Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| root-knot nematode management in dryland taro with tropical cover crops. | twenty-two cover crops were evaluated for their ability to reduce damage by root-knot nematode, meloidogyne javanica, to taro, colocastia esculenta, in a tropical cropping system. cover crops were grown and incorporated into the soil before taro was planted. barley, greenpanic, glycine, marigold, sesame, sunn hemp, and sorghum x sudangrass dekalb st6e were poor or nonhosts to the nematode as measured by low population changes of nematodes in soil between cover crop planting and taro planting. al ... | 1997 | 19274275 |
| host suitability of twelve leguminosae species to populations of meloidogyne hapla and m. chitwoodi. | legumes of the genera astragalus (milkvetch), coronilla (crownvetch), lathyrus (pea vine), lotus (birdsfoot trefoil), medicago (alfalfa), melilotus (clover), trifolium (clover), and vicia (common vetch) were inoculated with a population of melaidogyne chitwoodi from utah or with one of three m. hapla populations from california, utah, and wyoming.thirty-nine percent to 86% of alfalfa (m. scutellata) and 10% to 55% of red clover (t. pratense) plants survived inoculation with the nematode populati ... | 1996 | 19277158 |
| early root response to meloidogyne incognita in resistant and susceptible alfalfa cultivars. | the early events of meloidogyne incognita behavior and associated host responses following root penetration were studied in resistant (cv. moapa 69) and susceptible (cv. lahontan) alfalfa. ten-day-old seedlings of alfalfa cultivars were inoculated with second-stage juveniles (j2) and harvested 12, 24, 48, and 72 hours and 7, 14, and 21 days later. both cultivars supported similar root penetration and initial j2 migration. by 72 hours after inoculation the majority of j2 were amassed inside the v ... | 1996 | 19277165 |
| biological relationship of meloidogyne hapla populations to alfalfa cultivars. | greenhouse and growth chamber studies were established to determine if there are pathological and physiological differences among meloidogyne hapla populations from california (ca), nevada (nv), utah (ut), and wyoming (wy) on alfalfa cultivars classified as resistant or susceptible to root-knot nematodes. in the greenhouse, plant survival was not consistent with resistance classifications. while all highly resistant nevada synthetic germplasm (nev syn xx) plants survived inoculation with all nem ... | 1995 | 19277299 |
| impact of multi-year cropping regimes on solanum tuberosum tuber yields in the presence of pratylenchus penetrans and verticillium dahliae. | five cropping regimes involving combinations of 2 legumes, alfalfa (medicago sativa) and yellow sweet dover (melilotus officinalis), 2 monocots, corn (zea mays) and sudax (sorghum halupeuse x sorghum sudanese), and potato (solanum tuberosum cv. superior) were tested for their impact on potato yields in a field infested with pratylenchus penetrans and verticillium dahliae. no differences in 1990 tuber yields were observed among the five cropping regimes (p < 0.05). in 1991, yields following 1 yea ... | 1995 | 19277337 |
| axenizing and culturing endomigratory plant-parasitic nematodes using pluronic f127, including its effects, on population dynamics of pratylenchus penetrans. | a non-chemical technique for surface sterilizing plant-parasitic nematodes for aseptic cultures is described. the method is most applicable to nematodes with active migratory infective stages and requires only a few starting specimens. rate of achieving a primary aseptic culture with the technique ranged from 60%-100% depending on the conditions of the specimens collected for culturing. aseptic cultures of species of meloidogyne, rotylenchuluz, pratylenchus, and radopholus initiated with the met ... | 1996 | 19277353 |
| comparative response of alfalfa to pratylenchus penetrans populations. | four populations of pratylenchus penetrans did not differ (p > 0.05) in their virulence or reproductive capability on lahontan alfalfa. there was a negative relationship (r = -0 .7 9 ) between plant survival and nematode inocula densities at 26 +/- 3 c in the greenhouse. all plants survived at an inoculum level (pi) of 1 nematode/cm(3) soil, whereas survival rates were 50 to 55% at 20 nematodes/cm(3) soil. alfalfa shoot and root weights were negatively correlated (r = - 0.87; p < 0.05) with nema ... | 1993 | 19279795 |
| effects of mixed cropping on a soil nematode community in honduras. | nematode-resistant tropical legumes are effective in reducing populations of plant-parasitic nematodes when used in rotation systems. mixed cropping is a common practice of many small farmers in central america, but little is known about the effects of tropical legumes on nematode communities under these systems. to examine the effects of intercropping on the nematode fauna associated with squash (cucurbita pepo) and cucumber (cucumis sativa) in honduras, two field experiments were conducted to ... | 1993 | 19279824 |
| host status of selected crops to meloidogyne chitwoodi. | various crops were tested in greenhouse and field trials for their potential utility in the rotation sequence in the potato cropping system in meloidogyne chitwoodi-infested soils of the klamath basin in northeastern california and southern oregon. two solarium accessions from the international potato center in peru were potential sources of resistance to m. chitwoodi. cultivars of barley, oat, rye, wheat, and white lupine were maintenance hosts, supporting the nematode population at its current ... | 1993 | 19279852 |
| inheritance of resistance to pratylenchus penetrans in alfalfa. | fifty-two alfalfa (medicago sativa l.) clones, randomly selected from the cultivar baker and the experimental line mngrn-4, were evaluated for resistance (based on nematode reproduction) to pratylenchus penetrans in growth chamber tests (25 c). twenty-five clones, representing the range of nematodes and eggs per plant, were selected and retested. four moderately resistant and two susceptible alfalfa clones were identified. inheritance of resistance to p. penetrans was studied in these six clones ... | 1994 | 19279915 |
| effect of single and interplantings on pathogenicity of pratyenchus penetrans and p. neglectus to alfalfa and crested wheatgrass. | alfalfa is a host of pratylenchus penetrans and p. neglectus, whereas crested wheatgrass is a host of p. neglectus but not of p. penetrans. in a 120-day greenhouse experiment at 24 ñ 3 c, p. neglectus inhibited the growth of 'lahontan' alfalfa and 'fairway' crested wheatgrass. there were no differences in persistence and plant growth of alfalfa and crested wheatgrass, or reproduction of p. neglectus, in single plantings of alfalfa (ao) or crested wheatgrass (cwo), or in interplanted alfalfa and ... | 1994 | 19279916 |
| distribution in the western united states on alfalfa and cultivar reaction to mixed populations of ditylenchus dipsaci and aphelenchoides ritzemabosi. | ditylenchus dipsaci and aphelenchoides ritzemabosi were extracted from 29 of 40 plant samples (72.5%) collected from arizona, california, colorado, idaho, montana, oregon, south dakota, utah, washington, and wyoming. percentages of a. ritzemabosi in tissue of the 29 samples ranged from 1.77 to 67.82%. only ditylenchus dipsaci was recovered from the remaining 11 samples. all of the 16 fields sampled in wyoming contained both nematodes. percentages of a. ritzemabosi in the wyoming samples ranged f ... | 1994 | 19279952 |
| diet selection and milk production and composition in girgentana goats with different alpha s1-casein genotype. | in goats, alpha s1-casein polymorphism is related to different rates of protein synthesis. two genetic variants, a and f, have been identified as strong and weak alleles based on a production of 3.5 and 0.45 g/l of alpha s1-casein per allele. the aim of the trial was to test whether goats can select their diet as a function of their genetic aptitude to produce milk at different casein levels and whether this selection can influence milk production or composition. two groups of 8 animals, homozyg ... | 2009 | 19281625 |
| stem nematode-fusarium wilt complex in alfalfa as related to irrigation management at harvest time. | a high moisture level in the top 10 cm of soil at time of cutting of alfalfa increased the incidence of plant mortality and fusarium wilt in soil infested with ditylenchus dipsaci and fusarium oxysporum f. sp. medicaginis in greenhouse and field microplot studies. ranger alfalfa, susceptible to both d. dipsaci and f. oxysporum f. sp. medicaginis, was less persistent than moapa 69 (nematode susceptible and fusarium wilt resistant) and lahontan alfalfa (nematode resistant with low fusarium wilt re ... | 1992 | 19283002 |
| resistance of lathyrus species and accessions to the northern root-knot nematode, meloidogyne hapla. | the leguminous plant genus lathyrus contains many species useful for soil conservation and reclamation. some of these species may also have vaiue in the united states for forage production. the extent of genetic variation among lathyrus populations in reaction to most disease pathogens is not known. we examined 28 usda agricultural research service plant introduction accessions representing 16 lathyrus species for their ability to tolerate attack by the northern root-knot nematode, meloidogyne h ... | 1992 | 19283053 |
| influence of selected plant species on hatching of eggs and development of juveniles of heterodera glycines. | the influence of selected plant species on egg hatch and subsequent development of heterodera glycines race 3 was investigated. plants tested included four soybean cultivars, red clover, alfalfa, hairy vetch, field corn, sweet corn, cabbage, tobacco, cotton, and wheat. soybean stimulated egg hatching more than any of the other plant species, with h. glycines-resistant cultivars being more stimulating than susceptible ones. hairy vetch also increased hatch. roots of cabbage, red clover, alfalfa, ... | 1991 | 19283087 |
| penetration of celery and alfalfa roots by pratylenchus penetrans as affected by temperature. | a greater percentage of females than juveniles or males of p. penetrans penetrated celery roots grown in infested soil at 5, 18, or 30 c; the difference was greatest at 5 c. the time of initial penetration of alfalfa seedlings inoculated with single nematodes on water agar varied with temperature. females penetrated the seedlings earlier and over a wider range of temperatures than did males or juveniles. the rate of penetration was highest for females. after initial penetration, the penetration ... | 1991 | 19283112 |
| relationship of ditylenchus dipsaci and harvest practices to the persistence of alfalfa. | persistence of dormant ranger and nondormant moapa alfalfas, both susceptible to ditylenchus dipsaci, varied with stand age and cutting frequency. stand reduction increased with cutting frequency. in d. dipsaci-infested soil, stand reductions in ranger 1, 4, and 5 years old exceeded reductions in stands 2 and 3 years old; persistence was greatest in 2-year-old stands. in moapa alfalfa, d. dipsaci reduced stands the most in years 2 and 3; whereas persistence was greatest in 1-year-old stands. har ... | 1991 | 19283131 |
| effect of cropping regime on populations of belonolaimus sp. and pratylenchus scribneri in sandy soil. | the host efficiencies of corn, sorghum, soybean, and wheat were compared for a kansas population of belonolaimus sp. under greenhouse conditions. in a related field study conducted in 1989 and 1990, the responses of belonolaimus sp. and pratylenchus scribneri populations to eight cropping regimes were monitored at depths of 0-30 and 31-60 cm in sandy soil. with the exception of alfalfa, all crop species examined supported substantial increases in populations of both nematodes. largest nematode p ... | 1991 | 19283178 |
| pathogenicity of two populations of meloidogyne hapla chitwood on alfalfa and sainfoin. | the pathogenicity of two populations of the northern root-knot nematode, meloidogyne hapla chitwood, population 1 (p1) from alfalfa and population 2 (p2) from sainfoin, was studied on both alfalfa and sainfoin for 25 weeks. alfalfa and sainfoin plants inoculated with p2 had significantly (p </= 0.05) higher mortality than plants inoculated with p1. plant stands over all weeks for the uninoculated control, p1, and p2 were 90.5, 78.5, and 64.0% for alfalfa and 84.5, 51.0, and 41.0% for sainfoin, r ... | 1989 | 19287580 |
| biological control of meloidogyne hapla on alfalfa and tomato with the fungus meria coniospora. | this study was to determine whether arthrobotrys flagrans, a. oligospora, and meria coniospora would control the root-knot nematode meloidogyne hapla on alfalfa and tomato. alfalfa seeds were coated with a fungus-rye powder in 2% cellulose and were planted in infested soil. three-week-old seedlings from seed treated with m. coniospora had 60% and 58% fewer galls in two experiments than did seedlings from untreated seeds. numbers of j2 in the soil were not reduced. plant growth did not improve. w ... | 1989 | 19287596 |
| a nematicide seed treatment to control ditylenchus dipsaci on seedling alfalfa. | three nematicides were evaluated as seed treatments to control the alfalfa stem nematode (ditylenchus dipsaci) on seedling alfalfa. alfalfa seeds were soaked for 10 hours in a 0.5% (formulated by weight) concentration of either carbofuran, phenamiphos or oxamyl in acetone with no adverse effect on seed germination. all three treatments decreased nematode damage and increased survival of 'ranger' (susceptible) and 'lahontan' (resistant) alfalfa plants, when seeds were planted in soil infested wit ... | 1989 | 19287597 |
| efficacy of oxamyl coated on alfalfa seed with a polymer sticker in pratylenchus and meloidogyne infested soils. | a polymer sticker was used as a coating in which oxamyl was applied to seeds of alfalfa cultivar saranac for the control of pratylenchus penetrans and meloidogyne hapla. the sticker, diluted 1:1 (sticker:water) to 1:5, delayed seedling emergence during the first 4 days after planting. by day 13, however, emergence from all sticker treatments was comparable to the control. shoot growth of seedlings at day 21 was less than that of the control only from seeds coated with a 1:1 dilution; root growth ... | 1989 | 19287603 |
| susceptibility of nevada synthetic xx germplasm to a california race of meloidogyne hapla. | 1989 | 19287611 | |
| ultrastructural pathology of cells affected by pratylenchus penetrans in alfalfa roots. | cortical parenchyma cells penetrated and fed upon by pratylenchus penetrans for 48 hours contained only cytoplasmic debris. proximal cells had an increase in tannin deposits, degenerated mitochondria, increased numbers of ribosomes, and no internal membrane structure. often the endodermis was collapsed and contained massive tannin deposits on the inner cell wall and cell lumen. similar observations were made in the stele, except tannin deposits were not as prominent. multivesicnlate structures w ... | 1989 | 19287649 |
| pathological relationship of ditylenchus dipsaci and fusarium oxysporum f. sp. medicaginis on alfalfa. | ditylenchus dipsaci and fusarium oxysporum f. sp. medicaginis synergistically affected the mortality and plant growth of ranger alfalfa, a cultivar susceptible to stem nematode and fusarium wilt. the nematode-fungus relationship had an additive effect on mortality and plant growth of lahontan (nematode resistant and fusarium wilt susceptible) and of moapa 69 (nematode susceptible and fusarium wilt resistant). mortality rates were 13, 16, 46, and 49% for ranger; 4, 18, 26, and 28% for lahontan; a ... | 1990 | 19287729 |
| interaction among a nematode (heterodera glycines), an insect, and three weeds in soybean. | a 2 x 3 x 4 factorial field experiment was established to determine the interaction among a nematode, an insect, and three weed species on soybean in 1983-86. low (nematicide treated) or high (untreated) population densities of the soybean cyst nematode (scn), heterodera glycines, and 0, 30, or 70% main stem girdling by the threecornered alfalfa hopper (tcah), spissistilus festinus, were combined with no weeds, one common cocklebur (cc), xanthium strumarium, one sicklepod (sp), cassia obtusifoli ... | 1990 | 19287788 |
| [effects of rotation and intercropping on bacterial communities in rhizosphere soil of cucumber]. | by the method of pcr-dgge, this paper studied the effects of rotation with wheat, soybean, villose vetch, clover, and alfalfa and intercropping with onion and garlic on the bacterial communities in rhizosphere soil of cucumber. the results showed that rotation and intercropping with test plants increased the diversity and evenness indices of bacterial communities in cucumber rhizosphere soil, and also, cucumber yield. the sequencing of dgge bands indicated that most of the bands had high homolog ... | 2008 | 19288729 |
| evaluation of cultivars, experimental lines and plant introduction collection of sainfoin for resistance to meloidogyne hapla chitwood. | stands of several cultivars and experimental lines of sainfoin (onobrychis viciifolia) were severely reduced (92% average loss) in a field naturally infested with meloidogyne hapla. stands of two alfalfa cultivars included in the test were unaffected. in studies conducted in the greenhouse with plants inoculated at the time of seeding, average mortality was 55% for sainfoin entries and 7% for ladak alfalfa. little mortality occurred when plants were inoculated after establishment. three months a ... | 1987 | 19290103 |
| nematode-degree days, a density-time model for relating epidemiology and crop losses in perennials. | the impact of meloidogyne hapla on alfalfa (medicago sativa) yield was described by a multiple point damage model as a function of current plant status, cumulative pest stress, and crop history. nematode-degree days (ndd(female symbol)), calculated on a physiologic time scale as total area under the adult female population density curve, were used to express m. hapla parasitism as cumulative nematode dosage. ndd(female symbol) increased exponentially over physiological time at rates relative to ... | 1987 | 19290114 |
| effects of environmental factors and cultural practices on parasitism of alfalfa by ditylenchus dipsaci. | cool humid weather enhanced development and reproduction of ditylenchus dipsaci in alfalfa in laboratory and field studies in utah. relative humidity and nematode reproduction were positively correlated (p < 0.05), whereas air temperature and nematode reproduction were negatively correlated (p < 0.05). the greatest number of nematodes per gram of alfalfa tissue was found in nondormant moapa alfalfa tissue at st. george during april, whereas the greatest numbers of nematodes were found in dormant ... | 1987 | 19290142 |
| effect of ditylenchus dipsaci and pratylenchus penetrans on verticillium wilt of alfalfa. | verticillium albo-atrum wilt symptoms appeared faster and were significantly more severe in the presence of ditylenchus dipsaci in vernal, a wilt-susceptible cultivar, than in marls kabul, a wilt-resistant cultivar. winter kill in the field was not affected by the nematode during the first winter, but 50% of plants were killed in the second winter. forage yield from nematode-infected plants was significantly reduced the second year. interaction with v. albo-atrum did not significantly reduce for ... | 1987 | 19290158 |
| interaction of ditylenchus dipsaci and meloidogyne hapla on resistant and susceptible plant species. | numbers ofditylenchus dipsaci or meloidogyne hapla invading ranger alfalfa, tender crop bean, stone improved tomato, ah-14 sugarbeet, yellow sweet clover, and wasatch wheat from single inoculations were not significantly different from numbers by invasion of combined inoculations. d. dipsaci was recovered only from shoot and m. hapla only from root tissue. combined inoculations did not affect reproduction of either d. dipsaci or m. hapla. d. dipsaci suppressed shoot growth of all species at 15-3 ... | 1987 | 19290168 |
| control of pratylenchus penetrans and meloidogyne hapla and yield response of alfalfa due to oxamyl seed treatments. | alfalfa (medicago sativa l. cv. saranac) seed were soaked for 20 minutes in water, acetone, or methanol containing 10 or 50 mg/ml of oxamyl (vydate l) or coated with a 2% aqueous cellulose solution containing the same amounts of oxamyl. seed were analyzed for oxamyl by hplc immediately after treatment and after 9 and 26 months of storage. oxamyl content of alfalfa seed did not decline after 26 months of storage. the effects of seed treatment on growth of alfalfa and nematode control were examine ... | 1987 | 19290170 |
| differential response of thor alfalfa to meloidogyne chitwoodi races and m. hapla. | second-stage juveniles (j2) of races 1 and 2 of meloidogyne chiiwoodi and m. hapla readily penetrated roots of thor alfalfa and columbian tomato seedlings; however, few individuals of m. chitwoodi race 1 were able to establish feeding sites and mature on alfalfa. histopathological studies indicate that j2 of race 1 either failed to initiate feeding sites or they caused cell enlargement without typical cell wall thickening. the protoplasm of these cells coagulated, and juveniles of race 1 did not ... | 1988 | 19290231 |
| host tests to differentiate meloidogyne chitwoodi races 1 and 2 and m. hapla. | the reproductive factor (r = final egg density at 55 days / 5,000, initial egg density) of meloidogyne chitwoodi race 2 (alfalfa race) on 46 crop cultivars ranged from 0 to 130. the reproductive efficiency of m. chitwoodi race 1 (non-alfalfa race) and m. chitwoodi race 2 was compared on selected crop cultivars. the basic difference between the two races lay in their differential reproduction on thor alfalfa and red cored chantenay carrot. m. chitwoodi race 2 reproduced on alfalfa but not on carr ... | 1988 | 19290239 |
| effects of aldicarb on nematodes, early season insect pests, and yield of soybean. | the effects of aldicarb on soybean cyst (heterodera glycines) and root-knot (meloidogyne incognita and m. arenaria) nematode populations, early season insect pests and soybean (glycine max) yield were evaluated in five field experiments in northern and southern alabama. aldicarb significantly (p = 0.05) reduced nematode populations in only two cases: m. arenaria in centennial soybean in the wiregrass site and m. incognita in bedford soybean in a tennessee valley site. no significant difference ( ... | 1987 | 19290282 |
| transport of the nematicide oxamyl in roots transformed with agrobacterium rhizogenes. | infection of roots transformed with agrobacterium rhizogenes by meloidogyne incognita and heterodera schachtii second-stage juveniles was established in bicompartmental petri dishes. one compartment contained the murashige and skoog agar medium and the nematicide oxamyl, and the other compartment contained water agar. transformed roots of carrot, tomato, alfalfa, cowpea, rape, and sugarbeet were placed in the nutrient compartment and grew over the barrier that divided the petri dishes and into t ... | 1988 | 19290298 |
| host specificity of four populations of pratylenchus brachyurus. | four populations of the lesion nematode pratylenchus brachyurus were tested in a greenhouse on seven selected plant species to determine host suitability and usefulness in identifying physiological races of the nematode. the differential plants were 'florida 77' alfalfa, 'harvester' snap bean, 'rough lemon' citrus, 'pioneer 304c' corn, 'florunner' peanut, 'braxton' soybean, and 'rutgers' tomato. fresh shoot or root weights of plants inoculated with all populations were similar to each other and ... | 1988 | 19290320 |
| effect of soil temperature on reproduction of meloidogyne chitwoodi and m. hapla alone and in combination on potato and m. chitwoodi on rotation plants. | meloidogyne chitwoodi developed and reproduced more rapidly than m. hapla in potato roots at 15, 20, or 25 c when both species of nematodes were inoculated simultaneously at 250 or 1,000 juveniles of each. at 30 c significantly more m. hapla than m. chitwoodi females were found at the lower inoculum level after 41 days. more m. chitwoodi than m. hapla juveniles were extracted from soil at 15, 20, and 25 c, but only at the lower inoculum level at 30 c. potato was considered a more suitable host f ... | 1984 | 19294027 |
| effect of ditylenchus dipsaci on alfalfa mortality, winterkill, and yield. | ditylenchus dipsaci-infected and noninfected alfalfa plants in a naturally infested field were studied from july 1980 to september 1982. forty-one percent of the plants died during the study. ninety-seven percent of the plants that died were infected with d. dipsaci. sixty-nine percent of the observed mortality occurred during winter. forage yield of infected plants was significantly lower than yield of noninfected plants at each harvest. stored carbohydrates in infected plants were significantl ... | 1985 | 19294072 |
| influence of meloidogyne hapla on alfalfa yield and host population dynamics. | self-thinning in alfalfa, a dynamic process involving the progressive elimination of the weakest plants, was enhanced by meloidogyne hapla. alfalfa stand densities decreased exponentially with time and were reduced 62% (p = 0.05) in the presence of m. hapla. as stand densities decreased over time, mean plant weights increased at a rate 2.59 times faster in the absence of m. hapla. in a stepwise multiple regression analysis, 65% of the total variation in yield could be explained by changes in sta ... | 1985 | 19294119 |
| interaction of vesicular-arbuscular mycorrhizae and cultivars of alfalfa susceptible and resistant to meloidogyne hapla. | the interaction between vesicular-arbuscular mycorrhizal (vam) fungi and the root-knot nematode (meloidogyne hapla) was investigated using both nematode-susceptible (grasslands wairau) and nematode-resistant (nevada synthetic xx) cultivars of alfalfa (medicago sativa) at four levels of applied phosphate. mycorrhizal inoculation improved plant growth and reduced nematode numbers and adult development in roots in dually infected cultures of the susceptible cultivar. the tolerance of plants to nema ... | 1986 | 19294155 |
| differential reaction of alfalfa cultivars to meloidogyne hapla and m. chitwoodi populations. | meloidogyne hapla reproduced and suppressed growth (p < 0.05) of susceptible lahontan and moapa alfalfa at 15, 20, and 25 c. at 30 c, resistant nevada syn xx lost resistance to m. hapla. m. hapla invaded and reproduced on rhizobium meliloti nodules of lahontan and moapa, inducing giant cell formation and structural disorder of vascular bundles of nodules without disrupting bacteroids. at 15, 20, and 25 c a m. chitwoodi population from utah reproduced on lahontan, moapa, and nevada syn xx alfalfa ... | 1986 | 19294189 |
| influence of alfalfa plant growth on the multiplication rates and ceiling population density of meloidogyne hapla. | the rates of reproduction and multiplication of meloidogyne hapla decreased as a result of self-regulatory, density-dependent processes with time and nematode population increase in the soil and roots of medicago sativa cv. cuf 101. juvenile, egg, and mature female population densities increased at a maximum rate until damage to the host resulted in alfalfa yield reductions. temporal differences in multiplication and reproduction rates of m. hapla were observed to be a function of initial popula ... | 1986 | 19294220 |
| population dynamics of meloidogyne incognita on corn grown in soil in fested with arthrobotrys conoides. | microplot and greenhouse experiments were conducted to evaluate the effects of soil incorporation of the nematophagous fungus arthrobotrys conoides and green alfalfa mulch on the population dynamics of meloidogyne incognita on corn. reproduction of m. incognita and the incidence of root galling were reduced by the addition of a. conoides and/or green alfalfa in all tests. numbers of juveniles were reduced by as much as 84%, and eggs were fewest in early to mid-season soil samples from microplots ... | 1982 | 19295673 |
| effect of age of alfalfa root on penetration by pratylenchus penetrans. | penetration by all migratory life stages of pratylenchus penetrans into roots of alfalfa (medicago sativa l. cv. du puits) was inversely proportional to tissue age. two-day-old tissue in the root hair zone was penetrated twice as much as 10- or 20-day-old sections of the tap root. age-related differences were also observed in branch roots; these differences were not affected by increasing the number of nematodes from 1 to 10 per inoculation site, nor by increasing the length of the incubation pe ... | 1982 | 19295681 |
| interactions among selected endoparasitic nematodes and three pseudomonads on alfalfa. | meloidogyne hapla, pratylenchus penetrans, and helicotylenchus dihystera, reduced the growth of 'saranac ar alfalfa seedlings when applied at concentrations of 50 nematodes per plant. all except p. penetrans reduced seedling growth when applied at 25 per seedling. m. hapla reduced growth when applied at 12 per seedling. nematodes interacted with three pseudomonads to produce greater growth reductions than were obtained with single pathogens, suggesting synergistic relationships. ditylenchus dips ... | 1982 | 19295682 |
| the effect of arthrobotrys conoides on meloidogyne incognita population densities in corn as influenced by temperature, fungus inoculum density, and time of fungus introduction in the soil. | in greenhouse experiments, the effect of arthrobotrys conoides on meloidogyne incognita population densities as affected by soil temperature, inoculum density, and green alfalfa was determined. the effect on m. incognita population densities was greater at a soil temperature of 25 c than at 18 or 32 c. nematode control by a. conoides was most effective when the fungus was introduced into the soil 2 wk prior to nematode inoculation and planting of corn. inoculum density of a. conoides was positiv ... | 1982 | 19295692 |
| suppression of alfalfa growth by concommitant populations of pratylenchus penetrans and two fusarium species. | growth of alfalfa (medicago sativa cv. vernal) seedlings was compared after inoculation with combinations of either pratylenchus penetrans and fusarium soloni or p. penetrans and f. oxysporum f. sp. medicaginis. a synergistic disease interaction occurred in alfalfa when f. oxysporum and p. penetrans were added simultaneously to the soil. alfalfa growth was suppressed at all inoculum levels of p. penetrans and f. oxysporum, but not with f. solani. seedlings inoculated with the nematode alone gave ... | 1982 | 19295722 |
| morphological comparisons between xiphinema rivesi daimasso and x. americanum cobb populations from the eastern united states. | though in the past xiphinema americanum has been the most commonly reported dagger nematode in the eastern united states, our studies revealed the presence in pennsvlvania of a previously unrecognized and unreported species related to x. americanum, morphometric data and photomicrographs establish the identity of this form as x. rivesi and show expected variations in populations of this species from various locations. similar data and illustrations are given for x. americanum populations from pe ... | 1982 | 19295745 |
| the interrelationship of heterodera schachtii and ditylenchus dipsaci on sugarbeet. | heterodera schachtii significantly (p = 0.05) reduced sugarbeet root growth below that of uninoculated controls at 20, 24, and 28 c, and ditylenchus dipsaci significantly (p = 0.05) reduced root growth below that of uninoculated controls at 16, 20, 24, and 28 c. a combination of h. schachtii and d. dipsaci significantly (p = 0.05) reduced root growth below that of single inoculations of h. schachtii at all temperatures and d. dipsaci at 20, 24, and 28 c. single inoculations of h. schachtii and d ... | 1983 | 19295828 |
| response of two alfalfa cultivars to meloidogyne hapla. | 1983 | 19295860 | |
| effects of phenamiphos, methyl bromide, and fallowing on pratylenchus penetrans, yield of medicago sativa, and fusarium infections. | a field study was made of the effects of a residual nematicide (phenamiphos), a fumigant (methyl bromide), and fallowing on the number of root lesion nematodes (pratylenchus penetrans), forage yields of alfalfa, and the occurrence of fusarium spp. in plant roots and soil. fallowing controlled nematodes initially, but by the end of the second growing season, nematode numbers were as high as in plots which had grown a nematode-susceptible crop. forage yield was greater in fallowed plots only for t ... | 1979 | 19300645 |
| effect of nonhost cultivars on heterodera schachtii population dynamics. | broadcast plantings of nonhost cultivars (alfalfa, barley, bean, onion, potato, and wheat) in soil in redwood boxes (4.2 x 30 x 14 cm) infested with heterodera schachtii reduced the initial nematode populations (p = 0.05). the reduction was greater with sugarbeets, a host, than with all other cropping treatments except onion, bean, and fallow (p = 0.05). after 80 days, when the root growth of all treatments had completely penetrated the soil, the nematode population was lower under onion than un ... | 1980 | 19300671 |
| plant-parasitic nematode distributions in an alfalfa field. | a 7-ha alfalfa field (medicago saliva l. cv mesa sirsa) was sampled systematically on a 6 x 6-m grid by removing individual cores (2.54 cm diam) to a depth of 45 cm from each of the 1,936 grid intersections. the soil was mainly coarse-textured with a fine-textured streak running centrally, north to south. nematodes were extracted by a semiautomatic elutriator and sugar flotation-sieving technique. five plant-parasitic species were consistently present: meloidogyne arenaria, pratylenchus minyus, ... | 1980 | 19300685 |
| interrelationship of meloidogyne hapla and ditylenchus dipsaci on resistant and susceptible alfalfa. | simultaneous inoculations of alfalfa with meloidogyne hapla larvae and ditylenchus dipsaci at 16, 20, 24, and 28 c did not depress penetration of either nematode in 'nev syn xx' -a selection resistant to m. hapla and d. dipsaci, 'vernal 298' -a selection resistant to m. hapla and susceptible to d. dipsaci, 'lahontan' -a cultivar resistant to d. dipsaci and susceptible to m. hapla, and 'ranger' -a cultivar susceptible to both m. hapla and d, dipsaci. infection with d. dipsaci depressed growth of ... | 1980 | 19300705 |
| influence of nonhosts, crucifers, and fungal parasites on field populations of heterodera schachtii. | heterodera schaehtii egg number decline under nonhosts was surveyed for 3-4 years at soil depths of 0-30 cm and 30-60 cm in three fields in the imperial valley, california. in the two fields continously cropped to alfalfa, annual decline rates were 49 and 63%, respectively, and did not differ (p = 0.05) between depths. in the third field, cropped to annual nonhosts and fallowed, decline rates of 56 and 80% at 0-30-cm and 30-60-cm depths, respectively, were significantly different (p = 0.05). egg ... | 1981 | 19300739 |
| sample optimization for five plant-parasitic nematodes in an alfalfa field. | a data base representing nematode counts and soil weight from 1,936 individual soil cores taken from a 7-ha alfalfa field was used to investigate sample optimization for five plant-parasitic nematodes: meloidogyne arenaria, pratylenchus minyus, merlinius brevidens, helicotylenchus digonicus, and paratrichodorus minor. sample plans were evaluated by the accuracy and reliability of their estimation of the population and by the cost of collecting, processing, and counting the samples. interactive f ... | 1981 | 19300768 |
| influence of soil temperature and ph on pratylenchus penetrans and p. crenatus in alfalfa and timothy. | numbers of pratylenchus penetrans in alfalfa and timothy, and to a lesser extent p. crenatus in timothy, increased substantially as temperature increased from about l0 c to 30 c. however, p. crenatus in alfalfa decreased in number as temperature increased. mobility of p. crenatus in vertical soil columns decreased as temperature increased from 9.5 c to 28.5 c. raising the soil ph from 5.0 to 6.9 in which alfalfa was grown increased the numbers of p. penetrans and greatly reduced the numbers of p ... | 1981 | 19300772 |
| effects of dcpa, eptc, and chlorpropham on pathogenicity of meloidogyne hapla to alfalfa. | treatments wilh the herbicides chlorpropham (isopropyl m-chlorocarbinilate), dcpa (dimethyl tetrachloroterephthalate), and el'tc (s-ethyl dipropylthiocarbamate), alone or in combination with meloidogyne hapla chilwood, significantly reduced the growth of both nemalode-resistant 'nev syn xx' atttt susceptible 'ranger" alfalfa (medicago saliva l.) seedlings. m. hapla infection of both alfalfas was reduced by all herbicides because of fewer available infective courts in the treated plants. eptc, ho ... | 1979 | 19305525 |
| penetration and development of meloidogyne hapla in resistant and susceptible alfalfa under differing temperatures. | studies were conducted to examine under differing temperatures (12, 16, 20, 24, 28, and 32 c) the penetration anti development of meloidogyne hapla in resistant lines '298' and 'nev. syn xx', and susceptible 'lahontan' and 'ranger' hardy-type alfalfas. the results indicated that resistance to m. hapla was similar to that previously described for m. incognita in nonhardy alfalfa. although initial penetration in resistant seedlings was similar to that of susceptible seedlings, nematode larvae fail ... | 1977 | 19305571 |
| resistant host responses to ten california populations of meloidogyne incognita. | resistant and susceptible cultivars of tomato, lima beans, cotton, and alfalfa were tested with 10 populations of meloidogyne incognita from different california locations. nine of the populations differed in aggressiveness on the nine cultivars tested. two populations were especially aggressive toward resistant tomato cultivars. | 1978 | 19305845 |
| infectivity of pratylenchus penetrans on alfalfa. | the infectivity of pratylenchus penetrans on alfalfa seedlings cv. du pulls was studied. the dense root-hair zone was the preferred zone of penetration by females, males, and third-stage larvae. a lesion initially appeared as a water-soaked area at the root surface, becoming yellow and elliptical as the nematode entered the cortex, with dark-brown cells later appearing in the centre as the nematode fed. at 20 c, females penetrated roots earlier, faster, and in greater numbers than either males o ... | 1978 | 19305861 |
| nutrient demand interacts with forage family to affect nitrogen digestion and utilization responses in dairy cows. | the effect of preliminary feed intake on responses to diets containing alfalfa silage or orchardgrass silage was evaluated using 8 ruminally and duodenally cannulated holstein cows in a crossover design experiment with a 14-d preliminary period and two 15-d treatment periods. responses measured were intake, digestion, and utilization of n. cows were 139 +/- 83 (mean +/- standard deviation) days in milk at the beginning of the preliminary period. during the 14-d preliminary period, 3.5% fat-corre ... | 2009 | 19307641 |
| increasing physically effective fiber content of dairy cow diets through forage proportion versus forage chop length: chewing and ruminal ph. | a study was conducted to evaluate whether the risk of acidosis in dairy cows can be lowered by increasing the physically effective fiber (pendf) concentration of the diet, either through increased theoretical chop length of alfalfa silage or higher proportion of forage in the diet. the experiment was designed as a replicated 4 x 4 latin square using 8 ruminally cannulated lactating dairy cows. treatments were arranged in a 2 x 2 factorial design; 2 forage particle lengths (fpl) of alfalfa silage ... | 2009 | 19307642 |
| near-infrared reflectance spectroscopy prediction of neutral detergent-soluble carbohydrates in timothy and alfalfa. | carbohydrates in forage crops can be divided into neutral detergent-insoluble fiber and neutral detergent-soluble carbohydrates (ndsc); the latter includes organic acids (oa), total ethanol:water-soluble carbohydrates (tesc), starch, and neutral detergent-soluble fiber (ndsf). the accurate and efficient estimation of ndsc in forage crops is essential for improving the performance of dairy cattle. in the present study, visible and near-infrared reflectance spectroscopy (nirs) were applied to eval ... | 2009 | 19307652 |
| alfalfa pellet-induced subacute ruminal acidosis in dairy cows increases bacterial endotoxin in the rumen without causing inflammation. | a study was conducted to determine if subacute ruminal acidosis (sara) induced by feeding alfalfa pellets results in increases in free bacterial lipopolysaccharide (lps) in rumen fluid and peripheral blood, and acute phase proteins in plasma, and to determine the effect of alfalfa pellet-induced sara on feed intake, rumen fermentation characteristics, milk production and composition, and blood metabolites. eight lactating holstein cows, 4 of which were ruminally cannulated, were used in a 6-wk e ... | 2009 | 19307653 |
| effect of a mixture of supplemental dietary plant essential oils on performance of periparturient and early lactation dairy cows. | plant essential plant oils (eo) are volatile aromatic compounds with antimicrobial activity that can alter ruminal fermentation when used as dietary supplements. a feeding trial was conducted to determine the effects of dietary supplementation of periparturient and early lactation dairy cows with a specific mixture of eo. forty multiparous holstein cows were randomly assigned to either control (c) or eo-supplemented (1.2 g/cow per day) total mixed rations (tmr). feeding of treatment diets commen ... | 2009 | 19307655 |
| technical note: effects of forage protein-binding polyphenols on chemistry of dairy excreta. | forage chemistry can affect intake, digestion, milk production, and manure excretion. although information is available on the effects of forage protein-binding polyphenols on small ruminant production and manure excretion, little information is available for dairy cattle. the objective of this study was to compare fecal and urinary n excretion of diets formulated with alfalfa (medicago sativa l.) silage versus condensed tannin-containing birdsfoot trefoil (lotus corniculatus) or o-quinone-conta ... | 2009 | 19307659 |
| mass culturing of ditylenchus dipsaci to yield large quantities of inoculum. | methods are described for rearing large quantities of ditylenchus dipsaci on alfalfa tissues. nematodes and alfalfa seed were disinfected and nematodes were reared in quantities sufficient to provide a continuous supply of inoculum for our alfalfa-breeding program. nematodes reproduced best in darkness at 20-25 c. cultures reached maximum numbers in 3-6 wk. | 1974 | 19308113 |
| effect of meloidogyne incognita on reproduction of pratylenchus penetrans in red clover and alfalfa. | roots of seedlings of red clover and alfalfa growing on 10(1) hoagland and arnon solution agar were inoculated with various combinations of meloidogyne incognita and pratylenchus penetrans. egg-laying by p. penetrans decreased as the number of nematodes, the ratio of entrant m. incognita to entrant p. penetrans, and the priority of invasion of roots by m. incognita increased. embryogeny and hatching of eggs of p. penetrans, and development of larvae of m. incognita, were not affected. in red clo ... | 1975 | 19308128 |
| feeding, egg-laying, and embryology of the columbia lance nematode, hoplolaimus columbus. | feeding and egg-laying of hoplolaimus columbus were observed on excised alfalfa (cultivar 'dupuits') root cultures in 1.0% nutrient agar. feeding was ectoparasitic on cortical cells in the maturation zone of the root. oocytes were first observed in the anterior ovary of the feeding female 8-9 days after feeding began. globular secretions emanating from the vagina and vulva preceded migration of the posterior-most oocyte of the anterior gonad into the columella. the egg shell was formed within 8 ... | 1975 | 19308148 |
| freezing and storing ditylenchus dipsaci in liquid nitrogen. | after 18 months of storage at -150 c, some larvae of ditylenchus dipsaci, which had been treated in a 7.5% solution of dimethyl sulphoxide and cooled to -25 c before storage, were still viable on thawing. some survivors penetrated and developed normally in stems of alfalfa seedlings. tests showed that active larvae could be frozen directly, thus eliminating the need to use the quiescent stage of this nematode previously thought necessary for successful storage at cryogenic temperatures. the meth ... | 1975 | 19308154 |
| parasitism of nonhost cultivars by ditylenchus dipsaci. | the alfalfa race of ditylenchus dipsaci parasitized and caused characteristic symptoms on nonhost seedlings of sweet clover, onion, tomato, sugarbeet, and wheat in controlled growth-chamber studies. although the nematode was unable to reproduce on any of the cultivars, it caused plant mortality ranging from 20% on sugarbeet and tomato to 100% on onion. | 1975 | 19308163 |
| effects of temperature on the fine-structural responses in the hypocotyl region of alfalfa lines to ditylenchus dipsaci. | fine-structural analyses were made of the response of host tissue, medicago sativa l. 'ranger' and 'lahontan', to infection by the stem nematode, ditylenchus dipsaci (kühn) filipjev. seedlings were grown at 15 and 25 c, and hypocotyl regions were sampled 1,3, or 7 days after inoculation. electron micrographs of infected alfalfa tissue indicated that the same types of damage were inflicted on lahontan (stem-nematode-tolerant)and ranger (stem-nematode-susceptible). only the infection rate and degr ... | 1975 | 19308164 |
| factors affecting the infection of alfalfa seedlings by ditylenchus dipsaci. | experiments were conducted to determine the effects of plant confinement, soil type, watering practices, stage of seed germination, inoculum level, and method of applying inoculum on stem nematode (ditylenchus dipsaci) infection of alfalfa (medicago sativa) seedlings grown in soil. results indicated that (i) confining seedlings together with the nematodes in small vials offered no advantage over growing plants in large flats, (ii) a very fine sandy-loam soil was superior to a fine sand for stem- ... | 1975 | 19308186 |
| effects of potassium fertilization and pratylenchus penetrans on yield and potassium content of red clover and alfalfa. | red clover and alfalfa were inoculated with pratylenchus penetrans and grown in an alberry sandy loam soil to which potassium (k) was added at seeding at 0, 41.5, 83, and 166 microg/g. in one experiment with alfalfa, additional k was added after each forage cut to replace that which was removed. nematode populations were not consistently affected by k fertilization. nematode infection stunted red clover and alfalfa and resulted in lower yields at all k levels, except for alfalfa at the lowest k ... | 1976 | 19308208 |
| morphological variation in pratylenchus penetrans. | variability of morphological characters used to separate pratylenchus penetrans from other species of the genus was studied in a population originating from a single gravid female. pronounced heteromorphism was observed and characterized. about 30% of females had a crenate-tail terminus. several shapes of stylet knobs were characterized; 50% of them were anteriorly flattened to indented. the outer margin of the cephalic framework extended into the body from one-half to two annules. the shape of ... | 1976 | 19308221 |
| analysis of antioxidant enzyme activity during germination of alfalfa under salt and drought stresses. | to understand the adaptability of alfalfa (medicago sativa l.) to environmental stresses, we analyzed the activity of several antioxidant enzymes, including superoxide dismutase (sod), peroxidase (pod), ascorbate peroxidase (apx), and catalase (cat), in alfalfa shoots and roots subjected to salt and drought stresses during germination. the germination rate of six alfalfa cultivars was comparatively studied under 200 mm nacl or 35% peg treatment. alfalfa xinmu no. 1 and northstar varieties were s ... | 2009 | 19318268 |
| effects of temperature and inoculation timing on the meloidogyne hapla/corynebacterium insidiosum complex in alfalfa. | 1972 | 19319247 | |
| effect of plant age on resistance of alfalfa to meloidogyne hapla. | meloidogyne hapla-resistant plants grown from cuttings and inoculated with m. hapla larvae were free of galls. however, 35 to 48% of the seedling intercross progeny of resistant genotypes that were inoculated in the germinated seed stage were galled. there was an inverse relationship between the age of plants grown from seed and the percentage of plants galled by m. hapla; the older the plants at inoculation, the greater the percentage of gall-free plants. the per cent of galled plants was signi ... | 1972 | 19319252 |
| infection of seedlings of alfalfa and red clover by concomitant populations of meloidogyne incognita and pratylenchus penetrans. | invasion of 2-day-old seedlings of 'buffalo' alfalfa and 'kenland' red clover by larvae of m. incognita and adults of p. penetrans, during 1-3 day periods of incubation at 24 c, was investigated in 50-mm petri dishes on 1% agar. penetration by both nematodes increased arithmetically with increased numbers in inocula. p. penetrans invaded alfalfa more readily than red cover, but m. incognita invaded red clover more readily than alfalfa. both nematodes inhibited root-elongation of alfalfa more tha ... | 1972 | 19319281 |
| effects of soil ph on reproduction of pratylenchus penetrans and forage yield of alfalfa. | 'vernal' alfalfa was grown for 30 weeks in nematode-free soil and in soil infested with pratylenchus penetrans. charlottetown fine sandy loam soil was used at its ph of 4.4 and at adjusted reactions of 5.2, 6.4 and 7.3. nematode reproduction was significantly greater at pit 5.2 and 6.4 and was not related to alfalfa root production over the full ph range studied. a significant nematode infestation x soil pit interaction on forage yield was recorded. nematode infestation significantly decreased f ... | 1972 | 19319283 |
| extraction of eggs of pratylenchus penetrans from alfalfa callus and relationship between age of culture and yield of eggs. | 1973 | 19319305 | |
| fine structure analyses of stem nematode-induced white flagging in medicago sativa. | white flagging of alfalfa, medicago sativa 'ranger, found associated with ditylenchus dipsaci in the columbia river basin was observed in northern utah during 1971. this is a report on chloroplast changes, induced by d. dipsaci in alfalfa leaves, as observed with an electron microscope. leaves from alfalfa plants infected with d. dipsaci were either devoid of normal pigmentation or displayed various shades of yellow-green. cells of leaf tissue from noninfected plants exhibited normal chloroplast ... | 1973 | 19319316 |
| hatching of meloidogyne incognita eggs in the neutral carbohydrate fraction of root exudates of gnotobiotically grown alfalfa. | meloidogyne incognita eggs were hatched in soil sterilized by gamma kradiation and wetted with root exudates from alfalfa plants in different stages of development and subjected to various levels of clipping. carbohydrate components of the exudates were identified by gas chromatography-mass spectrometry. although significant stimulation of hatch was detected in exudates of seedling and flowering plants, the practical importance of the increase is doubtful as hatch in distilled water was always g ... | 1973 | 19319320 |
| ultrastructure changes induced by stem nematodes in hypocotyl tissue of alfalfa. | scarified seeds of medicago sativa l. 'ranger' and 'lahontan' alfalfa were allowed to imbibe water for 36 hr and then were inoculated with stem nematodes, ditylenchus dipsaci kühn. seedlings were grown in sterilized provo sand at 20 c and hypocotyl sections harvested at 1, 3 and 7 days. evidence from electron micrographs indicated that cells of noninfected control plants contained normally developing chloroplasts bearing stroma, thylakoids, starch grains and plastoglobuli. the cytoplasm containe ... | 1973 | 19319326 |
| influence of concomitant pratylenchus brachyurus and meloidogyne spp. on root penetration and population dynamics. | populations of pratylenchus brachyurus on cotton were increased significantly in the presence of either meloidogyne incognita or m. arenaria.this occurred with either simultaneous inoculation or prior invasion by m. incognita. p. brachyurus penetrated cotton roots previously invaded by, or simultaneously inoculated with, m. incognita, as well as, or better than, in the absence of m. incognita. prior invasion by m. incognita, however, suppressed p. brachyurus populations on tomato, while it had n ... | 1973 | 19319334 |
| effect of acclimation temperature on infection of alfalfa by ditylenchus dipsaci. | ditylenchus dipsaci showed an affinity, in relation to infection, for the temp at which it had been acclimated. the optimum infective temp was also correlated with field temp when collections were made during different seasons and from climatically different geographical areas. nematode developmental stage did not influence infectivity. | 1974 | 19319367 |
| symptomless resistance of alfalfa to meloidogyne incognita acrita. | penetration, development and migration of the cotton root-knot nematode, meloidogyne incognita acrita, in resistant and susceptible alfalfa varieties was compared. larvae entered both resistant and susceptible plants in approximately the same numbers. after 3 to 4 days, the number of larvae in resistant roots decreased sharply until at 7 days fewer than 5 larvae/seedling and no nematode development could be found. in susceptible roots, larvae became sedentary and developed normally; egg producti ... | 1970 | 19322284 |
| penetration of alfalfa roots by different stages of pratylenchus penetrans (cobb). | 1970 | 19322310 | |
| calcium nutrition and resistance of alfalfa to ditylenchus dipsaci. | stem nematode-susceptible 'atlantic' and resistant 'lahontan' alfalfa seedlings, grown in sand and watered with complete nutrient solutions containing 0.75, 1.5, 3.0, 6.0, or 12.0 mm ca/liter, were inoculated with ditylenchus dipsaci (the stem nematode) 5-6 days after emergence. approximately equal numbers of nematodes entered the tissues of each variety/ca concentration within 2 days. penetration was reduced at 12 mm ca/liter. reproduction during 21 days following inoculation yielded 3-fold, or ... | 1970 | 19322318 |
| agriculturally-polluted irrigation water as a source of plant-parasitic nematode infestation. | water from a major irrigation canal and water from a deep well was used to irrigate plants growing in methyl bromide fumigated screenhouse ground beds. nematode populations in these beds were compared during three seasons of continuous cropping to alfalfa, bean, eggplant, mint, sugarbeet, or wheat. beds irrigated with canal water became heavily infested with a variety of plant parasitic nematodes while those receiving well water did not. | 1970 | 19322327 |
| attraction of ditylenchus dipsaci and meloidogyne hapla by resistant and susceptible alfalfa seedlings. | ditylenchus dipsaci kühn were equally attracted to and equally invaded resistant ('lahontan') and susceptible ('ranger') germinating alfalfa (medicago sativa l.) seedlings exposed singly in moist sand except at a distance of 12.5 mm at 20 c when the susceptibles proved more attractive than the resistants. larvae hatching from egg-masses of meloidogyne hapla chitwood were also attracted equally to germinating seedlings of resistant ('m-9') and susceptible ('lahontan') alfalfa offered singly. when ... | 1971 | 19322372 |
| host races of the pea aphid acyrthosiphon pisum differ in male wing phenotypes. | the evolution of reproductive isolation without geographic isolation (sympatric speciation) has recently gained strong theoretical and empirical supports. it is now widely admitted that many host-specific phytophagous insect species have arisen through shifting and adapting to new plants. the pea aphid acyrthosiphon pisum has received considerable attention in this context and is now considered as a probable case of incipient sympatric speciation through host specialization. in europe, three hos ... | 2010 | 19323853 |
| a comparison of alternative plant mixes for conservation bio-control by native beneficial arthropods in vegetable cropping systems in queensland australia. | cucurbit crops host a range of serious sap-sucking insect pests, including silverleaf whitefly (slw) and aphids, which potentially represent considerable risk to the australian horticulture industry. these pests are extremely polyphagous with a wide host range. chemical control is made difficult due to resistance and pollution, and other side-effects are associated with insecticide use. consequently, there is much interest in maximising the role of biological control in the management of these s ... | 2010 | 19323854 |
| assessment of in-stream phosphorus dynamics in agricultural drainage ditches. | the intensive agricultural systems in the midwestern united states can enrich surface waters with nutrients. agricultural drainage ditches serve as the first and second order streams throughout much of this region, as well as other highly productive agricultural areas in humid regions throughout the world. this project was conducted to evaluate in-stream processing of soluble p (sp) in agricultural drainage ditches. soluble p injection studies were conducted at seven sites along three drainage d ... | 2009 | 19324397 |
| thermotactic response of some plant parasitic nematodes. | attraction of ditylenchus dipsaci and pratylenchus penetrans to a temperature gradient was tested. heating wires, infrared radiations and germinating alfalfa seeds were used to create a temperature gradient as small as 0.033 c/cm in agar. p. penetrans, d. dipsaci, and tylenchorhynchus claytoni responded to a temperature gradient of 0.033 c over a 4-cm distance from the heat source. trichodorus christiei and xiphinema arnericanum showed no response. individuals of p. penetrans oriented their head ... | 1969 | 19325653 |
| population dynamics of plant nematodes in cultivated soil: effect of sod-based rotations in cecil sandy loam. | in a 6-year study of four nematode species in sod-based corn (zea mays) rotations, population densities varied with different cropping systems. continuous corn, with or without a winter rye (secale cereale) or vetch (vicia villosa) cover, favored an increase of pratylenchus zeae and suppressed trichodorus christiei, helicotylenchus dihystera, and xiphinema americanum. a four-year sod-based rotation (3 years sod, 1 year corn) of 'coastal' bermudagrass (cynodon dactylon) and fescue (festuca arundi ... | 1969 | 19325691 |