Earthworm
The term earthworms is an imprecise, slang term for the ground-dwelling caterpillars of various species of owl butterflies , some of which can occasionally appear as pests .
In the narrower taxonomic sense, earthworms are the caterpillars of species of the genera Agrotis and Euxoa ( earth owls , ground owls ) or all genera of the tribe Agrotini. In the general horticultural sense and in the plant protection literature, all species of the subfamily Noctuinae or even all owl butterfly caterpillars living in the ground in the broadest sense are often called this.
distribution
In Central Europe, the caterpillars of the seed owl ( Agrotis segetum ) and the Ypsilone owl ( Agrotis ipsilon ) are particularly harmful in agriculture and gardens. The exclamation mark ( Agrotis exclamationis ) is often found in gardens, the pine owl ( Agrotis vestigialis ) is less common and can be found in sandy areas. Species from the difficult-to- identify Euxoa tritici species group are also considered pests.
Way of life
The females of the butterflies usually lay small groups or rows of eggs on the leaves of various plants, from which the caterpillars hatch. Usually these overwinter and pupate only in the next spring.
The caterpillars feed on the roots of numerous cultivated plants . They still live above ground as young caterpillars, in the older stages they usually only come to the surface at night and can cause damage through root and leaf damage if they occur heavily.
The gray, gray-brown, brown and yellowish-brown colored, barely noticeably hairy, up to 5 cm long caterpillars are very difficult to identify, the easiest way to identify them by feeding them through to the moth. The butterflies that arise from the caterpillars fly between early summer and autumn, depending on the species.
Some species, such as the sow owl, develop two to three generations in Central Europe, and more generations in Southern Europe.
Prevention and control
Provide balanced soil moisture through mulching and regular watering. Create mixed cultures (e.g. tomatoes and celery). It is often recommended to remove weeds in order to make it more difficult to lay eggs, but this usually only means that the crops are more affected by the feeding.
In the case of severe infestation, the caterpillars can be baited and destroyed with a mixture of 200 g bran , 20 g sugar, 20 cm 3 quassia and 400 ml water (sufficient for approx. 100 m 3 soil).
In vineyards , it is good practice to leave weeds standing, as these are first eaten by owl caterpillars before they climb onto the vines. Excellent results were obtained from keeping chickens in vineyards, which are effective in reducing earthworms.