Leaf miner

Leaf miner damage to a horse chestnut tree
Leaf with minor miner damage
Tomato with leaf miner damage
Leaf mines by the moth Phyllocnistis hyperpersea on a Persea borbonia leaf.
Leaf Miner trail on a fallen leaf in a Gondwana cool temperate rainforest. Note the initial thin width of the insect trail, becoming wider as the insect grows while it navigates around the leaf. Cryptocarya foveolata from Cobark Park, Barrington Tops, Australia

A leaf miner is the larva of an insect that lives in and eats the leaf tissue of plants. The vast majority of leaf-mining insects are moths (Lepidoptera), sawflies (Symphyta, close relatives of wasps) and flies (Diptera), though some beetles also exhibit this behavior.

Like woodboring beetles, leaf miners are protected from many predators and plant defenses by feeding within the tissues of the leaves, selectively eating only the layers that have the least amount of cellulose. When attacking Quercus robur (English oak), they also selectively feed on tissues containing lower levels of tannin, a deterrent chemical produced in great abundance by the tree.[1]

The pattern of the feeding tunnel and the layer of the leaf being mined is often diagnostic of the insect responsible, sometimes even to species level. The mine often contains frass, or droppings, and the pattern of frass deposition, mine shape, and host plant identity are useful to determine the species and instar of the leaf miner. A few mining insects feed in other parts of a plant, such as the surface of a fruit.

It has been suggested that some patterns of leaf variegation may be part of a defensive strategy employed by plants to deceive adult leaf miners into thinking that a leaf has already been preyed upon.[2][3]

Relationship with humans

Horse-chestnut leaf miner (adult)

Leaf miners are regarded as pests by many farmers and gardeners as they can cause damage to agricultural crops and garden plants, and can be difficult to control with insecticide sprays as they are protected inside the plant's leaves. Spraying the infected plants with Spinosad, an organic insecticide, can control some leaf miners. Spinosad does not kill on contact and must be ingested by the leaf miner. Two or three applications may be required in a season. Make note that it will have harmful ecological effects, especially if sprayed when bees or other beneficial insects are present.

Leaf miner infection can be reduced or prevented by planting trap crops near the plants to be protected. For example, lambsquarter, columbine, and velvetleaf will distract leaf miners, drawing them to those plants and therefore reducing the incidence of attack on nearby crops. This is a method of companion planting.

See also

References

  1. ↑ Paper linking Quercus species and the leaf miner
  2. ↑ Walker, Matt (19 June 2009). "The plant that pretends to be ill". BBC News. Retrieved 13 April 2016.
  3. ↑ Soltau, U.; Dötterl, S.; Liede-Schumann, S. (2009). "Leaf variegation in Caladium steudneriifolium (Araceae) – A case of mimicry?" (PDF). Evol. Ecol. 23: 503–512. doi:10.1007/s10682-008-9248-2. Retrieved 12 April 2016.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.