Vine weevil
Semicircular notches in the leaf edges of rhododendron, yew, hydrangea and strawberry give away the adult beetles. Their white, C-shaped grubs with a brown head eat the roots in the ground and in pots, so the plant suddenly wilts.
The black, 1 cm beetles feed at night and lay eggs in the soil in summer, especially in pots.
What can you do?
- Look for the beetles by torchlight in the evening, or tap the plant over a sheet and pick them up.
- Water nematodes onto moist soil against the grubs: Heterorhabditis bacteriophora in April–May or August–September (soil from 12 °C), or Steinernema kraussei in cooler soil (from 5 °C).
- Take a wilted pot plant out of its pot, remove the grubs and repot in fresh compost.
Prevention
Welcome hedgehogs, shrews, ground beetles and birds into your garden. Check the root ball of new pot plants for grubs before planting them.
When to watch out: May–August