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, 89 fruit tree fields (18 avocado, 42 guava, 9 mamey, 5 longan, 4 starfruit, 3 mango, 3 lychee, 2 dragon fruit, 2 passionfruit, and 1 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 (73.0% incidence; mean abundance 58.5/100 cm3 soil; and maximum 900/100 cm3 soil), Mesocriconema (54.6%; 55.4; 568), Helicotylenchus (33.7%; 14.3; 185), Meloidogyne (41.6%; 15.6; 260), Pratylenchus (18.0%; 1.3; 20), Xiphinema (13.5%; 0.74; 16), Hoplolaimus (11.2%; 2.13; 72), Tylenchorhynchus (9.0%; 2.43; 102), and Paratrichodorus (8.9%; 0.74; 28). Principal component analysis and Spearman correlation analysis showed that fruit crops, organic matter, and EC influenced PPN distribution. Organic matter was positively correlated to Rotylenchulus, whereas EC was positively correlated to Hoplolaimus, Pratylenchus, and Helicotylenchus. Species in the genera Hoplolaimus, Rotylenchulus, and Pratylenchus were associated with avocado; Meloidogyne and Helicotylenchus with guava and dragon fruit; 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.

Organic vegetable production faces challenges in managing plant-parasitic nematodes (PPNs) and weeds, as chemical options are prohibited. This study evaluated the effects of cover crop termination timing (90 and 120 days after planting, DAP) and cover crop incorporation, along with the application of an organic bioherbicide (Suppress EC), on PPN and weed suppression during the 2021 and 2022 winter seasons. The experiment utilized seven treatments of oilseed radish, oat, rye, mustard, a rye-oat mixture, and two fallows (with and without weeds), replicated five times per season for each termination timing and terminated at 90 and 120 DAP and incorporated into the soil. Results showed that termination timing significantly influenced PPN populations, with rye and oat reducing Meloidogyne incognita densities when terminated at 90 DAP, while mustard and radish increased nematode populations at 120 DAP. Incorporation of cover crops did not consistently enhance nematode suppression, especially in low-biomass scenarios. Weed suppression was more effective with later termination (120 DAP), particularly for rye and oat, which reduced weed biomass through shading and allelopathic effects. The combination of cover crops with bioherbicide further improved weed control, with significant reductions in corn spurry (Spergula arvensis) and cutleaf geranium (Geranium dissectum) compared to cover crops alone. However, the bioherbicide was less effective in suppressing weeds in mustard and radish plots. These findings highlight the importance of selecting appropriate cover crops and optimizing termination timing to manage PPNs and weeds. Integrating bioherbicides with cover crops offers a promising strategy for organic vegetable production, enhancing weed suppression and contributing to sustainable agroecosystems.

-Comprehensive surveys in nine coffee-growing counties in Kenya, involving 53 farms and comprising 116 soil and 63 root samples, revealed a total of 12 genera of plant-parasitic nematodes, including: Meloidogyne, Paratylenchus, Pratylenchus, Helicotylenchus, Rotylenchus, Rotylenchulus, Scutellonema, Trophotylenchulus, Xiphinema, Trichodorus, Aphelenchoides and Hemicycliophora. Meloidogyne was the most abundant genus, with densities of up to 210 juveniles (100 ml soil)-1. Morphological and molecular characterisation enabled the identification of several nematode species including Meloidogyne javanica, M. africana, Rotylenchulus borealis and Trophotylenchulus obscurus. For T. obscurus, the 18S rDNA sequences obtained in this study are the first ever reported for the genus. Additionally, the 18S and D2-D3 of 28S, as well as ITS sequences, marked first for this species. In total, six partial 18S, seven D2-D3 of 28S, four ITS sequences of rDNA, ten COI, and two nad5 gene sequences were generated in this study. In conclusion, our study reveals that our knowledge of plant-parasitic nematode occurrence on important crops even, such as coffee, remains poorly documented and understood, highlighting the potential for new discoveries in such areas.

-A previously undescribed Pratylenchus species obtained from maize and coffee in Kenya was identified utilising morphological, morphometrics, and molecular data from the D2-D3 of 28S, 18S, and ITS rDNA gene sequences. Morphologically, P. mahindii n. sp. is characterised by a female body length of 347-428 mu m, body straight to ventrally curved after fixation, labial margin elevated hemispherical-like, elevated oral opening having mostly three lip annuli, a strong basal plate, a stout stylet of 13.6-16.0 mu m, spermatheca oval with, or sometimes without, round sperms, four lateral lines, and a subcylindrical tail that tapers gradually to a smooth conical tip. The matrix code of Pratylenchus new sp. according to key characteristics following Castillo & Vovlas (2007) is A2, B2, C3, D3, E1, F2, G2, H3, I1/2, J1, K2. Molecularly, based on the phylogeny of the D2-D3 expansion segments of 28S, 18S and ITS of rDNA sequences, P. mahindii n. sp. is distinctly different from all known species with a molecular record, and is most closely related to P. bhattii. This study illustrates the need to conduct more diversity studies based on both morphological and molecular data to uncover potentially neglected species in important crops.

BACKGROUND:Organic vegetable growers face significant challenges in managing plant-parasitic nematodes, particularly root-knot nematodes (RKN; Meloidogyne spp.), because of restrictions on the use of synthetic chemicals. This study evaluated the efficacy of seven commercially available Organic Materials Review Institute-certified bionematicides against Meloidogyne incognita under greenhouse and field conditions. A cucumber plasticulture field study was also conducted to compare the efficacy of four best-performing bionematicides, including azadirachtin, cold-pressed neem oil, thyme oil and saponins of Quillaja saponaria, identified in the greenhouse study and a chemical nematicde (oxamyl) using two application regimes: calendar-based (following the product label) and nematode life-cycle-based (following the M. incognita life cycle using degree-days assessment). RESULTS:In the greenhouse study with tomato, azadirachtin and thyme oil significantly reduced M. incognita root galling and reproduction factor (final nematode population/initial nematode population) compared with a positive control. In the field trial with cucumber, the nematode life cycle was completed in 23 days during the spring season and 24 days during the fall season, accumulating 380 and 398 degree-days, respectively, above a base temperature of 10 °C. For calendar-based applications, only azadirachtin significantly reduced nematode density, whereas for life-cycle-based applications, all treatments except saponins of Q. saponaria were effective. Oxamyl was more effective when applied according to the nematode life cycle than on a calendar-based regime. Life-cycle-based applications generally outperformed calendar-based applications based on numerical values, even in cases in which the differences were not significant. For the galling index, calendar-based applications of azadirachtin and cold-pressed neem oil reduced the galling index more than life-cycle-based applications at mid-season. At the end of the season, only azadirachtin under the calendar-based application differed significantly from the control, while all other treatments (except saponins of Q. saponaria) had lower root galling indices than the calendar-based applications. CONCLUSION:These findings indicate that both application regimes can be used to manage M. incognita in organic farming systems. Of particular significance is the novel life-cycle-based approach developed in this study, which may confer enhanced sustainability benefits by optimizing nematicide application timing and reducing treatment frequency, ultimately leading to a decline in soil nematode population densities. © 2025 Society of Chemical Industry.

Integrating cover crops and bionematicides presents a sustainable approach to managing plant-parasitic nematodes (PPN) in organic vegetable production systems. The integration of sunn hemp, Crotalaria juncea ('Crescent sun') and sorghum-sudangrass, Sorghum bicolor x S. sudanense ('Sweet Six BMR') with bionematicides was evaluated in two locations in central (Gulf Coast Research and Educational Centre-GCREC) and south (Fort Lauderdale Research and Educational Centre-FLREC) Florida for the effectiveness of PPN suppression. Field experiments were conducted with establishing cover crops in each location 3 months before planting organic zucchini on plastic beds equipped with a drip application system used to inject three commercial bionematicides (thyme oil, neem oil and azadirachtin) and the broth culture of Xenorhabdus bovienii bacteria associated with Steinernema feltiae. Cover cropping with sunn hemp and sorghum-sudangrass significantly reduced population densities of root-knot nematodes (Meloidogyne spp.) at GCREC, whereas only sunn hemp reduced the root-knot nematode population at FLREC. Galling severity on zucchini roots caused by Meloidogyne spp. was significantly lower in azadirachtin and neem oil applications integrated with sunn hemp. The impact of integrating cover crops with bionematicides on other PPN, such as Mesocriconema spp., Nanidorus minor and Hoplolaimus spp., varied among the treatments at both locations. Integrating cover crops with bionematicide applications provided additional control options for zucchini, but the efficacy of different bionematicides depended on the nematode species present in the soil and the cover crop species used. These findings underscore the importance of adaptive nematode management, where control strategies are customised to target the specific nematode populations causing economic damage in each field.

Papaya trees showing disease symptoms caused by root-knot nematodes (Meloidogyne spp.) were detected in a tropical fruit farm in Vero Beach, FL, USA. Roots were severely galled containing a high population density of root-knot nematode eggs. The nematode species causing damage was identified as M. incognita based on the morphometrics of body, stylet, and tail length of the second-stage juveniles, and morphological characteristics of female perineal patterns. Molecular analyses using both species-specific and universal primers also confirmed the species identity. A pathogenicity test confirmed M. incognita reproduction on papaya by producing nematode females and egg masses within the root galls. This report documents the first confirmed detection of M. incognita in papaya in Florida, USA, providing detailed information on the nematode's morphology characteristics and DNA sequence data.

Summary Four criconematid populations were uncovered in three avocado orchards in Homestead region, Miami-Dade County, Florida, USA, with three of them in relatively high densities. Two of the populations were identified as Criconema mutabile (Taylor, 1936) Raski & Luc, 1985 and Mesocriconema basili (Jairajpuri, 1964) Loof & De Grisse, 1989, whereas the other two populations were identified as Criconemoides sp. and Ogma sp. The identification of the nematodes was based on morphological analysis and C. mutabile was also confirmed based on the 28S rRNA gene. The molecular data of M. basili (18S and 28S rRNA genes) are presented for the first time and phylogenetic trees based on the genes are provided illustrating the relationships of M. basili with other criconematid species. This study further reports the presence of C. mutabile and M. basili for the first time in Florida, USA, and the association of the latter species with avocado rhizosphere.

Passion fruit ( Passiflora edulis ) is one of the tropical fruits well-adapted to Florida’s hot and humid climate. A high population of root-knot nematode, Meloidogyne incognita was identified morphologically from soil samples taken from declined passion fruit vines in an organic field in North Florida. Species identification was also confirmed based on DNA-based diagnostics using species-specific primers and sequencing based on D2-D3 of 28 S and ITS of ribosomal DNA. To the best of our knowledge, this is the first report of infection of purple passion fruit with M. incognita in Florida, USA.

Abstract A new root-knot nematode (RKN) species, Meloidogyne karsseni n. sp., associated with sweet pepper from Mexico, and a population of M. paranaensis from Guatemala, are described using data from morphological, biochemical (isozyme enzymes), molecular, and phylogenetic analyses. Meloidogyne karsseni n. sp. can be morphologically diagnosed using the combined features of the second-stage juveniles, viz. body length (345 to 422 μm), a conical rounded head region, a post-labial annule lacking transverse striation, a thin stylet 11 to 12 μm long, rounded to oval and backwardly sloping knobs, dorsal gland orifice (DGO) at 5.2 to 6.0 μm from the knobs, a hemizonid just above the secretory-excretory (SE) pore, a tapering tail with finely rounded terminus and one or two very weak constrictions at hyaline tail tip; the female characters viz. oval-to-rounded perineal pattern with coarse striation on lateral sides around the anus, low dorsal arch with finer striations, and distinctly visible lateral lines; and the male characteristics viz. a rounded and continuous head, a post-labial annule without transverse striations, a robust stylet 20 to 24 μm long, rounded-to-oval and slightly backwardly sloping knobs, and a DGO at 2.4 to 2.9 μm from the knobs. In all the studied males of M. paranaensis, a characteristic sclerotization around the duct of SE-pore was also observed for the first time. Sequences of 18S, D2–D3 of 28S, and ITS of rDNA, and cox1 of mtDNA were generated for the two species, and in the phylogenetic trees based on these genes, both species appeared in the tropical RKN species complex clade.

Guava is a nutritious and profitable high-yield crop. Guava root-knot nematode (GRKN), M. enterolobii Yang & Eisenback, 1983 (= M. mayaguensis Rammah & Hirschmann, 1988), cause detrimental damage in guava orchards in more than 15 countries. Fifteen guava orchards in Homestead, Florida, were randomly sampled to check for potential plant-parasitic nematode damage to the trees. The guava RKN, M. enterolobii, was detected in 80% of the sampled orchards, causing damage to white and pink guava. Morphological and molecular analyses confirmed the identification of nematode species, and the host pathogenicity test showed the guava’s susceptibility to M. enetrolobii.

Study was conducted on abundance, composition, and damage of wood-boring beetles on Acacia xanthophloea, and associated natural enemies. Infested wood samples were collected, placed in containers, and kept in the laboratory for emergence of beetles and natural enemies, which were identified and recorded. Distribution of heterostigmatic mites Tarsonemus sp. on Xyloperthodes nitidipennis was investigated. A total of 5,003 wood-boring beetles (Bostrichidae, Buprestidae, Curculionidae, and Cerambycidae), 1,162 predatory beetles (Histeridae and Cleridae), and 30 parasitoids (Chalcididae, Braconidae, Ichneumonidae, Pteromalidae, and Eupelmidae) were recovered. Xylion adustus accounted for 55.33% followed by X. nitidipennis (13.51%). Hister sp. was the dominant predator accounting for 17.36%. Highest Tarsonemus sp. mite load on X. nitidipennis was recorded on the abdominal sternites (25.66 ) followed by head (12.48) and thorax (9.86). Size of exit holes differed (df.1,4; F = 61.03; p < 0.0001) with 1–2 mm having a higher mean (523.2) followed by 2–3 mm (212.0).