Abstract
Rot in the root system is one of the main diseases of melon, which causes significant losses in yield. Therefore, increasing plant resistance levels can be a viable strategy for the management of this disease. Thus, the objective of this study was to know the physiological and biochemical effects of resistance elicitors on melon cultivated in an area with history of root rot. During the study, three experiments were conducted, one preliminary in masonry beds and two identical under field conditions. In the preliminary experiment, three abiotic elicitors (salicylic acid, Agro Mos® and Bion®) were applied alone and associated with a biotic elicitor (Compost Aid®). The treatments that promoted the lowest disease severity levels were selected (unpublished data), and the field experiments were conducted on a melon-producing farm. In the field experiments, a randomized block design was used, with five treatments and four replicates with eight plants each. The treatments were: standard (Management adopted by the farm), Bion®, Compost Aid®, Bion® + Compost Aid® and absolute control. Epidemiological, biochemical and physiological variables were evaluated. The association Bion® + Compost Aid® reduced the disease severity index by 68.1 and 65.4% compared to the absolute control and the standard, respectively. The elicitors Bion® + Compost Aid® when applied in association activate plant defense through increments in peroxidase, catalase and polyphenol oxidase enzymes and positively influence gas exchange and chlorophyll content.