The Scarlet Lily Beetle can devastate lily gardens, leaving you with just sticks, but a diligent eye can help you save your garden from this pest. Here’s how to find out if you have this insect, and what you can do to help control it.
Often mistaken for a ladybug without spots, the Scarlet Lily Beetle can damage lily leaves at an alarming rate. This beetle is more slender than a ladybug, has no spots, and has long antennae. Another distinguishing feature of this insect is its ability to make a clicking noise when approached. It also fakes its death when it feels threatened.
Where to Find this Pest
Larvae do the most damage and will stay to feed on true lilies. Adults’ main concern is to reproduce, but they will also feed on plants other than lilies, and can move great distances to eat a variety of plants. Keep in mind that this beetle will only reproduce on true lilies, Lilium, and Fritillaria. Adults are mostly found on true lilium species.
Check the underside of leaves on the following plants if you see any damage:
-Asiatic, Oriental and Tiger Lilies
-Lily of the Valley
Life Cycle, What to Look for & Control Methods
Adult beetles overwinter in soil and plant debris. They emerge in early spring and immediately begin laying eggs. Larvae feed for roughly 16-20 days, drop to the ground and emerge 16-20 days later as adults. By checking weekly for adults, larvae and eggs, you can stop this reproductive cycle.
A chewed leaf is a great indication of these pests, but there are a few other things to look out for:
- Keep an eye out for eggs. Eggs are a cluster of bright red or brown masses on the bottom side of leaves. These eggs are usually laid vertically in irregular, narrow rows. It is best to remove these leaves and drop them in soapy-water to kill the eggs.
- Keep an eye out for larvae. They are usually small, bulbous orange-brown bugs with black heads. They will encrust themselves in fecal matter, and at this stage you will see a brown, massive clump on the leaves. Knock larvae that have not encrusted themselves in fecal matter into soapy water. If already encrusted, it is best to remove the leaf and drop it into soapy water before throwing the leaf out.
- Adults are easy to see on leaves. These long, bright red beetles often make a clicking noise when you approach them. Their defense mechanism of ‘playing dead’ makes them a bit harder to control. If startled, the beetle drops to the ground, and lays on its back revealing its dark underside. By laying on its bright-red back, it camouflages itself in the soil. A good control is to place a bucket of soapy water under the plant. Nudge the beetle or shake the plant to startle the beetle. This way, when the beetle drops, it will fall into the soapy water. As an added control, sprinkle Diatomaceous Earth around the base of the plant before trying to knock down any adults. If any beetles miss the bucket, they will crawl over the Diatomaceous Earth, which will kill them.
- Diatomaceous Earth can also help control the adult stage as they emerge from the ground. Sprinkle Diatomaceous Earth around the base of your plants weekly.
In fall, make sure you clean up any plant debris to prevent the beetles from overwintering. Check as soon as plants start to emerge for adults and eggs. If you start monitoring and controlling these insects at the beginning of the season, you have a better chance of stopping the cycle before too much damage is done.