Screening of ultraviolet protectants for Epicoccum purpurascens

In order to reduce the impact of UV on conidia of Epicoccum purpurascens strain XF1 and improve the biological activity of conidia in the field,the protective efficiency of ultraviolet protectant (UVP) combinations of 6 UV-absorbers and 4 light stabilizers against UV for conidia of E.purpurascens strain XF1 was tested in laboratory.The results showed that the protective efficiency of different UVP combinations was different,combinations of benzotriazole and hexamethyl phosphorus triamide (a3b1),and combinations of oxybenzone and hexamethyl phosphorus triamide (a4b1 and a5b1),were confirmed to be more effective than the other UV-protectants,with protective efficiency over 90% after 40 min exposure to UV light (at λ 253.7 nm),while that of combinations of salicylic acid benzyl ester and hexamethyl phosphorus triamide (a1b1) was only about 37.12%.UVP combinations without protective efficiency included combinations of salicylic acid benzyl esters and light stabilizer 770,benzotriazole and light stabilizer 770,benzophenones and light stabilizer 770 (a1b2,a3b2,a4b2,a5b2).The appropriate solvent combination was V (solvent n -hexane)∶V (peanut oil)=1∶1 for (a3b1,a4b1,a5b1).For the three UVP complexes selected,the effective concentration of a4b1 and a5b1 should be higher than 7.5 mg/mL,while that of a3b1 should be higher than 10 mg/mL.After 90 min and 180 min exposure of conidia to UV light (at λ 253.7 nm),the protective efficiency of the three selective UVP combinations were over 88% and 63%,respectively.