Effect of Antagonists and Plant Extracts in the Control of Protea Wilt (<i>F. oxysporum</i>)

Abstract

In laboratory experiments were evaluated TRICHOD ® , FOLIGUARD ® , Trichoderma sp, and watery extracts of pine, marigold and eucalyptus, respectively, against F. oxysporum. There were no significant differences between TRICHOD ® and FOLIGUARD ® . The extract of marigold of 120 g/L was the best result in reducing the area of the colony of F. oxysporum. In field pots experiment were evaluated the extract of marigold (120 g/L), potassium phosphite (400 g/L), TRICHOD and benomyl (1.5 g/L) to control F. oxysporum. Treatments were applied to the soil, 15 days after inoculation with F. oxysporum. The best obtained heights were of 32 cm with extract of marigold 120 g/L, followed by potassium phosphite with 31 cm, and the control reached 26 cm of height. The treatment with an extract of marigold 120 g/L, obtained the best dry weight average of 6.5 g, statistically different from the control. The extract of marigold presented the best efficiency against the disease, because it reduced the length of the vascular symptom in 88.5%; followed by TRICHOD ® , benomyl and potassium phosphite that showed reductions of 86, 85 and 84 percent, respectively.