Using Bacillus thuringiensis and Trichoderma harzianum in Managing Root-knot Nematodes (Meloidogyne incognita) on Tomato Crop under Pot Conditions

Abstract

The study was conducted to evaluate the nematicidal effects of three local Bacillus thuringiensis and Trichoderma harzianum isolates to control root-knot nematodes, Meloidogyne incognita, on tomato plants, under shade conditions. Molecular diagnosis was conducted to identify the three local Bacillus thuringiensis and Trichoderma harzianum isolates, as well as Meloidogyne incognita. Universal primers were used to amplify the ITS region, 16S rRNA, and 28S rRNA. B. thuringiensis, T. harzianum isolates, and M. incognita were identified and documented using sequencing techniques based on their ITS, 16S rRNA, and 28S rRNA genes. The results of the sequencing of the three local isolates of T. harzianum, B. thuringiensis, and M. incognita were deposited at NCBI under the accession numbers PQ069313.1, PQ069314.1, PQ069315.1, PQ069308.1, PQ069309.1, PQ069310.1, and PQ6008991, respectively. The results of the pot trial revealed that the lowest gall index and reproduction factor, as well as the highest shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, plant height, and root length of tomato were observed with the combination treatment of Bt isolate Sh.Sa.3 (30 ml) + Th isolate Sh.Sa.6 (30 ml) and were in the ranges of 0.33, 0.515, 82.67 g, 21.72 g, 15.25 g, 3.66 g, 93.67 cm, and 36.33 cm, respectively, compared with control groups and other treatments. The results showed that all isolates, both pre-nematode inoculation and post-nematode inoculation, had significant effects on root gall index and enhanced plant growth parameters compared with control groups.