1. a small dark-colored biting fly that breeds in running water
2. a small black aphid that feeds on plants

Examples

• The blackfly swarms made hiking near the river unbearable.
• She applied insect repellent to protect against blackfly bites.
• Blackflies are most active during the early morning hours.
• The gardener noticed blackfly colonies on the bean plants.
• Blackfly infestations can damage crops if left untreated.
• The stream’s fast-flowing water provided ideal breeding conditions for blackflies.
• Ladybugs help control blackfly populations in the garden.