Hi Master Gardener, we have an infestation of bugs on oxeye daisies that are like mini beetles but black soft shell with whitish yellow zig zag stripes. Is there anything I can spray on these plants to kill the bugs? Last year they ate the middle of the daisies.
Thank you for the photo.
While it can be difficult to identify small insects, it appears this is a variety of beetle commonly called a “carpet beetle”, likely Anthrenus verbasci. Sometimes these beetles can live in our houses. Outdoor populations feed primarily on pollen or nectar from plant families including Asteraceae which includes “oxeye daisy” (Leucanthemum vulgare).
The good news is that these beetles are pollinators of the plants they feed on. They shouldn’t be causing serious damage to the flowers, even though it may be unnerving to see them. As such, I would not recommend pest management measures outdoors for these insects.
If indeed you would like to reduce the population of these beetles in your garden, Toronto Master Gardeners do not recommend particular products or home remedies. We instead would suggest that you consider the use of a commercial product such as an insecticidal soap that you will find at major home and garden centres and nurseries. A cautionary note: any insecticide used for these beetles may also affect other beneficial pollinators. The most effective prevention measures for beetles target the larvae, which is difficult to do outdoors, since they are so small. The use of pesticides (including insecticides) in Ontario is controlled and regulated for cosmetic uses, and you can read more about that here.