Scarlet beetles (6mm - 8mm long) with black heads eat the leaves, flowers and seedpods of lilies and other members of the lily family. Don't mistake them for ladybirds. Between April and September the beetles lay eggs on the undersides of leaves. After a week they hatch into reddish-brown maggot-like grubs, and feed on the same parts of the plant as the parents. Possibly to deter predators or disguise themselves, the larvae cover themselves in their own wet, black excrement.
Solution
Organic
Pick off the grubs and adults as soon as you see them. The adults will drop to the ground at the slightest touch, so spread newspaper under the plants to catch them. Be quick and crush them under foot or they'll fly off.
Chemical
At the first sign of attack, spray plants with imidacloprid, thiacloprid or sunflower oil. Treatment is more effective on larvae than adults.
Comments and rating
Overall rating (from 4 ratings):
5 out of 5
every year i have to pick these little demons off my lillies their little grubs are a bit grim to remove but using something as easy to obtain as sunflower oil will make my life easier
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5 out of 5
Thank you for the advise I will be trying the sunflower oil! I have read that the insecticide, imidacloprid, you have recommended is possibly linked to honeybee colony collapse - is this true? I am off to stamp on a few lily beetles and spray!
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Have had this problem for 2 years now and will try the sunflower oil. Does anything remain on the plant and go down into the bulb ready to infest next season?
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5 out of 5
I was surprised to read that sunflower oil can work. I will try that this year.
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kaycurtis rated and commented on this article
02 April 2009
5 out of 5
Goodness me , the dreaded Lily beetle along with all the other things that attack our lovely plants, well if you water the plants with vine weeval killer it does help to protect them also against Lily beetles, killing two pests for the price of one!!
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