A plant bio-stimulant is any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance, disease resistance and/or crop quality traits, regardless of its nutrients content. Certain aqueous plant extracts of five plants i.e., Neem (Azadirachta indica), Moringa (Moringa oleifera), Garlic (Allium sativum), Basil (Ocimum basilicum) and Eucalyptus (Cinnamomum camphora) extracts and fungicide (Dithane M-45) as well as tap water as control were evaluated as foliar spray under field conduction at Experimental Farm of Horticulture Department Faculty of Agriculture Menoufia University Shibin El-Kom, during fall seasons of 2018 and 2019 against Downy mildew disease caused by (Bremia lactucae), growth, yield, quality, water relation , photosynthetic pigments and some chemical analysis of lettuce plants cv. Balady (Local lettuce cultivar). The obtained results indicated that, application of plant extracts, and fungicide significantly decreased the disease severity, disease incidence and increased the growth characters and yield of lettuce plants.