Lepidoptera : Tortricidae

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Light Brown Apple Moth (Epiphyas postvittana) is a moth in the family Tortricidae. Light Brown Apple Moth (often abbreviated as LBAM) is native to south-eastern Australia and spread to Western Australia in the 1960s. It has become an invasive species in several other countries, including New Zealand, the UK, Ireland, France, and California and Hawaii in the US.

The moth itself is harmless, but its larvae are not. Light Brown Apple Moth larvae feed on a wide variety of plants and is one of the most polyphagous (i.e., able to feed on various kinds of food) insect pests we have in Australia. A recent study shows that Light Brown Apple Moth larvae can feed on at least 545 plant species in 363 genera from 121 plant families.

Best Treatment for Light Brown Apple Moth

Control of any plant-damaging pest begins with keeping an eye on your plants and detecting pest damage early. It’s a matter of being out in your garden on a regular basis and being observant. For example, you could watch for minor leaf damage on your plants while you are watering the garden.

For this to work you will need to know what to look for (see Symptoms of Light Brown Apple Moth Damage). If you find damage, you should have a closer look to see if you can find the culprits – therefore, caterpillars. To confirm that it is Light Brown Apple Moth larvae causing the problem, you will need to know what they look like (see Description). If there aren’t too many larvae, you could squash them right then and there.

Prevention is always better than cure, and there are several things that you can do to prevent serious damage from Light Brown Apple Moth larvae (see How to Prevent Light Brown Apple Moth Appearing). Regular monitoring of your garden will ensure that a major infestation of pest caterpillars doesn’t occur ‘overnight’.

If you want to use a spray, try Yates Nature’s Way Caterpillar Killer - Dipel. The product is based on naturally occurring bacteria (Bacillus thuringiensis) which act as a stomach poison against caterpillars. The product will only affect caterpillars, so your ‘good bugs’ are safe. You need to find Light Brown Apple Moth larvae in the early stage, before they create their leaf shelters. Follow the label directions and it will work against Light Brown Apple Moth larvae in your garden.

What are Light Brown Apple Moth &
How to Get Rid of Them

Light Brown Apple Moth is a serious horticultural pest. Light Brown Apple Moth larvae are ‘leafrollers’ - meaning they tend to join two leaves together with silk, creating a protective shelter. This means the larvae are difficult to control with contact insecticides.

Light Brown Apple Moth adults are buff-coloured moths about 10 mm long that shelter in foliage during the day. The moths rest with their wings folded back over their bodies forming an arrowhead shape. When the moths assume this position, it is easy to see the differences between male and female moths. Female moths are almost completely buff coloured with an overall speckled appearance, and a single dark mark about a third of the way down the back. Male Light Brown Apple Moths are much less uniform in colour than females, and often have a motley appearance. The important distinguishing feature is that male moths usually are distinctly darker in the lower two thirds of their wings than the upper third.

Eggs are whitish to pale yellow when first laid and turn yellow-green as they mature. The eggs are flattened and broadly oval and are laid in overlapping scale-like or tile-like masses of about 25 to 35 eggs.

Larvae are yellowish-green in colour. When they hatch from eggs they are about 1.5 mm long, and later grow to about 15–20 mm long. Disturbed larvae wriggle rapidly away or drop down on a silken thread. Pupae are light brown, spindle-shaped and about 10 mm long.

Life Cycle

Female Light Brown Apple Moths lay their scale-like eggs in batches of about 30 on the upper surfaces of leaves or fruit. Female moths lay 100 to 200 eggs over a 2 week period. Larvae hatch and crawl away, or drop away on silk threads, to spread out through the plant. Early stage Light Brown Apple Moth larvae settle on the underside of leaves and spin a protective web. Mature larvae web the sides of a leaf together, or web two adjacent leaves together, and larvae feed protected in these shelters.

Light Brown Apple Moth larvae pass through five to six instars and pupate in their shelters from which the next generation of moths emerge a few weeks later. Light Brown Apple Moth can have three to five generations each year with some generational overlap.

What Plants are Impacted by Light Brown Apple Moth

Light Brown Apple Moth larvae feed on many plants:

  • Fruit trees and vines including apple, citrus, grapevines, pear, stone fruit, strawberry and blueberry.
  • Ornamental plants such as camellia, chrysanthemum, fuchsia and roses.
  • Vegetables including tomatoes, parsley, carrot and brassicas.
  • Native plants such as correas and wattles.
  • Light Brown Apple Moth larvae also breed in weeds such as capeweed and dock.

Symptoms of Light Brown Apple Moth

  • Grazed leaf surfaces and holes chewed in leaves.
  • Rolled leaves, or leaves webbed together.
  • Furrows chewed on fruit surfaces.
  • Grapes in bunches chewed, bunches fouled with webbing and frass.

How to Prevent Light Brown Apple Moth Appearing

Monitor

  • Look for egg masses. Check if they are parasitised (see Natural Enemies).
  • There are commercially available pheromone traps to lure Light Brown Apple Moths, or you could make a port wine trap. Mix four parts water to one part of port wine in a jar and suspend it near susceptible plants. The smell of the fermenting port attracts the moths to the suspended jar where they will drown. Traps are monitoring tools to alert you to the presence of egg-laying moths and are not control mechanisms.

Prevent

  • Remove weeds to reduce the number of breeding sites.
  • Install fine mesh nets over susceptible vegetables and berries.

Natural enemies

  • Tiny Trichogramma wasps parasitise Light Brown Apple Moth eggs (eggs turn black when parasitised). If you are unsure, just pick off some leaves with eggs and keep them in a jar for a few days. If tiny wasps emerge you can safely let them go in the garden. If tiny caterpillars hatch out, there are probably more in your garden also hatching. That is a good time to consider using Yates Nature’s Way Caterpillar Killer - Dipel.
  • Other parasitic wasps and flies lay eggs in or on caterpillars.
  • Assassin bugs, damsel bugs, ladybirds, lacewings, predatory shield bugs and spiders attack Light Brown Apple Moth larvae.

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