This study was carried out to optimize and enhance the production of phytotoxic metabolites from Lasiodiplodia pseudotheobromae (C1136) for its herbicidal properties using solid-state fermentation with various agricultural wastes available in Nigeria. The results obtained showed that banana peel (10.12 ± 0.10 g/100 g) and wheat bran (9.89 ± 0.11 g/100 g) had the highest protein content. Banana peel was observed to have the highest value of phosphorus (0.30 ± 0.05 g/100 g), closely followed by wheat bran (0.23 ± 0.06 g/100 g). Higher values of arginine contents were obtained for rice bran (3.06 ± 0.06 g/ 100 g), groundnut wastes (2.98 ± 0.08 g/100 g) and wheat bran (2.38 ± 0.08 g/100 g). These values are significant (p\0.05). Endoamylase (64 U/g), exoamylase (50 U/g), isoamylase (43 U/g), protease (15 U/g), xylanase (12 U/g), cellulose (4.8 U/g) enzymes that were obtained from groundnut waste showed the best activities when compared to other substrates. It was observed that as the concentration of the extract increases so also are the radicle length, shoot length and germination rate on the tested seeds. Leaf necrosis assay showed that the phytotoxic metabolite from strain C1136 produced the largest necrotic area (3.2 ± 0.2 mm) on Amaranthus hybridus leaves when grown on groundnut waste. In comparison, the necrotic area of (2.5 ± 0.2 mm) was observed for Echinochloa crus-galli leave from phytotoxic metabolites grown on pineapple waste. The efficacy of the phytotoxic metabolites produced from strain C1136 in this study.