I found these bugs on my rose of sharon, on top of the leaves. Underneath them, there seems to be hundreds of eggs. They are covering about 80% of the plant. It’s in a full sun location in Niagara Falls.
Thank you for contacting Toronto Master Gardeners about insects on your Rose of Sharon shrub. The photograph of both the insects under the leaf and on top of the leaf are quite blurry.
You mention that the leaves have insect eggs underneath. Could they actually be small insects such as aphids gathered together as in photo, below right? Aphids congregate closely on plants.
Aphids can also be considered plant lice. They are sucking insects that may be green, pink or black in colour. Reproduction takes place without fertilization by a male and live young, not eggs are produced. Aphids feed on the roots and bark of woody plants, and can form galls. A typical aphid is small – under 2mm or 1/12 inches.
Aphids can be present in high numbers as on your Rose of Sharon tree. Leaves are defaced and tend to pucker and curl. Often viruses and bacteria are transferred from one plant to another by aphids. Using a sharp stream of water from a hose or spray can dislodge them from the leaves. Spraying with insecticidal soap may also work to remove aphids. Insecticidal soap is readily available from your local garden centre. make sure to follow the directions on the label.
Because it’s difficult to see the beetle’s characteristics in your photo, I’m including a photo of the Lady Beetle larvae. One of my Toronto Master Gardener colleagues suggested it. The larvae has an alligator-like texture on its back and the stance of its legs look similar to your beetle photo.
Lady beetles are the most effective of insect predators. An adult eats about 50 aphids per day, and after 10 days or so the female begins laying eggs – usually where aphids are congregated. The larvae eat approximately 25 aphids per day. Below is a link to University of Guelph which describes the variety of Lady Beetles. If you have Lady Beetles on your Rose of Sharon, then you have a friend, trying to rid it of aphids. This link has more information on this effective biological control insect .