Hey there, Gardening Friends!
If there's one pest that can really bug us, it's the Colorado Potato Beetle. These little critters are a major pain, especially if you’re trying to grow a lush, healthy potato crop. But don’t worry, I’m here to share some effective organic methods to keep them at bay!
Row Cover
Row covers are a pre-emptive strategy for controlling potato bugs. These covers act as a physical barrier to prevent adult beetles from laying eggs on your plants. Set them early in the season— when your potato plants are emerging, before you see any adults and before they are able to play any eggs.
Egg Crushing: Nip It in the Bud
If your seeing adult activity check the underside of your potato for their eggs— you’re looking for small, bright orange clusters. Wear gloves and crush those eggs before they hatch. Trust me, it’s much easier to handle at this stage than dealing with the larvae later on. This little chore can save you a lot of hassle down the road.
Colorado Potato Beetle laying eggs on the underside of the leaves.
Bacillus Thuringiensis
Bt (Bacillus thuringiensis var. tenebrionis) is a type of soil bacteria that stops the digestive systems of certain insects from working when they are larvae. In effect, the insects starve to death.
Bt can be effective if applied before the the eggs of the potato beetle hatch. So you have to apply the Bt to the eggs for the treatment to be effective. Since the eggs are usually on the underside of the potato leaves, it is difficult to ensure all the eggs are treated. Therefore, this strategy should be used in combination with other control strategies. Also note that there are several Bt strains out there— so seek out the specific strain known to work on the Colorado potato beetles— as referenced above.
Hand-Picking: With a Twist
Believe it or not, one of the most straightforward ways to tackle these beetles is by hand-picking— but don’t go the tedious route of picking individual bugs or larvae. Here's how we speed up the task: grab a light-weight oval-shaped or rectangular bucket— one that maximizes the side length of the container but allows you to get right next to your plants.
Walk down your potato row and use your lower arm to quickly slap it across the tops of the plants to knock the beetles and larvae into the bucket. Or simply use your hand to bat the plants to the side, dislodging the pests into your container.
Larvae waiting to be knocked into your bucket!
You may still have to pick a few larvae out to the center growth point of the potato plants, where the leaves are more curled. Sometimes its hard to knock ‘em out of there.
Pro-Tip: Go out in the cool of the morning when the adult beetles are less active and moving more slowly. They’re pretty big and clumsy, so they shouldn’t be able to escape easily. If they do, add a little water mixed with dish soap or rubbing alcohol to the bottom of the bucket. This makes it even harder for them to fly or crawl out.
After you've dealt with the adults and any larvae, check again for those orange clusters of eggs on the underside of the leaves-- so EASY to spot!
Natural Predators: With a Little Help From Our Friends
Attracting natural predators into your garden is a fantastic organic method to control beetle populations. Ladybugs, spined soldier bugs, parasitic wasps, lacewings, and the tachinid fly love to feast on these pests. These beneficial insects are attracted to calendula, cosmos, coreopsis, caraway, cilantro/coriander, dill, fennel, yarrow, thyme, parsley, marigolds, sunflowers and Mexican sunflowers, flowering feverfew, and buckwheat. By keeping a diverse and welcoming garden environment, you'll attract these helpful insects that naturally keep the beetle numbers in check.
Diatomaceous Earth
Diatomaceous earth is nontoxic, works on contact, and can control many pests. It’s made of a silica powder from crushed aquatic organisms and has sharp edges. As insects come in contact with it, it damages their outer protective layers, inflicting tiny wounds and absorbing moisture and fluids, causing them to lose essential body fluids and dry out.
Kaolin Clay
Kaolin clay when applied forms a protective barrier film; it prevents damage from any chewing pests and can be effective in dealing with potato bugs.
Mulching: Another Barrier Strategy
Consider using mulch, like hay, leaves, straw or wood, around your potato plants. Mulch can help by obstructing the beetles’ access to the soil where they pupate. This simple barrier can significantly reduce their ability to reproduce and grow their numbers.
Rotation!
Don’t plant potatoes in the same place as you did last year. If any larvae successfully pupate— you’re just conveniently providing them with their food source right when they emerge! By rotating your crops, the emerging pest have to at least ’search’ for your potato patch.
Organic Sprays: Keeping It Natural
If an infestation gets really bad, you can resort to organic insecticides like Neem Oil or Spinosad. These solutions can be effective without harming your beneficial insects and are OMRI approved for certified organic production. Just remember to use them sparingly and follow the label instructions to ensure you're treating your garden safely.
Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It can be used to control a wide variety of pests including thrips, leafminers, spider mites, mosquitoes, ants, fruit flies, the young nymphs and eggs of the squash vine borer (before they burrow into the stem) and Colorado potato larvae.
Please note that neem oil should not be applied where bees are active. Always follow label driections.
Wrapping It Up
Colorado Potato Beetles might be stubborn, but with a combination of these organic practices, you can keep your garden healthy and thriving. Hand-picking, egg-crushing, encouraging natural predators, using mulch, and even a bit of organic spray will go a long way in managing these pests. Happy gardening, and remember—every little effort counts towards a bountiful harvest!
I hope these tips help you get ahead of those pesky beetles!
Your garden coach,
Theresa
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