Effectiveness of onion germplasm, fungicides, and plant extracts in managing purple blotch disease of onion

Abstract

In the present study conducted at Ayub Agricultural Research Institute, Faisalabad, ten specific onion lines were evaluated for disease resistance against purple leaf blotch. The variety Phulkara emerged as the top performer with the lowest disease incidence of 6.57% and an AUDPC value of 55.67, indicating resistance to this disease. Various fungicides demonstrated differing effects on disease management. Copper hydroxide proved to be the most effective at 0.10%, reducing disease incidence from 17.59% in the first spray to 12.70% in the third. The second-best fungicide was trifloxystrobin 25% + tebuconazole, which reduced disease incidence from 67.51% in the first spray to 61.67% in the third compared to the control. Among all plant extracts, three sprays of Nicotiana tabacum extract at S/50, S/25, and S/15 proved to be most effective, reducing disease incidence from 43.51% to 35.59%. Similarly, Moringa oleifera extract reduced disease incidence from 42.61% to 35.70% compared to the control. These findings suggest that the onion variety Phulkara, copper hydroxide fungicide at a concentration of 0.10%, and extracts of N. tabacum and M. oleifera exhibit promising potential in managing purple leaf blotch disease in onions. However, further studies are necessary to corroborate these results and to fully understand the biological and chemical implications of their usage.