Bioscience Methods 2026, Vol.17, No.1, 1-8 http://bioscipublisher.com/index.php/bm 5 in potato plants. This strain can persist stably within plant tissues and is less affected by external environmental factors, such as UV radiation and rain wash-off, thereby ensuring its continuous action within the plant. The strain not only inhibits Phytophthora infestans but also exhibits insecticidal activity against the Colorado potato beetle (CPB). By expressing the Cry1Ia toxin, the strain demonstrates potent insecticidal activity against pests. When insects feed on plant tissues containing the 26DCryChS strain, the Cry1Ia toxin disrupts the insect’s gut cells, causing severe intestinal damage and ultimately leading to insect death (Figure 2). Figure 2 Mesenteron structure of L. decemlineatabeetles 24 h after feeding of potato plants, which contained cells of Bacillus strains. Scale bars, 200 μm. (I) Healthy larva; (II) bacteriosis on alive larva on the 5th day after eating of plants containing Bacillus sp. (Adopted from Sorokan et al., 2020) 5.3 Control of rhizoctonia root rot Rhizoctonia root rot, caused by Rhizoctonia solani, is another significant disease affecting potato crops. Bacillus subtilis EG21 has shown strong antagonistic potential against both P. infestans and R. solani. The strain produces cyclic lipopeptides, such as surfactins, which exhibit antifungal and anti-oomycete activities. Microscopic examinations have revealed extensive damage to R. solani mycelium upon interaction with EG21. The cell-free culture filtrate (CF) of EG21 has been found to be chemically stable and effective in inhibiting the growth of both pathogens under various conditions (Alfiky et al., 2022). Field applications of EG21 have confirmed its disease-inhibiting effects, making it a promising candidate for integrated pest management strategies aimed at controlling Rhizoctonia root rot and other potato diseases. 6 Challenges and Limitations of Biocontrol Agents 6.1 Variability in field performance One of the primary challenges in the application of biocontrol agents for managing potato pests and diseases is the variability in their performance under field conditions. While laboratory and greenhouse experiments often show promising results, translating these findings to the field has proven problematic. For instance, biocontrol agents such as Bacillus sp. JC12GB43 have shown near-complete inhibition of pathogens in controlled environments but exhibited variable efficacy in the field due to differing environmental conditions (Cray et al., 2016; Yang, 2024). Similarly, the endophytic microbe Fusarium oxysporum 47 (Fo47) demonstrated effective biocontrol in laboratory settings, but its performance in large-scale field trials was inconsistent, highlighting the challenge of maintaining inoculum viability and effectiveness in diverse agricultural environments (Constantin et al., 2020). This variability necessitates extensive field trials and optimization of application methods to achieve reliable results.
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