Squash bugs attack watermelons by sucking the plant juices. They deprive the plant of nutrients and water, resulting in yellowing leaves, which eventually dry. A large infestation will cause the entire plant to wilt. Squash bugs also feed on young watermelon fruits, resulting in severe damage.
Squash bugs are tiny, measuring ⅝ inch (1.6cm) long. However, they cause extensive damage to various plants. Their primary targets are squash and pumpkin, but they also attack young juicy fruits like watermelons.
I’ll discuss how to identify squash bugs, the extent of damage to the watermelons, and what you can do to save your watermelons.
How Squash Bugs Attack Watermelon
At a glance, squash bugs appear harmless. Unfortunately, they reproduce quickly. The females lay eggs in clusters that hatch every 7-14 days. The nymphs mature in 4-6 weeks. A high squash bug infestation will result in the intensive feeding of young watermelon plants.
Squash bugs attack watermelon in multiple ways:
- They use their sharp, piercing mouths to suck sap from leaves.
- The leaves wilt because of the interference in the movement of nutrients and water through the plant.
- Intense feeding will cause the watermelon to dry and turn crisp and brittle.
- Smaller, younger watermelons die after long-term feeding.
- Squash bugs also create ragged holes through the leaves as they feed.
- The bugs pierce and suck the juices from small watermelon fruits resulting in a bruised or scarred rind.
The nymphs and adults attack watermelon and can cause extensive damage if not detected and controlled early. Larger and studier watermelons are more tolerant of squash bugs.
Signs Squash Bugs Are Attacking Your Watermelon
The best time to tell if you have a squash bug problem in your garden is during spring. This is when the adult squash bugs emerge from the leaf litter and debris where they took refuge during winter.
Spring is when squash bugs are ready to mate and lay eggs, just as the watermelon vines start to grow, leaving the young plant vulnerable to infestation.
Here are the signs you have squash bugs in your garden:
- Bronze to brick red clusters of eggs (usually 15 – 40) on the underside of leaves. Some squash bugs lay eggs on stems, so you should check the stems as well.
- A whitish powder that covers nymphs. The eggs hatch every one to two weeks.
- Nymphs are 0.1 – 0.5 inches (2.54 mm – 12.7 mm) long.
- Newly hatched nymphs are white to greenish-gray. As they grow older, their abdomens turn brownish-gray.
- Adults are dark gray to dark brown. Some have orange abdomens, while others have orange-brown stripes.
- They have black legs and black antennae.
The squash bug’s life cycle lasts 4 – 6 weeks. Once they turn into adults, they can survive for 75 – 100 days. Their survival is highly dependent on food availability.
When you see many eggs or nymphs, you need to be concerned because a high density of squash bugs means you are likely to see a lot of damage on the watermelon. It is best to deal with the squash bugs as soon as you identify them, irrespective of the stage.
How To Get Rid of Squash Bugs
The best time to get rid of squash bugs is before the eggs hatch or when they are nymphs. When they grow into adults, they become more challenging to control. Monitor your watermelon and look for signs of squash bugs.
- Use a blunt object to lightly scrape the eggs from under the leaves. Once they fall on the ground, beetles will feed on them, and they will not have the chance to hatch.
- Look out for more eggs every week. Squash bugs keep laying eggs through early to mid-summer. Since it takes 1 – 2 weeks for the eggs to hatch, you should be vigilant. If you go too long without monitoring your garden, you will have more eggs and nymphs.
- Place cardboard and newspapers in your garden in the evening. The adults and nymphs will shelter underneath the layers of newspapers. Collect the squash bugs in the morning and crush them before disposing of them.
- Check the watermelon vines daily. If a few show signs of squash bug damage, you should keep collecting the bugs and destroying the eggs.
- Remove plant debris in your garden.This will reduce the hiding places for the squash bugs.
- Use insecticides and pesticides on eggs and nymphs. Unfortunately, they don’t work on adult squash bugs. The best time to apply the treatment is in the morning and evening because there is minimal pollinator activity.
- Check other plants in the garden for squash bugs. Young plants and popular hosts, like cucumbers, squash, and pumpkins will probably have infestations as well. Look out for wilting leaves and be vigilant so that you can control the spread of squash bugs to your watermelon.
- Provide habitat for squash bug predators. A common predator, Trichopoda pennies, often hovers in squash gardens in search of squash bugs. The adults feed on nectar. Plant goldenrods, asters, meadowsweet, or wild carrots close to the garden to attract these parasitic flies.
Some pesticides are effective on squash bugs but also kill bees and other beneficial insects. It is best to use control measures that are safe for beneficial bugs and only target squash bugs. Timing is critical if you want to control squash bugs.
This video offers tips on how to control squash bugs.
How To Keep Squash Bugs Away From Your Watermelon
Although it is sometimes difficult to control squash bugs, you can take measures to keep them from attacking your watermelon. Sanitation will initially help to protect young watermelons from squash bugs.
- Remove old plants after harvest. Squash bugs will have no food or a place to hide as they wait for the new crop. Burn or compost the old vines, depending on your interest.
- During winter, remove all debris from the garden. Adult squash bugs usually overwinter underneath the rubble.
- Thoroughly till the garden before planting watermelon. Compost all vegetation to reduce egg-laying sites for squash bugs.
- Mow the area around the garden. Adult squash bugs may hide in the vegetation close to the garden, primarily if you use treatments against the eggs and nymphs.
- Hand pick adult squash bugs and the nymphs early in the season. This will prevent their numbers from growing.
- Use a trellis to support watermelon vines. This makes the environment unsuitable for squash bugs because they prefer hiding under vines and leaves close to the soil.
- Practice crop rotation. For example, plant butternut and royal acorn before planting watermelon because they are less vulnerable to squash bugs. By the time you plant watermelon, your garden will be free of squash bugs, giving young watermelons a chance at survival.
- Use floating garden nets. It will keep squash bugs from your watermelons. However, you should remove the cover when the watermelon starts blooming to allow pollinators onto the plant. If you intend to mulch your garden, you should combine it with row covers to keep squash bugs from the mulch, the perfect hiding place for them.
- Practice companion planting. Nasturtiums repel squash bugs. It is best to plant them around your garden to keep squash bugs from your watermelon.
This SUNPRO Garden Netting Pest Barrier (available on Amazon.com) has an ultra-fine mesh that prevents squash bugs, birds, and other pests from destroying fruits, flowers, and all kinds of plants. It is durable and allows in air, light, and water. It is lightweight, and you can easily remove it when giving bees and other pollinators access to the plants.
Squash bugs attack watermelon throughout their life cycle. The nymph stage is the most dangerous and the easiest to destroy with insecticides. It is best to destroy the eggs before they hatch. Close monitoring is critical in the management of squash bugs.
Thankfully, squash bugs don’t carry diseases, so your watermelons will recover quickly after the bugs are eradicated.