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A molecular protocol is presented for distinguishing seven of the most common and economically important Meloidogyne spp. DNA was extracted from individual second-stage juvenile (J2) nematodes of Meloidogyne spp. and amplified by PCR (polymerase chain reaction). Fifteen PCRs including amplification of rDNA, specific SCAR (sequence characterized amplified region) and RAPD (random amplified polymorphic DNA) fragments were possible from the extracted DNA. This enabled a molecular diagnostic key for M. incognita, M. javanica, M. arenaria, M. mayaguensis, M. hapla, M. chitwoodi and M. fallax to be designed. The key unifies published methods into a single logical schematic using primer combinations that were previously validated and shown to work reliably and specifically. The protocol can be used with single juvenile or adult nematodes and the schematic can readily be expanded to accommodate more species. The use of RAPD amplification to assist with identification of samples which do not yield diagnostic amplification products after the first three steps of the molecular key is also described. [ABSTRACT FROM AUTHOR]

Root and stem extracts of Fumaria parviflora showed strong nematicidal activity against Meloidogyne incognita in in vitro and in planta experiments. Phytochemical screening of F. parviflora revealed the presence of seven classes of bioactive compounds (alkaloids, flavonoids, glycosides, tannins, saponins, steroids and phenols). Quantitative determination of the plant extracts showed the highest percentages of alkaloids (0·9 ± 0·04) and saponins (1·3 ± 0·07) in the roots and total phenolic contents in the stem (16·75 ± 0·07 μg dry g−1). The n-hexane, chloroform, ethyl acetate and methanol extracts of roots and stems at concentrations of 3·12, 6·24, 12·5, 25·0 and 50·0 mg mL−1, significantly inhibited hatching and increased mortality of second-stage juveniles (J2s) compared with water controls. Percentage J2 mortality and hatch inhibition were directly related to exposure time. In pot trials with tomato cv. Rio Grande, root and stem extracts at concentrations of 1000, 2000 and 3000 ppm, applied as soil drenches, significantly reduced the number of galls, galling index, eggs masses, eggs and reproduction factor compared with the water control. Regardless of concentration, all the extracts significantly increased the host plant growth parameters studied. The n-hexane extracts from the roots and stem were the most active, followed by the methanol ones, at all concentrations. The in vitro and in planta results suggest that extracts from the roots and stem of F. parviflora may be potential novel nematicides. [ABSTRACT FROM AUTHOR]