TRICHODERMA HARZIANUM AS GROWTH STIMULATOR AND BIOLOGICAL CONTROL AGENT AGAINST BACTERIAL LEAF BLIGHT (BLB) AND BLAST OF RICE

Abstract

Rice blast and BLB diseases caused by Pyricularia oryzae and Xanthomonas oryzae respectively has a significant impact on rice yield and quality worldwide. Biological disease control has been shown to be one of the most effective ways to manage rice diseases. The present study was conducted at Rice Research program, CSI, NARC, Islamabad to evaluate the in vitro and in vivo management of BLB and rice blast diseases by Trichoderma harzianum. T. harzianum inhibits almost 58% mycelial growth of the P. oryzae and 50% colony growth of X. oryzae. Effect of T. harzianum on seed germination was observed on agar media at three different concentrations (10⁶, 10⁸, and 10¹⁰). T. harzianum at concentration of 10¹⁰ showed enhancement of plant growth; the maximum root length augmented from 38 to 47% and the shoot length was 15 % in KSK-434 and 44% in other three varieties as compared with control. Plant growth were examined under the impact of Volatile Organic compounds of T. harzianum. Root and shoot length were increased 24 to 48% and 15 to 39%, respectively compared with control. In the in vivo management, T. harzianum applied on the rice plants sown in pots. The disease pathogens Xanthomonas oryzae and Pyricularia oryzae were inoculated in rice plants, T. harzianum controlled the diseases at two concentrations i.e., 10⁸ and 10¹⁰. The disease was controlled 70 to 77% as compared to control. It was concluded that the characters as plant height, panicle length, number of tillers, and number of grains per panicle and yield of rice also increased with the application of T. harzianum. T. harzianum may serve an efficient biological agent in rice crop to mitigate the diseases stress.