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Black Vine Weevil

Otiorhynchus sulcatus

 
 


Black Vine Weevil (Otiorhynchus sulcatus)
? Agriculture Western Australia


Description
The adult Black Vine Weevil has a typical weevil snout, is black and 10 mm long. Larva are legless, white with brown heads and have a c-shaped appearance.

Black vine weevil is a widespread and serious pest on many plants outdoors and in the greenhouse. Originally from Europe it has been introduced to the United States approximately 150 years ago, and subsequently reached New Zealand (1976), Tasmania (1979) and Victoria (1984). Spread is mainly through human activity, such as movement of potted material or fruit of plants within the host range. Current distribution includes Europe, Russia, Japan, Egypt, Saint Helena, Canada, Chile, Columbia, USA, New Zealand and Australia (Tasmania and Victoria).
 
Life cycle
All adult weevils are female and therefore reproduce parthenogenetically (development of an unfertilized egg). Weevils feed at night and hide in the soil during the day. There is one generation of the black vine weevil every 1 to 3 years. Weevils feed for 3-4 weeks before females begin to deposit eggs. They are laid in the soil with any one female producing as many as 500 eggs. The eggs hatch in 10 - 15 days and the hatching grubs burrow into the soil searching out roots to feed on. Larval feeding occurs through the growing season and when colder temperatures arrive, larvae burrow deeper in the ground to overwinter. They resume feeding the following spring for a short while before pupating for approximately 1 month.
 
Damage
Grubs feed on the roots and undergroung stems of plants. This can lead to stunting and yellowing of foliage. Severe infestation will often results in the death of the plant. Plants may fail to put out new growth, or may initially shoot out new growth, and subsequently die. Adult weevils feed on foliage creating characteristic notches in the leaves. This damage is generally not severe, but can be unsightly.

Black vine weevil has a very wide host range and damage can extend to many industries, particularly strawberries and the cut flower industry.
 
Control
Hand removal of weevils can be effective in small plantings or for individual plants. Spraying of adult weevils can also be done, however the adults should be treated before egg laying occurs (2 to 3 weeks after emergence).
 

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