How to Take Care of Diamondback Moth Larvae

The larvae of the tiny, ½-inch diamondback moths (Plutella xylostella) are straightforward to rear. Generally, it is not advisable to release the resulting moths, because they are a pest species. However for a science project, the little caterpillars only need a suitable house and an abundant supply of cabbage leaves. Diamondback moths have a short life cycle and a tiny caterpillar will grow, pupate and become a moth within a few weeks.

Things You'll Need

  • Fish tank or plastic box
  • Paper towels
  • Cabbage leaves
  • Muslin
  • Large elastic band
  • Artist's paintbrush or fine cosmetic brush
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Instructions

    • 1

      Place a few sheets of paper towel in the bottom of an old fish tank or large plastic box.

    • 2

      Collect a couple of cabbage leaves and place in the tank. Diamondback moth caterpillars also eat related plants such as kale, broccoli, cauliflower and sprouts. Use the leaves, not the flowering part of the plant. If using leaves from a plant that was not grown organically, rinse them thoroughly and pat dry with paper towels first.

    • 3

      Brush the caterpillars onto the leaves using a small artist's paintbrush. A cosmetic brush for eyeshadow is also suitable. Alternatively, if you collected the caterpillars from your yard, tear off the leaf they are crawling on and place in the tank.

    • 4

      Place a piece of muslin over the tank and secure with an elastic band to hold it in place.

    • 5

      Add new cabbage leaves once the old leaves wilt or the caterpillars eat most of them. Place the new leaves next to the old ones and let the caterpillars crawl across by themselves. Remove the wilted leaves.

    • 6

      Replace the paper towels once a week to keep the tank clean.

    • 7

      Leave the cabbage leaves in the tank once the caterpillars pupate. The moths will emerge in about a week.