What are the disease-resistant apple cultivars recommended for Wisconsin?

The following are some of the cultivars that will grow well in Wisconsin:

• Redfree: This is an early season, medium-sized, attractive red apple. You can store these apples up to 30 days.

• Prima: Prima produces medium to large fruit, red blushed on yellow skin. Mild, juicy, white flesh matures a week before McIntosh. You can store this apple for one to two months.

• Priscilla: This is a medium to large apple if you thin trees adequately after …

What causes the yellow leaf spots that later develop a brown center on my apple leaves?

This a fungal disease called cedar-apple rust. Cedar-apple rust is a common disease of apple and crabapple. The fungus that causes the disease, Gymnosporangium juniperi-virginianae, is unusual because it must spend a phase of its life cycle as a parasite on Juniperus species, such as red cedar or ornamental junipers. Control: Grow resistant apple or crabapple varieties. Apple varieties that normally show good to excellent resistance to cedar-apple rust include ‘Red Delicious’, ‘McIntosh’, ‘Arkansas Black’, ‘Winesap’, ‘Mollies Delicious’, ‘Spartan’, …

Which rootstocks are winter hardy?

Rootstocks can affect the development of cold hardiness in apple trees, but this is a complex trait, and it may depend on what time of the winter with which one is concerned. Some rootstocks, such as Robusta 5, can cause a tree to harden early in the winter, and these trees are very cold tolerant during the early winter. Some rootstocks, such as Robusta 5, that induce early cold hardiness also lose their hardiness early in the winter in response …

What experimental rootstocks for apples are being looked at in the U.S.?

Many apple rootstocks are being evaluated for potential use in the United States by the NC-140 Multi-State Research Committee. These rootstocks have come from breeding programs in the United States (CG, G), Great Britain (M), Germany (PiAu and Supporter), Poland (P), Czech Republic (J-TE), Japan (JM), and Russia (B). Specific rootstocks that are currently under evaluation in NC-140 plantings include the following: B.9, B.10, B.7-3-150, B.7-20-21, B.67-5-32, B.64-194, B.70-6-8, B.70-20-20, B.71-7-22, G.11, G.16, G.41, G.202, G.935, CG.2034, CG.3001, CG.4003, …

How do nurseries grow rootstocks?

Rootstocks are commonly propagated by layering to form large stool beds. The “mother plant” is set out in the field. The plant may either be mounded, or it may be trench layered. In mounding, the plant is cut off close to the ground. As the new shoots emerge from the mother plant, they are partially covered with soil or well-decomposed sawdust. The sawdust is renewed periodically during the growing season to prevent the base of the shoot from exposure to …

How do I find out what variety my apple tree it is? Can my local Extension office tell me ?

It is difficult to identify apple varieties unless your variety is a very common one. There are more than 10,000 named apple varieties in the world today. Sometimes we may be able to tell what “type” of apple it is (e.g., Jonathan type, Delicious type). When planting fruit in the landscape, it is important to create a plan showing where different varieties are planted. Put the plan in a notebook and a copy in the garage or planting shed.…

When is the proper time to thin fruit on apple, pear, and peach trees?

Apples and pears have three periods when some immature fruit drops naturally from the tree. The June drop (Zones 6 and 7) is the last one, and many growers feel that thinning should follow this drop. However, if a heavy bloom has coincided with good weather so that bees worked the blooms, the chances are that relatively few fruit will drop from the tree. In this instance, heavy thinning is required. The earlier the fruit are thinned, the greater the …