Phosphorus Phthalocyanine as Eco-friendly Photoactive Insecticide Enhanced by Fucoidan Against Fruit Fly

A metal-free and degradable photoactive insecticide was developed using tetracarboxyl dihydroxyl phosphorus (VI) phthalocyanine (PPc(COOH)4) as sensitizer. The addition of fucoidan enhanced the phototoxicity and uptake of PPc(COOH)4 by the insects. The maximum lethality of PPc(COOH)4/fucoidan against Drosophila melanogaster (fruit fly) was 100% with an LC50 of 5 × 10−6 mol L−1. PPc(COOH)4 was decomposed by 95% on spinach leaves under natural irradiation for 24 h, and thus, it has the potential to be a safe insecticide for vegetables and fruit. The use of phosphorus phthalocyanine can achieve effective lethality against fruit fly under light irradiation. Fucoidan can enhance the phototoxicity and uptake efficiency of phosphorus phthalocyanine. The phosphorus phthalocyanine can be degraded in 3–4 days under natural condition, indicating its safe and eco-friendly properties as an insecticide.