Root-Knot Nematode Management in Double-Cropped Plasticulture Vegetables

Combination treatments of chisel-injected fumigants (methyl bromide, 1,3-D, metam sodium, and chloropicrin) on a first crop, followed by drip-applied fumigants (metam sodium and 1,3-D ± chloropicrin) on a second crop, with and without oxamyl drip applications were evaluated for control of Meloidogyne incognita in three different tests (2002 to 2004) in Tifton, GA. First crops were eggplant or tomato, and second crops were cantaloupe, squash, or jalapeno pepper. Double-cropped vegetables suffered much greater root-knot nematode (RKN) pressure than first crops, and almost-total yield loss occurred when second crops received no nematicide treatment. On a first crop of eggplant, all fumigants provided good nematode control and average yield increases of 10% to 15 %. On second crops, higher application rates and fumigant combinations (metam sodium and 1,3-D ± chloropicrin) improved RKN control and increased yields on average by 20% to 35 % compared to the nonfumigated control. Oxamyl increased yields of the first crop in 2003 on average by 10% to 15% but had no effect in 2004 when RKN failed to establish itself. On double-cropped squash in 2003, oxamyl following fumigation provided significant additional reduction in nematode infection and increased squash yields on average by 30% to 75%.     

Management of Meloidogyne incognita with Chemicals and Cultivars in Cotton in a Semi-Arid Environment

Management of Meloidogyne incognita (root-knot nematode) in cotton in the United States was substantially affected by the decision to stop production of aldicarb by its principle manufacturer in 2011. The remaining commercially available tools to manage M. incognita included soil fumigation, nematicide seed treatments, postemergence nematicide application, and cultivars partially resistant to M. incognita. Small plot field studies were conducted on a total of nine sites from 2011–2013 to examine the effects of each of these tools alone or in combinations, on early season galling, late-season nematode density in soil, yield, and value ($/ha = lint value minus chemical costs/ha). The use of a partially resistant cultivar resulted in fewer galls/root system at 35 d after planting in eight of nine tests, lower root-knot nematode density late in the growing season for all test sites, higher lint yield in eight of nine sites, and higher value/ha in six of nine sites. Galls per root were reduced by aldicarb in three of nine sites and by 1,3-dichloropropene (1,3-D) in two of eight sites, relative to the nontreated control (no insecticide or nematicide treatment). Soil fumigation reduced M. incognita density late in the season in three of nine sites. Value/ha was not affected by chemical treatment in four of nine sites, but there was a cultivar × chemical interaction in four of nine sites. When value/ha was affected by chemical treatment, the nontreated control had a similar value to the treatment with the highest value/ha in seven of eight cultivar-site combinations. The next “best” value/ha were associated with seed treatment insecticide (STI) + oxamyl and aldicarb (similar value to the highest value/ha in six of eight cultivar-site combinations). The lowest valued treatment was STI + 1,3-D. In a semi-arid region, where rainfall was low during the spring for all three years, cultivars with partial resistance to M. incognita was the most profitable method of managing root-knot nematode in cotton.     

Management of Globodera rostochiensis as Influenced by Nematode Population Densities and Soil Type

The effects of aldicarb, oxamyl, 1,3-D, and plastic mulch (solarization) on soil population densities of the golden nematode (GN) Globodera rostochiensis was assessed in field and microplot experiments with different soil types. Oxamyl was evaluated in both soil and foliar treatments, whereas aldicarb, 1,3-D, and solarization were applied only to soil. Soil applications of aldicarb and oxamyl resulted in reduced nematode populations after GN-susceptible potatoes in plots with initial population densities (Pi) of > 20 and 7.5 eggs/cm³ soil, respectively, but nematode populations increased in treated soil when Pi were less than 20 and 7.5 eggs/cm³soil. In clay loam field plots with Pi of 19-76 eggs/cm³ soil, nematode densities increased even with repeated foliar applications of oxamyl, whereas nematode populations at Pi greater than 76 eggs/cm³ soil were reduced by foliar oxamyl. Treatment with 1,3-D or solarization, singly or in combination, reduced GN soil population densities regardless of soil type or Pi. Temperatures lethal to GN were achieved 5 cm deep under clear plastic but not 10 or 15 cm deep.     

Control of potato cyst nematodes and economic benefits of application of 1,3-dichloropropene and granular nematicides

The two species of the potato cyst nematodes (PCN) Globodera pallida and G rostochiensis are the most problematic pests of the potato crop in the UK. There are no commercially available cultivars with full resistance to G. pallida and both crop rotation and granular nematicides are less effective at controlling this species than G. rostochiensis. In situations of very high PCN levels it may be possible to reduce populations and yield losses by using an autumn application of the soil fumigant 1,3-dichloropropene (1,3-D) followed by a spring application of a granular nematicide. Two field experiments were done to look at the integration of methods for the control of PCN. The Common Field experiment (G. rostochiensis infested) compared the use of 1,3-D with the granular nematicides aldicarb, oxamyl and fosthiazate when growing the susceptible cv. Estima. The Four Gates experiment (infested with both PCN species but mainly G rostochiensis) compared the performance of cv. Santé (partially resistant to G. pallida, fully resistant to G. rostochiensis) with that of the susceptible cv. Estima when treated with 1,3-D and oxamyl at full and half-rates. The results of the experiments show that an integrated approach to nematode control on heavily infested sites, including granular and fumigant nematicides and cultivar resistance, can lead to significant decreases in nematode population densities and reduce yield losses. An economic evaluation of the experiments modelled the gross margins from the different nematicide treatments. In Common Field, the highest gross margins were achieved with the combined use of fumigant and granular nematicides. In Four Gates, there was a clear economic benefit for both cultivars from the use of 1,3-D. In this experiment, oxamyl was of economic value to Estima but not to Sante and full-rate oxamyl was of more benefit than half-rate to Estima.     

Management of Root-Knot Nematode,Meloidogyne Incognita,by integration of Paecilomyces Lilacinus with organic materials in Chilli

Studies were made to determine the efficacy of Paecilomyces lilacinus in management of root-knot nematode (Meloidogyne incognita) in soil amended with various organic matters. The soil amendments with organic additives except gram and rice husks significantly reduced the multiplication of M. incognita and the root galling caused by root-knot nematode which consequently increased the plant growth. The greatest improvement in plant growth and reduced reproduction factor and root galling was recorded in soil amendment with leaves of Calotropis procera while the least was in kail saw dust. The best protection against M. incognita was observed on the integration of organic additives with P. lilacinus, which resulted increased plant growth and reduced population build-up of nematodes and root gallings. The leaves of C. procera with P. lilacinus were most effective than all other organic materials used among the different integrated approaches. The organic amendments also increased the parasitism of P. lilacinus on M. incognita.     

Influence of rock dust-based soil re-mineralisation on root-knot disease of organic watermelon plants

Deplorable soil fertility characterising resource-poor agrarian communities remain a major constraint for sustainable global food security. Re-mineralisation through application of rock dust encourages maintainable productivity of degraded soils. This study was planned to appraise the effect of rock dust on root-knot disease of Citrullus lanatus caused by Meloidogyne incognita (Mi). The experiment was laid out in Randomised Complete Block Design with three replications. Soil and root populations of the nematode were estimated and galling damage of the crop was diagnosed and censured at 60?days after inoculation. Additional data were collected on vine length, number of leaves, days to 50% flowering and dry matter content. Data collected were subjected to analysis of variance and the means were separated using least significant difference. The treated watermelon plants were low in root-knot disease, significantly reduced Mi nematode populations and flowered far much earlier (p?=?0.05) than the untreated organic watermelon plants.     

Host Plant Resistance as an Alternative to Methyl Bromide for Managing Meloidogyne incognita in Pepper

Pre-plant soil fumigation with methyl bromide and host resistance were compared for managing the southern root-knot nematode (Meloidogyne incognita) in pepper. Three pepper cultivars (Carolina Cayenne, Keystone Resistant Giant, and California Wonder) that differed in resistance to M. incognita were grown in field plots that had been fumigated with methyl bromide (98% CH₃Br : 2% CCl₃NO₂ [w/w]) before planting or left untreated. Carolina Cayenne is a well-adapted cayenne-type pepper that is highly resistant to M. incognita. The bell-type peppers Keystone Resistant Giant and California Wonder are intermediate to susceptible and susceptible, respectively. None of the cultivars exhibited root galling in the methyl bromide fumigated plots and nematode reproduction was minimal (<250 eggs/g fresh root), indicating that the fumigation treatment was highly effective in controlling M. incognita. Root galling of Carolina Cayenne and nematode reproduction were minimal, and fruit yields were not reduced in the untreated plots. The root-galling reaction for Keystone Resistant Giant was intermediate (gall index = 2.9, on a scale of 1 to 5), and nematode reproduction was moderately high. However, yields of Keystone Resistant Giant were not reduced in untreated plots. Root galling was severe (gall index = 4.3) on susceptible California Wonder, nematode reproduction was high, and fruit yields were reduced (P ≤ 0.05) in untreated plots. The resistance exhibited by Carolina Cayenne and Keystone Resistant Giant provides an alternative to methyl bromide for reducing yield losses by southern root-knot nematodes in pepper. The high level of resistance of Carolina Cayenne also suppresses population densities of M. incognita.     

Control of Paratrichodorus allius and Corky Ringspot Disease in Potato with Shank-injected Metam Sodium

Corky ringspot disease (CRS) of potato produces necrotic areas in tubers that are considered quality defects that can lead to crop rejection. CRS is caused by tobacco rattle virus that is vectored by stubby-root nematodes (Paratrichodorus spp., Trichodorus spp.) at very low population densities, making disease management difficult and expensive. Fumigation with metam sodium (MS) is a common practice to control soil-borne fungi and increase potato yield. MS is generally applied in water via chemigation (water-run, WR) but is ineffective at controlling CRS when WR-applied, even at high rates. Therefore, WR MS is often used in combination with 1,3-dichloropropene (1,3-D), aldicarb or oxamyl to attain adequate CRS control. Between 1996 and 2000, fields with a history of CRS were treated with WR MS, shank-injected MS, and/or 1,3-D, and tubers were evaluated for symptoms of CRS. Shank injection of MS (SH MS) at depths of 41 cm, 15 and 30 cm, or 15, 30 and 45 cm controlled CRS over 3 years of testing. All rates of 280 liters/ha or greater were effective. Shank injection of metam potassium (MP) at rates of 448 liters/ha was also effective. 1,3-D controlled CRS alone or in combination with WR or SH MS. Proper shank application of MS or MP may adequately control CRS without the additional cost of other nematicides at low (<10 P. allius/250 g soil) to moderate (10 to 30 P. allius/250 g soil) populations of the nematode vector. Although SH MS was superior to WR MS, additional research is necessary to determine if this practice would be sufficient at higher CRS disease pressure or if addition of other nematicides would be necessary.     

Influence of Six Varieties of Cynodon on Four Meloidogyne spp.

Two years of giant star grass, Cynodon nlemluensis var. nlemfuensis, in a field plot markedly reduced the incidence of the root-knot nematodes. Tomato planted following the grass showed very little or no root galling and the yield was thrice that of tomato planted on an adjacent field plot previously cropped to tomato. Replicated greenhouse experiments indicated that six varieties of Cynodon were resistant to root-knot nematode but it took up to 6 months of grass growth to appreciably lower the nematode population. The nematodes were eliminated from the soil by all the six grass varieties after 18 months.     

Pasteuria penetrans for Control of Meloidogyne incognita on Tomato and Cucumber,and M. arenaria on Snapdragon

Meloidogyne incognita and Meloidogyne arenaria are important parasitic nematodes of vegetable and ornamental crops. Microplot and greenhouse experiments were conducted to test commercial formulations of the biocontrol agent Pasteuria penetrans for control of M. incognita on tomato and cucumber and M. arenaria on snapdragon. Three methods of application for P. penetrans were assessed including seed, transplant, and post-plant treatments. Efficacy in controlling galling and reproduction of the two root-knot nematode species was evaluated. Seed treatment application was assessed only for M. incognita on cucumber. Pasteuria treatment rates of a granular transplant formulation ranged from 1.5 × 10⁵ endospores/cm³ to 3 × 10⁵ endospores/cm³ of transplant mix applied at seeding. Additional applications of 1.5 × 10⁵ endospores/cm³ of soil were applied as a liquid formulation to soil post-transplant for both greenhouse and microplot trials. In greenhouse cucumber trials, all Pasteuria treatments were equivalent to steamed soil for reducing M. incognita populations in roots and soil, and reducing nematode reproduction and galling. In cucumber microplot trials there were no differences among treatments for M. incognita populations in roots or soil, eggs/g root, or root condition ratings. Nematode reproduction on cucumber was low with Telone II and with the seed treatment plus post-plant application of Pasteuria, which had the lowest nematode reproduction. However, galling for all Pasteuria treatments was higher than galling with Telone II. Root-knot nematode control with Pasteuria in greenhouse and microplot trials varied on tomato and snapdragon. Positive results were achieved for control of M. incognita with the seed treatment application on cucumber.     

Host-Parasite Relationship of Meloidogyne chitwoodi on Potato

The soil fumigant 1,3-dichloropropene gave good to excellent control of the Columbia root-knot nematode, Meloidogyne chitwoodi, on potato, Solanum tuberosum L. Nonfumigant nematicides (aldicarb, fensulfothion, carbofuran, ethoprop, and phenamiphos) were less effective in controlling M. chitwoodi, since the nematode affects tuber quality more than quantity. Soil temperature during the growing season affected parasitism of M. chitwoodi on potato more than did the initial nematode population. There were positive linear correlations between degree-days and infected and galled tubers (r = 0.92), degree-days and nematode generations (r = 1.00), and infected and galled tubers and nematode generations (r = 0.91). Differences in degree-days and resultant nematode reproduction caused great variability in infection and galling of potato tubers during four growing seasons: 89% for 1979, 0% for 1980, 13% for 1981, and 18% for 1982, giving positive linear correlation (r = 0.99) between final nematode soil population (Pf) and percentage of infected and galled tubers. Corresponding increases in the soil populations of second-stage juveniles (J2) during the growing season were 9,700% in 1979, 170% in 1980,552% in 1981, and 326% in 1982. There was a negative linear correlation (r = -0.87) between initial soil J2 populations (Pi) and the degree of parasitism (infection and galling) of potato tubers, Pi being of secondary importance to degree-days.     

Use of chitin for controlling plant plant-parasitic nematodes

Summary Bean and tomato seedlings, treated with different amounts of ammonia and chitin, and inoculated with the root-knot nematode,Meloidogyne javanica, were reared in two consecutive 35-day growth of shoot and root and the condition of the root systems of both plant species and degree of infection byM. javanica were decreased by increasing amounts of ammonia. Chitin caused a relatively small reduction in gall formation but almost no changes in fresh shoot weights. The effect of chitin on plant growth and nematode attack were also compared in irradiated and non-irradiated soil. In the first cycle galling index of the chitin treated plant was similar to that of untreated plants maintained in the irradiated soil conditions, while in the non-irradiated soil, chitin treatment reduced galling index. In the second cycle, chitin treatment reduced galling index in both irradiated and non-irradiated soils, especially in the latter, where galling index greatly decreased compared with the non-treated plants. Differences in fresh shoot weight between nematode-infected and nematode-free plants amended with chitin were greater under non-irradiated than irradiated conditions, especially in the second cycle. In non-irradiated soil, a higher level of chitinolytic microorganisms, particularly actinomycetes, was found in the second cycle. Contribution from the Agricultural Research Organization (ARO), Bet Dagan, Israel. No. 1520-E, 1985 series.     

Nematicide Efficacy,Root Growth,and Fruit Yield in Drip-irrigated Pineapple Parasitized by Rotylenchulus reniformis

A 3-year field trial near Kunia, Oahu, Hawaii, was conducted to evaluate four nematicide treatments for efficacy against Rotylenchulus reniformis in drip-irrigated pineapple (Ananas comosus L. (Merr.)). The treatments were (A) preplant fumigation with 1,3-dichloropropene (1,3-D) (336 liter/ ha) and postplant drip application of fenamiphos (3.4 kg/ha) with restricted irrigation, (B) preplant 1,3-D only, weekly irrigation, (C) 1,3-D fenamiphos, weekly irrigation, and (D) postplant fenamiphos only, weekly irrigation. Fenamiphos was applied at 3-month intervals for 1 year after planting in three treatments. Although nematode populations increased in all treatments 1 year after planting, no differences in fruit yield were detected among treatments in the first (plant crop) harvest 19 months after planting. In the second (ratoon) crop (33 months after planting) significant yield differences, larger fruit size, and greater root biomass were obtained in the dual nematicide treatments. Root biomass increased continuously throughout the crop cycle, was greatest near the drip line, and showed a shallow depth distribution (30-40 cm). Rotylenchulus reniformis populations and fenamiphos concentrations were negatively correlated in soil profiles taken 13 months after planting. In the absence of postplant fenamiphos applications, nematode numbers were positively correlated with root biomass.     

Transfer and Development of Pasteuria penetrans

Pasteuria penetrans isolate P-20 has been attributed as the cause of soil suppressiveness to peanut root-knot nematode in Florida. In this study, P. penetrans was transferred from a suppressive site to a new site and established by growing susceptible hosts to the peanut root-knot nematode during both summer and winter seasons. When two soil fumigants, 1,3-dichloropropene (1,3-D) and chloropicrin, were applied broadcast at the rate of 168 liters/ha and 263 kg/ha, respectively, the bacterium was not adversely affected by 1,3-D but was adversely affected by chloropicrin. In autumn 2005, after the harvest of the second peanut crop, the greatest number of J2 was recorded in the chloropicrin-treated plots, followed by the non-fumigated plots and 1,3-D-fumigated plots. The percentage J2 encumbered with endospores, endospores per J2 and percentage of P. penetrans-infected females were greatest in the non-fumigated plots, followed by 1,3-D- and chloropicrin-fumigated plots. This study demonstrates that P. penetrans can be transferred from a suppressive site to a new site and increased to suppressive densities against the peanut root-knot nematode.     

Control of Meloidogyne chitwoodi in Potato with Shank-injected Metam Sodium and other Nematicides

Metam sodium (MS) is often applied to potato fields via sprinkler irrigation systems (water-run, WR) to reduce propagules of soil-borne pathogenic fungi, particularly Verticillium dahliae, to prevent yield loss from potato early dying disease. However, this procedure has not been effective for controlling quality defects in tubers caused by Columbia root-knot nematode (Meloidogyne chitwoodi). In five trials from 1996 to 2001, application of MS by soil shank injection (SH) provided better control and tuber quality than that generally obtained by WR MS, in three of five trials. Results were similar when SH MS was injected at one (41–45 cm), two (15 and 30 cm) or three (15, 30 and 45 cm) depths. In the two trials where SH metam potassium was tested, culls were reduced to 3% and 0% and were equivalent to those resulting from a similar rate in kg a.i./ha of SH MS. A shank-injected tank mix of MS plus ethoprop EC and SH MS plus in-season chemigation applications of oxamyl provided acceptable control in trials where SH MS alone was inadequate. In-furrow application of aldicarb at planting following SH MS did not appear to increase performance. Most consistent control (0–2% culled tubers in five trials) occurred when SH MS at 280 liters/ha was used together with 1,3- dichloropropene (140 liters/ha), applied simultaneously or sequentially. This was similar to combinations of 1,3-D and WR MS, but SH MS may be preferred under certain conditions.     

Response of Resistant and Susceptible Bell Pepper (Capsicum annuum) to a Southern California Meloidogyne incognita Population from a Commercial Bell Pepper Field

To determine the presence and level of root-knot nematode (Meloidogyne spp.) infestation in Southern California bell pepper (Capsicum annuum) fields, soil and root samples were collected in April and May 2012 and analyzed for the presence of root-knot nematodes. The earlier samples were virtually free of root-knot nematodes, but the later samples all contained, sometimes very high numbers, of root-knot nematodes. Nematodes were all identified as M. incognita. A nematode population from one of these fields was multiplied in a greenhouse and used as inoculum for two repeated pot experiments with three susceptible and two resistant bell pepper varieties. Fruit yields of the resistant peppers were not affected by the nematodes, whereas yields of two of the three susceptible pepper cultivars decreased as a result of nematode inoculation. Nematode-induced root galling and nematode multiplication was low but different between the two resistant cultivars. Root galling and nematode reproduction was much higher on the three susceptible cultivars. One of these susceptible cultivars exhibited tolerance, as yields were not affected by the nematodes, but nematode multiplication was high. It is concluded that M. incognita is common in Southern California bell pepper production, and that resistant cultivars may provide a useful tool in a nonchemical management strategy.     

Reducing Meloidogyne incognita Injury to Cucumber in a Tomato-Cucumber Double-Cropping System

The effects of a root-knot nematode-resistant tomato cultivar and application of the nematicide ethoprop on root-knot nematode injury to cucumber were compared in a tomato-cucumber double-cropping system. A root-knot nematode-resistant tomato cultivar, Celebrity, and a susceptible cultivar, Heatwave, were grown in rotation with cucumber in 1995 and 1996. Celebrity suppressed populations of Meloidogyne incognita in the soil and resulted in a low root-gall rating on the subsequent cucumber crop. Nematode population densities were significantly lower at the termination of the cucumber crop in plots following Celebrity than in plots following Heatwave. Premium and marketable yields of cucumbers were higher in plots following Celebrity than in plots following Heatwave. Application of ethoprop through drip irrigation at 4.6 kg a.i./ha reduced root galling on the cucumber crop but had no effect on the nematode population density in the soil at crop termination. Ethoprop did not affect cucumber yield. These results indicate that planting a resistant tomato cultivar in a tomato-cucumber double-cropping system is more effective than applying ethoprop for managing M. incognita.     

Impact of certain oil-seed cakes or powder in comparison with oxamyl or urea on Meloidogyne incognita infecting eggplant

A pot experiment was conducted to evaluate the influence of certain oil-seed cakes i.e. fennel, sesame, anise or plant dry seed powder of red pepper as soil amendments in comparison with oxamyl or urea on controlling Meloidogyne incognita infecting eggplant seedlings under greenhouse conditions at 27 ± 5°C. Results indicated that all tested materials significantly improved the growth of eggplant and suppressing the number of galls, females and egg masses of M. incognita as compared to nematode alone. Moreover, anise oil-cake gave the best growth of total plant fresh and dry shoot weights as percentage increase (160.8 and 64%) followed by sesame oil-cake (143.5 and 64%), respectively. However, the highest values of percentage reduction for number of galls (64.2%), females (58.5%) and egg masses (55.7%) on eggplant roots were achieved by sesame-oil-cake application, followed by anise-oil-cake treatment with values of 63.0, 59.6 and 51.1% for the same nematode criteria, respectively. Meanwhile, oxamyl or urea treatment showed remarkable reduction percentages for nematode parameters tested.     

Field Tests of Formulated Products Containing EitherVerticillium chlamydosporiumorArthrobotrys dactyloidesfor Biological Control of Root-knot Nematodes

Granular formulations containing eitherVerticillium chlamydosporiumorArthrobotrys dactyloideswere applied at 55–880 kg/ha in seven field trials on a range of soils in Queensland, Australia. Granules were incorporated into soil prior to planting tomatoes and the effectiveness of the formulated fungi in reducing damage caused by root-knot nematodes was compared to an untreated control and a granular formulation of fenamiphos. Formulations ofV. chlamydosporiumwere used in three experiments but the fungus did not increase egg parasitism or reduce galling or nematode numbers at harvest. Formulations containingA. dactyloideswere more effective, as galling was reduced 4–8 weeks after planting in four of five experiments. However, these effects generally disappeared later in the season, as significant reductions in galling were only observed in one of seven experiments at harvest. Fenamiphos generally reduced galling both at 4–8 weeks and at harvest. Yield increases due to fenamiphos or any of the biological treatments were not obtained in any experiment. The results suggested that formulations ofA. dactyloidesapplied at 220–440 kg/ha substantially reduced the number of nematodes present in roots 4–8 weeks after planting. Since tomato is relatively tolerant of nematode damage under the crop management systems used in northeastern Australia, such formulations could provide useful nematode control, particularly if used in conjunction with other control measures. However, formulations with greater biological activity will be needed if the level of nematode control obtained with chemical nematicides is to be achieved withA. dactyloides.     

Control of Root-Knot Nematodes on Tomato by the Endoparasitic Fungus Meria coniospora

The endoparasitic nematophagous fungus Meria coniospora reduced root-knot nematode galling on tomatoes in greenhouse pot trials. The fungus was introduced to pots by addition of conidia at several inoculum levels directly to the soil or addition of nematodes infected with M. coniospora to the soil; both methods reduced root galling by root-knot nematodes. These studies represent a part of a recently initiated effort to evaluate the potential of endoparasitic nematophagous fungi for biocontrol of nematodes.