Hosts
Verbascum species and sometimes figwort (Scrophularia species) and Buddleja.
Symptoms
In some years caterpillars of this moth can defoliate verbascums. Rounded holes appear
in the foliage and caterpillars up to 50mm long can
be found feeding on the leaves and flower spikes. The caterpillars
are greyish-white with prominent black and yellow spots.
Biology
The adult moths emerge and lay eggs on their host plants during late April to May. The caterpillars are active between late May and mid-July. When fully fed they go into the soil and pupate inside silk cocoons.
Control
Because the caterpillars are easily seen, hand removal is an option.
Where this is not feasible the plants can be sprayed with bifenthrin (Bayer Sprayday Greenfly Killer Plus, Doff All In One Garden Pest Killer or Scotts Bug Clear Gun) or pyrethrum (Py Spray Garden Insect Killer, Doff All in One Bug Spray, Scotts Bug Clear Gun for Fruit & Veg, Gem Stop Bugs). The older caterpillars are less susceptible to insecticides than the younger ones. Protect bees by spraying in the evening if the plants are in flower.