Description

The word caterpillar means “hairy cat” or “hairy ravager” which is quite apt as many are hairy or bristly and considering their appetite. Caterpillars are the larvae of moths and butterflies. There are many types of caterpillars and sometimes their markings will be determined by the plant they are feeding on. Some have stinging hairs over their bodies so care should be taken if handling them. Caterpillars can be distinguished from insect larvae by the number of legs they have. Most insect larvae only have six legs but caterpillars have six true legs and up to ten “prolegs” which help for walking and balance. There are always exceptions such as the sawfly larvae which have six true legs and fourteen prolegs. Caterpillars range in size from 1 mm up to 14 cm. There are number of related species that are found in the garden including Armyworm, Cluster caterpillars, Earworm, Helicoverpa, Heliothis, Loopers, and Cutworm. Species include: * Bogong moth cutworm (Agrotis infusa) / *Brown/Pink cutworm (Agrostis munda) / *Black cutworm (Agrostis ipsilon) / *Variable cutworm (Agrostis prophyricollis / *Cucumber moth (Diaphania indica) / *Cabbage moth – Diamondback moth (Plutella xylostella) / *Cabbage looper (Chrysodeixis subsidens) / *Small cabbage white butterfly (Pieris rapae) / *Large cabbage white butterfly (Pieris brassicae) / *Cluster caterpillar (Spodoptera litura) / *Night-flying hawkmoth (Sphinx ligustri) (privet hawk moth)-currants, olives-insignificant damage / *Citrus swallowtail butterfly (Papilio aegeus)-citrus- insignificant damage .

Adult size: 30-60 wingspan

Out and about

Spring through to summer and autumn. Found worldwide, except Antarctica, in many different environments but particularly in tropical regions.

Reproduction and Life cycle

Butterflies and moths go through complete metamorphosis, having four stages in their life cycle: egg, larva, pupa and adult. Adult females lay their eggs on plants that the caterpillars can eat. Many will have a specific plant that they feed on. Once the eggs have hatched, the larvae will start to eat and continue eating, moulting four or five times before it is fully grown. The caterpillar stores its energy for when it is an adult as it will only feed on nectar or not at all at this stage. Once the caterpillar is fully grown it will produce a chrysalis or in the case of some moths, a cocoon, in which it pupates emerging as a butterfly or moth. Depending on the species and environmental factors, the time taken for the pupa to become an adult can be a few weeks or months or even longer.

To deter

Plant the following nearby or bruise a few shoots and leaves then strew around. Alternatively, squeeze juice and smear on plant stems. Amaranthus (cutworm) / Artimisias- daisy family (cabbage butterfly and caterpillar) / Borage (tomato and cabbage worm) / Dill (cabbage moth) / Feverfew (moths) / Hyssop (aroma confuses cabbage white butterflies) / Mint (cabbage moth and caterpillars) / Oregano (cabbage butterfly) / Rosemary (moths) / Sage (cabbage moth) Spearmint (cabbage caterpillar) / Tansy (cabbage butterfly, moths) Wormwood (cabbage butterflies, moths) Land cress (Barbarea vulgaris), belonging to the mustard family, can be planted near brassicas as a ‘trap and kill’ plant. Moths and butterflies are attracted to this plant, favouring it over brassicas, and lay their eggs on it. When the larvae hatch and begin to eat it they will actually be poisoned and die. Also known as winter rocket, bittercress, herb Barbara, and upland cress.

To control

- Bacillus thuringiensis (Bt) is available commercially. It is a bacterium which attacks the digestive system of caterpillars. It only affects caterpillars and is therefore harmless to other animals. - Spinosad is another bacterium available commercially. It may have an effect on newly hatched larvae when sprayed on the eggs as many larvae eat their egg shells. - Sift flour over leaves will kill caterpillars as it blocks their breathing pores and they suffocate. - Sprinkle pepper on the leaves in the morning when they are still moist will deter - A garlic tea laced with pepper as a spray will help - Molasses spray - Neem oil spray - Place cardboard collars around seedlings as a physical barrier for cutworm - Collect dead caterpillars after treating and blend them up then use this as a spray on other live caterpillars - Pieces of raw potato and carrot will trap wire worm - Keeping area clear from weeds will help with cutworm in particular as this eliminates areas for them to shelter - Lightly digging the soil surface can disturb pupae and expose the cutworms for birds and other predators

Plants to repel

Plants to attract

Predators

Some ground beetles / Lacewings / Tachinid flies / Parasitic wasps / Assassin bugs/ / Robber flies

Why they are a Pest

They are pests because they eat the leaves of crop plants. You really don’t need to know exactly what type of caterpillar is feeding on your plants as all of them do the same damage. Ibis digging around in the garden will usually indicate army worm as they eat them. A sign of caterpillars around is their poo (frass) on leaves.