Preliminary study on non-chemical management factors for bulb mite Rhizoglyphus robini (Acari: Acaridae) control in the saffron crop

Saffron is the most expensive agricultural product and like other products, is affected by some limiting factors, including soil pests such as bulb mite Rhizoglyphus robini Claparede (Acari: Acaridae). Due to its polyphagous habit, it remains in the soil for a long time and is one of the most important pests of saffron. To determine the effect of non-chemical management factors including soil solarization days, fertilization and year on the population of bulb mite and yield of saffron, a split-plot experiment based on a randomized complete block design in three replications was conducted between 2007 and 2011 in Gonabad, Iran. Fertilization (Cow manure) of zero, 20 and 40 t/ha as the main plots and soil solarization of zero, 10, 20, 30 and 45 days as sub-plots were studied for four years. The results showed that simple and interaction effects of the three factors including year, fertilization and soil solarization days on the population of bulb mite and saffron yield were significant. Simple linear regression was fitted between the population of bulb mite and saffron yield as well as multiple linear regression for population of bulb mite and saffron yield separately. The population of bulb mite increased during the experiment by increasing the two factors of the year and fertilization separately. Whereas, with increasing soil solarization days, population of bulb mite decreased except for 10 days solarization treatment and, unexpectedly, in 45 days of solarization treatment, the population increased in the fourth year.