Pesticides can alleviate plant problems

Wednesday, July 7, 2004

June and July should be designated as National Plant Problem Months. Although I have never recorded results, I can assure you that horticulturists are asked more questions and are given more plant problem samples to identify in June and July than in any other months of the year.

Usually the identification of a plant problem leads to the questions, "How can I control the disease?," or "How can I kill the insect infestation?" Cultural practices can often be altered, such as watering in the morning versus the evening, removing mulch and weed barrier around plants, picking off damaging insects, etc. These cultural changes usually reduce the problem, and in some cases actually eliminate the problem.

Yet, even after cultural practice change suggestions are made, most gardeners still ask, "What can I spray on the diseased or infested plant?" I go to the chemical shelf and show the gardener a pesticide that will do the trick. Then I usually think my job is done. Yet I am beginning to get one more question from gardeners that I would like to discuss today. "How do I apply this product?"

I may get into trouble with this next statement, but I am going to make it anyway. Try to find a pesticide in liquid or soluble form if you are going to apply it to growing plants. I think that you will get better results with a liquid or soluble concentrate (goes into liquid form when mixed with water), and I also think that you will find it easier to apply.

You can use a trigger sprayer with your liquid pesticide. This is by far the cheapest sprayer on the market. In fact, many ready to use pesticides come in a trigger sprayer applicator. Trigger sprayers are OK if you are only going to spray one very small plant. Have you ever tried to spray several plants or one large plant with a trigger sprayer? I can assure you that your trigger finger is not up to the task.

Probably the most common sprayer used to apply liquid pesticides is the pressure sprayer. Pressure sprayers work great when first purchased, but require maintenance to keep them working over time. I usually find that the tank leaks, the wand or valve leaks, the spray tip is lost, or the leather or rubber cup on the piston is dry and won't create pressure in the tank. Finding parts to repair these sprayers is probably harder than making the repair itself.

Using a pressure requires mixing chemicals, something many gardeners detest. You have to pour the concentrate into a measure cup and then pour it into the tank. Have you ever done this without getting some pesticide concentrate on your hands? I sure haven't. In addition, the directions on the pesticide label sometimes require you to be a mathematician to make the proper dilutions.

After you have made the proper dilutions, you have to clean up the measuring cup. I usually find that I have spilled some of the concentrate on the outside of the sprayer and have to rinse it off also.

Finally after you have made your application, you find that you still have some diluted pesticide left. What should you do with it? If you keep it in your sprayer and use it next week, you will probably find that the active ingredient is no longer any good. If you spray the excess out of the sprayer, you are just spraying more than you need to. Pouring out the excess on the ground is not a good idea because it could contaminate the soil in the dumping area.

I would like to suggest that you try using a hose end sprayer to make most of your pesticide applications in your landscape. First of all, it is inexpensive. Most pressure sprayers cost as much or more to purchase.

The hose end sprayer is very versatile. You can use it to spray trees (the height it sprays depends upon your water pressure). You can set it to spray a fan pattern that is great for applying pesticides to a lawn. You don't have to mix or dilute pesticides. You can throw away your measuring cup. Just pour the concentrate into the tank, set the dilution dial, turn on the water hose and spray away. The hose end sprayer will automatically dilute the concentrated pesticide as water goes through the sprayer.

If you still have concentrated pesticide in the tank of the hose end sprayer when finished spraying, just pour the excess concentrate back into its original container. Flush the tank and sprayer by running a tank of clean water through the sprayer. Apply this dilute pesticide to any other target areas. This eliminates any concentrated pesticide being dumped into a small area.

If cleaned after each pesticide application, you will not have any maintenance problems with your hose end sprayer. There are no moving parts.

The only drawback with the hose end sprayer is that you have to have a hose long enough to reach the plants you are going to spray. Unless you have an estate, this is usually not a problem.

If you want an inexpensive pesticide applicator that is versatile and easy to use, try a hose end sprayer. I think you will be happy with your investment.

Send your gardening and landscape questions to Paul Schnare at P.O. Box 699; Cape Girardeau, Mo. 63702-0699 or by e-mail to

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