Control of <i>Pestalotiopsis</i> Leaf Spot of Palms by Fungicides, Plant Hormones, and Biological Agents

This study investigates fungal leaf spots of palm, an ever-present threat to the nursery and floriculture industry. Fungicides, plant hormones, and biological agents were used to consider their implications for <i>Pestalotiopsis</i> leaf spot disease management in palms. A survey of different locations in Pakistan's Kasur and Faisalabad districts was conducted, collecting data on disease incidence of debilitating leaf spot disease in <i>Roystonea regia</i> (royal palm) and <i>Ravenea rivularis</i> (ravenea palm). Pathogenicity tests were performed on healthy seedlings using <i>Pestalotiopsis</i> sp. The results indicate that the fungicide Flumax with 86.11% growth inhibition of the pathogenic fungus and the biological agent <i>Trichoderma asperellum</i> with 76% growth inhibition have a significant impact in suppressing pathogen growth. Compared with the fungicide or salicylic acid (SA) application alone, the combined application of SA with 50% less fungicide (Flumax) in an integrated program significantly reduced disease severity to 5.9 and 6.2% in royal and ravenea palms, respectively. Our findings highlighted that integrated disease management (IDM) could be crucial in addressing <i>Pestalotiopsis</i> leaf spot disease. Adapting to IDM can improve the aesthetic value and profitability of palms by allowing a reduction in fungicide use while maintaining effective control of the disease.