*3.3. Fungicidal Activities*

The in vivo fungicidal activities (EC<sup>50</sup> values) of compound **6**, compound **7,** positive control fenclorim and pyrimethanil against *B*. *cinerea* are listed in Table 6. Compound **6** displayed the greatest activity with an EC<sup>50</sup> value of 20.84 mg/L, which was much greater than that of compound **7** (215.45 mg/L), fenclorim (319.95 mg/L) and pyrimethanil (30.72 mg/L). This result indicates that the combination of the (*Z*)-methyl-2-iodo-3-methoxyacrylate group substituted phenoxyl group with fenclorim could improve the in vivo fungicidal activity of fenclorim against *Botrytis cinerea*.



To further study the fungicidal activity of compounds **6** and **7**, the in vitro inhibitory rate of compounds **6**, **7**, fenclorim, and pyrimethanil against *P. cubensis*, *E. cichoracearum*, *B. graminis*, *R. Solani*, and *P. polysora* were evaluated at different concentrations (Table 7). At 200 mg/L, compound **6** displayed the strongest fungicidal activity against *P*. *cubensis*(94.00% control) and against *R. Solani* (91.67% control), while compound **7** showed the strongest fungicidal activity against *E*. *cichoracearum* (91.00% control), *B*. *graminis* (90.67% control) and *P***.** *polysora* (90.67% control). Furthermore, fenclorim exhibited no activity against the *E***.** *cichoracearum* control and pyrimethanil only displayed good fungicidal activity against *P. cubensis* (89.00% control). As the concentration decreased, most of the fungicidal activity of these compounds brought to gradually. Surprisingly, compound **6** exhibited 80.33% activity of that of the control against *P. cubensis*, when pyrimethanil displayed only 20.67% of that of the control, when at 25 mg/L. These results revealed that the combination of active groups in commercial fungicides with the lead fenclorim could improve the in vitro fungicidal activity of fenclorim significantly.


**Table 7.** The in vitro fungicidal activities of compounds **6** and **7**.

*P. cubensis: Pseudoperonospora cubensis; E. cichoracearum: Erysiphe cichoracearum; B. graminis: Blumeria graminis; R. solani: Rhizoctonia solani;* and *P. polysora: Puccinia polysora*.
