Efficacy evaluation of a neem (Azadirachta indica A. Juss) formulation against root-knot nematodes Meloidogyne incognita
2009
Ntalli, N.G. | Menkissoglu-Spiroudi, U. | Giannakou, I.O. | Prophetou-Athanasiadou, D.A.
The nematicidal-nematostatic activity of AzaNema, 1% azadirachtin, against Meloidogyne incognita was evaluated both with motility and pot bioassays at different rates equal or greater than that recommended for nematode control (6L ha^-^1). To avoid issues that could have interfered with efficacy, such as formulation inconsistency and storage instability, technical grade azadirachtin 11.8% was used to verify the test product's active ingredient (azadirachtin A) and to study the direct motility effect of azadirachtin on second stage juveniles (J2). Finally, the stability of both azadirachtin formulation types was studied under experimental conditions. Azadirachtin did not provide adequate control of nematodes, at the recommended or higher doses. In pot bioassays, a compensatory effect was achieved with 30.72@mg a.i g^-^1 of soil but, in general, one application per biological cycle failed to protect the plants from Meloidogyne incognita. In motility experiments, only exposure of J2 to doses higher than 12.8@mg a.i ml^-^1 resulted in a significant increase of immotile J2 for both AzaNema and azadirachtin technical grade. Nevertheless, the test product was found, after HPLC analysis, consistent with active ingredient content. Moreover, azadirachtin A concentration remained stable during the experiments, regardless of the formulation type tested. In conclusion, further research will be necessary to improve the efficacy of azadirachtin against Meloidogyne incognita.
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