Investigation of the nematicidal activity of native beauveria bassiana and metarhizium anisopliae isolates on root-knot nematode meloidogyne incognita

Root-knot nematodes (Meloidogyne spp.) cause damage to almost all cultivated plants and cause serious problems. This study was carried out to determine the activity of native entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae on root-knot nematode, Meloidogyne incognita in greenhouse. Sensitive tomato and cucumber varieties were used as cultivars in the studies. Beauveria bassiana YK23, YK26 and Metarhizium anisopliae YK41 and YK45 isolates was applied to pots containing root-knot nematode tomato and cucumber seedlings at 1x105, 1x106 and 1x107 spore ml-1 concentrations. Experiments were carried out with 5 repetitions for each group. Three control groups were set as positive control (nematode treated), negative control (untreated) and bio-nematicide treated control. The trials were carried out in accordance with the randomized blocks trial design. At the end of the trials; plant height (cm), plant fresh and dry weight (g), root fresh and dry weight (g) were determined for each, plant isolate and dose. Damage from root-knot nematodes was assessed using the Zeck gall formation scale. Entomopathogenic fungi are expected to show significant nematicidal activity on root-knot nematode. B. bassiana and M. anisopliae displayed significant reduction on the gall formation and larval density in tomato and cucumber plants. The gall index was 8.00 for control, but this ratio decreased gradually to 3.20, 2.00 and 2.20 for B. bassiana, M. anisopliae and P. lilacinum in tomato, respectively. The highest reductions (%) in gall formation (control index) were estimated as 59.40, 75.20 and 74.48 % in these species, respectively. In control, gall index was 7.60, but decreased gradually to 3.60, 2.00 and 2.20 for B. bassiana, M. anisopliae and P. lilacinum in cucumber, respectively. The highest control indexes were 51.63, 71.71 and 70.95% for these species, respectively. In control, the number of the second instar juveniles of M. incognita was recorded as 2240 in tomato. However, this value reduced to 508, 332 and 328 by B. bassiana, M. anisopliae and P. lilacinum, respectively. The highest control indexes for the second instar juveniles were 77.13, 85.16 and 85.27% for these species, respectively. The number of the juveniles of M. incognita was recorded as 2320 for control in cucumber, but this value reduced to 524, 356 and 332 by B. bassiana, M. anisopliae and P. lilacinum, respectively. Likewise, the highest control indexes were 77.29, 84.90 and 85.65% for the same applications, respectively. The results showed that B. bassiana and M. anisopliae can be considered as an alternative in controlling plant parasitic nematodes.