Should You Spray an Insecticide as Soon as You Spot Bugs on Your Shrubs

An insecticide application should be based on need. Before making one, there are a few things to consider.

Depending on the landscape and plant species involved, numerous insect species may be present. The presence of an insect on a plant does not mean it is a plant-feeding insect, and even if it is, it does not mean it will cause serious damage to the plant. So, the first question to answer is: what is the insect? There are online resources and phone identification apps that can help. For a human interaction, samples can be taken to a local Extension office. There may be an educator on staff who can identify the specimen.

Once the insect is identified and found to be a plant feeder, an assessment must be made of whether it poses a serious threat to plant health or will only cause short-term aesthetic damage. The threshold for cosmetic damage will be based on the individual.

If the decision is made to treat, and depending on how and where the insect(s) is feeding, the correct insecticide has to be selected.

• Contact insecticides must hit both the insect and the feeding site on the plant.
• The other group of insecticides is systemics. These insecticide active ingredients move through the plant. They are taken up through insect feeding and are not found on the plant’s surface.