The current research was conducted to evaluate the effectiveness of clove and thyme essential oils (emulsion and nanoemulsion) and two biocides (Bio-Arc and Bio-Zeid) as fungicidal alternatives for the management of tomato early blight disease caused by Alternaria solani. The images obtained by transmission electron microscopy showed the stability of the prepared clove and thyme oil nanoemulsions after 12 weeks of storage at room temperature (27°C) in spherical form and di-disperse or mildly mono. The droplet size of clove essential oil nanoemulsion ranged between 36.0 and 51.3 nm, and between 25.1 and 44.6 nm in the case of thyme. In vitro tests, clove oil nanoemulsion at a concentration of 6000 μg/ml was the most effective treatment, which completely inhibited the mycelial growth of A. solani. In greenhouse and field conditions during 2018/2019 and 2019/2020 growing seasons, Bioxan 72% was the most effective treatment for reducing disease severity, followed by clove and thyme oil nanoemulsion, clove emulsion, and Bio-Zeid. Under field conditions, clove and thyme oil nanoemulsions had superiority for increasing no. of fruits/plant, mean of fruits weight/ plant, plant height, and tomato yield, followed by clove emulsion and Bio-Zeid in both growing seasons. On the other hand, clove and thyme oil nanoemulsions had superior activity for increasing peroxidase, polyphenoloxidase, catalase, β-1, 3 glucanase, and chitinase compared to the other treatments. Therefore, it could be suggested that clove and thyme oil nanoemulsion, clove emulsion, and Bio-Zeid could be used for controlling tomato early blight disease.