LARVA. The immature, wormlike stage of insect development.

LEACHING. The washing of soluble materials from the soil by the downward movement of water.

LAI (Leaf area index).

LAI =

area of leaves area of soil over which they grow

LC50. The concentration of a pesticide in the air that will kill 50 of a test population that breathes it. (LC stands for lethal concentration).

LD50. The amount of pesticide taken orally or dermally required to kill a test population. Expressed in terms of mg/kg of body weight. A low LD50 indicates high toxicity.

LEMMA. A bract that encloses one grass floret and usually ends up as the outer hull of the grass seed.

LIGNIN. A hard, woody component of some grass stems. Lignified stems in a thatch layer make it almost totally resistant to normal decomposition.

LODICULE. A minute perianth part in the grass flower which swells at anthesis to spread the palea and the lemma and open the flower for pollination.