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n. A chemical plant growth regulator, C6H12N2O3, formerly used to increase the storage life of fruit, and currently used as a growth retardant for azaleas, chrysanthemums, and other plants.

n. a chemical sprayed on fruit trees to regulate their growth so the entire crop can be harvested at one time

"Consumers Union criticized the FDA for using antiquated and insensitive laboratory techniques that could not measure Alar below 500 parts per billion ppb, stating in Consumer Reports: "Looking for daminozide [Alar's a trade name] in apple juice with PAM II [the test method used by FDA] is like trying to catch speeders with a radar gun that doesn't work for speeds under 100 mph.""

chemical substance    chemical