Effect of chitosan on root-knot nematode, Meloidogyne javanica on tomato plants

In our study two different chitosan with low and high molecular weight at different dilutions i.e. standard, 1:1, 1:2, 1:3, 1:4, 1:5 and 1:10 were evaluated against root-knot nematode, Meloidogyne javanica in vitro and in vivo under greenhouse conditions. In vitro results revealed that both chitosan with all used concentrations significantly reduced the egg hatching when compared to control. No hatched eggs were shown with the standard concentration of both chitosan. The high molecular weight chitosan gave no significant results in egg hatching with the most evaluated concentrations i.e. standard, 1:1, 1:5 and 1:10 compared to the control. In vitro results revealed that both low and high molecular weight chitosan significantly affected the larvae mortality of M. javanica at all evaluated dilutions concentrations compared to control. Results found that standard, 1:1 and 1:2 dilutions were the most effective concentrations of the high molecular weight chitosan as they prevent completely the larvae to live. In vivo results revealed that both chitosan with all evaluated concentrations significantly reduced nematode parameters i.e. number of galls, females, developmental stages/root system and number of juveniles/250 g soil. Standard concentration of the high molecular weight chitosan was the highest effective one on nematode parameters as the reduction percentage was 92, 97, 92, 88 and 79%, respectively. The same trend of results was recorded with the antioxidant enzymes i.e. peroxidase and phenoloxidase as the standard concentration of both chitosan was encouraged the contents of enzymes compared to the treated plants with nematode alone. Results found also that both chitosan at all evaluated concentrations markedly enhanced the plant growth parameters i.e. root and shoot length and weights compared to the plants treated with nematode alone.