Mosquito/insect spraying means …

When the mosquito fogging/spraying truck comes down your road or your neighbor sprays in his yard, what does that mean for your butterfly/pollinator garden? It can mean disaster. Or it may not affect your host plants at all.

Part of what determines the effect it has on your plants depends on several factors.

  1. Type of pesticide: what are the active ingredients?
  2. Is it a systemic or non-systemic pesticide?
  3. Where are your host plants located?
  1. Pesticides cause different symptoms in caterpillars, depending on the active ingredient. Whether it is organic or not doesn’t make a difference. Organic pesticides are as deadly as inorganic pesticides. What matters is the mode of action of the ingredient. Does it affect the nervous system, growth changes, or something else? As homeowners, we have no voice in the pesticide that is used. So, even if we know how it would affect our caterpillars, that bit of knowledge can’t actually help us at all.
  2. Is the pesticide non-systemic (lasts only a few days) or systemic (lasts for months)? If it is non-systemic, covering our plants before the fogging/spraying happens can help if we wait a good 9 hours before removing the covering. If it is systemic, it can be washed into the soil and the plant draw it up into its system. If systemic pesticides are used near you, growing host plants in pots placed on saucers can help. This prevents water from reaching the roots as it flows across your yard.
  3. Where are your host plants located? This is the area where you have greatest control. If your host plants are close to the road, where a fogging truck passes, you will see more deaths after the county fogs for mosquitoes. If your host plants are close to your neighbor’s yard, it would be easy for over-spray or wash to reach your plants. By planting your host plants away from the road and your neighbor’s property, you gain a great deal of control. Over-spray won’t reach very far except on windy days. Rain or irrigation water can wash the spray over into your lawn. Planting uphill from your neighbor, if possible, offers additional protection.

As we talk about pesticides, I want to again mention that those of us who must have our houses treated for termites, we should either plant at least 15′ away from the house foundation or plan treatments at the end of the growing season, about the time of your first hard freeze. For some of the US, this means that the systemic pesticide has time to work out of the plants before the last freeze and plants are growing again. (For the northern states, pesticide may take longer to work out of the soil. It is possible that termite treatment is not available just before the first hard freeze. If it is not, planting host plants away from the foundation may be your only option.)

There are some cities and counties that have caring people in the right job. A nice, polite, and short letter or visit may do a great deal of good. Some counties will avoid spraying in front of a house where someone has asked for their property not to be treated. Rudeness and anger rarely bring the desired results, so politeness and education is the key.

Remember, if your caterpillars have been exposed to pesticide, you can try saving them. This does not work with all pesticides, only a few.

One of the wonder advantages of living in a city or subdivision is that there are neighbors to help when we need help. One of the disadvantages is that if they are too close, many things that they do will affect us.

Bright green liquid that stays green after five minutes is a sign of pesticide exposure.
Bright green liquid that stays green after five minutes is a sign of pesticide exposure. (Photo by Lorena Popelka)

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