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 …
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, …
Parentage of Apple Cultivars
Nearly all apple cultivars have two parents – just like humans! Apples have a genetic system that generally prohibits self-fertilization. This self-incompatibility system is a way of insuring that each apple seed will be a hybrid between the maternal (seed) parent and a paternal (pollen) parent. The self-incompatibilty system is also the reason why two or more cultivars must be planted in an orchard to achieve fruit production through insect-vectored movement of pollen from one cultivar to the other.
Chance
…Managing Apple Trees and Orchards: Insects, Diseases, Wildlife and Other Challenges
Insect Management in Apple Trees and Fruit
- Dogwood Borer
- Wooly Apple Aphid
- Apple Maggot
- Plum Curculio
- Green Fruit Worm Complex
- San Jose Scale
- Mites (two-spotted spider, European red)
- Leaf Rollers (oblique, red-banded, variegated)
- Rosy Apple Aphid
- Aphids (green apple, spirea)
- Spotted Tentiform Leafminer
- Oriental Fruit Moth
- Codling Moth
- Tufted Apple Bud Moth
- Tarnished Plant Bug
- Leafhoppers
- Japanese Beetle
- Stink Bugs
…
Disease Management in Apple Trees and Fruit
- Apple Mosaic Virus
- Apple Scab
- Armillaria Root Rot
- Bitter Rot
- Blister Spot
- Black pox
- Black Root Rot
- Black Rot
- Blue Mold
- Brooks Spot
- Cedar-Apple Rust
- Fire Blight
- Fly Speck
- ‘Golden Delicious’ Necrotic Leaf Blotch
- Latent Viruses
- Nectria Canker
- Nectria Twig Blight
- Phytophthora Root, Crown and Collar Rot
- Powdery Mildew
- Quince Rust
- Sooty Blotch
- Southern Blight
- Thread Blight
- Union Necrosis and Decline
- Viruses
- White Root Rot
- White Rot
- Wood Rots
- X-Spot
Wildlife Problems of Apple Trees and Fruit
- Deer Damage on Apple Trees
- Mouse/Vole Damage on Apple Trees
- Raccoon Damage on Apple Trees
Other Challenges of Growing Apples
- Effect of Temperature on Apple Trees
- Effect of Water on Apple Trees: Not Enough or Too Much?
- Timing of Apple Tree Bloom
- Apple Fruit Thinning
- Hail Injury on Apple Trees and Fruit
- Effect of Wind on Apple Trees
- Sunburn of Apple
- Pre-harvest Drop
- Sunscald of Apple
- Sunscorch of Apple
- Fruit Cracking of Apple
- Bitter Pit and Calcium Deficiencies in Apple Fruit
- Apple Skin Russetting
Bitter Rot of Apple
Bitter rot is a fungus disease that causes fruit rot during the summer and preharvest period. The bitter rot fungi are almost worldwide in distribution and cause an especially important economic disease in the southern areas of the United States. Outbreaks can occur rapidly, and losses can be severe, especially under prolonged warm, wet weather. Several host species can be affected. On peach and nectarine, the same fungus causes a disease known as anthracnose, and on grape it causes ripe …
Effect of Wind on Apple Trees
Strong wind, especially wind associated with tropical storms that saturate the soil, can cause fruit trees to lean and sometimes be totally uprooted. Due to small and brittle root systems, dwarfing rootstocks tend to be prone to wind damage.
Susceptibility to wind damage appears to be related to the combination of rootstock and scion cultivar. Some brittle cultivars, such as ‘Gala’ and ‘Golden Delicious’, when propagated on brittle rootstocks, such as G.30 or M.26, may snap at the bud union. …