Characterization of Puccinia horiana causing Chrysanthemum rust disease and its management by altering planting date and foliar application of fungicide

The five pathogenic isolates of Puccinia horiana causing rust disease in Chrysanthemum representing different growing areas exhibited diversity with respect morphological characters such as length and breadth of teliospores and basidiospores. In order to prove the pathogenicity, spore suspension preparation of P1 isolate was prepared using 0.1 M phosphate buffer, 1% Glucose and sterile distilled water and artificially inoculated on seedlings of Chrysanthemum. The disease symptoms were noticed on all the suspensions. However, spores suspension prepared using sterile distilled water resulted in least incubation period. All the five isolates were characterized using specific primers. The sequences of all isolates were submitted in GenBank with accession numbers MH656784.1, MH656785.1, MH656786.1, MH656787.1 and MH656788.1. In order to identify the effect of planting date on disease status, planting was done at different dates from May to October in open field conditions. It was observed that early planting would reduce the disease on seedlings. Further, various fungicides were evaluated to know their effect in field conditions for two years viz., 2017 and 2018. Among the fungicides, thiophanate methyl at 0.1 per cent resulted in maximum disease reduction in both the years and was followed by Propiconazole at 0.1 per cent. In addition to this, the same treatment could also improve the flower yield in both years.