The Impact of Resistance Enhancement in Tomato Plants on Tetranychus urticae Life history traits

Abstract

The duration of developmental stages and life table parameters of the two spotted-spider mite; Tetranychus urticae Koch were carried out at the laboratory on 27±3oC and 65±5% R.H. on leaves of two tomato hybrids; Supper-gekal and Salymia treated with improve resistance compounds, (Potassium humates, Potassium silicates, Salicylic acid and Methyl jasmonate) and untreated plants as control. These compounds used in enhancement resistance in tomato plants are significantly related to oviposition and developmental rates of T. urticae and playing an important role in the direct defence to the mite. The adult longevity and fecundity of T. urticae, female decreased when reared on leaves of two treated tomato hybrids than leaves of untreated. The net reproductive rate (Ro) of T. urticae, decreasing when rearing on leaves of two the tomato hybrids treated, averaged (22.96, 24.87, 27.20, 23.45 & 19.10, 13.38, 19.65 and 18.45 females/female /day respectively, compared with rearing on leaves of untreated tomato hybrids (control) averaging 48.17 and 37.72 females/female /day respectively. Also, the intrinsic rate of natural increase (rm) showed similar trend as the net reproductive rate (Ro). The thickness μm of the epidermis, parenchyma cells and components in sponge and palisade parenchyma cells (cellular wall, chloroplasts, intercellular space and sgnumerous starch grains) where affected by these compounds used in resistance enhancement in tomato plants, investigated them with transmission electron micrograph.