Maize white spot, caused by the bacterium Pantoea ananatis, is one of the main leaf diseases of maize in Brazil. However, until now, its presence in corn seeds has not been detected. In this study, P. ananatis was detected in corn seeds using a semi-selective culture medium. A bacterial suspension of P. ananatis was serially diluted ten-fold and plated on 523, YDC or semi-selective PA20 media, with or without the addition of methyl thiophanate. The detection of bacteria in seeds was evaluated in three seed lot samples, collected from field maize plants with white spot symptoms. Seed washings were prepared, ten-fold serially diluted and plated on the same three culture media. Addition of methyl thiophanate to 532, YDC and PA20 culture media did not inhibit bacterial growth. Pantoea ananatis was detected in two corn seed samples on YDC and PA20 media, which was confirmed by biochemical, physiological and molecular characterization as well as by pathogenicity tests. This is the first report of P. ananatis detection in corn seeds.

Passion fruit wilt, caused by Fusarium spp., is one of the most severe diseases for this crop. Although yellow passion fruit is propagated mostly by seeds, the use of rootstocks tolerant to early death could be a management strategy for cultivation in areas with disease history. Thus, this study characterized Fusarium isolates obtained in Triângulo Mineiro and determined the most suitable genotype to use for grafting to reduce losses caused by this pathogen. Mycelial growth and sporulation of Fusarium isolates, in three different growth media, was quantified by measuring colony diameter and by counting the conidia in Neubauer chamber 10 days after growth in malt extract-agar 2%, PDA or CMA at 22 ± 3ºC and 12 hours lighting. Five days later the color of the colonies was evaluated. The experimental design was a 4x3 factorial completely randomized design, with five replications. Characterization of morphological structures of isolates was done with minimum cultivation in Malt extract-agar 2% amended with sterilized soil + sand (1:1). Three Passiflora species and two seedling types were used as rootstock to evaluate field resistance to fusariosis, in a randomized block design, as a 3x2 factorial, with three Passiflora species (P. alata, P. setacea and P. edulis) and two seedling types (ungrafted or grafted with P. edulis). The medium PDA was the least favorable for mycelial growth of the isolates. The best medium for conidium production was Malt extract and the most sporulating isolates were Fus-01 and Fus-02. Isolate color varied from white to pink to violet. Only Fus-02 and Fus-04 formed macro and microconidia. Shape, dimensions and septa number of macroconidia and microconidia, as well as the presence of characteristic monophyalides allowed the classification of all isolates as Fusarium oxysporum f.sp. passiflorae. Passiflora alata and P. setacea, used as rootstocks for P. edulis in the field, were resistant to fusariosis. Despite its low survival, P. edulis grafted on itsef, promoted similar growth of secondary branches as P. setacea in the field.

Significant losses in agricultural production are due to abiotic stresses, such as herbicide phytotoxicity. Dicamba (diglycolamine salt) is a herbicide used for post-emergent control of broadleaf weeds. It has a possibility to vapor-spread into neighboring fields causing damage to other crops. However, not every stress can be easily identified. Therefore, remote sensing has the potential as a new tool in early injury detection. This study evaluated the effects of simulated dicamba drift on the occurrence of phytotoxicity in soybeans (Glycine max). Soybean was assessed in seven dicamba doses (0, 0.056, 0.56, 5.6, 11.2, 28, 112 g ha⁻¹) for changes in plant injury (scale of notes), spectral aspects (triangular greenness index (TGI), and shoot dry mass. The plants were photographed using a digital camera positioned at 1.2 m above the planting media level. The results indicate a positive effect of low dicamba doses (0.56 and 0.056 g a.e. ha⁻¹) on TGI canopy distinction and shoot dry mass. Soybean TGI canopy distinction and the injury scale estimated at 45 days after sowing, and the soybean shoot dry mass observed at 99 days after sowing, presented significant and moderate Pearson’s r coefficient of correlations (r = −0.609 and 0.625), indicating TGI as a valid and practical spectral index for plant dicamba-injured evaluations.

Diante de sua grande importância econômica, quando se pensa no manejo da seringueira, deve-se dar grande atenção aos problemas fitossanitários que podem contribuir para redução na produção. Todavia, pouca atenção tem sido dada aos nematoides, mesmo já relatados os danos causados por Meloidogyne exigua Goeldi (²⁶; ²⁸). Esses nematoides além de promoverem a formação de galhas e lesões, respectivamente, reduzem a absorção de água e nutrientes da planta, comprometendo ou, em alguns casos, até inviabilizando o cultivo das mais diversas culturas (²⁸).

Significant crop losses are due to plant-parasitic nematodes. Nematicides are expensive and potentially toxic to men, the environment, and plants. This study evaluated the hidden phytotoxicity effects of nematicides in soybeans. Two soybean cultivars (8473RSF and M7198IPRO) were evaluated with five nematicide treatments (biological, cadusaphos, abamectin, fluensulfone, and an untreated control) for changes in chlorophylls, biometrics, and spectral (TGI visible spectral index captured with a smartphone camera) variables to determine and anticipate the identification of plant stresses. Evaluations occurred 33, 47, and 66 days after sowing (DAS). The a/b chlorophyll proportion was greatest for M7198IPRO and cadusaphos. The chlorophyll variables did not present significant interactions or differences at 47 DAS, indicating that possible nematicide effects were transient and should be evaluated earlier than 33 DAS. Leaf area, leaf mass, and shoot mass were smaller for 8473RSF and outstanding for abamectin and fluensulfone. The response of the spectral index did not present significant interaction among the factors; however, at 33 and 47 DAS, the index was low for 8473RSF and lowest for cadusaphos only at 33 DAS. The correlations between the spectral index and other variables were significant and moderate for soybean total leaf area. Although no apparent phytotoxicity symptoms caused by nematicides were observed, the visible vegetation index generated using a smartphone camera can still improve crop management solutions.