PBZ stands for paclobutrazole basically a growth retardant..in mangoes if water, nutrition especially N and Relative Humidity or in some cases variety are not limiting factors then mangoes keep giving new vegetation..basic role is after harvest one uniform & healthy vegetative flush is sufficient and it can only be achieved with pruning (synchronized vegetative flush) when it is achieved then PBZ is applied to help tree not to flush again in the same cycle “artificial induced dormancy: usually applied through collar drench then irrigated (No irrigation after this Until the end of Dec or Jan depending up on the temp and nutrient requirements of the tree) the cost/lit I think right now is 4000-6000 PKR and application rate is 30-50 ml/tree (depending upon the age of tree) but never applied to those trees which are under stress. Results good uniform flowering, good fruit retention and better quality..