No abstract

Common bean (Phaseolus vulgaris L.) is one of the main Brazilian agricultural crops. Numerous diseases have affected such a crop during its life cycle, such as white mold, caused by Sclerotinia sclerotiorum. This fungus is quite aggressive and requires an intensive use of pesticides. This study aimed at evaluating white mold control and antimicrobial activity against S. sclerotiorum using extremely diluted aqueous solutions of Phosphorus and Calcarea carbonica, at 6CH, 12CH, 24CH, 36CH and 48CH dynamizations (centesimal Hahnemannian). The tests were carried out in a completely randomized design, with 10 treatments and 5 replicates each, considering water as control. Variables including disease progression, the number of dead plants, the number of sclerotia, and mycelial growth were evaluated by in vivo and in vitro tests. The treatments Phosphorus 12CH, Phosphorus 48CH, Calcarea carbonica 12CH, and Calcarea carbonica 48CH presented resistance-inducing action by slowing down the disease progression up to 83% and decreasing the number of dead plants up to 90%. In vitro tests showed that the treatments Phosphorus 12CH, Phosphorus 48CH and Calcarea carbonica 48CH slowed down the mycelial growth. The latter also completely inhibited the production of sclerotia. These results indicate the potential of Phosphorus 12CH, Phosphorus 48CH, Calcarea carbonica 12CH, and Calcarea carbonica 48CH for controlling S. sclerotiorum in common beans.

Alternative methods for the control of nematodes, such as the use of plant secondary metabolites, can be explored for integrated pest management systems. The objective of this work was to assess the best solvent for obtaining allyl isothiocyanate from Crambe abyssinica leaves, and the effects of this extract on Meloidogyne incognita and M. javanica. Dry leaves of C. abyssinica at 200 mg L -1 were used to prepare extracts by using water (by infusion and grinding), acetone, water + ethanol (hydroalcoholic extraction), methanol, hexane, and chloroform as solvents. Following the evaporation of the solvents, the residue was resuspended in water for use in the experiments. Distilled water and chemical nematicide were used as control treatments. Once the most effective extracts were defined, the following dosages of dried crambe leaves were used: 0, 200, 300, 400, and 500 mg L -1 . High performance liquid chromatography (HPLC) was used to quantify the allyl isothiocyanate present in the extracts. After the solvents evaporated, the residues were eluted with water and used in assays with 200 eggs for the hatching test or 200 second stage juveniles (J2) for mobility and mortality tests. The hydroalcoholic extract was the most effective in reducing the hatching of M. incognita and M. javanica juveniles, by 71.6 and 74.4 percentage points, respectively. The mortality of M. incognita and M. javanica in the hydroalcoholic extract was 93.2 and 64.4%, respectively, followed by the methanol extract (17.6 and 34%) and the extract obtained by grinding (9.2 and 28%). The hydroalcoholic extract at 250 mg L -1 showed high nematicidal effect. The HPLC analysis of the extracts revealed that only the methanol and hydroalcoholic extracts had allyl isothiocyanate, indicating that the inhibitory effects on the hatching, mobility, and mortality were not solely attributed to the presence of this compound.

Common bean (Phaseolus vulgaris) is one of the main Brazilian agricultural crop. It is affected by numerous diseases during its life cycle; one of these includes the white mold caused by the fungus Sclerotinia sclerotiorum. The objective of this study was to verify the control of white mold in bean plants by homeopathic medicines. Two tests were performed: In the first test, the medicine Calcarea carbonica was used, while phosphorus was used in the second test. Both medicines were administered at dynamizations of 6, 12, 24, 36, and 48 CH (Hahnemanniana Centesimal). In the control treatment, 30% hydroalcoholic solution was used. The study was conducted using a completely randomized design, analyzing the following variables: Area under the disease progress curve and percentage of dead plants. The results were submitted to Tukey's test and regression analysis (p > 0.05). Calcarea carbonica at 6 CH and Phosphorus at 6 CH, 12 CH, 24 CH, 36 CH, and 48 CH reduced the intensity of white mold in bean plants. With the exception of Calcarea carbonica at 12 CH and 24 CH, no other medicine reduced the percentage of plant death due to white mold disease.

Root-knot nematodes (Meloidogyne