How to Get Rid of Lily Beetles

Lily beetles can be a frustrating pest for gardeners growing true lilies and fritillaries. With their bright red bodies and voracious appetites these insects can quickly defoliate ornamental lilies. However with persistence and the right techniques, you can get rid of lily beetles and save your precious lilies.

What Are Lily Beetles?

The scarlet lily leaf beetle (Lilioceris lilii) and the lily leaf beetle (Lilioceris merdigera) are the two main species that affect lily plants They are native to Europe and parts of Asia but have spreadinvasively to North America and other regions

These red and black beetles grow up to 1/2 inch long. They chew holes in leaves,flower buds, and stems. Heavy feeding damage can weaken and even kill lily plants. The larvae are even more destructive, stripping leaves down to the veins.

Both adult beetles and larvae cover themselves in their own feces. This disguises them and deters predators. Understandably, many gardeners find them quite disgusting to handle.

How Do Lily Beetles Spread?

Lily beetles easily travelto new areas as adults. They fly from garden to garden and can hitch rides in nursery plants and cut flowers.

Once present, the females lay up to 450 eggs on the undersides of leaves. These hatch into ravenous larvae in 1-2 weeks. After pupating in the soil, more adults emerge to continue the cycle.

Diligence is required to prevent exponential population growth. Otherwise, beetles spread rapidly and can overwhelm a lily planting within a season or two.

Natural Ways to Control Lily Beetles

While preventing initial infestation is ideal, reality is that lily beetles do slip through. When an active infestation strikes, organic controls are the safest options. Here are some of the most effective methods:

Handpicking

One of the best ways to control small lily beetle populations is simply squishingadults and larvae by hand. It’s disgusting but very satisfying! Check plants at least twice per week and drop any pests into soapy water or alcohol. Removing eggs is also important to prevent new larvae.

Horticultural Oils and Insecticidal Soaps

Spraying plants with neem oil or insecticidal soap smothers and kills young larvae. Direct contact is needed so thorough coverage of leaves and stems is key. Treat every 5-7 days while beetles are active. Oils deter adultfeeding but have limited effect on larger larvae protected by their “fecal shield.”

Beneficial Insects

Encouraging natural predators like ladybugs, green lacewings, and parasitic wasps can reduce lily beetle numbers without chemicals. They attack both larvae and eggs. Creating a diverse garden habitat supports these beneficial insects.

Pyrethrins

Botanical pyrethrins derived from chrysanthemums can be sprayed to kill lily beetle adults, larvae, and eggs. However, pyrethrins also kill beneficial insects, so use conservatively.

Diatomaceous Earth

Sprinkling diatomaceous earth at the base of plants kills larvae as they crawl through it. The sharp silica in DE scratches their exoskeleton, leading to dehydration. Reapply after rain.

Remove Plant Debris

Clearing all fallen leaves and stems in autumn helps destroy overwintering beetles. Tidying the garden in spring removes places for the next generation to pupate in soil.

When to Take Action Against Lily Beetles

Catching infestations early before they explode in number is crucial. Scout lily plantings at least weekly as soon as spears emerge in spring. Look on the undersides of lowest leaves for shiny red adults and tiny orange egg masses.

If beetles managed to overwinter in your garden, they will become active quickly with warm weather. Knock down the first adults and larvae before females start laying hundreds of eggs. Stay vigilant through summer and control late generationsin autumn to prevent overwintering.

Chemical Pesticides to Avoid for Lily Beetles

While some traditional insecticides are effective against lily beetles, they carry significant environmental and health risks. Broad-spectrum chemicals kill beneficial and pollinating insects along with pests. They easily drift to contaminate soil, water, and other plants.

Chemicals like imidacloprid have specifically been linked to honey bee colony collapse disorder. Instead of reaching for toxic pesticides, try preventive gardeningstrategies first. And opt for gentler organic controls like oils, soaps, and beneficial insects if pesticides are needed.

Prevent Lily Beetles from Establishing

Once lily beetles infest a garden, they can be difficult to fully eradicate. That’s why prevention is so important:

• Inspect new plants and bulbs. Check for beetles, larvae, or eggs before bringinghome from nurseries and plant swaps. Quarantine new plants for a few weeks.

• Situate lilies in full sun. Beetles prefer shaded conditions.

• Avoid planting near infested gardens. Don’t give beetles an easy flight path.

• Remove garden debris. Eliminate places for beetles to overwinter.

• Choose resistant lily varieties. Some Asiatic and Oriental types are lesspreferred by beetles.

• Rotate plants. Moving lilies to new beds every 2-3 years can disrupt beetle lifecycles.

• Encourage beneficial insects. They will help eat larvae and eggs.

With persistence using multiple organic control methods, you can successfully combat destructive lily beetles. Protect your precious lilies and enjoy their vibrant blooms. Just be prepared for an icky hands-on battle with these troublesome garden pests.