Tag: apple

Posted on

Pollinating Apples

Figure 1. Bumblebee on apple blossom (Alan R. Biggs, West Virginia University)

Apples require cross-pollination for optimal fruit set and size.  Cross-pollination involves the transfer of pollen from one apple cultivar to another by pollinating insects, such as bees which are referred to as pollinators.  The cultivar supplying the pollen is called the pollinizer.  For successful pollination to occur, bloom periods must overlap.  Triploids apple cultivars, such as ‘Mutsu’, ‘Jonagold’, and ‘Shizuka’, cannot supply viable pollen and are unsuitable as …

Posted on

Pre-harvest Drop

Apples sometimes drop to the ground before they reach the desired harvest maturity. This pre-harvest fruit drop can cause significant losses in apple orchards. As apples mature, an abscission layer of specialized cells naturally forms between the apple stem and the fruit spur to which it is attached. The abscission layer allows the apple to be released from the tree without causing damage to the tree. However, apples may fall off the tree before the ideal harvest maturity has been …

Posted on

Disease-Resistant Apple Cultivars

There are more than 100 modern apple cultivars, and several dozen antique varieties, that have been selected in part for their disease resistance. They offer a broad range of flavors, appearance, taste profiles, storage potential, and harvest dates from mid-summer to early winter. This disease resistance was achieved by hybridization with other apple species with resistance to significant diseases, primarily apple scab (Venturia inaequalis), through natural selection or controlled breeding. Malus floribunda, also known as Japanese flowering crabapple,  …

Posted on

Apple Fruit Shapes

 

Fruit shape is one of several characteristics used to identify apple cultivars. When apples are mature, the fruit is cut longitudinally in half  through the core to categorize the shape. Common fruit shapes include round, conic, oblate, oblique, oblong, and ovate as shown below (Figure 1).  Fruit shape may differ by growing location depending on environmental conditions. For example, ‘Red Delicious’ ripened in locations with cool evening temperatures are more elongated than those ripened in climatic zones with evening temperatures …

Posted on

Apple Fruit Cracking

Fruit of some apple cultivars tend to crack during the second half of the growing season. Sometimes cracking is limited to the stem end, and other times, the skin will split on other areas of the fruit surface. Cracking occurs most frequently during periods of high humidity following rains. Absorption of rain water through the skin, combined with the uptake of water from the roots, results in rapid enlargement of cells within the fruit. The internal pressure from the enlarged …

Posted on

Bitter Pit and Calcium Deficiencies in Apple Fruit

Calcium deficiencies contribute to certain fruit disorders in apple, including bitter pit.  Bitter pit is a physiological disorder of apple fruit that has caused serious losses in certain apple varieties for many years. The visible signs may be only slight indentations in the skin with no change in color. The skin over these depressions usually takes on a deeper green color than the surrounding skin, and finally, the disorder appears as small, brown, desiccated pits. The pits may be few …

Posted on

Apple Maggot


Figure 1. Adult apple maggot Rhagoletis pomonella (Walsh). (Joseph Berger, Bugwood.org)

Apple maggot (Rhagoletis pomonella (Walsh)) is a potentially serious pest of many types of fruit trees. Preferred hosts for apple maggot are apple, especially early maturing and sweet varieties, and the native hawthorns (Crataegus spp.).  In addition, apple maggot will attack apricot, cherry, sweet cherry, sour cherry, crab apple, cotoneaster, flowering dogwood, mountain ash, plum, peach, pear, roses, and serviceberries.

The adult fly (Fig. 1) is …

Posted on

Tarnished Plant Bug

The tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), is found in agricultural and disturbed areas throughout the United States. It has one of the broadest host ranges of any insect pest, feeding on 385 plants, 75 of which are economically important crops.  Tarnished plant bug has reached key economic pest status in several crops, including strawberry and cotton, and can be responsible for significantly reducing yields in apple.

BIOLOGY


Tarnished plant bug adult (Russ Ottens, University of Georgia, Bugwood.org )

…
Proudly powered by WordPress