Both the spotted and striped cucumber beetles are a pain to gardeners, and controlling the possible damage they can cause can be challenging. They can find their way easily to feed on your cucurbit crops through their sharp sight and smell.
However, a few natural approaches are found to be efficient in instantly getting rid of cucumber beetles.
Read on and learn how to eliminate or control the increasing number of cucumber beetles in your garden using natural strategies.
Discover how to prevent possible contact between the plant and the disease-transmitting beetles to avoid the spread of infectious disease in your backyard garden.
18 Effective Ways To Get Rid of Cucumber Beetles Naturally
Once bacterial wilt is introduced into your garden through cucumber beetles, there’s nothing you can do to stop the infection’s progression.
However, knowing what you are dealing with and learning some effective natural prevention will save your plants from inevitable damages.
The peak of feeding and transmission of infection activity usually happens in spring and lasts for two to four weeks.
It is the most crucial time to implement prevention and population control against infection carrier cucumber beetles.
1) Conduct Regular Inspection
- The key element to control the rapid increase of cucumber beetle population is frequent inspections.
- Regular monitoring for any signs of pests allows you to take action instantly and prevent the possibility of infestation when a few beetles happen to come near your backyard garden.
2) Dispose of Eggs and Pupae Immediately
- Make sure to inspect everything, including the growing medium, for any signs of eggs. When you discover pupae, handpick and make sure to dispose of them immediately.
- Beetles lay a ton of eggs in clusters and usually leave them on the underside of the foliage. The eggs that look red or brown are tiny, but they are easy to spot.
- Cut the leaves carefully using scissors where clusters of eggs lay and place them in a bucket carefully.
- Make sure no eggs drop on the ground and dump or destroy the eggs permanently far from your garden.
- Do not place the leaves with eggs in your compost pile to avoid the chance of returning beetles.
- You can hunt eggs and pupae regularly. Adding them to your daily garden activity is essential to keep infections from getting out of control.
3) Take Advantage of Sticky Traps
- Sometimes, beetles are hard to handpick one by one, but the process becomes easy when you use yellow rubber gloves coated in petroleum jelly.
- Beetles are attracted particularly to yellow color and to the smell of cucurbit leaf and flower.
- Also, place homemade sticky traps in your garden to catch cucumber beetles and other pests.
- You can make sticky traps out of cardboard, cups, or other objects coated with petroleum jelly or any thick syrup. It traps young beetles, aphids, and other small insects.
- You can also buy inexpensive pre-made sticky traps. The insect trap comes in yellow to mimic the color of cantaloupe and cucumber blossoms.
- It has a sweet smell to lure beetles and draw them in. Plus, it is easy to set up in the midst of the garden.
4) Introduce Beneficial Insects into Your Garden
- Introduce beneficial insects in the early stage of the growing season. Some of the common natural predators that attack cucumber beetles are braconid wasps, ladybugs, green lacewing, ground beetles, and wolf-spiders.
- You can apply beneficial nematodes to eradicate pupae in the soil. It helps control the developing pupal stage of the cucumber beetle.
5) Suck up Beetles with Handheld Vacuum
- A handheld vacuum or a reverse leaf-blower is an inexpensive option cucurbit growers use to suck up beetles. It is especially helpful in eliminating concentrated populations of adults.
6) Use Floating Row Covers
- Floating row covers do not only protect plants from frost. It is another option you can try to prevent cucumber beetles from coming near your plant.
- Row covers allow light, water, and air to penetrate to help the plant thrive, yet prevent beetles from coming near the plants.
- However, make sure to remove the covers a few hours during the day to allow pollination for the blossoming plant.
7) Maintain Cleanliness
- Maintain a clean growing area by removing garden trash and other debris to eliminate overwintering larvae.
- Overwintering female adult beetles hiding in plant debris and garden trash can deposit up to 800 eggs when they leave their winter sites in early spring.
- The beetle’s complete life cycle from egg hatching to the pupal stage to emerging adults requires about 6-9 weeks. It means cucumber beetles can produce about four generations in a single growing season.
- And the only way to reduce overwintering sites is to keep the garden free from debris and garden trash, especially after harvest.
8) Apply Crop Rotation Techniques
- Rotate cucurbit crops and harvest produce before fruit drops to the ground.
- Taking advantage of crop traps by rotating cucurbit is another natural control option to deter cucumber beetles.
- A three or four-year crop rotation cycle helps get rid of the disease brought by cucumber beetles. Also, the rotation cycle technique minimizes or eliminates the build-up of infection in the soil.
9) Use Insecticidal Soap and Horticultural Oils
- When you find pests intolerable, use hydrogen peroxide, insecticidal soap, and horticultural oils. These are the common organic treatments you can use to keep the garden in control.
- Neem oil is popular with gardeners who prefer to control pests in the garden organically. It is a natural pesticide with antifungal and antibacterial properties made out of seeds of the neem tree.
- The horticultural oil is often used as a foliar spray to repel beetles and other insects due to its bitter taste and garlicky smell.
- Some growers find organic insecticides to provide satisfying results. All you need is to apply and make sure to generously spray the leaves’ undersides and plant canopy where the insects hide.
10) Take Advantage of Kaolin Clay
- If adult feeding is in severe condition, apply kaolin clay to your plant foliage. It leaves a fine powdery film that insects find horrible for feeding and egg-laying.
- This gummy coating gums up the beetle’s antennae and irritates them, making it difficult for the insect to navigate.
11) Till and Use Wood Ash Spray
- Tilling and using wood ash spray in your cucurbit gardens effectively keep cucumber beetles out of your garden.
- Tilling your garden in the late fall and removing debris after fall harvest will expose overwintering cucumber beetles’ burrowing underground.
- This method will help eliminate their habitat and reduce beetle populations next year.
- If you opt for a no-dig garden, you can shred or chop any woody residues from the recent harvest to avoid the possibility of overwintering habitat.
12) Enjoy the Benefits of Companion Planting
- Nasturtiums and radishes are quite helpful in deterring cucumber beetles.
- Companion planting helps discourage insects and produce healthy crops. Planting nasturtiums and radishes next to your cucurbit crops will help repel beetles away.
- Intercropping is the growers’ technique of planting different kinds of plants to deter pests such as cucumber beetles. When growing with other plants, beetles do not find cucurbit crops attractive.
13) Prune Infected Vines
- If you see evidence of infection, immediately remove the diseased plant to prevent further transmission.
- Pruning infected vines with bacterial wilt will help minimize the spread of disease. It reduces the probability of rapid infestation in your garden. Infected plants will definitely not survive anyway.
- Cucumber beetles feed on infected plants and spread the infection to the entire garden.
14) Use Transplants
- Beetles have a knack for finding young seedlings. Seedlings are vulnerable to bacterial wilt, and once infected, there’s nothing you can do to stop the progression.
- Allow seedlings to grow a little larger before you transplant them either in larger pots or at an in-ground garden. This helps the seedlings be more resilient against bacteria’s threat.
15) Protect Plants with Mulch
- You can use a straw mulch to protect plants from cucumber beetles. It serves as a hiding shelter for natural predators such as wolf spiders.
- It encourages spiders to hide under the straw mulch and discourage beetles from laying eggs in the garden soil.
- The metallic-colored mulches, also known as reflective mulches, can help repel cucumber beetles, reduce feeding damage, and spread bacterial wilt.
16) Plant Resistant Cucurbit Varieties
- The bitter cucurbitacin in cucurbit crops attracts cucumber beetles to host plants.
- Beetles defend themselves against predators by absorbing cucurbitacin into their bodies.
- Planting cucurbit varieties in your garden with lower cucurbitacin levels are less attractive to cucumber beetles.
17) Kill Beetles with Flames
- Eliminating cucumber beetles using standard weed flamers may not be as popular as other options, but you can use this approach on a trap crop in the garden edges and not the main crop to kill beetles.
- This approach may be less effective with striped cucumber beetles, as the highly mobile insects may head down into the soil to hide.
- Pyrethrum is a broad-spectrum insecticide extracted from the flowers of daisy-like chrysanthemums. The extracted chemical is toxic to beneficial and harmful pests and requires caution when used in the plants.
- Growers mix the chemicals in water or oil or use them as a powder to treat the perimeter trap crop only to minimize the possibility of more significant harm.
- Use pyrethrum with care. People overexposed to pyrethrum may likely experience symptoms, including itching and sneezing.
Transmission and Damage Caused by Cucumber Beetles
Though mature plants can tolerate as much as 25% to beetle feeding with no yield reduction, cucumber beetles can cause cucurbit crop damage in severe conditions.
But, it is the spread of bacterial wilt that causes extreme damage that furthermore kills the plants in the garden.
Striped cucumber beetles love cucumber, muskmelons, summer squash, pumpkins, and gourds as the plant host.
Feeding on the flowers can reduce potential produce when massive amounts of flowers are eaten. Also, excessive feeding can cause yellowing of foliage and stunted growth.
Moreover, adult beetles can cause unattractive scars and pockmarks that will eventually sink to the fruit rind. The fruit produced on infected plants loses its quality and will not be marketable.
Damage of Plant’s Water Conducting Vessel
The beetles feeding on the plant, such as foliage, flowers, and stems, can move bacteria through the plant’s vascular tissue.
These bacteria will disrupt water transport in the plant, causing leaves to wilt and die in a short time. Among plants, cantaloupe and cucumber are the most susceptible crops to this disease.
Bacteria can multiply rapidly, blocking the water-conducting tubes of the plant, resulting in permanent wilting within 6-7 days after infection.
Runners Become Necrotic
When runners are infected, it first indicates a change of color by turning into dark green and gradually becoming necrotic as wilting does non-stop progression.
Infected foliage also appears to be chlorotic. You can see the development of necrosis and chlorosis around the leaf edges right before the plant dies.
Bacterial Spread through Mouth and Feces
The transmission of bacterial diseases such as bacterial wilt and viruses are often caused either by larvae or adult cucumber beetles. They are introduced into the plants through the beetle’s contaminated mouthparts or its feces.
The infection the cucumber beetle carries in their guts can also overwinter internally. The beetle can pass the infection onto the plants the next spring through feces.
When beetles reach densities of 10-20 per plant, the infection will almost spread in a short time. They can cause individual runners or the whole plant to wilt and die in no time.
Therefore, regular monitoring of the beetles’ population densities in your plant is essential for effective infection control.
Dispersal Through Infected Water
Aside from the plant’s wound through feeding, bacteria can move from one plant to another through inground water. Infected rainwater or dew can also significantly increase the existence of bacterial wilt.
Root-to-Root Contact Transmission
The root-to-root contact can also spread bacterial wilt through the larvae feeding on the roots and the plant’s underground stem.
Bacteria can enter plants either through contact with other infected roots or from the infected soil through wounds made at planting, cultivation, or caused by nematodes and burrowing insects.
The movement of infected nursery plants also contributes to a greater spread of bacterial wilt.
Once bacteria enter the roots, it starts to multiply in the water-conducting tubes, causing the plant of all stages to wilt and die.
Bacterial Spread through Garden Tools
The use of infected garden tools, shoes, and infected soil on machinery can also transmit bacteria into plants.
Also, make sure to wash your hands and disinfect garden tools after handling infected plants to prevent the possibility of a greater spread.
The Life Cycle of Striped Cucumber Beetles
Striped cucumber beetles lay eggs either at the undersides of your plant’s foliage or at the base of cucurbit crops. When in the soil underground, larvae feed on the roots of these plants.
Overwintering adults move fast on warmer days and start to feed, mate, and lay eggs. The eggs hatch and the larvae develop for 2-4 weeks on the plant’s roots and pupate on the soil.
The next generation of adult cucumber beetles emerge in August, and the population remains concentrated in mid until late September. The beetles then start to move and find overwintering sites in field edges.
Identify Symptoms of Infection
Symptom identification and early detection of bacteria in potentially infected plants allows you to implement spread control against infections.
In addition to this, a prevention control against the rapid increase of infection carrier cucumber beetles should be established immediately. Doing so will save the plants from the threat of disease.
You can diagnose the infection by cutting the stem and squeezing both cut ends of a wilted plant. Hold on for about 10 seconds and slowly pull apart.
When you see the white stringy sap between the two cut ends, it is a bacterial slime containing millions of bacteria blocking the plant’s water-conducting vessel.
The presence of bacterial slime on the stem is a positive indication of bacterial wilt in the plant.
Placing the cut runner or crown in water is another way to distinguish infection in your plant. The milky strands will start to form within 5-10 minutes oozing from the cut surface into the water.
Final Thoughts on How To Get Rid of Cucumber Beetles Naturally
Both striped and spotted cucumber beetles damage the plants they feed. The spotted beetles feed on over 200 different crop and non-crop plants, whereas striped beetles prefer cucurbit crops and seldom feed on other plants.
Cucumber beetles can damage cucurbit crops in your garden by feeding directly, causing the plants stunted growth.
The high population of insects can reduce fruit sets when flowers are eaten or cause scarring on the fruit rind reducing its quality and marketability.
And the most alarming damage cucumber beetles cause is the transmittal of bacterial wilt, an infection that plants definitely do not survive once infected.
Many backyard growers find natural ways to control severe damage caused by the concentrated population of cucumber beetles and the transmission of deadly bacterial wilt.
Growing cucurbit crops in your backyard garden and implementing natural disease prevention is the least expensive way to reduce the spread of infections to new uninfected plants.
Have you tried these natural ways to prevent damage caused by cucumber beetles before problems like bacterial wilt get out of control? Feel free to share your experience of what works for you. We’ll be glad to hear from you. Happy gardening!