The effect of Tetranychus urticae Koch (Acari: Tetranychidae) infestation on some plant nutrients and growth parameters of common bean under laboratory conditions

We investigated the effect of two-spotted spider mite Tetranychus urticae Koch infestation on some nutrient elements and growth parameters of common bean plants under laboratory conditions (28±2 °C, 65±10% RH, photoperiod of 16/8 (L/D) h). Three different plant growth stages (young: 2nd trifoliate-leaf formation, middle: pre-flowering, old; fruit formation) were infested with four mite densities (0, 20, 40, 80 (adult mites/plant)) and four replications per treatment in completely randomized design were used. The infested plants were left for 14 days, and then macro-(P, K, Ca, Mg) and micronutrients (Fe, Cu, Mn, Zn, B) in leaf samples were determined, number and length of leaves and height and dry weight of plant were recorded. The lowest phosphorus content (0.19%) was recorded in the old stage of the plant in the treatment with a density of 40-mites, while it was 0.29 and 0.25% in the young and middle stage, respectively. However, the lowest potassium content (6.59%) was observed at the density of 40 mites and in the young stage. As the density of mites increased, the calcium content in the plant decreased, but no change in the magnesium content. Micronutrients did not significantly vary with mite density, except for copper, which showed a difference. The increase in mite density resulted in an increase in the plant dry weight and a decrease in plant height and leaf length. This study may further suggest fertilization programs might help to overcome nutrient deficiencies in crops due to mite infestation.