Cabbage Pests And Diseases

Club root - A very common disease is club root, which takes the form of distorted leaves, the cabbage plants will also appear to wilt easily, and eventually it will rot the cabbage plant from inside. Club root is a particularly nasty disease as it can remain in the soil for up to 20 years. It is easily spread by your wellington boots, and prevention is the best form of cure. It is best to always grow your plants from seed and not buy them from an unknown source such as a car boot sale. There is no cure as such other than removing and destroying infected plants – Do not put them in your compost heap under any circumstances as the spores will remain active long after the plant has rotted away.

Cabbage whitefly – They are tiny white moth like in appearance, and they cause yellow and disfigured leaves, and secrete sticky honeydew onto the cabbage leaves, which in turn result in a dark soot like mould forming on the leaves. The females lay eggs on the underside of the leaves, and these develop into larvae, which fix themselves to the leaves until the adult fly develops. The good news is they can be easily treated with pesticides containing pyrethrum or surfactant based products.

Cabbage caterpillars – They are one of the most common cabbage pests and result in holes in the leaves appearing overnight, indeed these are one of the most aggressive pests that can attack your plants, and can result in good leaves being shredded to pieces overnight. If un-treated then they can ruin your crop in just a few days. They can be hard to spot as they cling to the underside of the leaves, and thus holes seem to appear with no predator in sight. They can be prevented by spraying Dipel or Thuricide on the leaves early on in the season. Young plants can be covered with a fleece to keep them off in the early months.

Cabbage root fly – It manifests itself in the form of wilting and discoloured leaves that may eventually kill the plant. The flies are very similar in size and shape to the common housefly. They will then lay small white eggs at the base of the plant, these eggs will then hatch into larvae and the larvae will attack the cabbages roots, this can kill younger plants but may just effect the yield in more mature plants.

The cabbage root fly can be prevented by the addition of fleece or netting over the plants. You can also place cardboard or plastic discs around 15cm across at the base of the cabbage plants. Long term crop rotation can help greatly.

Cabbage white butterflies – Prevent these and you will prevent your cabbages being attacked by cabbage caterpillars. The butterflies lay eggs on the leaves and these hatch in to larvae, which in turn mutate into caterpillars, which will cut holes in the leaves and kill the plant in just a few days. The use of fine netting to keep the white butterflies off, however the plants can be treated with pesticides containing pyrethrum.

Other commons pests include: -

Aphids - They take the form of micro sized dots on the plants, which are actually larvae. They can come in many colours, but all can be treated by a strong spray of water or washing with a soapy water solution (Although this may need doing repeatedly). The best solution though is to introduce natural predators such as ladybirds into the area, which love to feast on aphids.

Slugs and Snails – as ever these are the gardeners worst enemy but they can be treated easily with either slug pellets, traps or hand picking them off at night, which is particularly effective. Copper collars can also be placed around the plants and will put off both slugs and snails. Another trick is to place crushed eggshells around the cabbage plants as both slugs and snails hate the sharp edges.

Find out more about How To Grow Cabbages

By Richard Allen -