Haliplectus mexicanus sp. n. is described from rhizosphere soil of the breadnut tree, Brosimum alicastrum growing in the tropical forest at La Mancha Ecological Reserve of the Ecology Institute of Jalapa, Veracruz State, Mexico. The new species is characterized by females, males, and juveniles having a short conical tail with rounded terminus less than 38 µm long, body less than 500 µm long, anterior region of the body wider than the posterior one, cuticle with conspicuously ornamented annuli, and pores along the lateral and submedian regions of the body. The cephalic region has four fine annulations and is separated from the rest of body by a constriction. The amphidial fovea are very conspicuous, post-labial and circular. The stoma is tubular, curved in the posterior region. The pharynx has a short twisted procorpus, muscular bipartite basal bulb rounded with a transverse constriction. The female reproductive system is amphidelphic with reflexed ovaries. Males lack a bursa and have four contiguous midventral precloacal papilliform supplements. Spicules slender 27 µm long average, the gubernaculum wedge-shaped, broad anteriorly part, and tapering to a blunt tip. Phylogenetic relationships of new species and Haliplectus sp. from California with some representatives of this genus are given as inferred from the analysis of 18S, D2-D3 of 28S rRNA and COI gene sequences.
The soybean cyst nematode (SCN), Heterodera glycines, is a major constraint to soybean production in Brazil. This study evaluated the efficacy of biological and chemical nematicides on egg hatching, second-stage juvenile (J2) mortality, and nematode reproduction under controlled in vitro and greenhouse conditions. Four in vitro experiments were conducted using eggs and J2 as inoculum, with egg hatching assessed at 7 and 14 days and J2 mortality at 24 and 48 hr after treatment. In greenhouse assays, biological nematicides were applied either as seed treatments or through pre-treatment of nematode inoculum before plant inoculation. Additional experiments assessed both chemical and biological nematicides using eggs as inoculum. Biological nematicides increased J2 mortality in vitro, although their effect on egg hatching was inconsistent. In greenhouse conditions, pre-treating nematode inoculum generally resulted in lower SCN reproduction compared with seed-applied treatments. Both biological and chemical nematicides reduced SCN reproduction, with chemical nematicides, particularly fluopyram, showing the greatest reductions. These results demonstrate that nematicides can suppress SCN under greenhouse and in vitro conditions; however, further field validation is needed to confirm their potential as management tools for soybean production.
There is a need for evaluating nematode abundances from different soil types by optimizing extraction efficiency (i.e., nematode recovery) because soil texture, pH, and soil organic matter change as soil depth increases. Therefore, the extraction efficiency of a modified Baermann technique on soil recovered from different depths (0-30 cm, 30-60 cm, 60-90 cm, and 90-120 cm) at a long-term peanut-cotton rotation study in Quincy, FL, USA was examined. This was accomplished by evaluating the relative efficiency of reniform (Rotylenchulus reniformis) and free-living nematode extraction from these different soil depths based on the addition of known quantities of nematodes to microwave-treated soil. Depth and nematode inoculation levels both significantly affected extraction efficiency of reniform and free-living nematodes, but in different ways. For reniform nematode, extraction efficiency ranged from 36% at the deepest depth (90-120 cm) and increased to 47% at the shallowest depth (0-30 cm). Yet, for free-living nematodes, extraction efficiency ranged from 25% at the deepest depth and increased to 36% at the shallowest depth. Reniform nematode extraction efficiency was greatest (39%) with the lowest inoculation rate (i.e., 1,000 reniform nematodes per 100 cm3 soil), while trends with free-living nematode extraction efficiency were inconsistent. This work highlights the need to understand that true nematode population densities may be underestimated due to soil type and correction factors may need to be implemented for diagnostic and management purposes.
Root-knot nematodes (RKN, Meloidogyne spp.) are major yield-limiting pests in tomato production. Mi-tomato cultivars resist common RKN species, including Meloidogyne incognita, M. javanica, and M. arenaria, making them valuable tools in integrated nematode management. However, increasing reports of guava RKN, M. enterolobii, in Florida and worldwide, including tomato fields, raise concern, as the Mi-genes reportedly do not protect against this species. This study evaluated infection and reproduction of M. enterolobii and M. javanica from Florida on Mi-tomato cultivars ('Sanibel', 'Southern Ripe', 'Skyway 687', and 'Mariana') and one non-Mi cultivar ('HM1823') under greenhouse conditions in fall 2024 and spring 2025. Parameters assessed included gall numbers and nematode penetration at 14 days post inoculation (DPI) and gall rating, egg production, and reproduction factor and plant growth at 56 DPI. Except for 'Sanibel', all Mi-cultivars provided good protection against M. javanica with lower root gall damage and nematode reproduction. All Mi cultivars allowed high reproduction of M. enterolobii and were severely damaged by M. enterolobii, similar to the non-Mi cultivar. On the susceptible cultivar, M. enterolobii was also more damaging than M. javanica producing higher gall numbers, greater penetration rates, and more severe galling, higher egg numbers and reproduction factors, and smaller plants. These findings highlight the urgency of diversifying resistance sources and enhancing integrated management approaches to mitigate the threat of M. enterolobii in Florida tomato production.
Vald & eacute;s-Murillo, M., W. Peraza-Padilla, R. Artavia-Carmona, J. Ar & aacute;uz-Badilla and I. Hilje-Rodr & iacute;guez. 2026. Morphological and molecular characterization of populations of Hemicriconemoides strictathecatus Esser, 1960 and H. Rosae Rathour, Sharma, Singh & Ganguly, 2003 (Nematoda: Criconematidae) from Costa Rica. Nematropica 56: 1-19. During nematological studies conducted in Costa Rica, five populations of sheathoid nematodes (Hemicriconemoides spp.) were detected in samples collected in Alajuela, Puntarenas, and San Jos & eacute; provinces. Morphological and molecular analyses showed that five sheathoid nematode populations from Alajuela and San Jos & eacute; provinces match with Hemicriconemoides strictathecatus, a species described from Florida, USA and reported in many other countries. A population from Puntarenas province fit morphologically and molecularly with H. rosae, a species described in Uttar Pradesh, India and also reported in China. This is the first record of the occurrence of these two species in Costa Rica. Phylogenetic analysis of Hemicriconemoides species were performed based on partial sequences of the D2-D3 domains of the 28S ribosomal DNA gene, the ITS1 region and subunit I of the cytochrome c oxidase (COI) mitochondrial gene. This integrative approach also supported the identification of H. strictathecatus and H. rosae as valid species newly recorded in Costa Rica.
