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From 2016 to 2021, nematode surveys in Florida strawberry fields revealed several species of foliar nematodes (Aphelenchoides spp.). Aphelenchoides besseyi sensu stricto was detected only in 2016 and 2017 on photosynthetic strawberry leaves/buds, but other not well characterized populations of Aphelenchoides sp. were found on declining/dessicated leaves. Morphological analyses showed that these samples of Aphelenchoides sp. consisted of A. bicaudatus, a species detected in Florida for the first time, and A. rutgersi, a species previously reported in Florida from the citrus rhizosphere. These two species differed from A. besseyi in the shape of their tail terminus: bifurcate in A. bicaudatus; mucronate with a ventral thin mucro in A. rutgersi; and stellate in A. besseyi. One population each of these species was used for morphological and molecular analyses after being reared on Monilinia fructicola. Body and tail length differences were observed among Florida A. bicaudatus and other populations from the Far East and South Africa. Phylogenetic analyses of the rRNA gene sequences showed that Florida A. bicaudatus grouped with those of species from South Korea, Taiwan, and the Netherlands and several other populations listed as Aphelenchoides sp. from Brazil, Costa Rica, and Japan, which were considered as representatives of A. bicaudatus in this study. Similarly, sequences of Florida A. rutgersi grouped with those from environmental samples in Japan and North Carolina, which were listed as Aphelenchoides sp. and were considered as representatives of A. rutgersi in this study. Photosynthetic strawberry leaf samples were free from both A. bicaudatus and A. rutgersi, indicating that these two species did not damage strawberry. They were associated with desiccated leaves and/or propagative stolons, usually infected by fungi, confirming that they are mycetophagous under field conditions in this study. Results of soybean leaf inoculation on moist filter paper containing A. bicaudatus specimens showed that this species could become phytophagous under artificial conditions. Nematodes penetrated the leaf epidermis and migrated into the mesophyll causing leaf tissue discoloration/necrosis, which remained localized within the infested area. Soybean leaf damage was almost negligible, and no nematode reproduction was observed in the inoculated soybean areas.

In 2019–2022, declining symptoms were observed in two commercial strawberry farms in Hillsborough County, Florida. The fields in the two farms consisted of raised beds covered by plastic mulch. Both were fumigated with a mixture of 1,3-dichloropropene (40%) + chloropicrin (60%) before planting. Samples collected from large patches with declining plants were infested with stubby-root nematodes. No sting and root-knot nematode species were detected. The results of morphological and molecular analyses indicated that the stubby-root nematode populations were representative of the species Nanidorus minor. The two cultivars ‘Florida Brilliance’ and ‘Florida Sensation’ in the two fields included plants with stubby root symptoms showing a reduction in the size of the root system and arrested growth and elongation of the feeder roots on the first strawberry crop. The nematode population densities in the two fields increased at the end of strawberry season and averaged 66 and 96 specimens in 200 cm3 soil. In one of the fields, a second strawberry crop was established as in the previous year using the same practices (fumigation and raised beds covered with plastic). However, in this field the population of N. minor declined and did not reach damaging levels at the end of the season on the second strawberry crop. The factors causing the decline of the nematode population were not elucidated. This is the first report of a direct damaging effect of N. minor to strawberry.

Summary: Two species of sheath nematodes were studied using an integrative approach, combining morphological and molecular analyses. The first species was collected from an oak tree (Quercus sp.) imported from Texas into Florida, while the second one was obtained from the ornamental palm Phoenix sylvestris in a Florida nursery. These species were compared to a closely related species, Hemicaloosia uarki , which was originally described in Arkansas. Phylogenetic analyses using partial 18S rRNA, D2-D3 expansion segments of 28S rRNA, ITS rRNA, and COI gene sequences revealed that sheath nematodes from Texas and Florida represent two new species of the genus Hemicycliophora , which are described here as Hemicycliophora ornata sp. n. and H. silvestris sp. n., respectively. In the phylogenetic tree based on ITS rRNA gene sequences, Hemicaloosia uarki grouped within a clade of other Hemicycliophora species rather than within the Hemicaloosia species clade, indicating that this species belongs to the genus Hemicycliophora rather than to Hemicaloosia. Consequently, this species was reclassified as Hemicycliophora uarki comb. n. These findings confirmed that morphological characters traditionally used to distinguish Hemicaloosia species from those of Hemicycliophora are valid but insufficient for reliable identification when some life stages, such as males, are absent. The presence of males with straight spicules is a very useful character to validate the morphological identification of Hemicaloosia species. In absence of this life stage, phylogenetic analysis of gene sequences is the only reliable method to accurately differentiate sheath nematodes resembling Hemicaloosia from Hemicycliophora. [ABSTRACT FROM AUTHOR]

Summary: Two populations of needle nematode, Longidorus longicaudatus Siddiqi, 1962, are described from Quercus hemisphaerica , Q. nigra and Q. virginiana from north Florida, USA. These populations are characterised morphologically by females having a body shorter than 3800 μ m, a rounded or slightly flattened lip region, an amphidial fovea pouch-like often with two symmetrical lobes, an odontostyle 99-110 μ m long, a conoid tail ending in a bluntly pointed terminus, ranging values of ratio c′ greater than 2, and males very rare. The polytomous code for these populations is A34, B23, C2, D23, E2, F12, G12, H6, I12, J1, K6. Although the morphology and morphometrics of these two populations fit the original description of Longidorus longicaudatus , Florida specimens have greater diameters of lip region, mid and anal body than those of the five type specimens used for the description of this species. The Florida L. longicaudatus is similar to L. paralongicaudatus , but differs from the paratypes of this species in having smaller and greater values of ratios c (53.8 (43.8-64.5) vs 79.2 (61.9-103.5)) and c′ (2.4 (2.1-2.9) vs 1.8 (1.5-2.0)), respectively, and longer tail (60 (53-67) vs 46 (36-53) μ m). Molecular characterisation of one of the two Florida L. longicaudatus populations was made based on the D2-D3 of 28S rRNA, ITS1 rRNA and COI gene sequences. The results of the ITS1 rRNA gene sequence analysis indicated that it is genetically different from L. paralongicaudatus. A few specimens of a needle nematode associated with L. longicaudatus were identified morphologically and molecularly as the pine needle nematode, L. americanus. This detection is a new record of the occurrence of the pine needle nematode in Florida. [ABSTRACT FROM AUTHOR]

Summary: Populations reviously identified as Aphelenchoides besseyi were studied. Using an integrated approach, the A. besseyi species complex contains several cryptic species: A. besseyi sensu stricto , A. oryzae , A. pseudobesseyi sp. n. and other putative undescribed species. A population from Florida strawberry morphologically fits the A. besseyi of both Christie and Allen and is considered the only representative of this species. A Louisiana rice population fitted the descriptions of A. oryzae of both Yokoo and Fortuner; PUS length was consistently less than one-third of VA. Aphelenchoides oryzae , parasitising rice and other monocots, was re-established based on morphological and molecular datasets. Three populations from Florida ornamental plants (Dryopteris erythrosora , Echinacea sp. and Farfugium japonicum) differed from those of the two above-mentioned species and are described as A. pseudobesseyi sp. n. Populations previously identified as ' A. besseyi ' from several countries were considered representatives of this new species, which usually had a large and conspicuous PUS, 8-14 μ m wide and with a length greater than one-third of VA in 40-70% of studied specimens. Morphological variability made separation of A. pseudobesseyi sp. n. from A. oryzae and A. besseyi unreliable without the examination of numerous specimens and molecular analysis. [ABSTRACT FROM AUTHOR]

Summary: The stubby root nematodes are world-wide distributed polyphagous root ectoparasites and can cause damage to a wide range of crops and natural vegetation. In this study, 22 valid and putative species of stubby root nematodes were identified in 37 samples collected in Malaysia, Mexico, Russia, and the USA (California, Florida, Minnesota and Nevada). The analysis of 58 new sequences of the D2-D3 expansion fragments of 28S rRNA gene revealed the following species: Nanidorus minor from California, Florida and Mexico, N. renifer from Florida, two unidentified Nanidorus species from California and Malaysia, respectively, Paratrichodorus allius from Florida and Minnesota, P. pachydermus and Paratrichodorus sp. from Russia, Trichodorus californicus , T. intermedius , and T. obscurus from California, T. obtusus from Florida, eight unidentified Trichodorus species from California, one unidentified Trichodorus species from Nevada, and two unidentified species of stubby root nematodes, one of Trichodorus and another undetermined species from Mexico. Molecular characterisation of T. californicus , T. intermedius and T. obscurus is given for the first time. The phylogenetic tree reconstructed from the analysis of 108 D2-D3 of 28S rRNA gene sequences of 58 valid and putative species of the stubby root nematodes contained five major clades: i) Trichodorus from Europe, Asia and North America; ii) Nanidorus and Trichodorus from Asia; iii) Trichodorus from California; iv) Paratrichodorus from several distant geographical regions; and v) Monotrichodorus from Central and South America. It has been hypothesised that the California Floristic Province is one of the centres of origin and diversification of stubby root nematodes. There is no information on the economic importance of the stubby root nematode species found in California and Mexico. The confirmation of the occurrence of N. renifer and P. allius in Florida should be of concern for the blueberry and potato industries in the state. [ABSTRACT FROM AUTHOR]