The effects of crop rotation and the nematicides 1,3-dichloropropene (1,3-D), ethoprop, and fenamiphos on the relative frequency of Meloidogyne incognita race 3, M. arenaria race 2, and M. javanica and tobacco yields on a sandy loam soil were determined. Cropping sequences altered the species composition and population densities of Meloidogyne spp. Meloidogyne arenaria and M. incognita predomin...

Although marigold (Tagetes patula) is known to produce allelopathic compounds toxic to plant-parasitic nematodes, suppression of Meloidogyne incognita can be inconsistent. Two greenhouse experiments were conducted to test whether marigold is more effective in suppressing Meloidogyne spp. when it is active rather than dormant. Soils infested with Meloidogyne spp. were collected and conditioned i...

Sixty-nine herbaceous perennial ornamentals in 56 genera were evaluated for root galling after 2 months in soil infested with Meloidogyne hapla under greenhouse conditions. Plants were rated susceptible or resistant based on the number of galls present on the root system. Thirty-six percent had more than 100 galls on the roots (similar to 'Rutgers' tomato controls) and were rated susceptible. T...

The interspecific interactions of Meloidogyne javanica with races 1, 2, 3, and 4 of M. incognita on tomato were determined. Impacts of the interactions on fecundity and morphometrics of females were also examined. Mutually inhibitory interactions occurred between M. javanica and the races of M. incognita, but the negative interactions did not reflect in plant growth. Numbers of root galls, egg ...

A survey was conducted to determine the frequency and abundance of Meloidogyne spp. in tomato production sites located in Baix Llobregat County, Barcelona, Spain. Forty-five sites were sampled before planting and at harvest from February to October, 1991. Meloidogyne spp. occurred in 49% of the sites sampled. Preplant population densities ranged from 10 to 220 (x = 110)juveniles/ 250 cm(3) soil...

Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No repr...

The relative DNA content of hypodermal nuclei of preparasitic, 2nd-stage larvae was determined cytophotometrically in 19 populations belonging to 13 species of Meloidogyne, Heterodera and Meloidodera. In Meloidogyne hapla, M. arenaria, M. incognita and M. javanica, total DNA content per nucleus is proportional to their chromosome number, indicating that chromosomal forms with high chromosome nu...

Meloidogyne incognita race 1, M. javanica, M. arenaria race 1, M. hapla, and an undescribed Meloidogyne sp. were analyzed by comparing isozyme phenotypes of esterase, malate dehydrogenase, phosphoglucomutase, isocitrate dehydrogenase, and alpha-glycerophosphate dehydrogenase. Isozyme phenotypes were obtained from single mature females by isoelectric focusing electrophoresis. Of these five isozy...

Meloidogyne arenaria (Neal) Chitwood and M. incognita (Kofoid and White) Chitwood, prevalent in the sandy soils o f the southeastern United States, can severely limit soybean, Glycine max (L.) Merr., yield (10,12). Meloidogyne arenaria populations have increased in some southeastern states in recent years, apparently due to increased plantings of the soybean cultivar 'Centennial', which is resi...

Meloidogyne christiei isolated from turkey oak, Quercus laevies, from the type locality in Florida was characterized using isozyme profiles and ribosomal and mitochondrial gene sequences. The phenotype N1a detected from a single egg-laying female of M. christiei showed one very strong band of malate dehydrogenase (MDH) activity; however, no esterase (EST) activity was identified from macerate o...