Preventing sweet gum balls and other nuisance fruit

By John Fulton

[April 05, 2011]  One of the main things to discuss today is the removal of nuisance fruit. You may be thinking about those apples or peaches, but really the nuisance fruit category includes things that are much more a nuisance, like sweet gum balls, maple seeds and crab apples.

There are several products available to eliminate nuisance fruit. The most common is ethephon, and it is used as a foliar spray to reduce or eliminate undesirable fruit or seeds. A couple of the trade names are Florel and Ethrel. The product is effective at eliminating much of the fruit without affecting leaf growth and color, and it does not harm other plants that get some spray drift on them. It also does not affect the actual flowering of the treated trees.

With ethephon, the key is in the timing. The application must be made during flowering but before the fruit sets in. For most flowering trees there is a 10- to 14-day window of opportunity. Sweet gums are a little tricky since there are no showy flowers involved, so effective sprays should occur just as new leaves begin to emerge. Sprays should leave leaves wet, but not to the point of dripping. Good coverage of the tree is needed, so keep in mind the size of the tree when you are weighing this option. There are injectable products available, but they must be applied by a professional. The injectable products have not been as effective as the sprays.

This product is a growth regulator that naturally occurs. Its natural production is stimulated by stress, so make sure you aren't treating a tree that is under stress from drought, high temperatures, diseases or other environmental stresses. Treating stressed trees can cause severe injury to the plant, such as leaf loss or scorching.

Lawn updates

Crabgrass seed has already germinated and will continue to do so throughout the spring and summer months. Preventive treatments will still do some good for seed that will germinate over the next six to eight weeks but won't get seeds already germinated. The organic arsenicals, such as DSMA and MSMA, will control newly germinated grass. Remember, you should have a second preventive application around June 1 for summer control of crabgrass and other annual grasses.

The time to begin mowing has already arrived in some areas, and there are a few very simple rules for mowing grass. The first is to use equipment that is ready for the job. Make sure the mower has sharp blades. Dull blades will show up as injury on the grass blades, like brown tips and jagged edges. Blades can be sharpened in several ways. Using a file or grinder are the more common methods.

Next is the rule of one-third. Never remove more than one-third of the leaf blade at any one time. This rule must be followed if you don't want to catch or rake the grass. A good general mowing height for combination bluegrass and fine fescue is about 2 inches. This would mean that you would need to mow every time the grass reached 3 inches in height.

Bagging grass clippings may actually add to the build-up of thatch (that dead matted layer on the soil surface). Thatch is broken down by microbes at the soil surface. Without a food source, the microbe numbers crash, and any clippings remain without breaking down.

Mulching is OK. It isn't a cure-all, and it does take quite a bit of extra power to accomplish. The final word is that grass mowed on the one-third rule doesn't need to be caught or mulched. Bagging takes time and the clippings must then be disposed of. Mulching takes extra power and fuel.

Mowing intervals depend upon grass growth rather than a calendar schedule. The spring and fall periods will require more frequent mowing than during the summer. That is in a "normal" year. Mowing frequently really reduces the labor needed for overall operations.

[By JOHN FULTON, University of Illinois Extension]