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How To Kill Cucumber Beetles Organically

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This post may contain affiliate links, my full disclosure can be read here.

Are your cucumber plants starting to lose its leaves?  It’s likely you are having a problem with cucumber beetles.

How to kill cucumber beetles |

I gardened for years without seeing these little pests in my garden.  Then we moved and ever since we’ve had striped cucumber beetles after our plants.

Striped cucumber beetles are a small beetle only 1/4 inch long.  They are yellow with black stripes and easy to see in your garden.  At first, you might only notice one or two but left alone they will quickly multiply!

How To Get Rid Of Cucumber Beetles

cucumber beetle |

Cucumber Beetle Life-Cycle

Adult striped cucumber beetle overwinters in protected areas close to houses, fences and in the woods.  In the spring when the weather starts to warm they begging to come out.

They will quickly find plants to eat and then lay their eggs around the base of the stem.  The adult beetles eat the leaves, flowers, pollen and the larva eats the roots.  The larva emerges later in the summer as an adult beetle for the second round of their lifecycle.

Cucumber beetles are aptly named because cucumbers are their favourite food.  However, I’ve also found them eating zucchini and other summer squash, melons, and pumpkins in my garden.

Early in the season before these plants have sprouted I’ve also found them eating my tomatillos, ground cherries, peppers, and tomatoes!  See these are nasty little pests.

Cucumber beetles can quickly devour young plants but their damage goes beyond only eating your crops.  They also carry bacterial wilt disease.

cucumber beetle |

Bacterial Wilt

Cucumber beetles carry the bacteria that causes bacterial wilt in their guts.  As these beetles feed on your cucumber plants they can spread it through their mouths and feces.  Once the bacteria has been introduced it spreads quickly and causes the leaves of your cucumbers to wilt.

At first, you will notice your cucumber leaves start to flop down a little.  Then other leaves around it will droop and then the stem.  The bacteria spreads quickly and causes the entire plant to wilt and die.

There is little you can do to save an infected plant the best method is prevention.

Delayed Planting

You can try delaying your cucumber plantings by a few weeks.  Some gardeners and market growers who have longer growing seasons have had luck by doing this.

When the cucumber beetles emerge in the spring if they don’t find food nearby they will fly to where they can find it.  So by delaying your plantings any cucumber beetles that have overwintered in your garden should leave before your plants are up.

They will still be affected by the second round of beetles but by then your plants are larger and more established.

We live in a short zone 5 growing season so we have 3 months of summer and really we can get frosts into early June.  Delaying planting isn’t always a good option for us.

A few years ago we were having a really bad year for cucumber beetles but I found an organic solution!

Breeding cucumber beetles |

Using Diatomaceous Earth To Get Rid Of Cucumber Beetles

Diatomaceous earth works so well to keep cucumber beetles out of our garden!

Diatomaceous earth is a non-toxic powder that makes an excellent pest control for your garden.  Diatomaceous earth is a fine powder that is made from ground up fossils of diatoms a type of algae with a hard shell.

When it’s ground up it would look something like broken glass shards under a microscope.  You wouldn’t want to crawl through that and neither do the bugs!

To kill and prevent cucumber beetles I sprinkle diatomaceous earth all over my young plants and the ground around them.  Most of the beetles are gone that day and a few days later I don’t find any at all.

Diatomaceous Earth Food Grade 10 LbDiatomaceous Earth Food Grade 10 LbFood Grade Diatomaceous Earth - 2 PoundFood Grade Diatomaceous Earth – 2 PoundBio-D Food Grade Diatomaceous EarthBio-D Food Grade Diatomaceous Earth

I find Amazon has the best price and a wide selection of diatomaceous earth.

Now there are a few things you need to know.

Diatomaceous earth can kill any bug that crawls through it and that includes bees.  So I try to not use this on my plants when they are flowering.

Instead, I use it when my plants first come up and as needed until they are well established.  Now if my plants were flowering and under a heavy attack from cucumber beetles, yes I would still use the diatomaceous earth.  I would try to apply it mostly to the ground around the plants, though.  This way it would get the beetles without affecting the pollinating insects.

Tips for using Diatomaceous earth

  • Apply diatomaceous earth sparingly and only use it on plants that are heavily affected by insects.
  • Apply diatomaceous earth when the bees are less likely to be out.  This is early in the morning or late in the evening.
  • Apply diatomaceous earth on the soil around your plants where the pests are more likely to be and bees are not normally found.
  • Use a mask when applying diatomaceous earth, especially when it’s windy.  It’s a gritty powder and it’s not a good idea to be breathing that in.

I’ve tried many organic sprays over the years for different bugs in our garden.  So far diatomaceous earth is the only natural method I’ve found that successfully control cucumber beetles.

Do you need an easy way to keep track of your garden?  Click here to get your free printable garden journal.

How to naturally kill cucumber beetles and keep them out of your garden! |


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Kim Mills is a homeschooling mom of 6 and lives on an urban homestead in Ontario, Canada. Blogging at Homestead Acres she enjoys sharing tips to help you save money, grow and preserve your own food.

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