Are you tired of seeing your beautiful lilies being devoured by pesky red lily beetles? If so, you’re not alone.
These invasive insects can quickly destroy your garden if left unchecked. While there are several methods for controlling these beetles, one option that has gained popularity in recent years is neem oil.
But does it really work? In this article, we’ll explore the effectiveness of neem oil as a pesticide for red lily beetles and provide tips on how to use it safely and effectively.
So, let’s dive in and learn more about this natural solution for controlling these destructive pests.
Does Neem Oil Kill Red Lily Beetles?
The short answer is yes, neem oil can kill red lily beetles. This botanical insecticide is derived from the neem tree and has been used for centuries in traditional medicine and agriculture.
Neem oil works by disrupting the life cycle of insects, including red lily beetles. It kills young larvae and repels adult beetles, making it an effective option for controlling these pests.
However, it’s important to note that neem oil must be applied at five-day intervals for full effect. Additionally, the larvae’s “fecal shield” can provide some protection from sprays, so it’s crucial to ensure complete and heavy spray coverage.
Late-season larvae may also be somewhat resistant to neem oil, so it’s best to use this pesticide early in the season and on young larvae.
Introduction To Red Lily Beetles And Their Damage
Red lily beetles, also known as scarlet lily beetles or lily leaf beetles, are destructive pests that can cause significant damage to plants in the Liliaceae family. These include native and cultivated Lilium and Fritillaria species, which are particularly sensitive to attack. Daylilies (Hemerocallis spp.) are not at risk for attack.
The lily leaf beetle is an introduced pest from Eurasia and is the only Lilioceris beetle known in North America. It is not known to occur in Utah. The adult beetles overwinter in the soil or in plant debris and emerge in early spring to begin feeding and laying eggs. Each female can lay up to 450 eggs, which hatch in one to two weeks. The larvae of these beetles cause the most damage, as they are voracious feeders and can eat buds, flowers, stems, and leaves.
The larvae are yellow, brown, or orange and are covered in a “fecal shield” made up of their own excrement. This makes them difficult to spot and destroy, as well as unpleasant to touch. They typically feed for 16 to 24 days before entering the soil to pupate. Adult beetles will emerge 16 to 22 days later and continue feeding until fall.
A chewed and defoliated lily plant may be the first indication that red lily beetles have arrived in your garden. Both the adult and juvenile phases are voracious feeders and can do a lot of damage in a very short time. To prevent severe damage, it’s important to curb the insect’s reproductive cycle early in the season by examining your plants carefully several times a week, beginning as soon as the plants emerge from the ground.
In its native range, populations of red lily beetles are kept under control by native parasitoids and predators that have coevolved with them. In the northeastern U.S., wasp parasitoid specialists have been successfully introduced for control of these pests. However, without natural predators or control measures in place, red lily beetles can cause economic and aesthetic losses for commercial lily growers and home gardeners alike.
What Is Neem Oil And How Does It Work?
Neem oil is a natural insecticide derived from the neem tree (Azadirachta indica). It contains a compound called azadirachtin, which disrupts the hormonal systems of insects and interrupts their feeding and breeding cycles.
When applied to red lily beetles, neem oil kills young larvae and repels adult beetles. It works by disrupting the beetles’ feeding and reproductive processes, ultimately leading to their death.
Neem oil is also effective against other garden pests, including aphids, mites, and whiteflies. It’s safe for use on most plants and is non-toxic to humans and animals.
To use neem oil against red lily beetles, it should be applied every five to seven days throughout early summer. It’s important to ensure complete and heavy spray coverage, as the larvae’s “fecal shield” can provide some protection from sprays. Late-season larvae may be somewhat resistant to neem oil, so it’s best to use this pesticide early in the season and on young larvae.
Effectiveness Of Neem Oil On Red Lily Beetles
Neem oil is a relatively safe and effective insecticide for controlling red lily beetles. It contains azadirachtin, the active ingredient that disrupts the insect’s life cycle. Neem oil kills young larvae and repels adult beetles, making it an ideal option for controlling these pests.
However, neem oil needs to be applied at five-day intervals for full effect. It’s crucial to ensure complete and heavy spray coverage, especially on the larvae’s “fecal shield” that can provide some protection from sprays. Late-season larvae may also be somewhat resistant to neem oil, so it’s best to use this pesticide early in the season and on young larvae.
Compared to other pesticides listed on a Cornell factsheet about red lily leaf beetles, neem oil is less toxic and can be used by home gardeners. However, it’s essential to follow the label instructions carefully and avoid using insecticides on plants with open flowers.
How To Use Neem Oil To Control Red Lily Beetles
To use neem oil to control red lily beetles, first mix 1/4 cup of neem oil and 1/4 cup of dish soap with one gallon of water in a sprayer. Shake the tank back and forth every three to five minutes to ensure the neem oil doesn’t separate from the water.
Hold the tip of the spray wand 4 to 6 inches away from the plant’s infested foliage or flowers. Press the sprayer’s button to release the neem solution onto the plant. Move the wand back and forth while spraying to ensure even coverage. Coat all surfaces of leaves, stems, and flowers containing mature lily leaf beetles, larvae, and eggs until the solution begins to drip.
Remember that neem oil must be applied every 5-7 days for full effect. Also, make sure that the neem oil you buy contains azadirachtin, which is the active ingredient in neem products.
If you have only a few lily plants, hand-picking the adult beetles is very effective. You can hold a jar of soapy water under them and nudge them off the leaf. They will immediately fall into the water. Scout your plants several times a week, especially early in the season as the adults emerge from the soil.
Safety Precautions When Using Neem Oil
When using neem oil as an insecticide, it’s important to take some safety precautions to protect yourself and the environment. Here are some tips to keep in mind:
1. Wear protective clothing: Neem oil can cause skin irritation and allergic reactions, so it’s important to wear gloves, long sleeves, and pants when handling it.
2. Use the right concentration: Neem oil comes in different concentrations, so make sure to follow the instructions on the label and mix it correctly.
3. Avoid spraying in windy conditions: Neem oil can drift onto nearby flowers and harm beneficial insects like bees, so it’s best to spray on a calm day or in the evening when bees are not foraging.
4. Store neem oil properly: Neem oil can degrade quickly in heat and sunlight, so store it in a cool, dark place away from children and pets.
5. Read the label carefully: Always read the label before using any pesticide, including neem oil. Follow the instructions carefully and don’t exceed the recommended dosage.
By following these safety precautions, you can use neem oil effectively and safely to control red lily beetles in your garden.
Other Methods For Controlling Red Lily Beetles
While neem oil is an effective option for controlling red lily beetles, there are other methods that gardeners can employ to keep these pests at bay.
One option is spinosad, which is derived from a soil-dwelling bacterium. This insecticide is also effective against red lily beetles and should be applied weekly whenever the beetles are present.
Imidacloprid, a systemic insecticide, is another option for controlling red lily beetles. It can be applied as a spray, fertilizer spike, or soil drench in early spring. However, it’s important to follow pesticide instructions and apply it preferably in the evening when pollinating insects, such as bees, are not around.
For those who prefer natural methods, biological control using natural predators shows promise for controlling the spread of red lily beetles. The University of Rhode Island Biological Control Laboratory has identified several European insects that parasitize the lily leaf beetle grubs. These insects have been released at research sites in all New England states and are proving effective at decreasing the lily leaf beetle populations for at least several miles in the surrounding areas. However, these controls are not yet commercially available for gardeners.
Hand-picking the adult beetles and destroying their eggs and larvae is also an effective method for controlling red lily beetles. Gardeners should scout their plants several times a week, especially early in the season as the adults emerge from the soil. Adult beetles should be captured and destroyed by holding a jar of soapy water under them and nudging them off the leaf. Egg masses should be picked off the leaf and dropped into the jar of soapy water or crushed. Larvae can be picked off by hand or by picking off the whole leaf and dropping it into the jar.
Finally, some gardeners have had success with homemade remedies such as a mixture of ground eggshells and dish detergent or leftover coffee and coffee grounds spread on the leaves of their lily plants. While there are no controlled studies to evaluate the effectiveness of these remedies, they seem harmless to try for those who would like to avoid conventional pesticides.