Table 3.

Growth and phytotoxic response of various woody species to six plant growth regulating chemicals.

Growth and phytotoxicity response^{^a}
Chemical	0	+	++	+++	++++	–
Daminozide	White pine, eucalyptus, red oak, sycamore		Silver maple, cottonwood, Norway maple, white ash		American elm
Dikegulac	White ash, black locust, redwood, black walnut	Eucalyptus, white pine, cottonwood, poplar, black cherry, quaking aspen	Sycamore, water oak, river birch	Silver maple, Australian pine	Red oak
Maleic hydrazide	Cottonwood, Norway maple, redwood, red oak, aspen, melaleuca, red maple, black walnut, tilip tree	White pine, pin oak	White ash, eucalyptus, Australian pine, black cherry	Sycamore, poplar, hackberry, black locust, river birch, willow	Silver maple, white oak
DOWCO 391	Eucalyptus	White ash	Silver maple, black locust, sycamore
Krenite		Black locust, eucalyptus				Silver maple, white ash, sycamore
NAA		Silver maple, white ash, eucalyptus	Sycamore

↵a The growth and phytotoxic response was classified into six categories: 0 = non-significant growth reduction with acceptable toxicity; + = significant growth reduction of 25% or less with acceptable toxicity; + + = significant growth reduction between 25 to 49% with acceptable toxicity; + + + = significant growth reduction between 50 to 74% with acceptable toxicity; + + + = significant growth reduction of 75% or greater with acceptable toxicity and; - = non-significant growth reduction and toxicity unacceptable.