Description
There are about 1,500 species of weevil in Aotearoa New Zealand. Different species feed on different plants, fungi, and leaf litter. Many plant feeding weevils feed exclusively on one or a few different plant species.
Adult weevils are small beetles with long snouts (rostrum). They are usually 2 to 10 millimetres long and grey, brown, or black in colour. Some have cryptic patterns which make them difficult to see. Larvae are creamy white in colour and don’t have legs.
Pest species commonly found in nurseries, gardens, and horticultural crops include:
- Argentine stem weevil
- black vine weevil
- buddleia leaf weevil
- Fuller’s rose weevil
- garden weevil
- vegetable weevil
- white fringed weevil.
The New Zealand giraffe weevil is not a pest species but may be seen in a native nursery. They can grow up to 90 millimetres in length. Males use their long snout to fight for females. The female giraffe weevil has a shorter rostrum with antennae halfway along. Adults are sap or nectar feeders and larvae eat fungi.
Common native plant hosts
Broad range of native plant hosts.
Symptoms and damage
Adult weevils eat plant foliage causing notches and holes in leaves. Most larvae live in the soil and eat roots, corms, and tubers. Larvae feeding on roots causes plants to become weak.
As well as the above, weevil infestations can cause significant damage including:
- plant death
- stem boring
- wilting.
Prevention and control tips
- Weed control.
- Biological control organisms.
- Chemical insecticides.
- Larvae can be treated in soil with suitable insecticide granules.
Natural predators
Parasitoid wasps.
Image details
Image details are:
- Photo taken by Kyle Bland. Some rights reserved (CC-BY-NC).