Effects of benzothiadiazole and acetylsalicylic acid on β‐1,3‐glucanase activity and disease resistance in potato

Abstract

Benzothiadiazole (BTH), as Bion WG50, and acetylsalicylic acid (ASA) treatments of potato foliage of field‐ and glasshouse‐grown potato plants were compared for control of two foliar diseases, early blight (Alternaria solani) and powdery mildew (Erysiphe cichoracearum). The effect of these treatments on harvested tubers wound‐inoculated with the dry rot fungus (Fusarium semitectum) was also evaluated. BTH (50 mg a.i. L−1) gave almost complete control of both foliar pathogens on inoculated glasshouse‐grown plants and reduced the severity of leaf spotting diseases (mainly early blight) in the field. BTH (100 mg a.i. L−1) and ASA (400 mg a.i. L−1) reduced the severity of dry rot in field‐grown tubers in some post‐harvest wound‐inoculated treatments but not others and a similar reduction occurred with tubers inoculated post‐harvest from BTH‐treated plants grown under glasshouse conditions. BTH treatment increased β‐1,3‐glucanase activity in leaves > stem > tubers > stolons but not in roots. Increased enzyme activity was recorded for up to 45 days post‐treatment.