Ação de herbicidas sob trichoderma e eficiência da inoculação em mudas de mamão

Abstract

Fungi of the genus Trichoderma present potential for the control of phytopathogens and to promote plant growth. Different research cultures prove this ability and aggregate information about the mechanisms of action of these bioagentes, however, are still little known mechanisms of action in promoting growth in the absence of plant pathogens. In addition, the chemical control of plant diseases is not fully effective, since the pathogen penetrates the vascular tissue of the plant. Given this, this work had as objectives in three chapters presented, evaluating the fungitoxicidade of the herbicides Glyphosate and Sulfentrazone on the mycelial growth and sporulation of Trichoderma isolated from the soil in Tocantins; determine the effect of inoculation of Trichoderma in papaya seedlings in the greenhouse and assess spore count and viability of conidia of Trichoderma in different species using two substrates, rice (Oryza sativa) and pearl millet (Pennisetum glaucum). The herbicide glyphosate did not affect mycelial radial growth of the isolates UFT 202 and UFT 204, for other isolated herbicides promoted a small reduction in the number of spores of Trichoderma. For the inculação in all the isolates papaya provided plant growth in all the analyzed variables, with and without natural phosphate, comparing with the witness. The isolated UFT 201 was superior to the dry mass, the isolated UFT 202 to root dry mass and MIX to total dry mass with phosphate. Without natural phosphate isolate MIX was superior to others in all variables. The reviews on substrates after an incubation period of seven days, note that the isolates UFT 25, UFT 63, UFT 313 and UFT 14 were those who obtained the highest sporulation with averages ranging from 2.3 x 109 (UFT 14) and 2.7 x 109 (UFT 25) spores g-1 in brown rice and 3.9 x 109 (UFT 79) spores g-1, in millet. The isolates UFT 313, UFT 14, UFT 37, UFT 79, UFT 201, UFT 205 and UFT 314, demonstrated excellent sporulation and viability among the substrates, with percentages of 98 to 100% germination of the conidia mL-1, and 94 to 100% UFT 313, UFT 79, UFT 205, UFT 25, UFT 201 and UFT 37 in millet. For the compatibility test the isolates UFT 25 x UFT14, UFT25 x UFT313, UFT 63 x UFT37 demonstrated interaction UFT significant by comparison test by mixed culture between mycelium.