This is the point in summertime when your plants might be developing fungi or experiencing invasions by harmful insects. You may be asking yourself what you can do to control these unwanted invaders who may be damaging your plants or at least, their looks. Many of these problems can be controlled without using pesticides. There are many resources, including this from the University of Minnesota Extension (UMN), that explain what you can do to avoid using pesticides. The UMN recommends using the integrated pest management (IPM) methods for deciding the proper strategy for your yard. This diagram from the University of Massachusetts explains the IPM method.

Pesticides 

Let’s talk a bit more about pesticides. Pesticide is an umbrella term, it covers insecticides, herbicides, fungicides, bactericides and rodenticides (Rodenticides can also kill animals that feed on the rodents). Pesticides can either kill on contact or after being absorbed into tissues (systemic). Many of the same precautions that are on pesticides are also on fertilizers. Check out the sites from the UMN and University of Massachusetts to learn more about chemical and non-chemical ways to control pests and diseases.

Know what you are buying

There are many different chemical products on the market, so it is vital to know what you are buying and how to use it. 

If you decide to use a chemical product, here are some tips and legalities.

• The label will list the species of plants, fungus, bacteria, rodents or insects it will control. Don’t expect it to kill creeping Charlie if that plant is not listed.

• Contact products such as insecticidal soaps, and horticultural oil (mineral oil) will only kill the insect if it directly contacts the insect. 

• Systemic insecticides are applied to the plant, and any insect that feeds on the plant will die. There are fungicides and bactericides which protect the plant from diseases. For example, there are injections of a fungicide to protect elms from Dutch Elm Disease, and soil drenches or injections of insecticides to control Emerald Ash Borers.

Each pesticide and fertilizer that you use is required to have a label to inform you:

• What Personal Protective Equipment (PPE) you need to keep yourself safe. This can include but is not limited to; safety goggles, breathing masks, long sleeves and pants, footwear, chemical resistant gloves or even full-body coveralls with hood. 

• The label will explain how to clean up yourself and your equipment after using it. Wash hands before and after going to the toilet. Wash any exposed clothing on the hottest wash cycle. It doesn’t hurt to run the washer through the ‘clean’ cycle 

afterwards.

• Proper storage and disposal practices

Pay attention to precautionary statements

• Don’t spray during certain wind conditions and temperature ranges. If the temperature is above say, 80F, a sprayed pesticide can volatilize and drift onto non-targeted plants. If the wind is more than about 2-4 miles/hour, the pesticide can blow onto desirable plants.

• Don’t spray if rain is expected before the estimated drying time. If it runs off it will not affect the plant or insect, and can contaminate the water supply. 

• Where NOT to apply it, (usually not near bodies of water, because it can be toxic to fish and invertebrates). 

And directions for use

• The rate of application. You must measure the area and do the math. 

• How long before re-entry, or replanting.

• How to apply it, e.g. to the point of run-off, or otherwise.

• How often to apply it.

Organic Pesticides and others

• Products that are labeled for use on organic produce aren’t always ‘safe’. If not used in accordance with the label they can kill your plants and may harm you and/or the environment. Please read the labels on organic pesticides carefully. The above photos are all from an organic pesticide.

• Homemade products don’t have labels to tell you how to use them safely.

Happy and Safe Gardening this year!

Photo Credits: Marjory Blare (1,2,4,5), https://www.umass.edu/agriculture-food-environment/integrated-pest-management/about (3)