Abstract
Olive is a blessed and therapeutic fruit cultivated all around the globe in relatively temperate and dry regions. Keeping in view the quality and yield of the crop, use of pesticides is indispensable. Traditional pesticides used against crop enemies are effective but unsafe to environment, humans and predators. Olive fields of Saudi Arabia are the biggest in the world and facing infestation due to rapidly increasing number of diverse mite species. Recently, four mite species, Tegelophus hassani, Aceria olive, Oxycenus niloticus and Tetranychus urticae found to be causing severe damage to the plants, have been identified in the olive fields of Saudi Arabia. Huwa-San TR50 is a well-known water disinfectant and considered to be safe as its adverse effects on plants have not been reported as yet. The present study has been conducted to evaluate the use of Huwa-San TR50 as an acricide against four olive mites and two of their predators under laboratory and field conditions. Five different concentrations of Huwa-San TR50; 1000, 2000, 3000, 4000 and 5000 ppm were used based on previous studies to observe mortality of the selected phytophagous mites namely T. hassani, A. olive, O. niloticus and T. urticae. Gradual increase in mortality was observed when mites were treated with Huwa-San TR50 in the concentration range of 1000 - 5000 ppm. Optimum concentration of Huwa-San TR50 to be used against the mites was found to be 4000 ppm as there was negligible increase in mortality beyond this concentration. T. urticae was relatively resistant to Huwa-San TR50 with mortality of 76.58% at optimal concentration. Huwa-San TR50 has effectively impacted egg hatching especially in case of O. niloticus, where successful hatching was only 20%. Eggs of T. urticae are relatively resistant showing 57.97% hatching. The same trend and similar results of mortality and egg hatching were obtained under laboratory and field trials. As an essential part of this research, effect of Huwa-San TR50 was also observed on two predatory mites namely; Phytoseius plumifer and Agistemus exertus and it was found to be relatively safe to predatory mites showing mortality of 30 to 34% at optimum concentration. Again there was insignificant difference in mortality and egg hatching under field and laboratory conditions. Huwa-San TR50 being eco-friendly, safe to predatory mites and an effective acaricide against olive mites and their eggs is recommended for its commercial use in olive orchards.