CONTROLE DE Monosporascus cannonballus POR TIAZOLIDINA-2,4-DIONA E EFEITO SOBRE O AGENTE DE CONTROLE BIOLÓGICO Trichoderma spp

The objective of this study was to evaluate the effect of the synthetic compound Thiazolidines-2,4- dione on the ¿in vitro¿ development of Monosporascus cannonballus, the causal agent of the melon sudden wilt (vine decline) and Trichoderma sp., the biocontroller agent of the referred pathogen. The work was done through two experiments. In the first experiment the following concentrations of the composition were used: 0, 25, 50, 75, 100, 125, 150, 175 ìg.mL-1, combined with four isolates of M. cannonballus. The evaluated variables were mycelial growth inhibition (MGI), mycelial growth rate (MGR) and area below mycelial growth curve (ABMGC). In the second experiment the effect of the same concentrations of the synthetic compound were analyzed regarding a Trichoderma sp isolate. In the first experiment, there was a significant interaction between concentrations andisolates. High correlation coefficients confirmed the agreement of combination among the variables. The progress curves of the variables, according to compound concentrations, were adjusted by polynomial models. The most efficient concentration was 75 ìg.mL-1,, for inhibiting the mycelia growth until the experiment end, except for the Mc4 that showed TCM of 5.07. Regarding other isolates, Mc 3 was the least resistant, as with concentration of 50 g.mL- 1showed TCM of 2.36, while Mc1, Mc2 and Mc4 presented a higher growth rate, being 8.48; 8.08 and 8.97, respectively. The recommended dosage of the compound for the inhibition of M. cannonballus development when measured in vitro is 153 ug.mL .Neither concentrations influenced the mycelial development of Trichoderma sp.,as it didn¿t differ from control (P=0,05), demonstrating the potential of this synthetic compound as a complementary form of Monosporascus cannonballus control, together to the Trichoderma spp.