Yard and Garden.

Several fungal diseases can cause apple trees to lose their leaves. Apple scab causes olive green or black spots on the leaves. Leaves eventually drop from the tree.

Rust causes orange spots on the leaves. The infested leaves will eventually drop from the tree. The alternate host for this tree is the evergreen red cedar (Juniperus virginiana). This may have been the"pine tree" your experienced.

We see apple scab every year, but this year the disease has been especially severe in much of Iowa, causing defoliation earlier than usual and causing more severe leaf drop. The severity of many plant diseases is largely dependent on the weather.

Apple scab is favored by cool, wet weather in the spring, when the fungus infect the new leaves. Sep 05, Damaged leaves become curled and yellowish with lesions, eventually turning brown. Heavy disease pressure leads to premature leaf drop. Fruit infected by apple scab develops raised scab-like lesions and severely infected fruit will drop from the tree.

Crabapple varieties can vary greatly in their susceptibility to apple scab (Venturai inaequalis). Susceptible trees are often nearly without leaves by August, reducing the plant’s. The chart above indicates approximate bloom and ripening dates for northeastern Missouri. Columns on the left represent days of bloom within a normal year.

Bloom period will vary from year to year, depending on location. Warmer bloom periods are compressed, while cooler bloom periods are.