Red Lily Beetle

lily beetleIn the past few years more and more gardeners have been noticing lily beetles in their gardens. A small red beetle that resembles a ladybug without its black spots, and affects only true lilies (Lilium- daylilies, canna lilies, etc. are all of different families). The lily beetle has been working its way through Manitoba and seems to be getting worse every year. More questions about how to kill/prevent them have been coming to us daily.

From doing a quick internet search you will find a lot of tips on control and chemicals that are supposed to "kill" lily beetles. Many gadeners will find different methods that work, but then later find they have another infestation to deal with. Learning how to effectively control the beetles comes from understanding their life-cycle:

 1. Eggs on underside of leaf hatch in about 1 week.

2. Larvae then begins feeding on the leaf. They will cover themselves in their own feces to keep predators away.

3. After about 2-3 weeks the larvae will drop to the ground to pupate. They are dark in colour and can be very hard to see.  

4. After about another 3 weeks the adults will emerge from the soil and climb up the lilies. Here they will feed until fall.

5. Usually in August-September they will fly together to find new locations. They can over winter in the surrounding soil or plant debris. They usually do not mate until the spring.

Understanding this part about lily beetles can help us see what steps we need to take to effectively control them. The only control method that has seemingly been effective at keeping populations to a minimum (because it is becoming apparent that wiping them out completely is nearly impossible) is a multiple-step process. There are no known natural predators here or pesticides legal for use in Canada to help control them. The following is a list of steps that can be used to help monitor and control populations:

1. Monitor plants every couple of days. Part of their life-cycle might not be clear to you at that moment, or they may have flown into your yard since the last time you checked your lilies. Sometimes seeing the beetle or larvae can be difficult, but seeing the holes chewed in the middle of leaves is usually quite obvious.

2. Once you see them, make sure your neighbours are aware so they can keep an eye on their lilies as well. Start by picking them off and drowning them in a water and dish soap solution. Be careful, though, because when they fall to the ground they turn themselves over so you cannot tell their dark bellies from the soil.

3. Using a gloved hand (let's face it- you probably do not want your hands full of beetle feces), scrape off the larvae into a bucket as well.

4. Sprinkle diatomaceous earth (a product found in some ant killers) around the soil at the base of your lilies. Make sure all areas are covered. This will prevent the new adults from crawling back up your plants.

Making sure to stay on top of picking them off, especially before they get a chance to lay eggs, will help keep them from continuing their life cycle near or on your lilies.