Three high-pressure liquid injection machines were used to inject isazofos into the root zone of tuff`grass plots to evaluate its potential for control of Hoplolaimus galeatus and Tylenchorhynchus dubius. A Rogers root zone injector delivering isazofos at 2.3 kg a.i./ha through 30° and 60° spray tips at 5,000 psi (3.45 × 10⁷ Pascals) significantly reduced nematode populations at 32 days after a single application and 33 days after a second application. In a second experiment with the Rogers injector at 2.3 kg a.i./ha, H. galeatus populations were significantly lower at 16 days after a single application and at 42 and 61 days after a second application with the 60° spray angle tips. An Envirojet turfgrass injector used to inject isazofos at 1.15 kg a.i./ha and 2.88 kg a.i./ha at 3,000 psi (1.38 × 107 Pascals) significantly reduced nematode populations at 7 days after treatment at the low rate and at 63 days after treatment with both application rates. A Landpride material injector applying isazofos at 6.9 and 13.8 kg a.i./ha at 2,000 psi (1.38 × 10⁷ Pascals) significantly reduced nematode populations at 7, 14, and 63 days after treatment at the high rate and at 63 days after the low-rate application. Although suppression of nematodes with isazofos was found, the degree of suppression is probably not enough to warrant recommendation of high-pressure delivery of isazofos for control of H. galeatus and T. dubius populations infesting turfgrasses.
Agrostis canina; Agrostis palustris; annual bluegrass; control; creeping bentgrass; high-pressure liquid injection; Hoplolaimus galeatus; isazofos; Lolium perenne; nematicide; nematode; perennial ryegrass; Poa annua; tuff`grass; Tylenchorhynchus dubius; velvet bentgrass
Soybean (Glycine max) producers in Ohio rarely use soybean cyst nematode (Heterodera glycines, SCN)-resistant cultivars because of concerns over limited yield potential and lack of resistance to Phytophthora sojae. A two-year study was initiated to determine grain yield and nematode population increase on soybean cyst nematode-resistant cultivars in maturity groups II and III in production fields. Sites differed in soil texture, nematode densities, and P. sojae infestation at a number of locations in Ohio. Soil was assayed for nematode densities before planting and at harvest. Yields of resistant cultivars averaged 0% to 18% higher than those of susceptible cultivars in fine-textured soils with average preplant populations ranging from 463 to 14,330 SCN eggs/100 cm³ soil. In coarse-textured soils, yields of susceptible cultivars were 21% to 56% less than the resistant cultivars with average preplant densities ranging from 1,661 to 15,558 SCN eggs/100 cm³ soil. The reproductive index ranged from 0.1 to 5.5 for resistant cultivars and 0.4 to 112 for susceptible cultivars. In 1993, yield of P. sojae-susceptible, nematode-resistant 'Asgrow A 3431' was as high as yield of the P. sojae-resistant, nematode-susceptible cultivar 'Resnik' in a Phytophthora-infested field. The nematode-resistant cultivars Madison Experimental 131527 and Asgrow A3431 had higher yields than AgVenture AV1341 and susceptible cultivars Resnik and Kenwood when compared over five nematode-infested sites. Nematode-resistant cultivars were found to be excellent alternatives to currently grown susceptible cultivars for managing SCN where group III cultivars are used. However, better cultivar alternatives may be needed for sites with combined Phytophthora root rot and cyst nematode problems.
cultivar; Heterodera glycines; nematode; Phytophthora sojae; resistance; soybean; soybean cyst nematode
A list of plant-parasitic nematodes associated with hosts in New Zealand is provided comprising 703 records, including 207 new associations for New Zealand.
new records; New Zealand; plant-parasitic nematodes; pasture nematodes
"Glyceel" has been considered for many years to be the best sealant for whole mounts of soil, plant-parasitic, freshwater, and marine nematodes. However, "Glyceel" has not been available since the mid 1980s when its production was halted. Currently available substitutes are inadequate. The original formula for "Glyceel" has been found in the literature and is given here with a method of preparation. "Glyceel" prepared in this way by the author has been used and appears to function well.
Glyceel; nematode; nitrocellulose; slide sealer; Zut
Tannins, which are water-soluble polyphenols, are toxic to numerous fungi, bacteria, and yeasts. Our objectives were to study the efficacy of tannic acid in control of Meloidogyne arenaria on tomato and its effects on the behavior of M. arenaria, M. incognita, Heterodera glycines, and Radopholus similis. Three concentrations of tannic acid, 0.1, 1.0, and 10 g/500 cm³ of soil, were applied preplant (powder) and at-plant (powder and drench) into soil infested with M. arenaria. Tannic acid at the 1.0-g rate reduced galling compared with the untreated control, regardless of methods of application. The 0.1-g rate resulted in no reduction in galling when applied preplant but reduced galling when applied as a drench and in one of two experiments when applied at-plant. The 10-g rate was phytotoxic to tomato seedlings except when applied 7 days preplant. In the latter case, root galling was suppressed to very low numbers. In behavior studies on water agar, Meloidogyne second-stage juveniles were attracted to areas with an increasing tannic acid gradient. Radopholus similis was repelled from the tannic acid gradient in one of two experiments. There was no effect on H. glycines. The response of M. arenaria second-stage juveniles to different concentrations of tannic acid dissolved in alginate was tested. Movement behavior of the second-stage juveniles were observed at 1,000 and 10,000 μg/ml of tannic acid, but not at 10 and 100 μg/ml.
alginate; attractant; burrowing nematode; Heterodera glycines; Meloidogyne arenaria; Meloidogyne incognita; nematode; polyphenol; Radopholus similis; repellent; root-knot nematode; soybean cyst nematode; tannic acid
The yield response of Florunner peanut to different initial population (Pi) densities of Meloidogyne arenaria, M. javanica, and an undescribed Meloidogyne species (isolate 93-13a) was determined in microplots in 1995 and 1996. Seven Pi's (0, 0.5, 1, 5, 10, 50, and 100 eggs and J2/500 cm³ soil) were used for each Meloidogyne species in both years. The three species reproduced abundantly on Florunner in both years. In 1995, mean reproduction differed among the three species; mean Rf values were 10,253 for isolate 93-13, 4,256 for M. arenaria, and 513 for M. javanica. In 1996, the reproduction of M. arenaria (mean Rf = 7,820) and isolate 93-13a (mean Rf = 7,506) were similar, and both had greater reproduction on peanut than did M. javanica (mean Rf = 2,325). All three nematode species caused root and pod galling, and a positive relationship was observed between Pi and the percentage of pods galled. Meloidogyne arenaria caused a higher percentage of pod galling than did M. javanica or isolate 93-13a. A negative linear relationship between log₁₀ (Pi + 1) and pod yield was observed for all three nematode species each year. The yield response slopes were similar except for that of M. javanica, which was less negative than that of isolate 93-13a in 1995, and less negative than that of M. arenaria and isolate 93-13a in 1996.
Arachis hypogaea; damage function; Meloidogyne arenaria; Meloidogyne javanica; Meloidogyne spp.; nematode; peanut; root-knot nematode
The Journal of Nematology is a publication of the very highest quality for communicating the most recent discoveries in the science of nematology. The authors of this Viewpoint article desire to maintain the status of the journal while lessening the burden placed on the editorial staff. A few simple steps taken by authors during the manuscript preparation phase can greatly improve the quality of their papers. Authors should carefully review the "Author's Publication Handbook and Style Manual" before and during the preparation of a manuscript intended for publication in the Journal of Nematology. In addition, authors should submit a completed "Author's Checklist for Preparation of Papers" with each manuscript submitted to the journal. Reviewers should provide thorough reviews, return mantlscripts in a timely manner, and clearly define statements regarding revisions.
editor; manuscript; publication; reviewer; style manual
The efficacy of clean fallow, bermudagrass (Cynodon dactylon) as a rotational crop, and fenamiphos for control of root-knot nematode (Meloidogyne incognita race 1) and soilborne fungi in okra (Hibiscus esculentus), snapbean (Phaseolus vulgaris), and pepper (Capsicum annuum) production was evaluated in field tests from 1993 to 1995. Numbers of M. incognita in the soil and root-gall indices were greater on okra than on snapbean or pepper. Application of fenamiphos at 6.7 kg a.i./ha did not suppress numbers of nematodes on any sampling date when compared with untreated plots. The lack of efficacy could be the result of microbial degradation of the nematicide. Application of fenamiphos suppressed root-gall development on okra following fallow and 1-year sod in 1993, but not thereafter. A few galls were observed on roots of snapbean following 2- and 3-year fallow but none following 1-, 2-, and 3-year bermudagrass sod. Population densities of Pythium aphanidermatum, P. myriotylum, and Rhizoctonia solani in soil after planting vegetables were suppressed by 2- or 3-year sod compared with fallow but were not affected by fenamiphos. Yields of snapbean, pepper, and okra did not differ between fallow and 1-year sod. In the final year of the study, yields of all crops were greater following 3-year sod than following fallow. Application of fenamiphos prior to planting each crop following fallow or sod did not affect yields.
Bermudagrass; Capsicum annuum; Gynodon dactylon; Cyperus esculentus; fenamiphos; Hibiscus esculentus; management; Meloidogyne incognita; nematicide; nematode; nutsedge; okra; pepper; Phaseolus vulgaris; resistance; root-knot nematode; snapbean; sod-based rotation
Burrowing nematodes from Central America, Dominican Republic, Florida, Guadeloupe, Hawaii, and Puerto Rico were characterized for their ability to parasitize citrus, but citrus parasites were found only in Florida. Sequence tag sites originally amplified from a citrus-parasitic burrowing nematode were polymorphic among 37 burrowing nematode isolates and were not correlated with citrus parasitism, nematode isolate collection site, or amplification of a 2.4-kb sequence tag site (DK#1). Results of a RAPD analysis and characterization of the isozymes phosphoglucose isomerase, lactate dehydrogenase, and malate dehydrogenase indicated that the burrowing nematode isolates were highly similar. Citrus parasitism in Florida appears to be associated with limited changes in the burrowing nematode genome. Findings did not substantiate a previous report that R. citrophilus was present in Hawaii. Overall, these data do not support assignment of sibling species status to burrowing nematodes that differ with respect to citrus parasitism.
anthurium; banana; citrus; evolution; genetics; isozymes; molecular biology; nematode; phylogeny; quarantine; Radopholus; RAPD; STS; taxonomy
A computer program, "SeinFit," was created to determine the Seinhorst equation that best fits experimental data on the relationship between preplant nematode densities and plant growth. Data, which can be entered manually or imported from a text file, are displayed in a data window while the corresponding graph is shown in a graph window. Various options are available to manipulate the data and the graph settings. The best-fitting Seinhorst equation can be calculated by two methods that are both based on the evaluation of the residual sum of squares. Depending on the method, a range of values for different parameters of the Seinhorst equation can be chosen, as well as the number of steps in each range. Data, graphs, and values of the parameters of the Seinhorst equation can be printed. The program allows for quick calculation of the danaage threshold density - one of the parameters of the Seinhorst model. Versions written for Macintosh or DOS-compatible machines are currently available through the Society of Nematologists' World Wide Web site (http://ianrwww.unl.edu/ianr/plntpath/ nematode/SOFTWARE/nemasoft.htm).
computer program; crop loss assessment; damage threshold; management; nematode; SeinFit; Seinhorst equation; yield loss
Thalassomermis megamphis n. gen., n. sp. (Mermithidae: Nemata) was extracted from sediment collected off the coast of Brazil at a depth of approximately 1,000 m. Although the food of this new nematode is unknown, the reduction of the stoma and esophagus and presence of a trophosome indicate that it is parasitic in its juvenile stages. Thalassomermis megaraphis n. gen., n. sp. is assigned to Mermithidae because of its similarity to that family in the appearance of the cephalic sensory receptors, the long and tubular vagina, and copulatory muscles of the male extending posteriorly throughout most of the length of the tail. Thalassomermis megamphis n. gen., n. sp. differs from all other members of Mermithidae by the large, lenticular, intracuticular amphidial fovea with coiled, emergent terminal filaments as well as the small amphidial aperture situated over the center of the fovea.
Abyssal; Benthimermithidae; deep-sea; Foraminifera; marine nematode; Mermithidae; parasite; Rhaptothyreidae; Thalassomermis megamphis n. gen., n. sp.; taxonomy
The ITS region from a wide taxonomic range of nematodes, including secernentean and adenophorean taxa, and free-living, entomopathogenic, and plant-parasitic species, was evaluated as a taxonomic marker. Size of the amplified product aided in the initial determination of group membership, and also suggested groups that may require taxonomic reevaluation. Congeneric species often displayed identically sized ITS regions, but genera such as Pratylenchus and Tylenchorhynchus had species with large differences in size. ITS heterogeneity in individuals and populations was identified in several nematode taxa. PCR-RFLP of ITS1 is advocated as a method of taxonomic analysis in genera such as Helicotylenchus that contain numerous species with few diagnostic morphological characteristics.
diagnosis; genetics; internal transcribed spacer region; ITS; molecular ecology; nematode; systematics; taxonomy
The predominant root-knot nematode in New Zealand pastures is Meloidogyne trifoliophila, identified until recently as M. hapla. Clarification was needed on the host range of these two species on legumes found in New Zealand pastures and on clover species closely related to Trifolium repens. In a greenhouse test, 15 Trifolium spp. and Medicago sativa were inoculated with eggs of M. trifoliophila, M. hapla, M. incognita, or M. javanica. All legumes tested were hosts to some degree to each of the root-knot nematodes used, except for T. striatum and M. sativa whose status as hosts to M. trifoliophila was doubtful. Low galling rates occurred on T. glomeratum infected by M. hapla (mean of 3% of the root system galled), on T. semipilosum infected by M. javanica (2%), on T. striatum infected by M. trifoliophila (2%), and on T. micranthum (4%) and M. sativa (6%) infected by M. incognita. The most heavily parasitized clovers were T. repensinfected by M. trifoliophila (92%), T. pratense infected by M. incognita (91%), and T. argutum infected by M. incognita (88%).
alfalfa; breeding; clover; detection; diagnosis; lucerne; Meloidogyne hapla; Meloidogyne incognita; Meloidogyne javanica; Meloidogyne trifoliophila; nematode; New Zealand; pasture; resistance; root-knot nematode; Trifolium spp.; white clover
The ability of Meloidogyne trifoliophila to gall 230 species and cultivars of plants was determined in a greenhouse. All clovers (Trifolium spp.) were severely galled regardless of species or cultivar. Most soybean cultivars were moderately to severely galled. Among other legumes, broad bean, garden pea, Korean lespedeza, sweetclover, and common vetch were good hosts, but alfalfa, bird's-foot trefoil, peanut, and pole bean were poor or nonhosts. Among other plant families, most Apiaceae (Umbelliferae) and Brassicaceae (Cruciferae) were galled, but Cucurbitaceae, Iridaceae, Malvaceae, Poaceae, and Solanaceae were rarely or never galled. Results for Amaryllidaceae, Asteraceae, Lamiaceae, and Liliaceae were variable. This nematode was not found in a survey of pasture and soybean fields in southwestern Tennessee.
clover; distribution; host range; Heterodera trifolii; Meloidogyne grarainicola; Meloidogyne trifoliophila; nematode; rice; root-knot nematode; soybean; symptom
The relationship between Cricenemella xenoplax alone and in combination with Meloidogyne incognitaon the incidence of peach tree short life disease was studied in field microplots during 1989-96. The presence of M. incognita suppressed the population density of C. xenoplax on Lovell peach. Tree trunk diameter was significantly reduced in the presence of both nematode species prior to 1993. Soil pH was lowest in the co-infection treatment as compared with the uninoculated control on three of the four sampling dates. In 1994, 80% of the trees growing in soil infested with C. xenoplax alone developed typical disease symptoms and died. The remaining tree died in 1995. No trees died in the M. incognita alone, C. xenoplax + M. incognita, or uninoculated control treatments. Parasitism by C. xenoplax, but not by M. incognita, made Lovell peach trees more susceptible to the disease. These findings were confirmed in an orchard site naturally infested with both C. xenoplax and M. incognita where Redhaven trees budded to Lovell rootstock exhibited a reduction of 1.6 years in average tree life for every centimeter increase in trunk diameter.
concomitance; Criconemella xenoplax; disease complex; host-parasite relationship; interaction; Meloidogyne incognita; nematode; peach; peach tree short life; Prunus persica; ring nematode; root-knot nematode
Sampling of Xiphinema index for 2 years (1993-95) in two California vineyards indicated that a greater number of nematodes occurred during the winter months. The number of juveniles increased four-fold from December 1993 to January 1994, indicating a high reproductive rate during this time. Extremely high or low soil temperatures corresponded to low nematode numbers. Samples were taken from 0 to 31 cm and 31 to 62 cm deep both within and between the vine rows. Numbers of nematodes were greatest at the 0- to 31-cm depth in one vineyard with a loamy sand soil, and at a depth of 31 to 62 cm in the second vineyard, which had a silt loam soil. In both vineyards, X. index population densities were greater within the vine row.
nematode; population dynamics; soil moisture; soil temperature; soil texture; vertical distribution; Vitis spp.; Xiphinema index
Soil moisture control during evaluations of Heterodera glycines-Glycine max interactions has not been reported routinely as a standardized procedure. A novel soil moisture replacement system was examined in controlled environmental chambers for use in bioassays for female development. The system is compact, lightweight, and has a contained reservoir for moisture supply to multiple test units. Varied soil moisture treatment levels were sustained at or near replacement rates over extended periods of testing. Direct seeding of selected soybean cultivars consistently resulted in 100% seed germination. Subsequent shoot and root growth was successfully restricted to accommodate the size of the system with minimal shoot pruning. Numbers of mature H. glycines females extracted from the roots of susceptible soybean cultivars were consistently high. Inoculum levels of either 500 or 1,000 eggs/plant routinely resulted in numbers of females at more than 30% of the initial inoculum. No evidence of nematode contamination of uninfested plants was found at any level of observation. Results demonstrate a potential for the standardization of two additional variables in determining races and for screening cultivars or lines for resistance to H. glycines.
bioassay; direct seeding; Glycine max; Heterodera glycines; method; race determination; resistance; screening; soil moisture control; soybean; soybean cyst nematode
Popcorn cultivars were evaluated in field and greenhouse tests for resistance to the Columbia root-knot nematode, Meloidogyne chitwoodi, as potential resistant crops in potato rotations. A nematode reproductive factor (Rf) was calculated for each cultivar. Reproductive factor values also were compared on a relative basis as percentages of the Rf on a susceptible field corn standard, Pioneer 3578. Popcorn cultivars W206 and Robust 33-77 consistently supported low population densities of M. chitwoodi in repeated tests. However, WOC 9508 had the greatest resistance in any of the field tests, with an Rf value of 0.04. Cultivars with a mean field and greenhouse Rf value less than 50% of the value for Pioneer 3578 were WOC 9508 (8%), WOC 9554 (13%), W206 (15%), WOX 9512 (23%), Robust 33-77 (30%), Robust 20-70 (38%), WOC 9510 (41%), and WOC 9504 (42%). If these cultivars were used in rotation, M. chitwoodi population densities at the end of the popcorn season would be between 58% and 92% less than if Pioneer 3578 were grown. In greenhouse tests, WOX 9511, WOX 9528, WOC 9556, and WOX 9531 also had low Rf values (7-46% that of Pioneer 3578), but field testing of these cultivars is needed.
crop resistance; crop rotation; Meloidogyne chitwoodi; nematode; popcorn; root-knot nematode; Zea everta
Forty-six accessions of G. hirsutum and two of G. barbadense were examined for resistance to Meloidogyne incognita race 3 and Rotylenchulus reniformis in environmental growth chamber experiments, with the objective of finding new sources of resistance. Only the G. barbadense accessions, TX-1347 and TX-1348, supported significantly less reproduction by R. reniformis than the susceptible control, Deltapine 16 (USDA accession SA-1186). However, they were highly susceptible to M. incognita race 3. The G. hirsutum accessions TX-1174, TX-1440, TX-2076, TX-2079, and TX-2107 had levels of resistance to M. incognita race 3 as great as or greater than those of Clevewilt 6 and Wild Mexican Jack Jones, which are the primary sources of resistance to M. incognita race 3 in the most resistant breeding lines. No accession was as resistant as the highly resistant line Auburn 623 RNR (SA-1492). Resistant accessions were from the Mexican coastal states of Campeche, Quintana Roo, Tabasco, Veracruz, and Yucatan. Populations of R. reniformis from Alabama, Mississippi, Louisiana, and Texas, and of M. incognita race 3 from Mississippi, Texas, and California, had similar reproductive rates on resistant genotypes. Thus, new sources of resistance to M. incognita race 3 but not to R. reniformis were identified in wild accessions of G. hirsutum from southern Mexico.
cotton; Gossypium barbadense; Gossypium hirsutum; Meloidogyne incognita; nematode; reniform nematode; resistance; root-knot nematode; Rotylenchulus reniformis
Pasteuria penetrans is an obligate, mycelial, and endospore-forming bacterial parasite of Meloidogyne spp. with promise for the management of root-knot nematodes. Our objective was to use regression analysis of developmental time (days) to various temperatures to determine the minimal temperature for growth and development of P. penetrans in Meloidogyne spp. The data set for regression originated from a previously published report. The data fit well to hyperbolic equations. For various developmental stages of P. penetrans, the minimal growth temperature ranged from 16.7 °C to 17.8 °C and averaged 17.2 °C.
bacterium; biological control; degree-day; developmental threshold; endospore; Meloidogyne spp.; minimal growth temperature; Pasteuria penetrans; root-knot nematode; temperature
Stimulation of hatching of a tobacco cyst nematode (Globodera tabacum solanacearum) by root exudates from resistant NC 567 and susceptible K 326 cultivars of flue-cured tobacco, Nicotiana tabacum, was investigated. Root exudates were collected by soaking seedlings in deionized water for 2 hours at 22 °C in the dark. Fifteen mature and uniformly sized cysts were exposed at 15, 20, or 25 °C to undiluted root exudate, root exudate diluted 1:1 or 1:3 with deionized water, or deionized water alone. Hatched juveniles were counted and removed at weekly intervals during 42 and 53 days of exposure in experiments conducted in 1994 and 1995, respectively. Root exudates from both susceptible cultivar K 326 and resistant cultivar NC 567 stimulated more hatching than deionized water at 25 °C in 1994, and at all three tested temperatures in 1995. In 1994, dilution of root exudates 1:3 reduced stimulation of hatching at 25 °C compared to undiluted exudate. Hatching at 25 °C was similarly stimulated by exposure to undiluted root exudate and exudate diluted 1:1. In 1995, both dilutions reduced stimulation of hatching by root exudates at all the temperatures.
flue-cured tobacco; Globodera tabacum solanacearum; hatching; Nicotiana tabacum; resistance; root exudate; temperature; tobacco cyst nematode
Researchers have indicated that the C₉ fatty acid, pelargonic acid (nonanoic acid), has considerable nematicidal activity that could be increased by derivitization and improved emulsification. Microemulsions of methyl and ethylene glycol esters of pelargonic acid developed by Mycogen Corporation (San Diego, CA) were tested for nematicidal activity against root-knot and soybean cyst nematodes. All treamaents were compared to a deionized water control and a microemulsion "blank" (minus active ingredient). Methyl pelargonate reduced gall numbers at concentrations ≥0.8 μl a.i./liter, and ethylene glycol pelargonate reduced gall numbers at ≥6.4 μl a.i./liter in a laboratory bioassay of Meloidogyne javanica on roots of tomato seedlings. Microscopic observation of treated M. javanica second-stage juveniles suggested that methyl pelargonate was toxic to nematodes at concentrations as low as 0.2 μl a.i./liter. Cysts of Heterodera glycines per gram of root were significantly reduced by weekly soil drenches of methyl pelargonate at 6.4, 3.2, and 1.6 μl a.i./liter compared to controls in one greenhouse experiment. Weekly soil drenches of methyl pelargonate at 4.8 or 3.2 μ1 a.i./liter also significantly reduced the number of eggs produced by M. incognita on soybean in a greenhouse test. In both greenhouse tests with soybean, rates of methyl pelargonate ≥4.8 μl a.i./liter had considerable phytotoxicity. No significant interaction of chemical treatment and different soil mixtures affected the nematode numbers produced or plant vigor observed. Soil drenches with microemulsions of methyl pelargonate at 3.2 μl a.i./liter applied weekly, or as two initial applications, were effective as a nematicide for root-knot and soybean cyst nematodes with negligible effects on plant vigor.
fatty acid; Glycine max; Heterodera glycines; Meloidogyne incognita; Meloidogyne javanica; nematicide; nonanoie acid; pelargonic acid methyl ester; pelargonic acid ethylene glycol ester; phytotoxicity; root-knot nematode; soybean cyst nematode
Effects of yard waste compost and maize (Zea mays) cultivar on population densities of plant-parasitic nematodes were examined in four experiments in north Florida. In one experiment, eight maize cultivars were evaluated; the other three experiments involved split-plot designs with compost treatments as main plots and maize cultivars as subplots. The three compost treatments used in these experiments were: 269 mt/ha of a yard-waste compost applied to the soil surface as a mulch, 269 mt/ha of compost incolporated into the soil, and an unamended control. No interactions between compost treatment and cultivar occurred in any experiment. Effects of compost treatment on Mesocriconema spp., Meloidogyne incognita, and Pratylenchus spp. were inconsistent, whereas significant effects of compost on population densities of Paratrichodorus minor were found on four of six sampling occasions. Cultivar affected final population densities (Pf) of M. incognita. In two tests, Pf of M. incognita on a Florida subtropical experimental hybrid (Howard III) were only 36% and 23% of Pf on the standard tropical hybrid (Pioneer Brand X304C). In an integrated approach to management of nematodes in maize, the effects of compost amendment and culfivar choice acted independently. Apparently, cultivar choice is more important than amendment with yard waste compost for management of M. incognita population levels in a maize rotation crop.
compost; cultural practice; host plant resistance; integrated pest management; Meloidogyne incognita; mulch; nematode; organic amendment; Paratrichodorus minor; sustainable agriculture; Zea mays
The impacts of fosthiazate on potato (Solanum tuberosum) tuber yields and populations of root lesion nematodes (primarily Pratylenchus penetrans) were studied during 1991-1994 in experimental plots on Prince Edward Island. Tuber yields were greater in treated plots when compared to untreated plots by 8% and 30% during 1991 and 1993, respectively. Numbers of nematodes in roots were reduced by the treatments in every year, and nematode populations in soil were suppressed in 1991, 1993, and 1994. Tuber yields in 1993 and 1994 were higher, and nematode counts in soil and roots in 1991, 1993, and 1994 were lower in plots treated with the emulsifiable concentrate formulations of fosthiazate than in plots treated with the granular formulations. Yields of plots treated with fosthiazate did not differ consistently from yields of plots treated with aldicarb. The results indicated that fosthiazate should be useful for potato production in the Maritime region of Canada.
aldicarb; fosthiazate; management; nematode; potato; Pratylenchus penetrans