the scion. Photo by Wes Autio, UMass at Amherst.
Cleft Grafting 3: Placing the Scion

Several grafting techniques are possible. The one to use depends on the conditions under which the grafting is to be done. Whip grafting, sometimes called bench grafting, is one of the most common. Cleft grafting is the technique most frequently used in top working an apple tree. Other grafting techniques are variations of whip or cleft grafting.

Whatever the grafting technique used, it is necessary to match as …

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Southern Blight in Apple Trees

Southern blight is a fungus disease caused by Sclerotium rolfsii. The disease is a problem primarily in the Piedmont apple growing region in the southeastern United States. S. rolfsii is a widespread pathogen that affects several hundred plant species. The fungus affects the lower stems and roots of apple trees, killing the bark and girdling the trees. The disease is characterized by the presence of a white, weblike mycelium, which often forms at the bases and on the lower stems …

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Apple Scab

Apple Scab

Apple scab is a fungus disease caused by Venturia inaequalis. It is of major economic importance and, if not controlled, can cause extensive losses (70% or greater) where humid, cool weather occurs during the spring months. Losses result directly from fruit or pedicel infections or indirectly from repeated defoliation, which can reduce tree growth and yield.

Symptoms

Apple scab lesions occur on leaves, petioles, blossoms, sepals, fruit, pedicels, and less frequently, on young shoots and bud scales. The first lesions …

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What is fire blight, and how do I identify and manage the disease?

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 throughout the United States wherever apples are grown, 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, …

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What is Brooks spot, and how do I identify and manage the disease?

Brooks spot is a fungus disease caused by Mycosphaerella pomi. It is a minor disease that occurs throughout the northeastern and mid-Atlantic apple growing regions of the United States and occasionally as far west as Iowa. Some of the more susceptible common commercial cultivars include ‘Jonathan’, ‘Golden Delicious’, ‘Stayman’, ‘Grimes Golden’, and ‘Rome Beauty’. Read more about Brooks Spot in Apple.

Answer provided by Alan R. Biggs, West Virginia University.…

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