The squash vine borer is a common pest of squash plants across North America. This moth is less prevalent in some areas, but it is particularly damaging. If you want to maintain a healthy squash plant, it is especially important to identify moths and squash vine borer larvae and control them.
While aphids and thrips come in large numbers, the soybean vein banding virus (SVB) comes singly. If you’re not careful and don’t check for moths and their eggs, you can lose an entire vine.
This article covers basic information about the borer, its life cycle, and ways to prevent and treat its damage in a garden. We hope that you will use the advice given to have a good squash harvest!
What Is The Squash Vine Borer?
Its range extends from New England to Nebraska and south to Tennessee and Georgia. The squash vine borer (Melittia satyriniformis Lepidoptera: Ageiriidae) is a pest in the eastern half of the United States, extending from New England to Nebraska and south to Tennessee and Georgia. Squash vine borer is a native insect to a large geographical area that includes locations east of the Rocky Mountains, the Atlantic Coast, Canada, and South America. Crop losses caused by the weather phenomenon known as “derecho” can be significant east of a line in the United States that runs parallel to Interstate 35. Squash vine borer larvae damage plants by destroying tissue in the stem, causing the plant to die or a runner to die.
The squash vine borer is the larvae of the clearwing Melittia moth. The larvae eats the stem of the squash plant, which can ultimately lead to the plant’s death. The moth’s coloring can be easily confused with bees or wasps. The moth has a black body with red or red-orange coloring. The squash vine borer moth does not harm our squash plants directly, but the larvae feed on the plant stem. They burrow into the plant and eat the soft tissue, causing it to wilt and die eventually.
The other two species are more distantly related and include Melittia ducalis and Melittia oviabunda, the eastern and northern squash vine borers, respectively. There are four species of squash vine borer: the southwest squash vine borer (Melittia calabaza), the squash vine borer (Melittia cucurbitae), the eastern squash vine borer (Melittia ducalis), and the northern squash vine borer (Melittia oviabunda). Then there is Melittia gloriosa and Melittia grandis. The most damaging Melittia are Melittia calabaza and Melittia cucurbitae. The following pests are the most likely to be found in cucurbit crops. There are two types of Melittia, Melittia calabaza and Melittia cucurbitae. The difference between the two is that Melittia calabaza has an orange second abdominal segment, and Melittia cucurbitae has dark olive green on its second abdominal segment.
Characteristics and Life Cycle of Vine Borer
Squash vine borers spend the winter as larvae or pupae in the soil. In the spring, adult moths come out and lay eggs on a plant that their larvae will eat. Circular, dark brown eggs are laid one at a time near the bottom of the plant. After hatching, the larvae tunnel their way into the plant stem, traveling downward toward the base of the plant. An individual adult can lay up to 250 eggs, and as few as 10 moths can cause an infestation on a single acre of squash-family plants. Occasionally, small borers may also enter leaf stems. The larvae that burrow into the plant destroy the vascular tissue, causing the plant or runner to wilt and die. Feeding may continue for four to six weeks. The excrement is sticky and looks like wet sawdust. It is usually found near the entrance of where the insect is. If a vine dies before the borer has completed its larval cycle, the larva can migrate to a neighboring plant. If the larva resumes feeding there, it will cause damage to the plant.
The larvae of squash vine borers are small, white, wriggly worms with brown heads. They can grow up to 1 inch in length. The adult moth has see-through wings with a mix of shiny black and orange colors on the body and wing edges. The moth is a day flier, often mistaken for a wasp because of its similar coloring.
Approximately one generation of this insect is produced per year in northern states, while two generations are produced in many southern states.
Identifying Squash Vine Borer Damage
If you’re not sure what kind of damage your squash vine is displaying, look for the following: The first sign of attack is wilting vines. If you see a wilted plant in your garden, it may not just be because it’s hot outside. Check the vine for other signs to determine what’s wrong. You should look for small holes that have a margin of larval frass around them. This is caterpillar poop from larval feeding. If the stem is rotting and getting mushy, cut it open. You can sometimes find the larvae inside the stem and kill it before it gets worse.
Which Squash Do Squash Vine Borers Like?
Cucurbita maxima is their first choice. There are several varieties of this species, including Hubbard squash, buttercup, Lakota squash, Jarrahdale pumpkin, and others. These are mostly winter squash varieties. If you cannot find Cucurbita maxima plants, then Cucurbita pepo plants are the next best option. Summer squash are the most popular cucurbit varieties. This species includes most pumpkins, zucchini, acorn squash, straightneck or scallop squashes, and more.
The least susceptible species of squash is Cucurbita moschata. This species tends to have more rigid vines. The borers will usually go for easier targets over attacking the text. Most people think of butternut squash when they think of this species, but there are actually many more varieties including some types of crookneck squash. Some people will put eggs on the stems of other plants that are not cucurbits, such as celery. This is interesting because it shows that they are willing to experiment with other plants.
Controlling Squash Vine Borer
Since a small population of squash vine borers can be very destructive, it is very important to plan for their control. If a single borer insect feeds on the stem of a plant, it can kill the whole plant, or a large runner vine.
It can be tricky to eliminate these pests. Once you see the adult, it’s already laid eggs. Although you can kill off one moth at a time, it becomes difficult to get rid of them once the vine borer has gotten into the plant. Most sprays will not work on them at this point. Don’t panic, though! There are ways to handle these little devious pests.
Environmental controls are necessary to combat these bugs. One of the best options for controlling pests in your garden is to add beneficial nematodes to your beds. The microscopic soil-dwellers attack and destroy the pupae of borers along with a variety of other insects. Of all the nematode species, Steinernema-species nematodes are the most effective, with Steinernema feltiae being the most effective of them all.
There are two types of traps that can be effective: those that use color to attract the insect, and those that use pheromones (chemicals that attract mates).
There are two types of colored traps – yellow sticky traps and yellow bowl water traps. The color yellow is attractive to the adult squash borer, as they are typically drawn to yellow squash blossoms. The glue traps cause them to get stuck and die. Yellow bowls full of water cause them to drown. The pheromone traps use the adult insects’ sense of smell to lure them in, as well as their visual response to certain colors. This entices them to get close to the trap. Traps work by luring the insect with a scent or a light source, so once they’re in, they can’t get out and they eventually die.
The control of the squash vine borer can be enhanced by following field sanitation procedures. Vine residues (leftover plant material) should be removed as soon as possible after harvest to prevent late-stage larvae from developing into adults. Sanitation procedures that leave the ground bare for extended periods are not good for organic agriculture because it exposes the cocoons (pupae) to predation. There are measures you can take to prevent erosion and compaction of soil, such as planting cover crops.
Meaning: Even though squash vine borers can fly long distances, producers should be aware that they typically stay close to where they emerge from the ground.
Other Cultural and Physical Controls
One way to control squash vine borers is to delay planting. The conditions for success seem to be quite limited.
- A moderately long growing season
- No neighbors growing any of the cucurbits
- No wild cucurbits to serve as hosts
A method to control squash vine borer is syringe injection of the bacterial insecticide Bt (Bacillus thuringiensis) into each vine by hand. Growers who have home gardens or small market gardens often try to control squash vine borers by slit open each vine that is showing frass and extracting the larva before the vine is too damaged to be saved. Being limited to manual labor makes these methods unfit for large-scale commercial production.
Organic Removal of Squash Vine Borer
Diatomaceous earth can prevent egg-laying by SVB moths. The squash vine borer mothdevelops as an adult by feeding on the Larvae of the squash plant. To prevent this from happening, farmers will fill the plants with a chemical that will kill the larvae. Diatomaceous earth will not be effective if the plant is wet, so make sure to only apply it to dry surfaces. You should reapply diatomaceous earth after a rain, when the plant is dry.
If you find eggs that have hatched and larvae boring into your vine, you will need to do a surgery to kill them off. Look for a hole in the wood and examine it closely to figure out which direction the woodboring insect went. Make a shallow cut into the stem with a sterile razor blade or sharp knife. Find the bug and poke it with a toothpick or needle until it dies. It is not advisable to use surgical methods on the plant as it may be too risky. If you still want to go ahead with it, be sure to bury the wounded stem beneath the soil’s surface. Covering the exposed area of the tree’s roots may help protect against some bacterial or fungal diseases.
Organic growers have traditionally used botanical insecticides, such as sabadilla, ryania, and rotenone, or various blends of these, to control squash bugs. Whereas most botanicals are a bit pricey and only work to a small degree.
It is critical to time the use of pesticides correctly in all cases, whether they are natural or synthetic. The application should happen when most of the eggs have hatched, because that is when the nymph stage is most vulnerable. The timing of [an event] can be judged by frequent and careful field scouting. In organic farming, the farmer’s eye is irreplaceable. Squash bugs lay their eggs in clusters, so it is easy to find and identify signs of their emergence. The eggs are laid and hatch on the undersides of leaves, and the nymphs spend most of their time there. In order for pesticides to be effective, they must be sprayed or dusted onto the areas where pests are present, and the area must be covered completely. More treatments will be needed since hatching happens all season long.
All pesticides pose known and potential risks. When using a pesticide, follow the directions on the label and wear the right protective gear. While natural substances used as pesticides in organic production can be effective, they can also have toxic effects. The decision to use a pesticide should only be made when other methods of pest management, like an organic system plan, have failed. The organic system plan must be approved by an organic certifier before the pesticide can be used.
Squash Vine Borer Prevention
We’ve talked about how to deal with squash vine borers after they’ve infested your plants, but now let’s talk about how to prevent them in the first place. Wrap the stem base in aluminum foil when you plant squash to protect it from the cold. Cover the stem of the plant with foil, but don’t extend it down below the soil line. The following text is about how to prevent an adult squash vine borer from getting into the stem. After that, wrap any new growth to stop squash vine borers from being attracted to stems.
Floating row covers are most effective if you didn’t have squash in the beds the previous year. The best way to keep squash vine borers from laying eggs on your new plants is to place a floating row cover over the bed. If you planted other cucurbits in that spot last year, floating row covers will not be as effective. Instead, use a row cover for newly grown crops. Make sure to select a row cover that allows sunlight and moisture to pass through. If you are using row covers that block access by pollinators, you will need to hand-pollinate female flowers. To pollinate a flower, remove all the petals from a male flower. Rub the tip of the male flower on the stigma of the female flower.
Squash pests can be reduced by crop rotation, which is a recommended production practice. Rotation can help reduce pests by slowing population growth early in the season. Rotating fields does not control pests completely because adults can move between fields. Maintaining strong plant growth is crucial to any plan to manage borer populations. If you want your plants to be resistant to borers, you should fertilize them regularly. This will help them grow more quickly and develop more roots, which will make them stronger.