Distribution and abundance of a new pest “root and bulb parasitic nematode” at different elevation levels and soil abiotic factors in garlic growing centres in central Java

The distribution of root and bulb parasitic nematode in garlic crops at various elevation and the effect of abiotic factors on their distribution were investigated. The survey was done at the centers of garlic production area in Central Java, Indonesia. Soil abiotic factors such as temperature, pH, and C-Organic were measured in each location of sampling. Nematodes were analyzed using incubation and white head tray technique modification. Correlation and regression were used to determine the effect of abiotic factors. The results showed that the five locations with different elevations were positive for Ditylenchus dipsaci distribution. These nematodes were found in various elevation with different populations in the range of 8.00-16.67 nematodes per 100 g of soil and 14.34 to 26.67 nematodes per 2 g of bulb. The highest density of the nematode population both in bulb and soil was in Tegal at elevation <1000 m a.s.l. while the lowest nematode population both in soil and root were found in Temanggung at an elevation of 1000-1200 m a.s.l. Abiotic factors, such as temperature has a positive correlation with D.dipsaci nematode populations in bulb and soil, while pH has a negative correlation with nematode populations. C-organic has a positive correlation in abundance of nematode populations in the soil and negative in abundance of nematode populations in bulb. © 2020 Trans Tech Publications Ltd, Switzerland.