Western Raspberry Fruitworm: Appearance, Territory, Damage and Life Cycle

Latin Name: Byturus Bakeri

Appearance: Byturus unicolor, often known as raspberry fruitworm, is a species of fruitworm beetle in the Byturidae family. Other common names for this species are western raspberry fruitworm and fruitworm beetle. The adult is a tiny yellowish-brown beetle around 4-5 mm in length. The larvae measure 8 mm in length and are white with brown spots on the back of each segment. Adults eat fruit buds and newly unfolded leaves. This injury has the potential to be devastating in the spring. The beetle feeds on the stamens and pistils after the flowers open. Injured flowers frequently develop into deformed berries. The larvae feed on the receptacle of the immature blooms or fruit. The larvae are frequently found in the fruit after harvest and are a substantial contaminant in harvested fruit.

Hosts Plants: This bug loves raspberries in North America, although it may also infest loganberries. This species is found throughout the Prairie Provinces. Other species that are closely related to this one can be found in other parts of Canada and the United States.

Territory: It is found in Canada, Central America and North America.

Damage Insect Cause: Early season signs include longitudinal holes in the leaves that give it a ragged look. Adult feeding is to blame for this harm. Adults who eat excessively may produce leaf skeletonization. A large number of adult beetles can kill whole flower clusters. Larval tunneling through receptacles can loosen berries, causing them to fall off before harvest. Larvae contamination of harvested fruit can be a severe issue. Adults are less problematic than larvae.

Life History and Habits: Adult beetles spend the winter under the soil before emerging in late April or early May to feast on fresh leaves, flowers, and berries and lay eggs. Eggs are attached to the plant’s flower buds or stalks. The developing larvae make their way to the fruit’s core. They feed on the fruit for at least 30 days before dropping to the ground to pupate in the top three inches of soil. Each year, one generation is born.