Well spring has finally arrived here in Ottawa. Lilies and daylilies are popping up or shooting up all over the place. It's almost like they were anxious to get going after the long sleep they had this winter. We did not break the record for snow created in the winter of 1970-1971 but we came very close with the 436 cms we got this season. But thats over and spring is here finally and for Lily growers that means the dreaded Scarlet Lily Beetle. This year in my garden and a friend of mine they seem to be out in huge numbers.
What I do and recommend to other gardeners that want to grow lilies is to do daily "bug hunts" in your garden. I do at least two per day. First thing in the morning and then again after I get home from work. In the morning the weather is still cool so the Beetles are cold and slow. I seem to get more in the morning. In the afternoon when the temperature rises they are more active and quite often either drop from the plant or fly away as you approach. If they do drop off the plant they have a tendency to fall on their backs. They are black on their underside which makes it tough to see them against the darker ground. Be patient as they will turn around in a short period of time and then you will see their red shells.
While they do not eat daylilies, irises and echinacea, I quite often find them on these plants. So if you have them in your garden take a look there for them as well. They especially like to be in the deep fold of the daylily plants.
At this time of year they are mating so you will often find two or more together. This makes it harder for them to fall off the plant. But now you have to start checking for their eggs. These will appear as a single line of red spots on the underside of the lily leaf. Try to crush these and eliminate part of the problem in the future. The more eggs you find the less larvae will be around to chew on your lilies. They will go through this mating cycle a couple of times during the season so keep a close eyes on your plants. Larvae will be found under the leaves and look like a glop of black sludge. This is because they cover themselves with their own feces to protect themselves from predators. Which unfortunately in North America they do not have any natural predators as they are an introduced species.
Now how to eliminate them. Well Lily Beetle are resistant to most insecticides. I have not really heard of any true and tried insecticide that will positively work on them. Neem oil is said to have some effect on them. You could try insecticidal soaps but I have not had much success with them. Basically I just do the crushing method. It is messy and I try to be quick about it so they are killed as fast as possible. If your squeamish about crushing them then collecting them up in a ziplock bag and then stepping on the bag works as well. What ever way you find works for you then use it.
Unfortunately this is one pest you cannot ignore. The adults and larvae can strip your lily bare of leaves and flower in a very short period of time, this does not kill the bulb but will gradually weaken it until it cannot survive. This then adds to the problem for others as the population on this side of the ocean will continue to grow and spread. There are still some areas not affected by then but thats getting smaller each growing season. We all have a part to play in controlling these insects until a predator is found.