Managing the fruit size of tropical pumpkin with chemical and microbial root stimulants

A microbial formulation based on Azotobacter and Clostridium (Invigorate™) and a root stimulant formulation based on protein hydrolysate, humate, and glucoheptonate (Essential Plus 1-0-1™) were tried in Puerto Rico to determine their effects on the tropical pumpkin cultivar ‘Taina Dorada’. The formulations were applied as soil drench at the beginning of flowering. The rates evaluated were 0 (check), 1, 2, and 3 mL of microbial formulation L^‑1 water, and 5, 10 and 15 mL of the root stimulant, using 200 mL plant^‑1, repeating the treatment after 2 weeks from the first application. Plants treated with the root stimulant at the rates of 10-15 mL or with the microbial formulation at the rate of 3 mL L^‑1 water had significantly larger fruits than both control plants or those that received other bioregulator. This research showed that the bioregulators evaluated may be useful in increasing the fruit size of ‘Taina Dorada’ tropical pumpkin.