## 1 Introduction  
Lettuce (_Lactuca sativa_ L.) is one of the most economically important vegetable plants worldwide, and it is the most popular salad vegetable in Thailand [1]. The cultivation and production of lettuce are often obstructed by a leaf spot disease caused by _Cercospora lactucae-sativa_[1, 2]. Leaf spot disease is a common and destructive disease of lettuce that occurs mostly during the rainy season and leads to high yield losses of up to 80% [3]. Infection begins on the lower, older leaves and progresses to the younger leaves through the penetration of the fungal hyphae via leaf stomata. The lesions are light to dark brown and further characterized by light ash to white-colored spots and, later, holes in the leaves, a symptom unique to _C. lactucae-sativa_ on lettuce [4]. _C. lactucae-sativa_ is a slow-growing hemibiotrophic fungus with a narrow host range restricted to brassiaceae plants [4, 5]. To control leaf spot disease, fungicides are routinely used. However, fungicide usage has harmful effects and leaves residues on plants, humans and the environment [6]. Recently, non-thermal plasma (NTP) technology usage has expanded to new biological areas of application for the inactivation of harmful microorganisms, the preparation of ready-to-eat food and biofilm degradation, or in healthcare, the treatment of cancer cells, the initiation of apoptosis, prion inactivation, the prevention of nosocomial infections and the therapy of infected wounds [7, 8]. Plasma is an ionized gas, referred to as the fourth state of matter [7]. Plasma is a neutrally charged collection of ions, electrons, photons and atoms in their fundamental or excited states [9]. The plasma state can be produced by applying a high electric voltage to gas. Then, reactive species consisting of reactive oxygen species (ROS), reactive nitrogen species (RNS), charged species, UV radiation, free electrons and an electric field are generated in the plasma state, and these components can greatly affect biological processes [10]. Plasmas can be classified according to their temperature into two large groups: thermal plasmas and cold plasmas [11]. More specifically, low-temperature plasma can be distinguished into thermal plasma and non-thermal plasma (NTP) based on thermodynamic equilibrium [7]. NTP can be generated by different discharge configurators, such as atmospheric uniform glow, corona, dielectric barrier discharge, gliding arc, micro- hollow cathode, plasma jet and needle, by passing gases through electric fields [12]. The lethality of NTP depends on various processing variables, including input power (voltage and frequency), treatment time, gas type, flow rate and exposure mode. Higher frequencies and input voltages have been related to greater inactivation efficacy of NTP [13]. Gliding arc (GA) plasma is a hybrid plasma in which discharge takes place and is carried out between two divergent horn-like electrodes. Gliding arc plasma is produced as a low-impedance heat arc discharge at the narrow gap; it is then prolonged by the gas flow and quenched into a non-thermal plasma. The plasma cools down at the wide gap because no further discharge can take place. Accordingly, the primary plasma column disappears, and the travel cycle for the new plasma column is repeated [14]. Tesla coil (TC) is a self-resonance, self-breakdown discharge. The sharp electrode end generates a series of brief, transient pulses of electrical discharge to the surrounding gas; this is a short-lived phenomenon with a continuous cycle. Typically, it is much more efficient in gas dissociation with transient plasmas than with homogeneous plasmas [15]. Dielectric barrier discharge (DBD) plasma at atmospheric pressure is generally a nonuniform filamentary discharge. The formation and development of electric streamers arise from separated local sites of the dielectric barrier. Each streamer represents a so-called microdischarge, which is distributed in the gap and is unstable, moving around erratically [16].