Sisal leaf decortication liquid residue for controlling Meloidogyne javanica in tomato plants

The effect of sisal liquid residue (fresh and fermented) was evaluated in controlling the root-knot nematode (Meloidogyne javanica) in tomato plants. Bioassays were conducted in vitro with 100 mu L of an aqueous suspension containing 300 juveniles (J2) of M. javanica and 1000 mu L of sisal liquid residue. The treatments consisted of nematode immersion for 24 and 48 hours in sisal liquid residue, fresh or fermented, diluted in water to the final concentrations of 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5 and 20%, and nematicide Carbofuran at 350 mg/L of the active ingredient. Under greenhouse conditions, 4000 juveniles of M. javanica were inoculated on tomato plants grown in pots, and after one week, 100 mL of sisal liquid residue at concentrations of 0, 4, 8, 12, 16 and 20%, were added to soil around the tomato plants. Control treatments received either 100 mL of distilled water or 0.5 g of Carbofuran per pot. Forty days after inoculation, plants were harvested and evaluated for plant growth and root damage. In addition, the selective effect of sisal liquid residue on growth of beneficial soil microorganisms was evaluated. All concentrations of sisal liquid residue presented nematicidal effect, after 48 h of nematode exposure. A mortality rate of 100% was obtained for M. javanica juveniles exposed to liquid residue at a concentration of 20%. Application of increasing concentrations of both sisal liquid residues reduced the number of galls and egg masses per plant and per gram of roots, as well as the final population of M. javanica in soil. Growth of beneficial soil microorganisms was observed in soil amended with sisal fresh liquid residue, for all concentrations tested. The fermented residue caused inhibition of soil beneficial microorganisms. Future studies should be conducted to test the nematicidal effect on tomato plants under field conditions.