Rednecked Cane Borer (Agrilus difficilis)
Latin Name: Agrilus difficilis
Common Name: Rednecked Cane Borer
Appearance:
The adult Rednecked cane borer is a tiny metallic wood-boring beetle with a red neck. The adults are about 1/4 inch long and entirely black except for an iridescent coppery-red to golden thorax or “neck,” which is iridescent coppery-red to golden.
The larvae are white, without legs, and flattened behind the head. When fully grown, they are 5/8 to 3/4 inch long and feature a pair of dark-brown, toothed, forceps-like prongs.
Pupae are roughly 1/2 inch long and formed similarly to adults.
Host plants:
Raspberry, blackberry, and dewberry are all types of berries. Although it prefers blackberries, it attacks all kinds of raspberry and dewberry, both wild and cultivated.
Territory:
Throughout the USA
Damage caused by Rednecked Cane Borer:
Adult Rednecked cane borers eat on the upper surfaces of the leaves throughout the day, causing uneven holes. Larvae eat primocanes and create irregular swellings called galls as a result. Galls range from 1 to 3 inches long and frequently break the bark. Most galls are located at ground level, although they may also be found up to 4 feet above it. Infested canes perish or deteriorate to the point that they can no longer support a crop the following season. Winter damage is more likely with girdled canes.
Life history and Habits:
Females lay their eggs on the cane, and the ovipositor produces a yellow viscous fluid polished into a coating before fading to white or grey. Larvae depart the egg immediately inside the plant, never coming into contact with the outside world, and hence are impervious to sprays. Young larvae are limited to the cambium, spiralling three to four times around the cane, girdling the primocane, and forming gall-like swellings. Adults can be found between May to August or late April to early June, depending on where you reside. Between 20 and 40 days pass during the pupal stage. After emerging from the pupal skin, the adult spends around ten days in the tunnel before chewing a D-shaped emergence hole. Before initiating oviposition, adults graze on leaves for many days. They are most easily discovered on warm, bright days on the plants. Every year, there is a new generation.
