How to Kill Black Bugs That Eat Tomato Plants

Aphids

• 1

  Prevent aphids from attacking your tomato plants by limiting the amount of fertilizer you give your plants; over-fertilizing stimulates tender new growth, which aphids favor. Also, control ants because they carry aphids to plants, where they tend them for their sweet excretion called honeydew.

• 2

  Prune infested plant parts when you see a large number of small black aphids; they cause leaves to curl. Curled leaves can conceal aphids, so search for these and prune them off.

• 3

  Spray your infested plant or plants with a sharp stream of water to knock these insects off. Shaking plants also causes a number of aphids to fall to the ground.

• 4

  Introduce and encourage the natural enemies of aphids, such as ladybugs and lacewings. If you refrain from using chemical pesticides, such insects are more likely to inhabit your garden.

• 5

  Spray tomato plants with insecticidal soap every other day, covering the tops and undersides of leaves and stems. Continue spraying until you see no more evidence of the aphids.

Flea Beetles

• 6

  Prevent an infestation of flea beetles by closely monitoring young plants and by rotating the area where you grow tomatoes from year to year. Also, keep weeds pulled from the edges of your tomato patch.

• 7

  Spray plants with natural pyrethrin as soon as you notice tiny holes in the leaves and small black insects that are only 1/10 of an inch long or smaller.

• 8

  Spot-treat tomato plants that are growing on the outside border of your garden with natural pyrethrin spray. This area is more likely to become infested than areas further into your tomato garden.

• 9

  Introduce braconid wasps to your tomato-growing area. This insect is a natural predator of the flea beetle but does not sting.