Effects of Belonolaimus longicaudatus Management and Nitrogen Fertility on Turf Quality of Golf Course Fairways

Field experiments evaluated the effects of nematicide and fertility on performance of ‘Tifway 419’ bermudagrass parasitized by the sting nematode (Belonolaimus longicaudatus). Plot treatments were nontreated or nematicide (1,3-dichloropropene) treated combined with different nitrogen (N) fertilizer levels. Effects of treatments on numbers of B. longicaudatus and turf performance were compared. Nematicide consistently reduced numbers of B. longicaudatus, but fertilizer level had no effect on B. longicaudatus. Turf performance of nematicide-treated plots was improved compared with nontreated plots during both experiments. Increasing N fertilizer level improved turf performance in nematicide-treated plots in some cases, but had no effect on turf performance in nontreated plots in either experiment. Results suggest that increasing N fertilizer levels may not improve turf performance at sites infested with B. longicaudatus unless nematode management tactics are effective in reducing nematode densities.     

Managing Nematode Population Densities on Tomato Transplants Using Crop Rotation and a Nematicide

Millet, milo, soybean, crotalaria, and Norman pigeon pea were used in conjunction with clean fallow and a nematicide (fensulfothion) for managing nematode populations in the production of tomato transplants (Lycopersicon esculentum Mill.). Glean fallow was the most effective treatment in suppressing nematode numbers. After 2 years in tomato, root-knot nematodes increased in numbers to damaging levels, and fallow was no longer effective for complete control even in conjunction with fensulfothion. After 4 years in tomato, none of the crops used as summer cover crops alone or in conjunction with fensulfothion reduced numbers of root-knot nematodes in harvested tomato transplants sufficiently to meet Georgia certification regulations. Milo supported large numbers of Macroposthonia ornata and Pratylenchus spp. and crotalaria supported large numbers of Pratylenchus spp. Millet, milo, soybean, crotalaria, and pigeon pea are poor choices for summer cover crops in sites used to produce tomato transplants, because they support large populations of root-knot and other potentially destructive nematodes.     

Effects of a Commercial Formulation of Paecilomyces lilacinus Strain 251 on Overseeded Bermudagrass Infested with Belonolaimus longicaudatus

Belonolaimus longicaudatus is an important parasite of both warm-season bermudagrass and winter overseed grasses used on golf courses in the southeastern United States. Field trials were conducted to study the effects of a commercial formulation of Paecilomyces lilacinus strain 251 applied to overseed grasses during the winter and early spring on population density of B. longicaudatus and bermudagrass health in late spring after bermudagrass broke dormancy. These studies found that P. lilacinus reduced numbers of B. longicaudatus in most cases, but not below damaging levels. Multiple applications of 1 × 10¹⁰ spores/m² were generally more effective than 2 × 10¹⁰ spores/m² in reducing nematode numbers and improving turf roots. These results indicate that application of this formulation of P. lilacinus strain 251 to overseeded turf in the spring may be a useful integrated pest management tool for B. longicaudatus on bermudagrass, but is not sufficient as a stand-alone nematode management tactic.     

Effects of a Commercial Formulation of Bacillus firmus I-1582 on Golf Course Bermudagrass Infested with Belonolaimus longicaudatus

One of the primary pests of bermudagrass (Cynodon spp.) on golf courses in the southeastern United States is Belonolaimus longicaudatus (sting nematode). In 2011, a commercial formulation of Bacillus firmus I-1582, Nortica 5WG, was launched in the United States for management of plant-parasitic nematodes on turfgrasses. To test the efficacy of late winter/early spring application of this biopesticide on B. longicaudatus, two field trials in 2009 compared B. firmus with fenamiphos and untreated control treatments. In 2011, two additional field trials compared treatment with B. firmus with untreated control only. These trials measured treatment effects on the population density of B. longicaudatus, turf root length, and turf percent green cover. In all four trials, treatment with B. firmus improved root length and decreased numbers of B. longicaudatus in contrast to the untreated. These results indicate that late winter/early spring application of B. firmus is an effective biopesticide treatment for management of B. longicaudatus on golf course bermudagrass.     

Slit Injection of 1,3-Dichloropropene for Management of Belonolaimus longicaudatus on Established Bermudagrass

Belonolaimus longicaudatus is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. The cancellation of organophosphate nematicides necessitates that new management tools be identified for use on sports turf. Postplant application of 1,3-dichloropropene (1,3-D) on bermudagrass was evaluated for management of B. longicaudatus on golf course fairways and driving ranges. A series of 10 experiments were conducted to evaluate the effectiveness of 1,3-D in reducing population densities of B. longicaudatus and enhancing bermudagrass recovery from nematode damage. In 5 of 10 experiments, 1,3-D injected at 46.8 liters/ha was effective in reducing population densities of B. longicaudatus (P < 0.05) compared to untreated plots 2 to 4 weeks after treatment. One month after treatment, population densities of B. longicaudatus ranged from 59% to 97% of those in untreated plots. Nematode suppression generally lasted 2 months or less. Turf visual performance was improved following injection with 1,3-D (P < 0.05) over untreated plots when other factors were not limiting. Turf root development also was enhanced following injection with 1,3-D. Postplant injection of 1,3-D could be a useful nematode management tool for certain sports turf applications.     

Interaction of Fensulfothion and Phorate with Preemergence Herbicides on Soybean Parasitic Nematodes

The herbicides alachlor, linuron, vernolate, and metribuzin were applied to plots treated with the nematicide fensulfothion or the insecticide phorate and planted to soybean in two locations in North Carolina. In 1976 treatment with fensulfothion + alachlor or vernolate, phorate + alachlor or metribuzin resulted in greater nematode population densities than no treatment, or treatment with fensulfothion alone, or phorate alone. In 1977 fensulfothion and phorate alone and in combination with the preemergence herbicides effectively controlled Tylenchorhynchus cIaytoni. Late season population resurgence of Heterodera glycines occurred in fensulfothion + alachlor treated plots. Correlation coefficients for H. glycines vs. yield were -0.48 (P = 0.05) and -0.46 (P = 0.05) for 30 and 68 d after planting, respectively.     

Population Dynamics of Plant Nematodes in Cultivated Soil: Effect of Summer Cover Crops in Old Agricultural Land

In a 6-year cover crop sequence study, nematode population densities varied with different cover crops. Millet favored rapid increase of Belonolaimus longicaudatus and supported relatively large numbers of Pratylenchus brachyurus. Beggarweed and ''Coastal'' bermudagrass favored rapid increase of B. Iongicaudatus and to a lesser extent P. brachyurus and Trichodorus christiei. Hairy indigo and Crotalaria supported relatively large numbers of P. brachyurus but suppressed B. longicaudatus. Hairy indigo also supported increases of T. christiei and Xiphinema americanum. Marigold did not favor development of any parasitic nematode species present. Tomato transplant yield was inversely related to nematode population, particularly to B. Iongicaudatus. Largest yields were obtained from plots with smallest numbers of B. longicaudatus and smallest yields were from plots with largest numbers of B. longicaudatus.     

Behavioral Effects of Carbofuran and Phenamiphos on Pratylenchus vulnus. III. Penetration and Development

Penetration of bean roots by Pratylenchus vulnus was inhibited by continuous exposure of the nematode to carbofuran and phenamiphos and by drenches of higher concentrations of these chemicals. The inhibition was explicable by inhibition of motility, dispersion, and attraction. If incubated in aerated distilled water, nematodes treated with carbofuran and phenamiphos recovered and reproduced as well as untreated nematodes. Foliar treatments were ineffective. Apparently, no basipetal transport of carbofuran and phenamiphos occurs in beans. Both nematicides arrested nematode development by interfering with egg production and transitions between life stages.     

Comparison of Millet and Sorghum-Sudangrass Hybrids Grown in Untreated Soil and Soil Treated with Two Nematicides

Aldicarb and Bay 68138 (ethyl 4-(methylthio)-m-tolyl isopropylphosphoramidate) were effective in increasing the plant height and yield of millet and sorghum-sudangrass hybrids. Stunting of plants and reduction in yield were inversely proportional to the number of Pratylenchus spp. and Belonolaimus longicaudatus present in the rhizosphere. Millet and sorghum-sudangrass hybrids supported large numbers of Criconemoides ornatus, Pratylenchus spp., B. longicaudatus, and Xiphinema americanum. Funk''s sorghum × sudangrass Hybrid 78 was more sensitive to injury by the nematode complex than were Tift 23A × 186 or Gahi-I pearl millet. ''Tiflate'' pearl millet was more resistant than other millets or sorghums to injury caused by C. ornatus, Pratylenchus spp., Trichodorus christiei, and B. longicaudatus. Millet and sorghum-sudangrass hybrids are poor summer cover crops because they favor intensive development of P. brachyurus, P. zeae, T. christiei, and B. longicaudatus.     

Field Efficacy of Furfural as a Nematicide on Turf

A commercial formulation of furfural was recently launched in the United States as a turfgrass nematicide. Three field trials evaluated efficacy of this commercial formulation on dwarf bermudagrass putting greens infested primarily with Belonolaimus longicaudatus, Meloidogyne graminis, or both these nematodes, and in some cases with Mesocriconema ornatum or Helicotylenchus pseudorobustus. In all these trials, furfural improved turf health but did not reduce population densities of B. longicaudatus, M. graminis, or the other plant-parasitic nematodes present. In two additional field trials, efficacy of furfural at increasing depths in the soil profile (0 to 5 cm, 5 to 10 cm, and 10 to 15 cm) against B. longicaudatus on bermudagrass was evaluated. Reduction in population density of B. longicaudatus was observed in furfural-treated plots for depths below 5 cm on several dates during both trials. However, no differences in population densities of B. longicaudatus were observed between the furfural-treated plots and the untreated control for soil depth of 0 to 5 cm during either trial. These results indicate that furfural applications can improve health of nematode-infested turf and can reduce population density of plant-parasitic nematodes in turf systems. Although the degree to which turf improvement is directly caused by nematicidal effects is still unclear, furfural does appear to be a useful nematode management tool for turf.     

Action of Systemic Nematicides in Control of Xiphinema iindex on Grape

In greenhouse tests using potted grape plants three nematicides, aldicarb 10 G at 4.5 ai/ha, phenamiphos 15 G at 22 kg ai/ha, and oxamyl liquid at 4.5 kg ai/ha, were tested against Xiphinema index on ''Thompson Seedless'' grape. Different timings for chemical treatments and X. index inoculations were used to determine some of the aspects of the mode of action. When nematodes and nematicides were applied simultaneously, nematodes were reduced from the initial 500 to the averages 5, 1, and 4, respectively, for aldicarb, phenamiphos, and oxamyl. Similar counts (respectively, 3, 1, and 2) were obtained when the nematicides were added first and the nematodes 14 d later. Nematode counts were 83, 112, and 1,346 when nematicides were applied first, and 14 days later plants were washed free of soil, repotted in untreated soil, and then inoculated. In untreated controls the population increased to an average of 2,703. Plant growth was inversely related to the level of nematode population resulting from the treatment.     

Interactions of Concomitant Species of Nematodes and Fusarium oxysporum f. sp. vasinfectum on Cotton

Meloidogyne incognita, Hoplolaintus galeatus, and North Carolina and Georgia populations of Belonolaimus longicaudatus were introduced singly and in various combinations with Fusarium oxysporum f. sp. vasinfectum on wilt-susceptible ''Rowden'' cotton. Of all the nematodes, the combination of the N. C. population of B. longicaudatus with Fusarium promoted greatest wilt development. H. galeatus had no effect on wilt. With Fusarium plus M. incognito or B. longicaudatus, high nematode levels promoted greater wilt than low levels. The combination of either population of B. longicaudatus with M. incognita and Fusarium induced greater wilt development than comparable inoculum densities of either nematode alone or where H. galeatus was substituted for either of these nematodes. Nematode reproduction was inversely related to wilt development. Without Fusarium, however, the high inoculum level resulted in greater reproduction of all nematode species on cotton. Combining M. incognita with B. longicaudatus or H. galeatus gave mutually depressive effects on final nematode populations. The interactions of H. gateatus with B. longicaudatus varied with two populations of the latter.     

Early Growth of Soybean as Altered by Heterodera glycines,Phenamiphos and/or Alachlor

Greenhouse and field experiments were conducted to determine the effects of phenamiphos and/or alachlor on early growth of soybean, root morphology, and infection and resurgence of Heterodera glycines (race 1). All tests were planted to ''Ransom'' soybeans. In greenhouse experiments without nematodes, root growth was inhibited at 5 days by alachlor treatments and at 10 days by phenamiphos treatments; with nematodes, phenamiphos treatments enhanced root growth. Phenamiphos also suppressed early penetration of soybean roots by H. glycines in the greenhouse. Early soybean growth parameters among treatments were generally similar in the field. Nematode penetration was limited with treatments containing phenamiphos at one location. Plants treated with only alachlor had less nematode infection than did the control; however, plants treated with herbicide/nematicide combinations had more nematode penetration than did plants treated with phenamiphos alone. Alterations of root growth and interference with the efficacy of phenamiphos are two processes by which alachlor may enhance soybean susceptibility or suitability to H. glycines.     

Evaluation of Econem™, a Formulated Pasteuria sp. Bionematicide, for Management of Belonolaimus longicaudatus on Golf Course Turf

In 2010, a turfgrass bionematicide containing in vitro produced Pasteuria sp. for management of Belonolaimus longicaudatus was launched under the tradename Econem^™. Greenhouse pot studies and field trials on golf course fairways and tee boxes evaluated Econem at varied rates and application frequencies. Trials on putting greens compared efficacy of three applications of Econem at 98 kg/ha to untreated controls and 1,3-dichloropropene at 53 kg a.i/ha. Further putting green trials evaluated the ability of three applications of Econem at 98 kg/ha to prevent resurgence of population densities of B. longicaudatus following treatment with 1,3-dichloropropene at 53 kg a.i./ha. None of the Econem treatments in pot studies were effective at reducing B. longicaudatus numbers (P ≤ 0.05). Econem was associated with reduction in population densities of B. longicaudatus (P ≤ 0.1) on only a single sampling date in one of the eight field trials and did not improve turf health in any of the trials (P > 0.1). These results did not indicate that Econem is an effective treatment for management of B. longicaudatus on golf course turf.     

Applying Nematicides through an Overhead Sprinkler Irrigation System for Control of Nematodes

Phenamiphos, ethoprop, and carbofuran each at 6.7 kg a.i./ha were applied to squash, southern pea, and corn via injection into a sprinkler irrigation system. This method was then compared with a conventional application of phenamiphos and ethoprop granules spread on the soil surface and incorporated into the top 15 cm for control of Macroposthonia ornata and Meloidogyne incognita. Nematode populations in the soil and root-gall indices were lower, and yields greater, in treated than in untreated plots, but there were no significant differences between the methods of application in most comparisons.     

Control of Ditylenchus dipsaci in Infected Garlic Seed Cloves by Nonfumigant Nematicides

Different rates of granular formulations ofaldicarb, carbofuran, ethoprop, fensulfothion, and phenamiphos were applied directly onto garlic seed cloves in the seed furrow in sandy clay loam, clay loam, and loam soils at planting to assess efficacy for control of Ditylenchus dipsaci in infected seed cloves. All treatments were compared to hotwater-formalin clove dip disinfection treatment and to nontreated infected controls. Aldicarb and phenamiphos at 2.52 and 5.04 kg a.i./ ha, but not at lower rates, effectively suppressed infection by D. dipsaci and increased yields. Although both nematicides slightly slowed the rate of plant emergence, normal stands were established. Trace levels of infection occurred in all treatments, including the hotwater-formalin dip. Carbofuran at 5.04 kg a.i./ha controlled the nematode but was phytotoxic. Ethoprop was phytotoxic. Fensulfothion did not control D. dipsaci even at the highest application rate, 8.90 kg a.i./ha. Single and multiple applications of oxamyl at 1.12-8.96 kg a.i./ha, applied as a surface spray or in furrow irrigation water, slowed the early progression of disease symptoms but failed to provide season-long nematode control.     

Effects of Selected Nematicides on Hatching of Heterodera schachtii

Aldicarb, carbofuran, fensulfothion, and phenamiphos were tested in concentrations of 1-100 μg/ml for their effects on hatching of Heterodera schachtii. Exposure of cysts to 1 μg aldicarb or carbofuran/ml stimulated hatch whereas phenamiphos and, to a lesser degree, fensulfothion inhibited hatch. Addition of aldicarb to sugarbeet root diffusate or 4 mM zinc chloride suppressed activities of these hatching agents. Transfer of cysts previously treated with aldicarb or carbofuran to zinc chloride or water rapidly initiated hatch which finally exceeded the hatch from cysts not treated with the nematicides.     

Nematicide Treatments of Turfgrass Seed

Seed treatments of improved Kentucky bluegrass and fescue cultivars with carbofuran, oxamyl, and phenamiphos dissolved in acetone reduced seedling emergence, but treatments were not extremely phytotoxic. Phenamiphos was the most toxic, particularly at the 5,000 μg/ml concentration. Fresh weight of grass clippings 35 d following planting generally was greater in treatments than in controls except for the 5,000 μg/ml phenamiphos treatments on certain cultivars. All nematicide seed treatments reduced the number of Pratylenchus penetrans subsequently recovered from Pennlawn creeping red fescue roots 4-5 wk after treatment. The infusion of nematicides into grass seed with organic solvents appears to be an effective means of reducing nematode damage to turfgrass seedling with little environmental hazard.     

Factors Affecting Furfural as a Nematicide on Turf

Recently a furfural nematicide Multiguard Protect EC was launched for use on turfgrasses in the United States. A series of greenhouse experiments were conducted to determine the concentration and exposure time required for this formulation to irreversibly affect Belonolaimus longicaudatus, and to study factors that might affect the practicality of furfural use in turfgrass systems. One experiment exposed B. longicaudatus to increasing concentrations of furfural (0 to 990 ppm) in vitro for either 24 or 48 hr, followed by inoculation onto bermudagrass. A second experiment evaluated effects of exposure of B. longicaudatus to increasing concentrations of furfural in soil solution on bermudagrass with or without an organic thatch layer. A third experiment evaluated effects on B. longicaudatus of increasing concentrations of furfural applied as a spray treatment to creeping bentgrass. Results from the in vitro exposure experiment found decreasing numbers of B. longicaudatus with increasing furfural concentration beginning with the lowest concentration tested (270 ppm). Belonolaimus longicaudatus were virtually eliminated with furfural concentrations ≥ 720 ppm. Similarly, exposure to increasing concentration of furfural in soil solution resulted in increasing reduction in numbers of B. longicaudatus. Presence of thatch slightly reduced the population density of B. longicaudatus. Spray application of furfural only reduced numbers of B. longicaudatus at the two highest rates (3,600 and 4,950 ppm).     

Alternatives to Fenamiphos for Management of Plant-Parasitic Nematodes on Bermudagrass

Plant-parasitic nematodes can be very damaging to turfgrasses. The projected cancellation of the registration for fenamiphos in the near future has generated a great deal of interest in identifying acceptable alternative nematode management tactics for use on turfgrasses. Two field experiments were conducted to evaluate the effectiveness of repeated applications of several commercially available nematicides and root biostimulants for reducing population densities of plant-parasitic nematodes and (or) promoting health of bermudagrass in nematode-infested soil. One experimental site was infested with Hoplolaimus galeatus and Trichodorus obtusus, the second with Belonolaimus longicaudatus. In both trials, none of the experimental treatments reduced population densities (P ≤ 0.1) of plant-parasitic nematodes, or consistently promoted turf visual performance or turf root production. Nematologists with responsibility to advise turf managers regarding nematode management should thoroughly investigate the validity of product claims before advising clientele in their use.