An application of biostimulants is becoming an increasingly popular operation in agriculture because they positively affect crop performance and qualitative characteristics, and prevent stress-related losses. The objective of this study was to determine the effect of an application of the following biostimulants: PlonoStart, Aminoplant, and Agro-Sorb Folium, and the herbicide Avatar 293 ZC on total carotenoids in table potato tubers. The research material consisted of tubers of two table potato cultivars, Oberon and Malaga, which were produced in a 3-year field experiment. Chemical analyses of fresh material were conducted 4–6 days following harvest. Biostimulants applied with the herbicide significantly increased the table potato tuber content of carotenoids compared to tubers obtained from unamended control plots. The highest accumulation of carotenoids was determined following an application of the biostimulant Agro-Sorb Folium, and it was higher in the tubers of cv. Oberon versus cv. Malaga. It should be added that in the available literature there is no research on the effect of biostimulants on the content of carotenoids in potato, which is the main food in the world. Carotenoids perform many important functions in the human body. They exhibit antioxidant properties, which means that they protect cells from damage, and also have a beneficial effect on the immune system. Carotenoids are substances that show an indispensable effect on the health and appearance of the skin. Regular consumption of them in the form of vegetables and fruits ensures its firmness, elasticity, smoothness, as well as a healthy appearance. The protective function of carotenoids against free radicals simultaneously contributes to slowing down the aging process. This action, in turn, translates into preventing the development of cancer or diseases of the circulatory system.

Rice blast is the main disease of rice plants in Indonesia and several countries worldwide. Controlling this disease using chemical fungicides has harmful effects on the environment. Therefore, we need biocontrol agents which are more environmentally friendly such as rice phyllosphere bacteria. This study aimed to explore bacteria producing bioactive compounds from the rice phyllosphere environment to control blast disease. A total of 88 isolates were successfully isolated from rice leaves in Sukabumi, Situgede, and Jasinga (West Java, Indonesia). From them, we obtained 22 bacteria isolates with antifungal activity against Pyricularia oryzae in vitro assay. In addition, seven non-pathogenic bacteria were obtained from further screening in hypersensitivity, hemolysis and pathogenicity assays, namely STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1, STGV 8, and SKBG 78. To show their antifungal activity, we tested crude extracts of these seven isolates and the results revealed that all the crude extracts can inhibit the growth of P. oryzae. Based on a genetic approach, isolates STGG 3, STGG 7, and STGG 14 were found to have both nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) genes, while isolate SKBV 1 only had the NRPS gene. The NRPS and PKS genes from potential isolates were similar to NRPS and PKS genes of Bacillus sp. in different strains. Furthermore, molecular identification based on the 16S rRNA gene revealed that the seven potential isolates belong to three genera, i.e. Bacillus (STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1), Enterobacter (STGV 8) and Brachybacterium (SKBG 78). We suggest that the seven isolates found in this study have potency and could be recommended as biocontrol agents of blast disease caused by P. oryzae.