Pest identification
What's eating my watermelon?
Striped and spotted cucumber beetles (Acalymma vittatum / Diabrotica undecimpunctata)
Signs: Chew flowers, leaves, and rinds; transmit bacterial wilt, which causes rapid vine collapse.
Control: Use floating row covers until flowering; apply kaolin clay or pyrethrin; practice crop rotation to break beetle cycles.
Aphids (Aphis gossypii — melon/cotton aphid)
Signs: Dense colonies under leaves cause yellowing, curling, and honeydew-fueled sooty mold; vector mosaic viruses.
Control: Introduce or encourage natural predators; treat with insecticidal soap or neem oil; remove heavily infested leaves.
Squash vine borer (Melittia cucurbitae)
Signs: Larvae bore into the main vine near the base, causing sudden wilting and sawdust-like frass at entry holes.
Control: Wrap base of stems in row-cover fabric; inject Bt into the vine; destroy affected plant material after harvest.
Twospotted spider mite (Tetranychus urticae)
Signs: Stippled, bronze-colored leaves in hot, dry weather; fine webbing on undersides of foliage.
Control: Keep plants well-watered; spray forceful water jets on leaf undersides; apply neem oil or insecticidal soap.
Keep watermelon pest-free
Healthy plants resist pests best. Get the basics right:
Watermelon pests — FAQ
What is eating my watermelon?
Watermelons are most seriously damaged by cucumber beetles, which spread bacterial wilt and chew fruit rinds. Aphids, squash vine borers, and spider mites also attack. Protect transplants with row covers, remove covers at flowering to allow pollination, and scout regularly for beetles throughout the season.
How do I get rid of striped and spotted cucumber beetles (acalymma vittatum / diabrotica undecimpunctata) on watermelon?
Chew flowers, leaves, and rinds; transmit bacterial wilt, which causes rapid vine collapse. Use floating row covers until flowering; apply kaolin clay or pyrethrin; practice crop rotation to break beetle cycles.
How do I get rid of aphids (aphis gossypii — melon/cotton aphid) on watermelon?
Dense colonies under leaves cause yellowing, curling, and honeydew-fueled sooty mold; vector mosaic viruses. Introduce or encourage natural predators; treat with insecticidal soap or neem oil; remove heavily infested leaves.
How do I get rid of squash vine borer (melittia cucurbitae) on watermelon?
Larvae bore into the main vine near the base, causing sudden wilting and sawdust-like frass at entry holes. Wrap base of stems in row-cover fabric; inject Bt into the vine; destroy affected plant material after harvest.
How do I get rid of twospotted spider mite (tetranychus urticae) on watermelon?
Stippled, bronze-colored leaves in hot, dry weather; fine webbing on undersides of foliage. Keep plants well-watered; spray forceful water jets on leaf undersides; apply neem oil or insecticidal soap.