Spinosad is a bioinsecticide with a high degree of selective toxicity towards insects of different orders, but its toxicity towards the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is under debate. In this study, we compared the acaricidal properties of spinosad with the commercial bioacaricide abamectin on the life stages of TSSM. Adulticide and ovicide bioassays were performed on a susceptible laboratory strain using direct spraying of leaf disks with five rates of spinosad (20, 25, 30, 35 and 40 mg/l), five rates of abamectin (0.125, 0.25, 0.5, 1 and 2.5 mg/l), sublethal concentrations or a combination of spinosad and abamectin. Both adulticidal and ovicidal effects of spinosad against T. urticae in the laboratory were apparent, based on morality rates of the adults, reduction of female fecundity and death of offspring. Abamectin was also found to significantly reduce female fecundity and killed offspring when applied directly on the eggs. Interestingly, sublethal concentrations of spinosad reduced female fecundity stronger than abamectin. When a mixture of spinosad and abamectin was applied at LC50, mortality was 74%, fecundity reduction was comparable to abamectin alone and egg hatching rate was lower than by either compound alone. In conclusion, spinosad was more harmful than abamectin for TSSM life stages and the combined application is recommended.

A comparison was made for studying the effect of some Essential oils: Rosemary, Garlic, Jojoba and Fixed/Vegetable oils on the important mite pest, Tetranychus urticae. The sublethal concentrations of Rosemary oil (0.125%), Garlic oil (0.5%), Jojoba oil (0.25%) and Vegetable oil (0.125%) were used. Biological tests were carried out for a susceptible laboratory two-spotted spider mites strain reared under controlled conditions of 27±٢°C; 60% R.H. and 16L/8D photoperiod on Sweet Potato leaves. Results showed that Garlic oil caused the highest significant decrease in the number of deposited eggs as compared to the other tested oils. All the oils used have no effects on females mite fertility. Vegetable oil greatly affected the percentage of nymphs that reached adult stages followed by Jojoba oil then Garlic oil while Rosemary had no effects on nymph's developments. Results were tabulated, analyzed, discussed and prepared to be fit in any IPM program for combating these pest animals.

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Certain effects of different spectral light colors were studied on some biological attributes of the two-spotted spider mite, Tetranychus urticae. Rearing of animals was carried out under conditions of 27±0.5°C; 60% R.H. and 16 L/8 D photoperiod on Sweet Potato leaves. Thus, 5 artificial light colors were applied under controlled laboratory conditions on these animals: blue, red, green, yellow and white Neon. After treatment, the highest number of deposited eggs/female was observed by using the blue color (14.9±0.5 eggs/female) while the lowest one was the yellow (3.1±0.2 eggs/female) compared to 9.9±0.4 eggs/female for the control group. On the other hand, diapause incidence was observed for the target females under conditions of 18±2°C; 60±2% R.H. and the light and dark periods were set at 8 L/16 D, respectively. Results showed that white Neon color caused the highest percentage of diapausing females (88.66±1.8%) followed by green color (78±3.5%), yellow (68.66±2%), the blue color with (54±2%), and finally none of them entered diapause under red color. Results were analyzed and discussed for the aforementioned important economic pest animals.

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