Most horticulture experts define lawn and garden pests as insects, weeds or diseases. Once you have identified the pest in your yard and decided it is at an intolerable level, you might choose a pesticide as part of the management.
Go take a look at any pesticide label and it will say “It is a violation of federal law to use this product in a manner inconsistent with the labeling.” We need to be responsible when applying pesticides so we can protect our family, neighbors, pets and the environment. Here are some questions to consider as you care for your plants:
Will pesticide application at this time control the pest?
Sometimes we might catch a problem when it’s the wrong time of the life cycle. Spraying for a caterpillar that has already chewed foliage and left doesn’t undo current damage. Trying to kill weeds that have already flowered and dropped seeds is too late. And to control fungal infections, pesticides must be applied as a preventative, before they occur. A ‘revenge spray’ after the fact is a waste of your time and money.
Should I use other control techniques instead of, or in addition to, the pesticide?
Mowing grass at a height of 3 inches instead of 2 inches can reduce weeds. If you have a bacterial or fungal problem, cleaning up plant debris at the end of the season can help remove over-wintering diseases. And be sure to also select pest-resistant plant varieties when possible. Sometimes mechanical removal (aka good ol’ hard work) is a practical option for certain levels of weeds and insects.
Will using this pesticide also kill some beneficial insects?
Bees are needed for pollination. Some insects are actually good guys (natural enemies) that eat the bad guys. We need to be careful to select insecticides that are effective, but the least toxic.
The University of California has great Integrated Pest Management tools online. You can Google “Pesticide active ingredients database” to see a list of pesticides and their level of hazard to people and beneficial insects. For example, Sevin (carbaryl) has a very high rating as a potential hazard to honey bees. If you must use it, do so during times when honey bees are not active on blooms.
Be sure to read the signal words on pesticide labels. These tell you the toxicity if it is eaten, inhaled or absorbed through the skin. Many can also cause eye and skin irritation. Depending on the ingredients and their concentration, pesticides will have either “Caution,” “Warning” or “Danger” on the label (respectively in order from slightly toxic to extremely toxic). If no signal word is on the label, the pesticide falls into the lowest toxicity rating. These minimum risk pesticides often contain ingredients such as oil, salt, etc.
Sarah Hanson is the agricultural natural resources extension educator through the Johnson County Purdue Extension. She has a master’s degree in animals and public policy from Tufts University, Cummings School of Veterinary Medicine and a bachelor’s degree in animal science from Purdue University. Send comments to firstname.lastname@example.org.