# Combined Effects of Vegetable Oil-, Micronutrient-, and Activated Flavonoid-Based Biostimulants on Photosynthesis, Nematode Suppression, and Fruit Quality of Cucumber (Cucumis sativus L.)

## TL;DR

This study shows that using natural biostimulants improves cucumber growth, reduces nematode damage, and boosts fruit quality in a sustainable way.

## Contribution

The study introduces a novel combination of biostimulants that effectively suppress nematodes and enhance plant performance.

## Key findings

- Nematode infestation was reduced by 66% in soil and 41% in roots.
- Photosynthesis and plant vitality improved significantly compared to conventional treatments.
- Cucumbers had higher sugar, ascorbic acid, and better flesh consistency and color.

## Abstract

The agricultural industry faces increasing environmental degradation due to the intensive use of conventional chemical fertilizers, leading to water pollution and alterations in soil composition. In addition, root-knot and cyst nematodes are major constraints to cucumber production, causing severe root damage and yield losses worldwide, underscoring the need for sustainable alternatives to conventional fertilization and pest management. Under greenhouse conditions, a four-month cultivation trial evaluated vegetable oil-, micronutrient-, and activated flavonoid-based biostimulants, applying Key Eco Oil® (Miami, USA) via soil drench (every 15 days) combined with foliar sprays of CropBioLife® (Victoria, Australia) and KeyPlex 120® (Miami, USA) (every 7 days). Results showed reduced parasitic nematodes by 66% in soil and decreased gall formation by 41% in roots. Chlorophyll fluorescence and infrared gas analysis revealed higher oxygen-evolving complex efficiency (38%), increased PSII electron transport, improved the fluorescence decrease ratio, also known as the vitality index (Rfd), and higher CO2 assimilation compared to conventional treatments. Processed cucumbers showed higher sugar and nearly double ascorbic acid content, with improved flesh consistency and color. Therefore, the application of these bioactive products significantly reduced nematode infestation while enhancing plant growth and physiological performance, underscoring their potential as sustainable tools for crop cultivation and protection. These results provide evidence that sustainable bioactive biostimulants improve plant resilience, productivity, and nutritional quality, offering also an environmentally sound approach to pest management.