Onion is affected by several biotic and abiotic stresses. This study aimed to evaluate the impact of onion seed priming with different plant extracts. The results show that neem leaf extract treated seeds exhibited the highest mean seedling establishment (71.50 per cent), seedling length (11.21 cm), seedling dry weight (15.88 mg) and seedling vigour indices (800.70 and 1135.27). The biochemical analysis of primed seedlings showed significant enhancement in enzymatic and non-enzymatic antioxidants. Purple blotch caused by Alternaria porri is the most important foliar disease of onion leading to significant losses. The evaluation of plant extracts against Alternaria porri showed that neem leaf extract at a concentration of 25 per cent inhibits mycelial growth of pathogen by 81.18 per cent. The GC MS analysis of the crude extract of neem indicated the presence of forty different chemical compounds, among which the main components included Benzene, 1,4-bis (phenylmethyl)- (15.05%), Naphthalene, 1,6-dimethyl- (10.98%), 3-(2,4-Dimethoxyphenyl) butan-2-one (8.63%) and Phytol (7.99%). Evaluation of the four promising botanicals viz., neem, congress grass, turmeric and ginger under field conditions indicated foliar sprays of neem leaf extract to be effective in both managing purple blotch disease (23.08 per cent disease management) and enhancing yield attributes (5.24 per cent seed yield increase). This study establishes the antimycotic and plant growth promoting potential of neem leaf extract for managing onion purple blotch.

洋葱受到多种生物和非生物胁迫的影响。本研究旨在评估不同植物提取物对洋葱种子引发的影响。结果表明，印楝叶提取物处理的种子表现出最高的平均幼苗建立率（71.50％）、幼苗长度（11.21厘米）、幼苗干重（15.88毫克）和幼苗活力指数（800.70和1135.27）。引发的幼苗的生化分析显示酶促和非酶促抗氧化剂显着增强。由Alternaria porri引起的紫斑病是洋葱最重要的叶部病害，导致重大损失。对植物提取物抗黑斑病的评价表明，浓度为25%的印楝叶提取物可抑制病原体菌丝生长81.18%。印楝粗提物的GC MS分析表明存在40种不同的化合物，其中主要成分包括苯，1,4-二（苯甲基）-（15.05％），萘，1,6-二甲基-（ 10.98%）、3-（2,4-二甲氧基苯基）丁-2-酮（8.63%）和植醇（7.99%）。四种有前途的植物药的评估，即。田间条件下的印楝、国会草、姜黄和生姜表明，叶面喷施印楝叶提取物可有效控制紫斑病（23.08％的病害控制）和提高产量（种子产量增加5.24％）。本研究确定了印楝叶提取物在防治洋葱紫斑病方面的抗真菌和促进植物生长的潜力。