First Report of <i>Pratylenchus bolivianus</i> Infecting <i>Alstroemeria</i> sp. in Brazil

During a survey in April 2025 which aimed to identify the cause of stunting in Alstroemeria sp. (Figure 1), root and soil samples were collected from a field in the municipality of Munhoz, Minas Gerais state, Brazil (22.663752573340915, 46.27580040975547). The samples were processed by the centrifugal flotation method and a species of root-lesion nematode was detected: Pratylenchus bolivianus (Figure 2A) in all samples (434 specimens/g of roots) of cultivars Gypsy and Prestige. Ten adult females belonging to the Pratylenchus genus, with three lip annuli (Figure 2B), lateral fields with four lines and conoid tail with tip rounded and smooth (Figure 2C) were temporary slide mounted in water for study. The average measurements were as follows: stylet length (St) = 20.8 (±0.8) µm, body length (L) = 636.2 (±92.7) µm and vulva position (V%) = 79.6% (±2.9). Males were not found. Morphological and morphometric characters were consistent with those described for P. bolivianus (Castillo and Vovlas 2007). Molecular identification was confirmed through sequencing D2/D3 28S rDNA and applying DNA barcode technology (de Oliveira et al. 2009). The sequence data were submitted to GenBank under Accession No. PX171444. The specimens used for molecular analysis showed a high degree of sequence identity (99.8%) with P. bolivianus, isolate BJP1-13, KP780256 (Figure 3). This species was described by Corbett (1983) from soil samples around oat and potato roots in the Bolivian Andes. Pratylenchus bolivianus was also recorded affecting Alstroemeria sp. in the United Kingdom (Cotten et al. 1991), the Netherlands and in commercial cut flower crops in the Andean savanna region of Bogotá, Colombia (Riascos-Ortiz et al. 2024). This nematode has been reported previously in Brazil by Ribeiro et al. (2013) in soybean. However, this report presents a misinterpretation of the results. The identification was based solely on molecular data with low identity (78%–84%) and lacked complementary morphological studies for accurate species confirmation. Thus, the conclusion that the population was P. bolivianus is questionable. Following this finding, the Brazilian Ministry of Agriculture, Livestock and Food Supply has been contacted in order to implement phytosanitary measures to reduce the adverse impact of P. bolivianus.