HAUSTORIUM. A specialised fungal hyphae which penetrates the host and serves as an organ of attachment and suction.

HERBICIDE. A chemical used for the killing or inhibiting the growth of plants.

HOST. Any plant on which a parasite is living and obtaining its food.

HUMUS. Compounds which represent the end product of organic decomposition.

HYBRID. An organism produced by the crossing of two dissimilar parents.

HYDROPHOBIC. Nonwettable. Thatch, if heavy enough, may form a hydrophobic layer between the actively growing turf and the soil surface.

HYPHA. (Pl. Hyphae) A single thread or filament of fungal growth.