Squash vine borers are a type of clearwing moth. They’re a bit unusual because unlike other moths they’re active during the daytime. The adults resemble wasps, are about 1/2 inch long, and have an orange abdomen with black dots. The adults lay eggs near the base of squash plants. These eggs take only about a week to hatch and then they bore into the base of the squash plant and up inside the stem, preventing the plant from getting water or nutrients from the soil.
Signs of their presence include the plants wilting, holes at the base of the plant, and of course spotting adults flying around plants. If your plant has vine borers present you can slice into the stem and kill the insects. If you carefully bury the wounded part of the stem with moist soil and keep it well watered your plant may survive. While this is an option, the best methods for combating vine borers are preventative.
Depending on how long your growing season is you may be able to avoid vine borers by planting your summer squash at the end of July. Adult vine borers typically lay eggs in late June or early July so your late planting of squash won’t be mature until after vine borers are finished laying eggs.
Use crop rotation.
Once squash borers feed for 4-6 weeks they burrow into the soil where they spend the winter pupating. Rotating crops can help minimize the pressure on your plants.
Choose resistant plants.
Some cucurbits are much less likely choices for vine borers. Try planting squashes in the moschata and argyosperma family as well as watermelons and cucumbers. Check out the post below for how to use young winter squash like summer squash.
Covering your squash with row cover before late June can prevent vine borers from reaching your plants to lay eggs. This method needs to be used in combination with crop rotation as vine borers hatch from the soil.
Plant a trap crop.
You may be able to eliminate some of your garden’s vine borer population using a trap crop. Wait until your plants have vine borer larvae present and then pull and burn the plants. You may never get all of them this way but it can help reduce the problem next year provided you don’t have close neighbors also growing squash.
If you struggle with squash vine borers in your garden consider trying one of these preventative methods this summer. They can help you combat squash vine borers in without resorting to pesticides.
As lovely and romantic as organic gardening can be it can also be really tough. A huge struggle for many organic gardeners is dealing with pests in an efficient and economical way without the use of pesticides or rodenticides. Developing an organic integrated pest management system or IPM can help.
Monitor & Identify
The first step is to monitor your garden and identify any pest issues. Record any problems in a garden journal and be as specific as possible. Research the type of pests you’re seeing and their life cycles. Are they cabbage worms or cabbage loopers attacking your broccoli plants? Also record dates and conditions when they attack your garden. Do aphids destroy your fall crop of lettuce or do the only impact your spring sowings? The more you learn about these pests the easier it is to prevent them. You should also consider at this time if the pests are actually a problem. Having to pick off a few tomato hornworms may not be worth putting major preventative measures in place if they’re not actually affecting the productivity in your garden and are otherwise easily managed.
This is the most important part of an IPM. Once you’ve gathered information you can put preventative measures in place. Knowing a pest’s habitat and life cycle can be key. Examples of of preventative measures include planting a crop late or early to avoid a major pest season (ex. planting quick maturing cabbage early when it’s too cold for cabbage moths), attracting certain bird species to keep pest populations in check, encouraging or purchasing native predatory insect species (ex. ladybugs can be purchased online and are excellent at reducing aphid populations), growing pest resistant varieties, or using row cover over your most vulnerable crops. Sometimes you’ll need to employ a combination of these strategies. Often a well planned preventative strategy can keep your garden productive without a lot of additional work.
In severe situations where pest prevention has been ineffective control measures are used as a last resort. These controls may be very effective against pests however they’re typically costly in other ways. Some, like handpicking can be very time consuming while others may actually be pricey for the small gardener like neem oil. Even though they aren’t as problematic as chemical pesticides they also may have unintentional environmental impacts despite the fact that they’re organic. Organic pesticides like neem oil, diatomaceous earth, or milky spore powder may be implemented with the intention of only harming a single pest species but unfortunately there’s no way to protect the good species. These organic pesticides can still kill beneficial insects like butterflies, bees, parasitic wasps, predatory beetles, and more.
Using integrated pest management can help you successfully maintain an organic garden. While no strategy is perfect, researching and recording your specific pest problems and then implementing preventative strategies can be effective.
For many gardeners planting brassicas in anything but the very early spring or fall is asking to be devastated. Cabbage moths can quickly colonize a patch of brassicas leaving tons of eggs which seem to grow into caterpillars and strip entire plants in the blink of an eye.
Don’t give up on summertime brassicas just yet though! There’s many ways you can fight off the cabbage moths to reap bountiful harvests.
Pick the worms off by hand.
It’s certainly not fun but it can be effective particularly if you only have a few plants. Drop worms into a bucket of soapy water to kill them. Be sure to check the undersides of leaves. If you see a cabbage worm with little white cocoons on its back leave it be. The cocoons will hatch into parasitic wasps, killing that worm and eventually others.
Note: Know your worms! Species that also have a green caterpillar stage include Luna Moths, Black Swallowtail Butterflies, and Eastern Tiger Swallowtails.
Swat the moths.
Some gardeners swear by the tennis racket method. When the cabbage moths show up in the spring they head out with tennis rackets to swat them out of the air. If you go this route be sure avoid killing other non-harmful moths and butterflies.
Use your poultry.
If you have a backyard flock it may be worth letting a few birds into your cabbage patch once the plants have gotten big enough. Both ducks and chickens have been known to enjoy cabbage worms.
On the subject of birds, try to attract songbirds to your garden.
Many songbirds will eat cabbage moths but they need to be visiting your garden regularly to take notice. Make your garden more bird friendly by planting varying heights of plants for them to perch on or adding feeders, houses, and/or bird baths.
Try companion planting.
There are several crops that can be planted in your cabbage or broccoli patch to deter pests. Wormwood, thyme, marigolds, tomatoes, tansy and peppermint are all believed to help keep the cabbage worms away. You can also use companion plants like buckwheat and yarrow to attract beneficial insects to fight the cabbage worms for you.
You may also consider interplanting single brassicas throughout a garden. Unlike a monoculture bed having a plant here or there is much harder for cabbage moths to find.
While we haven’t tested it there’s a belief that cabbage moths are territorial and will leave your plants be if you hang decoy moths on and around your brassicas. Check out this article from The Good Seed Blog for more information and printouts.
Make your own plant spray.
Some people have found that tansy tea or oil deters cabbage worms when sprayed on the plants because of the volatile oils it contains. Others have had success with sprays made from dish soap, crushed garlic, or blended hot peppers.
Plant a trap crop.
Have you ever noticed that cabbage worms or another garden pest really love a specific variety? While you might initially think you should avoid planting that crop the opposite is really true. Plant the offending variety and then the pests will be less likely to go after other varieties you planted. Some people also choose to burn the trap crop with a flame weeder once it’s covered in pests to eliminate many of them. If you choose the burn method make sure your fire doesn’t get out of hand and you follow local regulations.
You may want to try organic pesticides.
Before you think we’re advocating the use of harsh chemicals know that there are organic and natural substances that are considered pesticides. Probably the most well known example is diatomaceous earth which is a powder made from crushed, fossilized, prehistoric crustaceans. This powder will cut insects (but not people or animals) as they crawl through it but it does need to be re-applied every time it rains. If you want to be sure whatever you buy is organic look for an OMRI (Organic Materials Review Institute) certification label.
It’s also important to note that pesticides affect all insects, good or bad. Consider what beneficial insects may also be harmed by your pesticide choice before you choose this strategy.
Practice crop rotation and cover cropping.
Both crop rotation and cover cropping are important to a healthy garden for a couple of reasons. First they help lessen disease and pest problems by ensuring the same crop isn’t planted in the same area helping to break pest and disease life cycles by moving their food source. Second they help ensure plants receive necessary nutrients and stay healthy which makes them less susceptible to pest and disease issues to start with.
Remove and compost any leftover plant material at the end of each season.
Cabbage worms overwinter in dead plant material so it’s important to remove and compost it. Alternatively you can till it under.
Use row cover.
If you can’t find another solution that works for you, row cover will do the trick. Cover the plants right after you get them in the ground and cabbage moths will never get to your plants to lay eggs.
Gardening is never easy but it’s especially difficult when you have to deal without a lot of pests. Hopefully among these tips you’ll find a strategy that works for you and your garden.
How do you deal with cabbage moths? Did we miss anything?