Insects feed on the roots, the stem base, and the leaves close to the ground. Plant growth is restricted. Plants wilt and die prematurely. Some of the plants get completely detached from their roots and are easily pulled from the soil.
Yellowish-white beetle larvae, up to 6 cm long, with dark-colored abdominal segments (May bug larvae, Melolontha spp.; Phyllopertha spp., Rhizotrogus sp., etc.), 3-4 cm long, brown-grey legless fly larvae with fleshy abdominal segments (cranefly larvae; Pales spp., Tipula spp.), or about 2.5 cm long, thin beetle larvae having a rigid cuticle (wire worms; Agriotes spp., Athous niger L., Melanotus brunnipes GERM.) can be found in the vicinity of the plants that have been affected.
Mainly at night, earth-colored, grey, or greenish-grey lepidopteran larvae (Scotia [Agrotis] spp.) feed on the tissues close to the ground. They spend the day curled up in the soil. Occasionally, the small, yellowish white larvae of the root fly (Delia [Phorbia] spp.) may cause the plant to die. In warmer climates, the mole cricket (Gryllotalpa vulgaris LATR. = Gryllotalpa gryllotalpa L.) and several millipede species (Blaniulus guttulatus [BOSC.], Cylindroiulus teutonicus [POCOCK], etc.) can seriously damage the roots. In humus-rich soil with a high proportion of decaying plant tissues (e.g., in gardener's substrates for the propagation of Roman chamomile), the larvae of the St. Mark's fly (Bibio spp.) may attack the plants.
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