Polyphenol and flavonoid contents of Parkinsonia aculeata L., extracts: Phytotoxicity in tomato

Parkinsonia aculeata L. (palo verde) it is native to semidesert region and seasonally dry tropical forests. A more detailed study of the biochemical composition of its organs could offer information for its use for pest and disease biocontrol in species of agricultural and economic interest. This research aimed to determine the content of polyphenols and flavonoids in hydroalcoholic extracts obtained from the stems and leaves of P. aculeata and its phytotoxicity in tomato seedlings applied at the early stages of growth. The extracts were applied at 15, 25 and 35 days after emergence (DAE). The highest content of polyphenols and flavonoids was obtained in the leaves, and the polyphenol concentration exceeded that of flavonoids. The hydroalcoholic extracts, of both stems and leaves, presented level 5 phytotoxicity in tomato plants at 15 DAE. However, from 25 DAE, there was no phytotoxicity. At 35 DAE, there was only phytotoxicity when the volume of both organs was 5 mL Plant-1. There was a significant interaction between organ and volumes factors. The study shows that leaf and stem extracts can be used for fusarium wilt biocontrol without causing phytotoxicity in tomato plants from 25 days, using volumes between 1 and 3 mL plant-1.