Achieving improved control of foliar diseases of sesame (Sesamum indicum L) intercropped with maize (Zea mays L) through foliar spray of plant extracts

摘要

Field trials were conducted to evaluate the effect of foliar spray of aqueous extracts of Tithonia diversifolia or Ocimum gratissimum on Cercospora leaf spot (CLS) and Alternaria leaf blight (ALB) diseases of sesame intercropped with maize. Spraying regime was at 2 weeks interval from 3 weeks after planting (WAP) until 12 WAP. Extracts of T. diversifolia or O. gratissimum reduced the incidence and severity of both diseases. CLS incidence and severity as well as defoliation was significantly (p < 0.05) reduced below what obtained in the unsprayed intercrop. ALB lesion size was significantly (p < 0.05) reduced by I diversifolia extract at 8.0% (w/v) from 154.7 mm~2 (sole crop) or 13.4 mm~2 (unsprayed intercrop) to 4.9 mm~2 (sprayed intercrop). T. diversifolia extract at 8.0% (w/v) enhanced higher values of grain yield/plant and incidence of normal seeds, and lower incidence of fungal infection of seeds than in the unsprayed intercrop.