TY  - EJOU
AU  - Ismail, Ahmed Mahmoud 
AU  - Elshewy, Eman Said 
AU  - Ahmed, Ayman Y. 
AU  - Darrag, Hossam M. 

TI  - Crude Extract of <i>Ulva lactuca</i> L., <i>Spirulina platensis</i> (Gomont) Geitler and <i>Nostoc muscorum</i> C. Agardh ex Bornet \& Flahault for Mitigating Powdery Mildew and Improving Growth of Cucumber
T2  - Phyton-International Journal of Experimental Botany

PY  - 2025
VL  - 94
IS  - 10
SN  - 1851-5657

AB  - Powdery mildew of cucumber (<i>Cucumis sativus</i> L.) is a destructive disease caused by <i>Podosphaera xanthii</i> (Castagne) U.Braun & Shishkoff. This study aimed to investigate the antifungal effect of extracts of <i>Ulva lactuca</i>, <i>Spirulina platensis</i>, and <i>Nostoc muscorum</i> against <i>P. xanthii</i> and to improve the physiological and morphological traits of cucumber under commercial greenhouse conditions. The chemical composition of the individual extracts from <i>U. lactuca</i>, <i>S. platensis</i>, and <i>N. muscorum</i> was analyzed utilizing High-performance Liquid Chromatography (HPLC) and Gas Chromatography/Mass spectrometry (GC/MS). Cucumber plants were sprayed twice with 5% of the crude extracts of <i>U. lactuca</i>, <i>S. platensis</i>, and <i>N. muscorum</i> and their mixture (<i>U. lactuca</i>, <i>S. platensis</i>, and <i>N. muscorum</i>). The fungicide Topas 100 EC (Syngenta) was applied at the recommended dose (0.250 mL/L) only for comparison. The HPLC analysis indicated that the <i>U. lactuca</i> extract was the richest in phenolic compounds (605.84 µg g<sup>−1</sup> DW) compared to cyanobacterial extracts of <i>S. platensis</i> (214.77 µg g<sup>−1</sup> DW) and <i>N. muscorum</i> (462.97 µg g<sup>−1</sup> DW). The GC-MS spectrum analysis of methanolic extracts revealed 12 compounds in <i>N. muscorum</i>, 11 compounds in <i>S. platensis</i> and 22 compounds in <i>U. lactuca</i> extract. In the 1<sup>st</sup> experiment, among treatments, the combined mixture (<i>U. lactuca</i>, <i>S. platensis</i>, and <i>N. muscorum</i>) and <i>U. lactuca</i> extract revealed the remarkable disease reduction attained 74.35% and 71.42%, respectively. However, the highest disease reduction was attributed to fungicide Topas 100 EC with value reached 85.28%. A similar pattern of results was also noted during the 2<sup>nd</sup> experiment. In both experiments, the extract of <i>S. platensis</i> had the lowest effectiveness in lowering the DS and AUDPC of powdery mildew disease. The combined mixture and <i>U. lactuca</i> extract resulted in a substantial (<i>p</i> < 0.05) increase in plant lengths, fresh and dry weights, leaves number, fruit number, and weight and yield/plant. Cucumber plants treated with either the extract of <i>U. lactuca</i> or the combined mixture exhibited the highest activity (0.084 and 0.088 U mL<sup>−1</sup>min<sup>−1</sup>) for peroxidase and (1.64 and 1.62 U mL<sup>−1</sup>min<sup>−1</sup>) for catalase, respectively, in the second experiment. The greatest increase in total phenolic content (7.97 mg g<sup>−1</sup> FW) was noticed in plants following treatment with the combined mixture. The treatment with <i>U. lactuca</i> and <i>S. platensis</i> revealed a significant increase in carotenoids contents, reached up to 17.99 and 17.53 mg g<sup>−1</sup> FW, respectively. We, therefore, support the need for considering sustainable management of powdery mildew of cucumber using the compounds derived from <i>U. lactuca</i>, <i>S. platensis</i>, and <i>N. muscorum</i> and to improve cucumber growth.
KW  - Antifungal; chemical composition; disease severity; enzymes; yield; greenhouse; phenolic compounds

DO  - 10.32604/phyton.2025.067444