Survival of Alternaria porri (ELL.) CIF. on shallot's leave debris in the field in dry season

Abstract

The objectives of the research was to study the survival of Alternaria porri in various burial depth periods under field condition in the dry season. The treatment were arranged as a factorial experiment in a randomize complete block design with two factors and four replications. The first factor was burial depth i.e. 0, 5, 15 and 25 cm, and the second factor was burial periods i.e. 0, 2, 4, 6, and 8 weeks. The infected leaves as much as 7 g were placed in the soil at particular depth. Survival of a porri was determined by assessing conidia producing ability of leaf debris. Physical and microbiological properties of soil in the experimental field were also recorded. Burial depth and periods dignificantly affected the survival of A. Porri, but there was no interaction between the two factor. The lowest survival of occured at the burial depth of 2 of leaves debris5 cm, followed by the burying at 0, 15 and 5 cm. With respect to burial periods only 8-week burial treatment in the dry season could reduce A. Porri survival 50 fold, the ability of leaves debris in producing conidia remained high i.e. 104 conidia/sampel. The decreasing in survival of A. Porri in infected leaf debris corresponded with the increase in soil water content and the abudance of total soil microorganism.