Study the Effect of Toxicity of Several Plant Essential Oils on Saffron Stem Mite (Acari: Acaridae) Claparède Rhizoglyphus Robini under Laboratory Conditions

Saffron or red gold is a strategic agricultural product with a very high non-oil export potential. Considering the ban on the use of synthetic chemical poisons against saffron pests and the growing trend of planting this product in the country, as well as the importance of producing certified seeds of agricultural products, it is inevitable to find non-chemical ways to control the pest and produce certified saffron onions. Meanwhile, the saffron mite Rhizoglyphus robini Claparède is one of the most important pests of saffron, which causes great damage to onions and saffron crops every year. In the present study, the toxicity of four plant essential oils from the Asteraceae family, including Artemisia sieberi Besser, Acroptilon repens (L.), Cichorium intybus L. and Achillea millefolium L., was evaluated on the adult female species of the saffron mite in laboratory conditions. Bioassay was performed by fumigation method inside a 5 cm petri dish in total darkness, with a relative humidity of 70% and a temperature of 26 degrees for 24 hours. For each essential oil, 6 concentrations and 3 repetitions were considered for each concentration. The results of the bioassay by fumigation method showed that the essential oil of A.sieberiwith LC50 = 160.09 ppm has the highest and C. intybus essential oil with LC50 = 440.12 ppm has the lowest toxicity on saffron bulb mite. Also, the highest concentration slope was observed in A. repens essential oil (5.801±0.719) and the lowest was observed in the essential oil of A. sieberi and A. millefolium. Based on the starting point of toxicity, the essential oil of A. sieberiwith the highest intercept (-2.177±0.323) caused the fastest initial toxicity on bulb mite at a concentration of 33.21 ppm.