Systemic action of benomyl against late‐wilt disease of maize.

Abstract

SUMMARY Benomyl (methyl‐I‐(butyl carbamoyl)‐2‐benzimidazole carbamate) at 2.5 to 100 ppm completely inhibited the growth in vitro of Cephalosporium maydis Samra, Sabet & Hingorani, the causal fungus of late‐wilt of maize. In pot experiments, late‐wilt was controlled by applications equivalent to 10 ppm benomyl/unit wt dry soil at sowing but not by applications 30 days after sowing or by seed treatments (dusts and dips). A fungitoxic substance was detected in benomyl‐treated soil, planted with maize, 120–150 days after treatment and for 150–180 days in unplanted soil. Sap expressed from maize grown in benomyl‐treated soil was also fungitoxic, especially that from the roots and distal parts of the leaf blades. In the field, soil applications of benomyl to 10 kg/feddan (4200 m 2 ) failed to control late‐wilt. Tests indicated little fungitoxicity in the sap of maize plants 25 days after sowing.