(chemical name (2RS, 3RS)-1-(4-Chlorphenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol) is a plant growth retardant and triazole
fungicide. It is a known opponent of the plant hormone gibberellin
. It acts by inhibiting gibberellin biosynthesis, reducing internodial
growth to give stouter stems, increasing root growth, causing early fruitset and increasing seedset in plants such as tomato
and pepper. PBZ has also been shown to reduce frost
sensitivity in plants.
PBZ is used by arborists
to reduce shoot growth and has been shown to have additional positive effects on trees and shrubs. Among those are improved resistance to drought
stress, darker green leaves, higher resistance against fungi and bacteria, and enhanced development of roots. Cambial
growth as well as shoot growth has been shown to be reduced in some tree species.
PBZ is normally applied to the soil to be taken up by the roots and transported via the xylem
to the upper parts of the plant. Foliar application is mostly ineffective. Seeds can be soaked with PBZ to reduce seedling growth.
PBZ is the active component of Bonzi TM with 4g/l.