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Root-knot nematodes are important pests of cut foliage crops in Florida. Currently, effective nematicides for control of these nematodes on cut foliage crops are lacking. Hence, research was conducted at the University of Florida to identify pesticides or biopesticides that could be used to manage these nematodes. The research comprised on-farm, field, and greenhouse trials. Nematicide treatments evaluated include commercial formulations of spirotetramat, furfural, and Purpureocillium lilacinum (=Paecilomyces lilacinus) strain 251. Treatment applications were made during the spring and fall seasons according to manufacturer's specifications. Efficacy was evaluated based on J2/100 cm 3 of soil, J2/g of root, and crop yield (kg/plot). Unlike spirotetramat, which did not demonstrate any measurable effects on Meloidogyne incognita J2 in the soil, furfural and P. lilacinum were marginally effective in reducing the population density of M. incognita on Pittosporum tobira. However, nematode reduction did not affect yield significantly. Although furfural and P. lilacinum have some potential for management of M. incognita on cut foliage crops, their use as a lone management option would likely not provide the needed level of control. Early treatment application following infestation provided greater J2 suppression compared to late application, suggesting the need for growers to avoid infested fields.

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Florida accounts for more than 75% of the national cut foliage production. Unfortunately, root-knot nematodes (RKN) (Meloidogyne spp.) are a serious problem on these crops, rendering many farms unproductive. Currently, information on the Meloidogyne spp. occurring on most commonly cultivated cut foliage crops in Florida, and tools for their rapid identification are lacking. The objectives of this study were to (i) identify specific RKN infecting common ornamental cut foliage crops in Florida and (ii) evaluate the feasibility of using the mtDNA haplotype as a molecular diagnostic tool for rapid identification of large samples of RKN. A total of 200 Meloidogyne females were collected from cut foliage plant roots. Meloidogyne spp. were identified by PCR and RFLP of mitochondrial DNA. PCR and RFLP of mitochondrial DNA were effective in discriminating the Meloidogyne spp. present. Meloidogyne incognita is the most dominant RKN on cut foliage crops in Florida and must be a high target for making management decisions. Other Meloidogyne spp. identified include M. javanica, M. hapla, Meloidogyne sp. 1, and Meloidogyne sp. 2. The results for this study demonstrate the usefulness of the mtDNA haplotype-based designation as a valuable molecular tool for identification of Meloidogyne spp.

The root-lesion nematode Pratylenchus penetrans is a major pathogen of potato worldwide. Yield losses may be exacerbated by interaction with the fungus Verticillium dahliae in the potato early dying disease complex. Accurate identification and quantification of P. penetrans prior to planting are essential for developing effective integrated pest control measures. However, distinction between P. penetrans and other Pratylenchus spp. based on morphology is a tedious task. A SYBR Green I-based qPCR assay was developed to discriminate, identify, and quantify P. penetrans in field soil. P. penetrans-specific qPCR primers were designed from the D2-D3 region of the 28S rDNA. The specificity of the assay was evaluated using eight isolates of P. penetrans populations and 31 isolates of other nematode species. A standard curve relating threshold cycle and log values of nematode number was generated from artificially infested soils. There was a high correlation between the P. penetrans numbers artificially added to soil or estimated from naturally infested field soils by conventional methods, and the numbers quantified using the qPCR assay. Grinding the field soil prior to DNA extraction improved P. penetrans detection from soil. The qPCR assay will not only be useful for differentiating P. penetrans from mixed populations of Pratylenchus spp., but also for efficient detection and quantification of P. penetrans from field soil. The assay requires no expertise in nematode taxonomy and morphology, and may serve as a useful diagnostic tool in research, diagnostic labs, and extension services for pest management.