The effect of aqueous extract of walnut green shell against root knot nematode Meloidogyne javanica and growth characters of tomato

In recent decades, many researches have been done to achieve plant compounds to replace chemicals against nematodes. In this study, the nematicidal and allelopathic effects of walnut green shell was studied in order to achieve effective, safe and economical methods for control of root knot nematode Meloidogyne javanica on tomato. In vitro and in vivo studies were conducted. Different concentrations of the extract significantly inhibit hatching and increased mortality rate of nematode larvae. The highest percentage of hatching inhibition in vitro was 75.5% and observed when treated with 25% extract. After 48 h of treatment 100% of larvae were killed by 20% and 25% concentration of extract. In green house, the virulence factors of nematode including gall index, the number of egg masses and the number of larvae in the soil were reduced significantly compared with the control. The results showed the extract concentrations of 5%, 10% and 15% significantly reduces virulence factors of root knot nematode compared to the control without a negative impact on plant growth characteristics. Overall, the results indicated that the aqueous extract of walnut green sell have high nematicidal ability.