The Effective of Potassium Phosphite Silica Protective Fertilizer on Nutritional Responses and Control of Two Spotted Spider Mite on Strawberry (Fragaria x ananassa)

Pesticides consumption, especially in fresh-use crops creates some concerns. The aim of this study is to investigate the effect of chemical synthesis of essential and quasi-essential elements along with complexing compounds and their effects on pest control of two spotted spider mite in Strawberry. Treatments included the combination of virogard commercial fertilizer in two concentrations (2 and 5 per thousand, recommended by the manufacturer) and protective fertilizer synthesized in this study at a concentration of 10 per thousand (effective concentration determined in the pre-test) and the combination of protective fertilizer + pesticide (half permissible concentration) and control treatment (distilled water) in two stages of application of fertilizer treatments (pre-infested and post-infested plants to mites) with six replications which were performed in greenhouse conditions. In the growth period after fertilizer application, the death mites percent was estimated by Henderson-Tilton formula. Also, after three months, the plants were harvested and some morpho-physiological and nutritional characteristics were measured. Determination of nutrient concentrations of potassium, phosphorus and silica in aerial parts of the plant as well as determination of pH and titratable acidity, Vitamin C, Total Soluble Solids and Antioxidant Levels of Fruit as Postharvest Properties of Strawberries were also measured. The highest death percentage of mite (79.2%) was due to the protective fertilizer + acaricide treatment in both stages before and after plant infestation to mite. The synthesized fertilizer had the greatest effect on fresh and dry shoots weight.  Virogard composition at 5/1000 concentrations, It had the greatest effect on fresh and dry weights. The highest concentration of potassium (29.26 g/kg) was belong to protective fertilizer+ acaricide and the highest concentration of phosphorus (6.48 g/kg) and silicon (753 mg/kg) was belong to the synthesized protective fertilizer individually. Considering the efficacy of the compounds used, it is recommended to use these compounds as inducers of plant resistance in order to reduce the use of pesticides and improve the product quality.