Rose Weevils

Facts, Identification & Control

Latin Name

Merhynchites bicolor 

Appearance

The rose weevil measures less than 5 to 6 mm in length and is red and black, with a pronounced snout. Despite their small size, rose weevils are serious threats to all horticulturists. A rose weevil’s snout can drill through flower buds and will cause irreparable harm to petals.

Behavior, Diet & Habits

Although they produce only one generation each year, rose weevils are capable of causing severe damage during each of their active life stages. Adults make punctures on rosebuds in order to feed, while larvae consume petals for sustenance. The holes made by adults also serve as egg laying sites. As eggs hatch, larvae feed on the flower’s reproductive parts. When infected flowers open, their petals are riddled with holes. In the absence of flower buds, adults will feed on shoots or stems instead.

Reproduction

Females deposit their eggs on the buds of roses in which she has bored a hole. Larvae will feed on the bud until time to pupate. The feeding of the larvae often result in the bud falling from the plant. The larvae crawl into the soil to pupate.

Signs of Rose Weevil Infestation

In order to control rose weevil populations, it is necessary to identify them immediately. Noting which rose varieties appear most attractive to these weevils will assist in proper identification. Discarding adult specimens and infested buds may also assist in preventing the reappearance of rose weevil populations the next year. Pesticides should only be used if other methods fail and should not be applied without first consulting a specialist in ornamental plant pest control.

Boll Weevils

Flour Weevils

Rice Weevils

Bean Weevils

Wheat Weevils

Black Vine Weevils

White Pine Weevils