2,4-Diacetylphloroglucinol is a polyketide antibiotic discovered in Pseudomonas fluorescens, exhibiting broad-spectrum toxicity against bacteria, fungi, oomycetes, nematodes, and plant pathogens.

2,4-Diacetylphloroglucinol (0–100 μM, 0–4 days) inhibited primary root elongation, promoted lateral root formation, and induced necrosis at the primary root tip along with purple stress phenotypes in the hypocotyl when applied to Solanum lycopersicum and Solanum melongena seedlings. Its mechanism of action is associated with the regulation of auxin signaling pathways [1].
2,4-Diacetylphloroglucinol (0–40 μg/mL, 0–6 hours) was capable of suppressing the formation and motility of zoospores in Plasmopara viticola and Aphanomyces cochlioides [2].

2,4-Diacetylphloroglucinol (0–100 μg/mL, incubation treatment for 0–7 days) exhibited toxic effects on adult Xiphinema americanum, with an LD50 of 8.3 μg/mL. It also inhibited the egg hatching rate of Meloidogyne incognita, but displayed a unique phenomenon of stimulating egg hatching during the early incubation period in Caenorhabditis elegans [3].