2024/25 results of target spot control in soybeans released

In the 2024/2025 harvest, cooperative trials carried out by 16 research institutions in 19 locations demonstrated that the appropriate use of fungicides significantly increased soybean productivity, even under high incidence of target spot, caused by fungus Corynespora cassiicola.

The most effective treatment (T8, a product not yet registered) achieved an average productivity of 4.576 kg/ha, an increase of 25% compared to the control without application (3.664 kg/ha). In the same statistical group is the treatment with Fox Supra + Milcozeb (T13), with 4.409 kg/ha.

Other treatments with high productivity were methyltetraprole + difenoconazole + Tróia (T7), Fox Ultra + Milcozeb (T12), Fox Xpro + Milcozeb (T10), Almada (T14), Evolution (T15), Curatis (T16) and metominostrobin + prothioconazole + Manfil (T5). The FRAC fungicide rotation program also showed consistent results, with 4.271 kg/ha.

Disease control at a high level

Target spot affected all experimental areas with severity above 20% in the control. Treatment T8 was also the most effective in controlling the disease, with a 68% reduction in severity. Followed by T10 (62%), T12 (60%), T14 (59%) and T13 (57%).

The addition of mancozeb proved to be advantageous. For example, treatment T4 (metominostrobin + prothioconazole) had 45% control, and with mancozeb (T5) this rose to 54%. A similar trend was observed in the pairs T6/T7, T9/T10 and T11/T12.

High correlation between control and productivity

The joint statistical analysis showed a significant negative correlation (r = -0,95) between target spot severity and productivity. This reinforces the importance of chemical control and the appropriate choice of active ingredients.

Recommendations for sustainable management

Resistance monitoring carried out by FRAC identified lower sensitivity of the fungus to fungicides. To avoid the selection of resistant strains, researchers recommend limiting the use of succinate dehydrogenase (ISDH) inhibitor fungicides to two applications per cycle and prioritizing mixtures with multisites and rotation of modes of action.

The trials used cultivars susceptible to target spot. Selecting resistant materials is one of the first prevention strategies. The use of treated seeds, rotation with grasses and monitoring of weather conditions complete the set of measures.