Influence of soil-related factors on distribution of plant-parasitic nematodes in tropical fruit fields in South Florida

Abstract

Plant-parasitic nematodes (PPNs) are known to damage the roots of tropical fruit crops in Florida, especially in South Florida's calcareous soils. From July 2022 to September 2023, 65 fruit tree fields (eighteen avocado, seventeen guava, nine mamey, five longan, four starfruit, three mango, three lychee, two dragonfruit, two passionfruit, one papaya, and one banana) were randomly selected for sampling in Homestead, Florida, to determine the incidence and distribution of PPNs and their relationship with soil-related factors such as pH, organic matter, electrical conductivity (EC) and soil texture. Nine PPN genera were detected: Rotylenchulus (73.8% incidence; mean abundance 67.4 /100 cm3 soil; maximum 900 /100 cm3 soil), Mesocriconema (49.2%; 33.4; 490), Helicotylenchus (46.2%; 19.6; 185), Meloidogyne (30.8%; 11.9; 260), Pratylenchus (21.5%; 1.3; 20), Xiphinema (18.4%; 1.0; 16), Hoplolaimus (13.8%; 2.9; 72), Tylenchorrhynchus (12.3%; 3.3; 102), and Paratrichodorus (12.3%; 1.0; 28). Principal Component Analysis (PCA) and Spearman correlation analysis showed that fruit crops, organic matter, and EC influenced PPN distribution. Organic matter was positively correlated to Rotylenchulus, while EC was positively correlated to Hoplolaimus, Pratyelchus and Helicotylenchus. Species in the genera Hoplolaimus, Rotylenchulus and Pratylenchus were associated with avocado; Meloidogyne and Helicotylenchus with guava and dragonfruit; and Mesocriconema and Helicotylenchus with lychee, longan, and mango. Results highlight that both host plants and soil-related factors are critical in determining PPN distribution and abundance in South Florida's tropical fruit fields, providing important insights for managing nematode pests.

Keywords: Detection; Incidence; damage; nematode distribution; tropical fruit trees.