Yponomeuta malinellus, the apple ermine, is a moth of the Yponomeutidae family. It is native to Europe and Asia, and has spread to North America.
The wingspan is 16-20 mm. The moth flies from June to October.
The larvae feed on apple species. It can defoliate apple trees and adversely affect fruit production for several years after an outbreak.
This species is difficult to separate adults from other Yponomeuta species, even by genital examination. The identification is more reliable if it is done on the basis of the plant larvae and some larval and pupal characteristics.
Y. larvae of malinellus at the beginning mine leaves of Malus, and then gregariously feeds on a silk cloth in May and early June. The larvae vary as they grow from dark gray to yellowish gray, and the size of the black spots changes. Different larvae can be found by sharing the same web. The full-grown larvae vary from 18 to 25 mm.
The white buds are arranged neatly side by side in a net under a leaf or twig.
The adult has pure white front wings (sometimes with a slight gray suffusion in the center), with black dots. The terminal cilia are usually a little gray, but they can be pure white. It has a white head with white palps.
Agronomic control measures: collection and destruction of fallen leaves in summer, elimination and burning of cloth nests with caterpillars and pupae. Biological control measures: introduction of the parasite Ageniaspis fuscicollis, application of biological preparations. Chemical control measures: treatments with insecticides (usually against a complex of lepidoptera harmful) in early spring, before the outbreak and before the departure of the caterpillars under the shields, and also at the end of the bloom of the apple , immediately after the falling of the petals. absence of treatments against the complex of plagues of lepidoptera of spring the population of Y. malinellus sometimes can surpass considerably the thresholds in some industrial orchards.