Herbivores Mining and Chewing on Flowers

Beetles of the genus Meligethes (1.5 to 2.7 mm in length, metallic green, shiny blue-grey to blue-purple, or nonshiny black in color) generally feed only on mature pollen already released by the anthers and rarely damage single florets and their anthers.

Severely reduced drug quality is caused by different insect larvae mining within the receptacle. Larval feeding tunnels form more or less circular horizontal patterns in the tissue. The above growing disc florets are the first to wither. Later on the entire flower head turns brown and larvae move further down into the receptacle.

The head and abdominal end of Olibrus aenaeus FABR. larvae are dark in color. Larvae have their thoracic legs developed. Beetles emerge from the early summer on. They are 1.8 to 2.5 mm long and black, sometimes with a shining metallic-green appearance. The same type of damage is caused by the legless dark-headed larvae of the weevil Pseudostyphlus pilumnus GYLL. Adults are brown to brown-black with grey-white scales and 2.5 to 3.3 mm in length. In rare cases, larvae of the weevil Ceutorhynchus rugulosus HERBST (see Section 6.6.5) also mine the receptacle. Finally, larvae of the blossom boring fly Trypanea stellata FRUNSLEY cause a very similar type of damage to chamomile flowers. Larvae are legless with a light-colored head capsule.

Flower mining does not significantly reduce allover yield, but affects flower color and integrity and thereby drug quality.

6.6.7 Sap Sucking on Flowers

A large number of thrips species feed on chamomile flower heads. They are whitish to yellow-brown, slender insects (from 0.5 mm to a maximum length of 1.5 mm) with short legs, and sometimes fringed wings. Different species of grass thrips suck between the tubular florets and thereby impair flower head integrity. Single tubular flowers wither and turn brown. Thrips physapus L. and Thrips tabaci LIND. are frequently observed on chamomile. Again, this type of damage mainly reduces drug quality not yield.

6.6.8 Other Quality Deteriorations Caused by Insects

Various ladybug (Coleoptera: Coccinellidae) species colonize aphid-infested chamomile plants. Since their brightly colored wing covers are difficult to remove from the harvested plant material, chamomile marked value can be significantly reduced.

6.6.9 Stock Pests

A wide range of pests feeds on the dried chamomile flowers, depending on the climate of the country of origin and the storage conditions. In Central and South America, the tobacco beetle Lasioderma serricorne F. (Coleoptera) has been recorded. In South America the hay or cocoa moth Ephestia elutella HB (Microlepidoptera) infests the chamomile flowers. In central Europe the dry fruit moth Ploida interpunctella HB (Microlepidoptera) and the carpet moth Anthrenus verbasci L. (Coleoptera) are known to feed on the stocks.

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