June 9, 1993

Flowering of Conifers

Some people find it hard to believe that plants must flower in order to set seed. In many woody plants the flower isn't very attractive. For some, the flowers are barely distinguishable from the leaves. Flowers of the conifers (pine, spruce, fir, and other cone-bearing woody plants) are called strobili, which means small cones. They do not have a calyx, corolla, stamens, or pistils as many flowers do. The strobili consist of a central axis with distinctively shaped scales and bracts. Male and female cones are separate and, in most cases, both are present on the same tree.

Hand Thinning of Fruit Trees

Many fruit trees bloomed heavily this spring and have set a large crop. Unfortunately, some fruit trees are bearing too many fruit. Trees loaded with fruit should be thinned to:

obtain large, high quality fruit at harvest allow development of flower buds for next year's crop, thus overcoming the tendency for some fruit trees to bear fruit in alternate years prevent limb breakage.

IPM Update--Apples and Strawberries


Pine Wilt Transmission by Wood Chips?

Pine wilt is a serious disease of pines, especially Scots pine, in the Midwest, including Iowa. Infected trees wilt and die within a matter of weeks to a few months. Although a nematode is the primary disease agent that blocks water flow in affected trees, pine sawyer beetles are the vectors that carry the nematodes from infected to helathy trees. The major recommendation to help control spread of the disease is to remove infected pines promptly and burn, chip, or bury them.