Synergistic effect of metham and solarization in controlling delimited shell spots of peanut pods

Necrotic spots of uncertain aetiology are frequent on peanut (Arachis hypogaea L.) shells in alluvial and loessial soils in Israel. Metham delivered by sprinkler irrigation, solarization by polyethylene tarping (solar heating of soil), and the combination of the two treatments, were employed in summer, and peanut (groundnut) was seeded the following spring. Although the total yield (approximately 5 t/ha) was not affected significantly, the percentage increase in yield of pods without necrotic spots, by metham (900 l/ha), solarization and the combined treatment, was 114%, 440% and 893%, respectively, over the control. Reduction of disease severity of affected pods was especially evident with the combined treatment, even at a reduced metham dosage. Synergism between metham and solarization, in reducing the incidence of symptoms and in increasing healthy yield, was subsequently verified.