| phenotypic and molecular analysis of a pasteuria strain parasitic to the sting nematode. | pasteuria strain s-1 was found to parasitize the sting nematode belonolaimus longicaudatus. s-1 spores attached to several strains of b. longicaudatus from different geographical locations within the united states. however, they did not adhere to any of the following species: heterodera schachtii, longidorus africanus, meloidogyne hapla, m. incognita, m. javanica, pratylenchus brachyurus, p. scribneri, p. neglectus, p. penetrans, p. thornei, p. vulnus, and xiphinema spp. the 16s rrna genes from ... | 2001 | 19266005 |
| survey of crop losses in response to phytoparasitic nematodes in the united states for 1994. | previous reports of crop losses to plant-parasitic nematodes have relied on published results of survey data based on certain commodities, including tobacco, peanuts, cotton, and soybean. reports on crop-loss assessment by land-grant universities and many commodity groups generally are no longer available, with the exception of the university of georgia, the beltwide cotton conference, and selected groups concerned with soybean. the society of nematologists extension committee contacted extensio ... | 1999 | 19270925 |
| effect of plant age and longidorus africanus on the growth of lettuce and carrot. | needle nematodes, longidorus africanus, were added to carrot and lettuce seedlings in a range of inoculum levels and at various times after seeding. the effects of inoculum density and delayed inoculation on plant growth were analyzed according to seinhorst's damage function. growth of both lettuce and carrot was severely affected by l. africanus, but delaying nematode inoculation until 10 days after seeding significantly increased estimated minimum yields in both crop species. tolerance levels ... | 2001 | 19266010 |
| influence of temperature on multiplication and egg hatching of longidorus africanus. | longidorus africanus multiplication on tomato was highest at 29 degrees c. few nematodes were recovered after 6 weeks at soil temperatures of 35 degrees c or below 23 degrees c. the time to egg hatching was shortest and the percentage of eggs hatching was highest at 29 degrees c. the minimum temperature and the heat sum above this temperature required for egg development were calculated to be 14.3 degrees c and 94.08 degree-days, respectively. the thermal times required for egg development by l. ... | 1999 | 19270878 |
| horizontal and vertical distribution of longidorus africanus in a bermudagrass field in the imperial valley, california. | the horizontal and vertical distribution of the needle nematode longidorus africanus was studied in a bermudagrass field in the imperial valley in southern california. a geostatistical method involving the use of semi-variograms was used to quantify the relationship between sampling distance and variation in l. africanus population levels. semi-variance between nematode numbers from different samples was very low when samples were taken close together, increased with sampling distances up to ca. ... | 1998 | 19274252 |
| revised host range and studies on the life cycle of longidorus africanus. | the host range of longidorus africanus was demonstrated to be much wider than previously reported. all commercial crop plants tested, except two of four crucifers, were hosts of l. africanus. the nematode was widespread in fields, and soil type did not appear to be related to its distribution. the minimum time to complete a life cycle was 9 weeks at 28 c in a plant growth chamber. field observations of population densities indicated, however, that in undisturbed field soils the life cycle requir ... | 1987 | 19290109 |
| relationship of grapevine yield and growth to nematode densities. | yield, growth, and vigor of individual grape vines were correlated with nematode population densities in a series of california vineyards. in a hanford sandy loam soil, xiphinema americanum densities showed negative correlations with yield, growth, and vigor of vines. when vines were categorized according to vigor, x. americanurn densities had little relationship to yield of high-vigor vines, but were negatively correlated with yield of low-vigor vines. densities of paratylenchus harnatus were p ... | 1975 | 19308172 |
| biochemical changes in terminal root galls caused by an ectoparasitic nematode, longidorus africanus - nucleic acids. | changes in dna and rna in roots of bur marigold fed upon by longidorus africanus were studied using analytical methods, radioactive precursors, and analytical csc1 density-gradient centrifugation. the analyses showed that almost twice as much rna and dna was present in parasitized root tips as in those of nonparasitized control plants. studies on the rates of incorporation of labeled thymidine and uridine confirmed the dna levels determined by analytical methods, but revealed a much higher incor ... | 1974 | 19319364 |
| biochemical changes in terminal root galls caused by an ectoparasitic nematode, longidorus africanus: phenols, carbohydrates and cytokinins. | biochemical changes occurred in roots of bur marigold and grapevine infected with longidorus africanus. phenols of infected root tips differed quantitatively from those of healthy root tips (optical density of 0.68 and 0.32, respectively). column chromatography of the phenol extracts resulted in more fractions in the infected than in the healthy root extract. of the enzymes involved in phenol metabolism, three were tested. no polyphenol oxidase activity was detected and no difference in catalase ... | 1972 | 19319273 |
| biochemical changes in terminal root galls caused by an ectoparasitic nematode, longidorus africanus: amino acids. | the amino acids of terminal root galls caused by longidorus africanus on bur marigold (bidens tripartita l.) and grapevine (vitis vinifera l.) were studied. the galled roots of bur marigold contained 73% more cell-wall protein and 184% more free amino acids. the main changes among the free amino acids of the galled tissue were a large increase (1900%) in proline and a decrease in aspartic acid (56%) compared with the respective check tissue. hydroxyproline decreased in the wall protein fraction ... | 1971 | 19322388 |
| observations on the feeding and symptomatology of xiphinema and longidorus on selected host roots. | in vitro feeding of xiphinema brevicolle, x. index and longidorus africanus on roots of host seedlings is described. both xiphinema spp. fed mainly along roots rather than at tips and up to several days at a single site. feeding of l. africanus was confined to root tips and lasted up to 15 min. no visible short term reaction of roots parasitized by the xiphinema spp. could be discerned, but both swelling and cessation of growth of root tips were observed within 20 hr after feeding by l. africanu ... | 1970 | 19322291 |
| a comparison of preparation techniques in taxonomic studies of longidorus africanus merny. | a comparison was made of ten different techniques for killing, fixing, and mounting longidorus africanus merny for microscopic study. the most satisfactory specimens were those killed by seinhorst's method, fixed in faa and mounted in glycerin by the slow method. specimens killed by "gentle heat," fixed in faa and mounted in glycerin were also acceptable as were those killed by hot formalin and mounted in glycerin or processed by baker's method. less satisfactory were: nematodes killed by "gentl ... | 1969 | 19325676 |
| exsheathment in longidorus africanus (nematoda: dorylaimoidea). | | 1969 | 19325660 |