The reproductive potential of a Meloidogyne javanica population on 64 commercial corn hybrids and 33 corn inbred lines was determined in greenhouse experiments. Reproduction was measured by determining RF values (final egg number per initial egg number) and number of eggs per gram of fresh root. All corn hybrids supported reproduction greater than RF = 1.0. RF values for the hybrids ranged from 1.1 for 'Pioneer 3147' to 15.5 for 'Coker 8575'. Three inbreds -- MpT03, NC246, and Mp307 -- maintained M. javanica below the initial population level, with RF values of 0.7, 0.7, and 0.8, respectively. Three other inbreds -- F6, Mp704, and T220 -- maintained M. javanica at RF = 1.0. RF values of the other 27 inbreds ranged from 1.2 for Mp313 to 9.5 for B37.
corn; host suitability; maize; Meloidogyne javanica; javanese root-knot nematode; resistance; Zea mays
A metal detector was used to relocate steel pins marking the boundaries of semipermanent plots in cranberry bogs and turfgrass where continuous use precluded the placement of permanent wooden stakes.
cranberry; metal detector; method; technique; turfgrass
Yield performance and host suitability to Hoplolaimus columbus of 18 soybean cultivars in maturity groups V and VI and 21 cultivars in groups VII and VIII were evaluated in 10 experiments. No cultivar was highly resistant to H. columbus. Within individual experiments, few differences were detected in yield losses among cultivars; however, over all locations Braxton, Coker 485, and Leflore were intolerant to H. columbus. Braxton also exhibited pronounced chlorosis at all locations. Coker 368, Coker 488, Deltapine 506, Foster, Kirby, Ring Around 680, and Young sustained high yields.
Columbia lance nematode; Glycine max; Hoplolaimus columbus; resistance; soybean; tolerance; yield
Three tests were conducted to evaluate the efficacy of fumigant and nonfumigant nematicides for control of Meloidogyne arenaria race 1 on peanut. Methyl bromide, 1,3-D, methyl isothiocyanate, and methyl isothiocyanate mixtures were applied 7 or 8 days preplant either broadcast or in-the-row. Aldicarb, ethoprop, fenamiphos, and F5145 were applied at different rates and by different methods at-plant or at early flowering. Of the 32 treatments evaluated, only seven resulted in yield increases (P = 0.05), although early season vigor was high in all treated plots. During the latter one-third of the growing season, however, nematode control was not adequate in most treatments resulting in heavy peg, pod, and root infection by M. arenaria.
1,3-D; aldicarb; Arachis hypogaea; chemical control; ethoprop; F5145; fenamiphos; fumigant; Meloidogyne arenaria; methyl bromide; methyl isothiocyanate; nematicide; nonfumigant; peanut; root-knot nematode
Three nematicides were evaluated for control of Belonolaimus longicaudatus, Hoplolaimus galeatus, Criconemella spp., and Meloidogyne spp. in 'Tifgreen II' bermudagrass mowed at golf course fairway height (1.3 cm) in Fort Lauderdale, Florida. Bermudagrass plots were treated with fenamiphos (13.5 kg a.i./ha), oxamyl (13.5 kg a.i./ha), or 30% formaldehyde (6.4 liter a.i./ha). The plots treated with fenamiphos or formaldehyde were split 14 days later and one-half of each plot received two biweekly applications of formaldehyde. Forty-two days after the treatments were applied, the turfgrass vigor ratings and dry root weights in plots treated with fenamiphos were higher (P < 0.05) than the control, oxamyl, or formaldehyde treatments. The population levels of B. longicaudatus were suppressed (P < 0.05) in the fenamiphos, fenamiphos plus formaldehyde, and oxamyl treatments.
Belonolaimus longicaudatus; bermudagrass; chemical control; Criconemella spp.; fenamiphos; formaldehyde; lance nematode; Hoplolaimus galeatus; Meloidogyne spp.; oxamyl; ring nematode; root-knot nematode; sting nematode; turfgrass
Soybean cultivars grown in pots in the greenhouse were tested for resistance by inoculation with Meloidogyne incognita or one of six races of Heterodera glycines. Selected cultivars were tested against each nematode isolate. The numbers of cultivars tested against each H. glycines race and the numbers resistant and (or) moderately resistant were as follows: Race 2 - 114 tested, 1 resistant and 9 moderately resistant; race 3 - 170 tested, 56 resistant and 17 moderately resistant; race 4 - 89 tested, 1 resistant and 13 moderately resistant; race 5 - 106 tested, 4 moderately resistant; race 6 - 95 tested, 10 resistant and 25 moderately resistant; race 14 - 81 tested, 2 resistant and 10 moderately resistant. No cultivar was resistant to all races. Meloidogyne incognita was tested on 139 cultivars; 50 were resistant.
Glycine max; Heterodera glycines; Meloidogyne incognita; race; root-knot nematode; soybean; soybean cyst nematode
A granular formulation of a chelate of metham-zinc (CMZ) which liberates the biocidal methyl isothiocyanate was tested for nematicidal activity on Tylenchulus semipenetrans in a jar soil screening and on Meloidogyne javanica (greenhouse test) and M. incognita (field test) infecting tomato. Comparisons were made with 1,3-D in the jar and pot experiments. The CMZ caused only 3.9% mortality of citrus nematode juveniles at 1.0 μg a.i./g soil, but 95.4% mortality at 10.0 μg a.i./g and 100.0% at 100.0 μg a.i./g. CMZ at 10.0 and 100.0 μg a.i./g significantly reduced tomato root infections by M. javanica in the pot test relative to the untreated control. In the field test, CMZ (11.5 g a.i./m² calibration rate) reduced M. incognita populations in the zone of incorporation but not below it, thus failing to provide season-long control for tomato. This material has good nematicidal activity at 10 μg a.i./g or more, but its effectiveness in the field may be limited by its lack of movement.
chemical control; citrus nematode; Lycopersicon esculentum; Meloidogyne incognita; Meloidogyne javanica; methyl isothiocyanate; root-knot nematode; tomato; Tylenchulus semipenetrans; 1,3-dichloropropene
The establishment ofHeterodera glycines race 3, from soil plugs infested with population densities ranging from 0 to 10⁵ eggs and second-stage juveniles per 10 cm³ soil, was compared in three soils (Haynie sandy loam, Eudora silt loam, and Chase silty clay loam) that were either pasteurized or unpasteurized. Final population densities of H. glycines in soil and on soybean (Glycine max cv. Williams 82) roots were affected by soil type but not by soil pasteurization (P = 0.05). Higher numbers of H. glycines females and cysts were recovered from the sandy loam than from the silty loams after 8 weeks. The relationships between initial populations in infested soil plugs and the levels of recovery in the previously uninfested soils were described by sigmoidal Gompertz growth models. Estimated threshold levels for establishment were approximately 75% lower in the sandy loam than in the silty loams.
establishment; Glycine max; Heterodera glycines; soil type; soybean cyst nematode; soybean
Yield responses of 24 soybean cultivars to ScuteIlonema brachyurum were evaluated in a naturally infested field. Yields between treated and untreated plots were not different (P = 0.05) for the nematicide x cultivar interaction. D-D reduced soil nematode population levels by 93% at 45 days after planting and 59 days after fumigation. Scutellonema brachyurum did not cause economic loss on soybean.
crop loss; D-D; Glycine max; nematicide; resistance; Scutellonema brachyurum; soybean; spiral nematode
Grain sorghum cultivars (Funk G-499GBR, Funk G-611, Funk G-522A, Funk G-522DR, Coker 7723, Coker 7675, Coker 7623, Pioneer B815, Pioneer 8222, Pioneer 8272) were evaluated in the greenhouse for resistance to populations of Meloidogyne incognita race 3, M. arenaria race 2, and M. javanica from South Carolina, and M. arenaria race 1 from Georgia. All the sorghum cultivars were poor hosts or nonhosts of Meloidogyne spp. with fewer than 1 or 2 egg masses per root system in all cultivar x nematode combinations. Sorghum (Coker 7723) planted in a field infested with M. incognita race 3 and M. arenaria race 2 was not galled; however, galling and egg masses were observed on tobacco (Coker 319). Populations of second-stage juveniles at harvest were 2,865 and 72/500 cm³ soil for the tobacco and sorghum plots, respectively. Sorghum was a poor host of Meloidogyne spp. and may be useful as a rotation crop to reduce populations of root-knot nematodes.
host suitability; Meloidogyne arenaria; M. incognita; M. javanica; root-knot nematode; sorghum; Sorghum bicolor
Several polyethylene plastics were evaluated as potential materials for disinfesting small volumes of soil containing nematodes. Bursaphelenchus seani, cultured on the fungus Monilinia fructicola in petri dishes, was used to bioassay the survival and reproductive capability of nematodes buried 7.5 cm deep in Margate fine sand (soil moisture = 4.9%). The soil was exposed to sunlight for 6 days in May 1987. The highest mean temperatures recorded at 7.5 cm deep were 38 ± 1 C, 43 ± 1 C, 43 ± 1 C, and 50 ± 1 C for the no plastic, clear plastic, black plastic, and clear + black plastic treatments, respectively. The temperature in the clear + black plastic treatment exceeded 47 C for more than 2 hours on clear days. Nematode survival averaged 98 ± 3%, 78 ± 22%, 38 ± 38%, and 0 ± 0%, whereas the reproductive success of B. seani following treatment was 100, 100, 75, and 0% for the no plastic, clear plastic, black plastic, and clear + black plastic treatments, respectively. Bursaphelenchus seani in petri dishes and Belonolaimus longicaudatus and Hoplolaimus galeatus in soil died when exposed to 48 ± 2 C for 2 hours.
Belonolaimus longicaudatus; Bursaphelenchus seani; Hoplolaimus galeatus; lance nematode; physical control; potted plant; preplant control; solarization; sting nematode
Bahiagrass (Paspalum notatum) cultivars Argentine, Pensacola, and Tifton-9 were non-hosts for Meloidogyne arenaria, M. incognita, and Heterodera glycines in a greenhouse experiment using field soil infested with these nematodes. The effect of Pensacola bahiagrass in rotation with peanut (Arachis hypogaea) on M. arenaria was studied in 1986 and 1987 in a field at the Wiregrass substation near Headland, Alabama. Each year soil densities of second-stage juveniles of M. arenaria, determined near peanut harvest, were 96-98% lower under bahiagrass than under peanut. In 1987 peanut yields in plots following bahiagrass were 27% higher than in plots under peanut monoculture. Juvenile population densities in bahiagrass-peanut plots were 41% lower than in plots with continuous peanut. Using bahiagrass for reducing population densities of M. arenaria and increasing peanut yield was as effective as using aldicarb at the recommended rates for peanut.
aldicarb; Arachis hypogaea; bahiagrass; control; cropping system; Heterodera glycines; management; Meloidogyne arenaria; Meloidogyne incognita; peanut; Pratylenchus brachyurus; root-knot nematode; rotation
Number of Pratylenchus spp. (primarily P. penetrans) were recorded at planting in experimental potato plots over a 9-year period at one location on Prince Edward Island. Tuber yields of 'Superior' and 'Russet Burbank' potatoes in plots treated with aldicarb were compared with yields in adjacent untreated plots. There was a linear relationship between the number of root lesion nematodes at planting and tuber yield increases after treatment for Superior, but not for Russet Burbank (P < 0.05). When counts of root lesion nematodes were greater than 500/kg dry soil, however, the tuber yields of Russet Burbank increased in treated plots. Additional trials at other locations and the inclusion of other cultivars are needed to make numerical relationships of this type available to a nematode advisory service.
advisory service; potato; Pratylenchus penetrans; root lesion nematode; Solanum tuberosum; tuber yield
Two soybean breeding lines (D82-2397A and J82-190) resistant to Heterodera glycines race 5 produced higher yields (P = 0.05) than the race 4-resistant cultivar Bedford for 2 years when planted in a field infested with H. glycines race 5 at Tiptonville, Tennessee. Yields were not different between D82-2397A and Bedford when planted in fields infested with race 3, race 9, or with no cyst nematodes. D82-2397A will be released as a cultivar in 1988.
Glycine max; Heterodera glycines; plant breeding; resistance; soybean; soybean cyst nematode
Rotating soybean (Glycine max cv. Kirby) with peanut (Arachis hypogaea cv. Florunner) for managing Meloidogyne arenaria race 1 was studied for 3 years (1985-87) in a field near Headland, Alabama. Each year soybean plots had lower soil numbers of M. arenaria second-stage juveniles (J2) at peanut harvest than did plots in peanut monocnlture. Peanut following either 1 or 2 years of soybean resulted in approximately 50% reduction in J2 soil population densities and a 14% (1-year soybean) or 20% (2-year soybean) increase in yields compared with continuous peanut. The soybean-peanut rotation increased peanut yield equal to or higher than the yield obtained with continuous peanut treated with aldicarb at 0.34 g a.i./mL.
Arachis hypogaea; cultural practice; Glycine max; integrated pest management; Meloidogyne arenaria; nematode control; peanut; plant breeding; population dynamics; root-knot nematode; soybean
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 the water agar compartment where juveniles were inoculated. The infective juveniles that thrust their stylets repeatedly into the apical cells of oxamyl-treated roots became immobilized. A comparison with previous studies on intact plants indicated that oxamyl was transported into the root tissues and diffused in the exudates.
Agrobacterium rhizogenes; Heterodera schachtii; Meloidogyne incognita; oxamyl; transformed root
irrigation; management; nematicide; chemical control
The effect of previous crops--soybean (Glycine max) or corn (Zea mays)--and aldicarb (2.2 kg a.i./ha) on yield and nematode numbers at harvest for soybean cultivars with various combinations of nematode resistance was determined in a sandy loam soil infested with Meloidogyne arenaria race 2 and Heterodera glycines races 3 and 4 at Elberta, Alabama, in 1987. Cultivars had an effect on yield and nematode numbers (P = 0.01), as did the interaction of previous crop and cultivar. The nematicide treatment x cultivar interaction was significant for yield, and the three-way interaction was significant for numbers of M. arenaria. A previous crop of corn had no effect on M. arenaria numbers, but it reduced numbers of H. glycines from 93 to 25 J2/100 cm³ of soil and increased soybean yield from 1,963 to 2,560 kg/ha. Aldicarb reduced M. arenaria numbers from 230 to 186 J2/100 cm³ soil and increased yield from 2,062 to 2,460 kg/ha but it had no effect on H. glycines numbers. Rotation with corn was an effective control measure for H. glycines and enhanced the yields of H. glycines-susceptible cultivars.
Alabama; aldicarb; crop rotation; Glycine max; Heterodera glycines; host-plant resistance; Meloidogyne arenaria; root-knot nematode; soybean cyst nematode; soybean
Three field experiments were established in 1987 to determine the reaction of five cotton cultivars to infection by Hoplolaimus columbus and the efficacy of selected nematicides against this nematode. At two sites in Calhoun County, South Carolina, early season plant growth and subsequent yields were greater in plots treated with aldicarb, fenamiphos, and 1,3-dichloropropene. Hoplolaimus columbus suppressed yields approximately 10% at site 1 and 25% at site 2; however, greater yield suppression at site 2 may have been influenced by low levels of Meloidogyne incognita. At one site in Barnwell County, South Carolina, nematicide treatments did not increase plant growth or yield. At sites 1 and 2 where yield losses occurred, no differences in infection rate or yield among untreated cultivars were observed, nor was any nematicide more effective than another in preventing yield losses.
aldicarb; chemical control; Columbia lance nematode; cotton; fenamiphos; Gossypium hirsutum; Hoplolaimus columbus; Meloidogyne incognita; nematicide; 1,3-dichloropropene; root-knot nematode
The effect of two cropping and tillage systems on the population dynamics of four nematode species was evaluated on a loamy sand. Hairy vetch succeeded by corn or grain sorghum was seeded in split plots randomized within whole plots of no-tillage versus conventional tillage over four growing seasons (1980-83). The vetch-corn cropping system increased the density of Meloidogyne incognita 2.9 x more than the vetch-grain sorghum cropping system. In contrast, the vetch-grain sorghum cropping system increased the density of Criconemella ornata 0.7 x more than the vetch-corn cropping system. Meloidogyne incognita and C. ornata were affected more by these cropping systems than were Pratylenchus brachyurus or Paratrichodorus minor. Multiple cropping systems, vetch varieties, and crop host preference affected nematode population densities, whereas tillage treatments, conventional or no-tillage, had little effect on them.
corn; Criconemella ornata; cultural practice; grain sorghum; lesion nematode; Meloidogyne incognita; multiple cropping; Paratrichodorus minor; phytoparasitic nematode; population dynamics; root-knot nematode; Pratylenchus brachyurus; Sorghum bicolor; stubby-root nematode; tillage; vetch; Vicia spp.; Zea mays
Thirty-two weed species common in South Carolina and one cultivar of tobacco were evaluated as hosts of Meloidogyne arenaria race 2 and M. incognita race 3 in the greenhouse. Egg mass production and galling differed (P < 0.05) among weed species. Chenopodium album, Euphorbia maculata, and Vicia villosa were good hosts of M. arenaria. Amaranthus palmeri, Rumex crispus, Amaranthus hybridus, Ambrosia artemisiifolia, lpomoea hederacea var. integriuscula, Setaria lutescens, Sida spinosa, Portulaca oleracea, and Rumex acetosella were moderate hosts. Taraxacum officinale, Ipomoea hederacea, Cyperus esculentus, Cynodon dactyIon, Echinochloa crus-galli, Eleusine indica, Sorghum halepense, Setaria viridis, Digitaria sanguinalis, and Datura stramonium were poor hosts for M. arenaria. Amaranthus palmeri, Amaranthus hybridus, Chenopodium album, Euphorbia maculata, Setaria lutescens, Vicia villosa, Sida spinosa, Rumex crispus, and Portulaca oleracea were moderate hosts and Ipomoea hederacea var. integriuscula, Xanthium strumarium, Cyperus esculentus, Cynodon dactylon, Paspalum notatum, Eleusine indica, Setaria viridis, and Rumex acetosella were poor hosts for M. incognita. None of the above were good hosts for M. incognita. Tobacco 'PD4' supported large numbers of both nematode species.
host suitability; Meloidogyne arenaria; M. incognita; Nicotiana tabacum; root-knot nematode; tobacco; weed
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 to the uninoculated control in both experiments. The numbers recovered from Harvester snap bean were different (P = 0.05) between populations in each test and from Braxton soybean in the second test. The differences between populations on snap bean were different in the two tests.
behavior; host-parasite relationship; host specificity; lesion nematode; Pratylenchus brachyurus
Two flue-cured tobacco cultivars, VA-81 and PD-4, resistant to Globodera tabacum solanacearum were tested for resistance to G. tabacum in field and greenhouse experiments. A G. tabacum-susceptible broadleaf cultivar CT86-4 was used for comparison. In a greenhouse screening procedure, VA-81 and PD-4 had, respectively, 1 of 24 and 0 of 24 plants with any cysts visible on the root systems. All 24 plants of CT86-4 had at least four G. tabacum cysts visible per plant. Up to 80% of juveniles emerged from cysts in response to all tobacco cultivars transplanted into pots. Subsequent reproduction was much less on VA-81 and PD-4 than on CT86-4. Staining nematodes in roots 5 weeks after inoculation indicated that fewer nematodes had developed in VA-81 and PD-4 than in CT86-4. During one growing season, population densities of G. tabacum in naturally infested field soil declined by 72-80% under VA-81 and PD-4 and increased by 144% under CT86-4.
Globodera tabacum; Nicotiana tabacum; resistance; tobacco; tobacco cyst nematode
Guidelines are suggested to implement the introduction of beneficial insect-parasitic nematodes into the United States from abroad. These suggestions result from experiences and research with these and other biological control agents and from the current need for procedures to import nematodes. Subjects considered are need to import, foreign exploration, taxonomy, shipment, quarantine facilities, permits, host range tests, release, and documentation. Nematodes covered under these suggested guidelines include entomopathogenic species of mermithids, sphaerulariids, aphelenchids, steinernematids, and heterorhabditids. Host specificity and safety tests are discussed. Concern over the possible concomitant introduction of plant-parasitic nematodes, insects, or other pests is expressed. Current information on the treatment of insect-parasitic nematodes by the Environmental Protection Agency and USDA's Animal and Plant Health Inspection Service is presented. These suggested guidelines are presented to stimulate the development of workable protocols for safe introduction of beneficial insect-parasitic nematodes into the United States from aboard.
biological control; entomogenous nematode; guideline; insect parasite; introduction; nematode introduction; permit form; procedure