Control of Sweet Pepper Anthracnose by Generally Recognized as Safe (GRAS) Substances in Combination with Heat Treatment

Abstract

Anthracnose disease caused by Colletotrichum gloeosporioides is a major problem of sweet pepper which reduces both its quality and shelf life. This research was conducted to study the effectiveness of Generally Recognized as Safe (GRAS, chemical or food additives) combined with heat treatment to control sweet pepper anthracnose disease. The GRAS substances had efficacy to control anthracnose disease of preinoculated treatment for 24 hr, then sweet pepper fruits were dipped in potassium sorbate, oxalic acid, propyl paraben and salicylic acid at four concentrations (100, 250, 500 and 1,000 mg/l) compared with dipping in prochloraz solutions at 100, 250 and 500 mg/l or water. The experimental design was a completely randomized design (CRD). Although, 250 mg/l oxalic acid solution could inhibit disease severity by 62.45%, the efficiency of GRAS compounds to inhibit disease severity was lower than prochloraz. To increase efficiency of disease inhibition, GRAS were combined with heat treatment. Sweet peppers dipped in 53 °C of 500 mg/l potassium sorbate for 7 minute had disease incidence only 35.00% and could inhibit disease severity at 91.45%. The pepper treated with 500 mg/l propyl paraben at 53 °C for 4 min. showed 88.83% disease severity inhibition while prochloraz inhibited by 84.86%.