Pygmy Leaf Mining Moth
Pygmy Leaf Mining Moth, Pygmy Leaf Mining Moths, Pygmies, Pygmy Moth, Midget Moths
Nepticulidae is a family known commonly as Pygmy Leaf Mining Moths, due to their minute sizes. The larvae are leaf miners and will create a series of galleries or channels in the leaf of the host plant, which eventually forms large discoloured blotches. They're also known to mine seeds and tree bark. Species in the group are polyphagous, meaning they can successfully infest a variety of plants, shrubs and herbs.
Leaf miner damage can be unattractive.
Leaf Miners generally don't affect the overall health of the plant, unless the plant is small and unestablished.
Adult: The adult moths are tiny (wing length: 1.5- 4.5mm). The wing colouring tends to be dark with pale mottling and central banding; others possess attractive metallic wing scales, which reflect various colours when under the light. When resting, the wings adjoin forming a roof-like tip. The width of the hindwings is smaller than the forewings. The antennae are thread-like and short. Larvae: Larvae are small. They can be green-yellow or white, still being slightly see-through. It's sometimes possible to see them when holding the mined leaf in front of a light source. Leaf Mines: They're highly variable. They can be difficult to identify for this exact reason. Pygmy Moth leaf mines always begin where the egg is left, so mines can appear 'semi-globular' at the source. The egg is unusually large, so can be seen with the naked eye. Sometimes, the mine can begin in the petiole, so it's always good to check here too. Experts advise using the following qualities to identify an insect in Nepticulidae: larvae colour, gallery/ blotch colour, colour and pattern of the insect excrement (frass), the path of the mine, time of the year, and location of the egg. Eggs: Unusually large for a tiny moth. Black-brown in colour.
Galleries, blotches and meandering lines on the leaves of trees, shrubs and herbaceous plants. Little grubs in the blotches of leaves.
Dealing with a Leaf Miner infestation can be tricky because the plant leaf itself protects them. Upon detection of a Leaf Mining pest, you should make an effort to remove the damaged leaves, making sure to squish any larvae or pupae before disposal. Always dispose of leaves in with the landfill. Never bin them in compost or food waste bins! Practise crop rotation annually. Pupae can sometimes lie dormant in the soil over winter when conditions are unfavourable. So by rotating your plants, you are making life more difficult for these insects. If you own a greenhouse or are a greenhouse grower, sticky traps are an effective and cheap way to monitor what insects are about. You can use physical barriers to prevent insects from laying eggs on plants. E.g. insect-proof netting can be useful when used on small trees and vegetable plants. On the other hand, using row covers and plastic sheeting can stop any pupae falling into the soil, disrupting the life cycle. This isn't always appropriate for large trees. Attract beneficial insects into your green spaces by planting indigenous plants, herbaceous-wildflower borders, bug hotels, or just by letting some areas grow a little wild! Likewise, birds are top predators of moths and leaf-mining insects. Incorporate bird feeders to encourage birds into the garden.
Unfortunately, no chemical treatments are effective against these insects because they are protected by the leaf epidermis.