Horizontal and vertical droplet dispersion mimicking soybean - Septoria glycines pathosystem

• Published in: European journal of plant pathology Vol. 154; no. 2; pp. 437 - 443
• Main Authors: Almeida, Álvaro Manuel Rodrigues, Sibaldelli, Rubson Natal Ribeiro, de Oliveira Negrão Lopes, Ivani, de Oliveira, Maria Cristina Neves, Farias, José Renato Bouças
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2019; Springer Nature B.V
• Subjects: Agriculture; Biomedical and Life Sciences; Dislocation; Dislocations; Dispersal; Dispersion; Drop size; Droplets; Ecology; Epidemics; Glycine max; Infections; Leaves; Life Sciences; Mimicry; Plant Pathology; Plant Sciences; Recording; Septoria glycines; Soil conditions; Soil water; Soils; Soybeans; Spores; Straw; Wheat; Wheat straw; Brown spot; Spore displacement; Simulation; Epidemiology; Rain drops
• DOI: 10.1007/s10658-019-01667-5
• ISSN: 0929-1873

The horizontal and vertical dispersion of droplets was assessed aiming at studying influence of their numbers and distances on spread of spores of Septoria glycines Hemmi simulating its pathosystem with soybean [ Glycine max (L.) Merrill] plants. Two drop diameters (1.8 mm and 3.4 mm) were assessed under two soil conditions: bare soil and soil covered with wheat straw. Results showed that larger drops had greater effect on producing droplets than smaller drops. The number of horizontally dispersed droplets increased with increase on number of drops assessed (5, 10, or 20 drops) on both diameters used; as well as for both soil conditions assessed. The number of droplets vertically dispersed was assessed using only 5 and 10 drops, and increased as drop size increased; mainly under bare soil condition. Twenty drops were also assessed, but such water amount drenched the soil and did not allow recording vertical dispersal of droplets. The epidemic caused by splashes of droplets on bare soil caused infection on a larger number of plants than the epidemic caused by splashes on soil covered with wheat straw. These findings confirm why this is one of the first soybean disease to occur in the field and show in vivo the upward dislocation of S. glycines spores for the first time. Such upward movement was based on the following infection levels: 1 = no infection; 2 = up to 15% of the leaf infected; 3 = up to 30% of leaf infected; 4 = up to 45% of leaf infected; and 5 = more than 60% of the leaf infected.