Integrated Control against Rice Blast and Leaf Spot by Trichoderma harzianum and Two Fungicides

Abstract

Integrated pest management is performed at intervals of 10 days, during all the season of rice cultivation, by the application of Trichoderma harzianum at a concentration of 10 8 spores/ml, in alternation with the mancozeb at 1000 ppm against rice blast and rice leaf spot and the pyrazophos at 750 ppm against blast. The assessment of symptoms is performed at the beginning of the panicles appearance, by estimating the incidence of the disease and the symptoms severity. Thus, at the end of treatment programs, the alternation of pyrazophos and T. harzianum reduced blast at a rate similar to that noted when pyrazophos is used alone (i.e. respectively 90.5 and 89.1%). This percentage is better than that recorded following treatment by T. harzianum alone (78.4%). Mancozeb alternated with T. harzianum reduced blast at a rate of (83.49%) compared with the fungicide or the antagonist alone (77 and 78.4%). The application of mancozeb alone reduced the leaf spot at a rate similar to that noted following its alternation with T. harzianum (79.2 and 75.64%) and better than that obtained after treatment with T. harzianum alone (69.5%).