Control of root- knot nematode in olive by nematicides and Tricoderma isolates

Root-knot nematode, Meloidogyne speceis is one of the five important plant pathogens in the world due to the wide distribution, host diversity, and interaction with the plant bacteria and fungi. Species M. javanica in some of olive orchards and also in 75 % of olive licensed nurseries of Khuzestan province have been detected during recent years. Olive trees and seedlings infested with nematode show chlorosis and slowdown. In order to control of the nematode, effect of granular and liquid nematicides compared with Trichoderma spp. on olive seedlings cv Baghmalek in greenhouse conditions were done during 2010-2013. For the selection of fungal isolates superior in two separate experiments, the effects of fungal parasitism and volatile metabolites of fungi were carried out with 8 treatments and 4 and 3 replicates on water agar medium 2% and sugar cane molasses respectively. Isolate 4 of T. longibrachiatum (Tl4) was selected according to 90 % of parasitism of eggs and larvae, and 68 % of mortality rates of larvae. In the greenhouse experiment, impact of four nematicides, Aldicarb, Oxamyl, Cadusafos and Sodium tetratiocarbonate concentrations of 6 PPM and Tl4 with 2 concentrations of 106 and 107 spores per ml on nematode were compared with 2 control treatments (with and without nematode) in 4 replicates. The results indicated that Aldicarb and Oxamyl treatments reduced, 51 and 49 of the gall index, 64 and 60 of the number of egg masses, 73 and 64 of the number of nematode females and 47 and 28 percent of the population of nematodes in the roots respectively, compared to the control. Although Tl4 isolate reduced the number of egg masses, the female nematode per root, number of galls on the roots and nematode population in root and soil, but the decrease was less than the nematicide treatments.