Darnel

DARNEL (golovolom, drunken bread), Lolium temulentum L., a plant of the grass family that is a frequent weed contaminant in seed grain of wheat, barley, oats, and millet; distributed everywhere except for the southern and eastern parts of the USSR. The seed is oval-elliptical in shape, resembles oats but is smaller, and is equipped at one end with a long hair-awn (see figure). The size of the grain in husks is 4.5–7 mm, the length of the awns 3.5–15 mm. The seeds of darnel contain a poisonous substance, temuline, which causes painful intoxication and dizziness. However, the toxic principle of darnel cannot be considered established with complete certainty. Some authors are inclined to attribute the toxicity of darnel to fungi parasitizing it. This is indicated by the frequent presence of fungal mycelium in the grains of darnel, as well as the circumstance that darnel does not always possess toxic properties. The detection of darnel in wheat and other grain crops is based on morphological characteristics and is performed by sorting a specific weighed sample of the material, isolating the discovered darnel grains, and weighing them.

Darnel: a - grain from the front; b - grain from the back; c - natural size of the grain.

Reliable methods for discovering darnel admixture in flour do not yet exist. It should be noted, however, that it is possible to detect darnel husks and hairs in flour by treating the latter according to Hartwich's method, namely by 15-minute boiling of 5.0 of flour in a mixture of 10 cm³ of strong HCl and 20 cm³ of distilled water. After settling, the sediment is examined under a microscope. Preparations from crushed, knowingly known darnel seeds should be prepared beforehand for comparison. There are no special measures for combating darnel as a poisonous weed, but those general measures recommended for combating weeds in general can be successfully applied against the development of this plant as well. For this purpose, purification of the seed material is recommended (sorting by weight using winnowing machines, sorting by size using sieves, sorting by shape in trieurs). These measures can reduce the weed content in the seed material a hundredfold. To avoid contamination of fields with weeds from balks, field margins, and roads, it is necessary to keep the named places clean. Good results are obtained by destroying those seeds that are already present in the soil, which is achieved by repeated plowing of unseeded fields.

F. Okopov