October 10, 2007

Next Issue, November 7

The next issue of the ISU Horticulture and Home Pest News will be published Wednesday, November 7. Until then, if there is something you would like to see in the newsletter, please let us know!

Twig Girdlers and Dropped Twigs

An occasional sight in late summer, especially in southern Iowa, is the accumulation of small broken twigs on the ground under oak, hickory and other shade, nut and fruit trees. The foliage at the ends of twigs turns brown prematurely before the twigs fall to the ground. The dropped twigs that look like they were neatly cut from the tree as with a pruning shear are the work of the twig girdler, Oncideres cingulata.

Plant and Insect Diagnostic Clinic Update - October 8, 2007

Samples with the following problems have been seen in the Clinic lately:

Plant Diseases

Ash tree bolete mushrooms

Brown spot needle blight on Scots pine

Oak wilt

Preparing Chrysanthemums for Winter

Garden mums (Chrysanthemum x morifolium) often don’t over-winter well in Iowa. Repeated freezing and thawing of the soil during the winter months can heave plants out of the ground and cause severe damage or even death. Damage is most likely in poorly drained soils.

Sulfur Shelf Fungi

Sulfur shelves are one of the most noticeable fungi. The bright yellow to orange lobed fruiting body, composed of many overlapping shelves, may be up to a foot in diameter. Sulfur shelves can be found growing on a large variety of deciduous and coniferous trees, both living and dead. The most common species of sulfur shelf is Laetiporus sulphureus. Shelves grow directly from the trunk of a tree, without stalks, and tiny pores on the undersides of the shelves produce spores. Shelves typically appear in the summer or fall.