Non-fumigant Nematicides Research Articles

Potential of non-fumigant nematicides at different formulations against southern root-knot nematode (Meloidogyne incognita) on tomato plants

Currently, plant parasitic nematodes (PPN) especially root knot nematodes, Meloidogyne spp. have been found involved in the global losses of tomato crops. The most employed tactic for managing PPN in Africa is non-fumigant nematicides. Recently, in Egypt abamectin was recorded as a new tool to control PPN. Thus, two pot experiments were conducted to evaluate the potential of abamectin and certain non-fumigant nematicides namely; oxamyl and ethoprophos at two different formulations (granular and liquid) against southern root knot nematode (Meloidogyne incognita) on tomato plants under greenhouse conditions. Results revealed the granular formulations of ethoprophos and oxamyl, in addition to abamectin, showed the same significance (P≤0.05) in suppressing tomato soil population and root galls of M. incognita, during both experiments. However, liquid formulations of ethoprophos and oxamyl gave relatively less decreasing in soil population and root galls. On the other hand, all applied treatments improved plant growth criteria ranging from 36.92 to 126.44% in shoot dry weight and from 31.25 to 137.50% in root dry weight for both experiments.

Evaluation of new chemical and biological nematicides for managing Meloidogyne javanica in tomato production and associated double-crops in Florida.

Two field experiments were conducted to determine the efficacy and field performance of three new non-fumigant chemical nematicides (fluensulfone, fluopyram, and fluazaindolizine) and two biological nematicides (Burkholderia rinojensis strain A396 and Purpureocillium lilacinus strain 251) for management of root-knot nematodes (Meloidogyne javanica) on tomato and associated double-crops in Florida. In experiment 1, soil fumigation with metam potassium increased plant growth and reduced root galling on tomato by 77% relative to that of the untreated soil. All non-fumigant chemical nematicides reduced root galling on tomato (47-85% reduction); however, only fluensulfone showed a trend towards yield enhancement. In experiment 2, soil fumigation with chloropicrin increased plant growth and reduced root galling on tomato by 35% relative to that of the untreated soil; however, end-of-season populations of M. javanica in soil were larger than that of the non-fumigated soil. Fluensulfone showed a trend towards reduced root galling and enhanced fruit yield, whereas other non-fumigant nematicides did not. Double-cropped cucumber was 69% more galled when planted into soil previously fumigated with chloropicrin relative to that of untreated soil, and also showed reduced plant vigor and fruit yield. Fluensulfone shows significant potential to be a component of an integrated pest management strategy for tomato in Florida. © 2019 Society of Chemical Industry.

Evaluation of fluopyram for southern root-knot nematode management in tomato production in China

The southern root-knot nematode (Meloidogyne incognita) is one of major challenges tomato growers face in vegetable production; and phase out of methyl bromide and the restricted use of soil fumigants have been accelerating application of non-fumigant nematicides for control of this economically important plant-parasitic nematode. Fluopyram, a succinate dehydrogenase inhibitor fungicide, has been widely used to control fungal diseases in vegetable crops. However, in China, little information is currently available about the efficacy of fluopyram against M. incognita and its effect on tomato yield. In this study, the nematicidal effect of fluopyram on M. incognita was investigated under laboratory and field conditions in China. In the laboratory, fluopyram was highly toxic to the second-stage juveniles (J2) and the eggs of M. incognita with the median lethal concentration (LC50) value of 2.78 and 1.70 mg L−1, respectively. In the field trials, fluopyram was effective in reducing population levels of M. incognita, meanwhile enhancing plant growth, particularly at 480 and 640 g ha−1 in two consecutive years, which was significantly greater than that of abamectin (a standard treatment) at 480 g ha−1. Moreover, there was a yield increase of 21.4%-58.5% from the treatments with fluopyram at three doses compared with the untreated control. The results from this study indicated that fluopyram was effective against M. incognita and could be used for control of root-knot nematodes in tomato production, while enhancing tomato growth and yield.

Sustainable alternatives to 1,3-dichloropropene for controlling root-knot nematodes and fungal pathogens in melon crops in Mediterranean soils: Efficacy and effects on soil quality

The control of agricultural pests is key to maintain economically viable crops. Increasing environmental awareness, however, is leading to more restrictive European policies regulating the use of certain pesticides due to their impact on human health and the soil system. Given this context, we evaluated the efficacy of three alternatives to the soil fumigant 1,3-dichloropropene (1,3-D), which is currently banned in Europe: two non-fumigant nematicides [oxamyl (OX) and fenamiphos (FEN)] and the soil fumigant dimethyl disulfide (DMDS). We analysed the efficiency of these pesticides against root-knot nematodes and soil fungal pathogens (determined by qPCR) as well as the soil biological quality after treatments application (estimated by enzyme activities). Among treatments, 1,3-D and DMDS significantly reduced nematode populations. FEN was more effective in sandy soil, while OX had no effect in any soil. OX and FEN had no effect on fungal pathogens, whereas DMDS reduced the abundance of Rhizoctonia solani and Fusarium solani at the root level in clay-loam soil. Soil quality decreased after treatment application but then recovered throughout the experiment, indicating the possible dissipation of the pesticides. Our findings support DMDS as a potential sustainable alternative for controlling root-knot nematodes and fungal pathogens due to its effectiveness in both studied soils, although its negative impact on soil biological quality in sandier soils must be taken into account.Main finding of the work. DMDS is a reliable alternative to 1,3-D for controlling agricultural pest but its inhibitory effect on soil enzyme activities varied according to the soil characteristics.

Control of Meloidogyne incognita in sweetpotato with fluensulfone.

In California, sweetpotato is mostly grown on light sandy soils in Merced County. Root-knot nematodes (Meloidogyne spp.) can reduce sweetpotato yields and quality. Fluensulfone is the active ingredient of the new non-fumigant nematicide Nimitz. Unlike fumigant nematicides, toxicity toward non-target organisms is low, and it does not emit volatile organic compounds which negatively impact air quality. In two field trials, the effect of fluensulfone on M. incognita levels, and on the yield and quality of sweetpotato was determined. Fluensulfone was applied as a pre-plant soil incorporated drench or as a drench followed by post-plant sprays. Fluensulfone treatments more than doubled the marketable yields over an untreated control and a metam-sodium treatment in both trials. It strongly reduced nematode symptoms on the harvested roots and nematode infestation of these roots. The lowest rate of fluensulfone was as effective as the higher rates, and post-plant sprays following a pre-plant soil incorporated drench did not result in any additional benefits. Fluensulfone did not reduce soil nematode levels at harvest. It was concluded that a pre-plant incorporated fluensulfone drench at a rate of 1.96 kg/ha could provide a viable alternative for currently used nematicides to mitigate root-knot nematode damage in sweetpotato.

The use of fluensulfone for the control of root-knot nematodes in greenhouse cultivated crops: Efficacy and phytotoxicity effects

A recently released non-fumigant nematicide, fluensulfone, belonging to the fluoroalkenyl chemical group, fluensulfone, was tested against field populations of root-knot nematodes Meloidogyne sp. i...

Evaluation of non-fumigant chemical and biological nematicides for strawberry production in Florida

In Florida, strawberry is an economically important horticultural crop. Plant-parasitic nematodes present a significant obstacle for strawberry growers in the sandy soils found in this state. Historically, nematodes have been controlled through the application of soil fumigants; however, there is interest in exploring the use of non-fumigant nematicides that can provide similar levels of control and at the same time be more environmentally friendly than fumigants. Using two field experiments, the effects of non-fumigant chemical and biological nematicides on plant vigour and fruit yield, populations of plant-parasitic nematodes, and populations of free-living nematode feeding groups were evaluated. In experiment 1, soil fumigation with metam potassium, as well as all non-fumigant chemical nematicides (fluopyram, fluensulfone, fluazaindolizine) failed to increase plant vigour, fruit yield, or suppress populations of plant-parasitic nematodes. In experiment 2, fluopyram increased fruit yield and suppressed Belonolaimus longicaudatus populations by the end of the growing season. Biological nematicides (Dazitol®, Majestene®, and Nemakill®) did not enhance crop establishment or suppress plant-parasitic nematode populations. Soil fumigation with 1,3-dichloropropene + chloropicrin provided consistent enhancement of plant vigour and fruit yield, as well as suppressed populations of B. longicaudatus; however, populations of free-living nematodes were also reduced. Overall, soil application of fluopyram shows potential to be a component of an integrated pest management strategy for the control of B. longicaudatus populations on strawberry in Florida.

Fumigant and Non-Fumigant Nematicides Labeled for Agronomic Crops in Florida

Plant-parasitic nematodes can cause severe yield loss of agronomic crops in Florida. Chemical products for managing plant-parasitic nematodes are called nematicides. This three-page facts heet describes the nematicides registered for use in Florida. Written by Zane Grabau and published by the Department of Entomology and Nematology.­http://edis.ifas.ufl.edu/in1152

Evaluation of some non-fumigant nematicides and the biocide avermactin for managing Meloidogyne incognita in tomatoes

Evaluation of some non-fumigant nematicides and the biocide avermactin for managing Meloidogyne incognita in tomatoes

Effect of different nematicide applications per year on banana (Musa AAA) root nematode control and crop yield

Objective: The objective of this study was to evaluate the effect of different nematicide applications per year on control of banana root nematode, root weight and crop yield in Belize. The relationship between cost and benefit of the nematicide applications was also estimated. Methodology and results: A field experiment was conducted in a 40 years old commercial banana ( Musa AAA cv. Grande Naine) plantation from November 2011 to February 2013. Four treatments were evaluated: 1. Three nematicides (Nemacur ® , Mocap ® , Vydate ® ) applications per year with a 4-month interval, 2. Two nematicides (Nemacur ® , Mocap ® ) applications per year with a 6-month interval, 3. Nematicides applied based on nematode threshold (100 nematodes per g of fresh root) which resulted in two applications; Nemacur ® and Mocap ® with a 7-month interval, and 4. An untreated control. Averaging the 12 root nematode samplings, the lowest R. similis (P= 0.0008), Helicotylenchus spp. (P< 0.0001) and total nematode (P< 0.0001) population were observed in the plots treated with the three nematicide applications per year. Compared with the untreated control, the three nematicide applications reduced R. similis in 53%, Helicotylenchus spp. in 48% and the total nematode population in 53%. Even though the three nematicide applications per year resulted in higher R. similis control efficacy with 42.4%, no difference (P= 0.6372) was detected with two 32% (at 6-month interval) applications per year, and two 33% (at 7-month interval) applications per year, based on nematode population threshold. For Helicotylenchus spp. (P= 0.0047) and total nematodes (P= 0.0018), three applications were better than two at 6-month interval or two applications per year based on nematode population threshold, with 65.3 and 58.5% of efficacy on nematode control, respectively. No difference in total root weight (P= 0.9812) and functional root weight (P= 0.7742) was observed among treatments, varying from 88 to 90 and 73 to 79 g / plant, respectively. At harvest, 12 months after the nematicide applications, bunch weight was increased (P= 0.0013) in 7.2 (41%), 4.8 (27%) and 4.7 (27%) kg per bunch resulting in an extra gain of $2468, $1660 and $1427 ha -1 with three, two at 6- month interval and two applications per year based on nematode population density, respectively. Conclusions and application of findings: The non-fumigant nematicide applications reduced banana root nematodes and improved crop yield. Rotation of the nematicides according to their physic-chemical properties and weather conditions is desirable in order to prevent their biodegradation. Keywords: Chemical control, Musa AAA, nematode control, nematicides

Parasitism and pathogenicity of curly-leaf parsley with the root-knot nematode Meloidogyne javanica in Southern Italy

Summary Severe infections of parsley plants and soil infestations with Meloidogyne javanica during an autumn surveys for the pathogenic root-knot nematode infestations were found in Monopoli at Bari province in Southern Italy. This unusual severe infection of parsley, considered a winter crop, was possibly instigated by a very warm autumn from the previous year. Nematodes were extracted from soil samples according to the Coolen’s method. Morphological analysis (based on stylet length, tail length and shape, adult females perineal pattern, excretory pore position and Ep/stylet ratio) and molecular studies were used for the nematode characterization and identification. In the soil of infested area a severely deformed root systems were observed, showing a galling rate = 2.5 - 4 (scale 0-5) and a soil nematode population densities ranging from 350 to 2,730 eggs and J2 per 5 g of fresh root. M. javanica attack on parsley roots is a limiting factor for plant growth. Considering that curly-leaf parsley varieties resistant to the nematodes are not yet available control strategies must be focused on reduction of soil infestation level below tolerance limit of the target nematode species. Due to the higher cost and reduced availability of fumigant and non-fumigant nematicides, soil solarization, organic amendments or biological control approaches should be preferably used as alternatives.

Efficacy and crop tolerance of 1,3-dichloropropene applied at low rates in established vineyards for the control of plant-parasitic nematodes

Plant-parasitic nematodes are the most important group of root pathogens affecting vineyards for fresh fruit and wine production in Chile. Due to the low efficacy of presently available nematicides and their high variability of control, new alternatives were evaluated in order to obtain a faster and more reliable control. The aim of this work was to assess the use of the soil fumigant Cordon®, containing 81.4% of 1,3-dichloropropene (1,3-D) plus emulsifiers that allow 1,3-D to be mixed with water and applied at low rate via drip irrigation systems over established vines for the control of Xiphinema index, the main nematode species associated with grapevine injury in the country. During the first year of studies, one trial was performed in a group of ungrafted vines cv Chardonnay, applying the treatments twice, one in autumn, and the second one in the next spring, with three Cordon® concentrations, 100, 200 and 400 ppm, equivalent to 3.7, 7.4 and 14.8 L ha−1 according to the irrigation system water flow. A second trial was performed the following year to determine limits of crop safety by applying 200, 400 and 800 ppm, equivalent to 12, 24 and 48 L ha−1 in two established vineyards, cv Thompson Seedless and Cabernet Sauvignon. Results showed that 200 ppm, equivalent to 7.4 or 12 L ha−1 depending of the field, achieved good results considering efficacy and phytotoxicity, with a 93.2% control and no crop damage. Two non-fumigant nematicides, Nemacur® 240 CS (24% Fenamiphos) and Rugby® 200 CS (20% Cadusaphos), used as chemical controls, did not show differences in X. index populations when compared to the untreated plants. At rates over 400 ppm of 1,3-D, although no visible foliar injury was observed, the pruning weight of treated plants was reduced, indicating a growth reduction.

Biocontrol potential of Pasteuria penetrans, Pochonia chlamydosporia, Paecilomyces lilacinus and Trichoderma harzianum against Meloidogyne incognita in

The root-knot nematode, Meloidogyne incognita , is a sedentary endoparasitic plant pathogen with a very wide host range, which causes annual crop losses amounting to millions of dollars. The small number of available nematicides and restrictions on the use of non-fumigant nematicides due to high toxicity to humans and non-target organisms hinder effective nematode control. A possible alternative to chemical nematicides is the use of biological control agents for the management of this nematode. In the present study, the efficacy of four biocontrol agents was tested against M. incognita at different doses. The biocontrol agents Pasteuria penetrans , Pochonia chlamydosporia , Paecilomyces lilacinus and Trichoderma harzianum were mass produced and mixed with the formalin sterilized soil at the rates of 2 × 103, 4 × 103, 6 × 103, 8 × 103, and 1 × 104 endospores/chlamydospores/cfu per g of soil. Okra seeds (cv. Sabz Pari) were sown in pots of soil amended with the different agents, and 10 d after emergence, the plants were inoculated with 2000 freshly hatched second stage juveniles of M. incognita. Data on plant growth parameters and nematode infestations were recorded 7 weeks after inoculation. The antagonists varied significantly in enhancing various growth parameters and reducing nematode infestations in a dose-responsive manner. Both P. penetrans and P. lilacinus were equally effective and caused maximum reductions in number of galls, egg masses, nematode fecundity and build up as compared with T. harzianum and P. chlamydosporia . Reductions in these parameters at the concentration of 8 × 103 were statistically similar with those caused at the concentration of 1 × 104 chlamydospores/ endospores/cfu. Our results indicate that application of antagonists can suppress galling and reproduction of M. incognita resulting in enhancement of plant growth.

Perception of the impact of root-knot nematode-induced diseases in horticultural protected crops of south-eastern Spain

With a surface area of 37 000 ha and an annual yield of 3 × 106 t, the south-east of Spain, predominantly the coast of Almeria, is the largest horticultural growing area under protected cultivation in Europe. A survey on perception of the impact of root-knot nematodes on vegetable production was carried out in this area by face-to-face interviews with 120 farm advisors. The survey was designed to evaluate opinions about prevalence and severity of root-knot nematode-induced diseases, percentage of infested area and effectiveness of root-knot nematode control methods. According to the answers, 17.7% of the fields were infested with root-knot nematode and 18.8% of the cultivable area within each site showed root-knot nematode disease symptoms, which came to 2.0% of the total area used to grow vegetables in the region. Average yield loss was estimated at about 30.8% of total vegetable production, and 38.1% of the farm advisors considered that root-knot nematode infections had increased over the last 5 years. Most farm advisors (78.3%) stated that the most commonly used control method was chemical soil fumigation. Non-fumigant nematicides were cited by 59.8% of them, grafting and resistant cultivars by 42.3%, soil solarisation 38.1%, plant extracts 14.4% and biofumigation 6.2%. The majority of farm advisors considered the application of fumigant nematicides combined with soil solarisation, and grafting onto resistant rootstocks as the most effective methods of root-knot nematode control. In addition to the interviews, plant and soil samples were taken from plastic greenhouses throughout the region to determine species of root-knot nematode present. Meloidogyne javanica was the most prevalent species followed by M. incognita and M. arenaria, but species distribution was linked to the predominating crop sequence in each area, since M. javanica occurred less frequently when sweet pepper rather than tomato appeared in the crop sequence.

Nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group, against the root‐knot nematode Meloidogyne javanica

The small number of available nematicides and restrictions on the use of non-fumigant nematicides owing to high toxicity to human and non-target organisms hinder effective nematode control. The nematicidal efficacy of MCW-2, a new nematicide of the fluoroalkenyl group, was evaluated against the root-knot nematode Meloidogyne javanica (Treub.) Chitwood. MCW-2 showed irreversible nematicidal activity against second-stage juveniles of M. javanica in vitro, following exposure for 48 h at concentrations as low as 0.5 mg L(-1), in contrast to fenamiphos or cadusafos. When exposed to MCW-2 for shorter periods, motile juveniles became immobile with time after rinsing in water. MCW-2 at 8 mg L(-1) inhibited nematode hatching, which, however, recovered after rinsing in water. In pot and plot experiments, 0.5 mg MCW-2 L(-1) soil and 2 kg MCW-2 ha(-1), respectively, controlled M. javanica similarly to or better than fenamiphos or cadusafos at the same concentrations or at their recommended doses. In the soil, the nematicidal activity of MCW-2 was less persistent than that of fenamiphos. MCW-2 has potential to be used as a new non-fumigant nematicide that probably has a novel mode of action.

The effect of soil fumigants methyl bromide and metham sodium on the microbial degradation of the nematicide Cadusafos

Rapid biodegradation of Cadusafos in a soil from a previously treated greenhouse site from the area of Vasilika in Northern Greece was observed using both incubation and bioassay studies with nematodes. The slow rates of Cadusafos degradation observed in soils from the previously treated site after sterilization with chloroform and also in soils from an adjacent previously untreated site suggested that soil microorganisms adapted to metabolize Cadusafos were responsible for its rapid dissipation. Fumigation of the soil from the previously treated site with methyl bromide (MB) 9 months prior to the experimental addition of Cadusafos (4 μg g −1) only temporarily inhibited degradation of Cadusafos, unlike metham sodium (MS) whose application significantly hampered degradation of the nematicide. However, when the time interval between fumigation of soil from the previously treated greenhouse with MB and MS and the experimental application of Cadusafos was minimized to 20 d, both fumigants halted the rapid degradation of the nematicide. The transient inhibitory effect of MB on the microbial degradation of subsequent Cadusafos applications was attributed to the recovery of the soil microflora within 9 months. In contrast, the persistent inhibitory effect of MS on the microbial degradation of Cadusafos might have been caused by the adverse effects of the fumigant on the microorganisms, which were responsible for the rapid degradation of Cadusafos in the specific soil, although this was not tested in this study. According to these findings, the combined application of MS as a pre-planting treatment with a post-planting application of Cadusafos would maximize the biological efficacy of the non-fumigant nematicide by extending its persistence and preventing the development of enhanced biodegradation for organophosphorus nematicides such Cadusafos.

Degradation and adsorption of fosthiazate in soil.

Adsorption and degradation behavior of a pesticide in soil has a strong effect on its environmental fate as well as efficacy for pest control. Fosthiazate is an organophosphate compound that is currently under development as a nonfumigant nematicide. In this study, we evaluated adsorption and degradation kinetics of fosthiazate in three U.S. soils with different properties. Adsorption of fosthiazate in mineral soil was negligibly weak but appeared to increase with soil organic matter (OM) content. The half-life (T(1/2)) of fosthiazate ranged from 0.5 to 1.5 months in nonsterile soils but was prolonged to 1-3 months after sterilization. Degradation of fosthiazate in soil appeared to be caused by both chemical and microbial transformations. The persistence of fosthiazate generally decreased with increasing soil pH, but increased with increasing soil OM and clay contents. This results suggest that fosthiazate may have an enhanced leaching potential in acidic soils with low OM content, and its efficacy in high pH soils may not last as long as in neutral soils because of faster degradation.

Evaluation of chemical and integrated strategies as alternatives to methyl bromide for the control of root‐knot nematodes in Greece

Current environmental awareness has led to a greater demand for alternative nematode control strategies. Three field experiments were established to compare management tactics on cucumber in commercial greenhouses naturally infested with root-knot nematodes (Meloidogyne spp). Cucumber rootstocks which have shown resistance to soil-borne diseases were tested to reveal any resistance/tolerance to root-knot nematodes, and integration of these rootstocks with nematicides was investigated. Metham-sodium and 1,3-dichloropropene (1,3-D) provided good control of nematode populations when their application was followed by the application of a non-fumigant nematicide such as cadusafos or oxamyl. Neither fumigant could provide season-long control of nematode populations, and a further application of cadusafos was required for satisfactory control. The efficacy of metham-sodium was significantly increased when injected into soil in comparison with its application through the drip irrigation system. The use of rootstocks resistant to soil-borne fungal pathogens used together with chemical means of nematode control provided promising results for their further use in integrated strategies as alternatives to methyl bromide. However, the latter was the superior treatment for the control of root-knot nematodes in soil infested with residues of galled roots. Dazomet, metham-sodium nor the non-fumigant nematicides oxamyl and fenamiphos could reduce nematode population as efficiently as methyl bromide. None of the chemicals tested except methyl bromide could enter galled roots and kill surviving nematodes.

Efficacy of Certain Nonfumigant Nematicides on the Control of Pigeonpea Wilt Involving Heterodera cajani and Fusarium udum

AbstractThe efficacy of aldicarb, carboturan and phorate nematicides on the control of wilt disease complex involving Fnsarium udum was studied in pot culture. The two pathogens interacted synergistically. The severity of the disease complex was significantly reduced at all the dosages of these nematicides but the greatest reduction occurred at the highest dosage (20 mg a. i. Kg soil). The final total population of H. cajani was significantly reduced by F. udum as well as by these nematicides. These nematicides adversely affected not only the developmental stages of nematode resulting in a significant increase in 3rd—4th stage juveniles and decrease in 2nd stage juveniles, adults and cysts, even impeded the fecundity of the nematode.

Effect of the nematicide oxamyl on lipid utilization and infectivity inGlobodera rostochiensis

SummaryAt field rates (ca 0·1–10 μg active ingredient/ml), non-fumigant nematicides such as oxamyl do not kill plant-parasitic nematodes directly but act by impairing neuromuscular activity. The present study has shown that neutral lipid levels in 2nd-stage (infective) juveniles ofGlobodera rostochiensis, which had been incubated with the oximecarbamate nematicide oxamyl (1 μg a.i./ml) for between 8 and 35 days, were significantly (P&lt; 0·05) greater when compared with controls maintained in water alone. The difference between treatments was found to be due principally to changes in the lipid content in the posterior half of the body which appears to act as the major long-term lipid store. When nematodes were allowed to recover for 72 h following incubation for 35 days with oxamyl, their infectivity was not significantly (P&gt; 0·05) different from that of controls. This work is discussed in relation to the action of oxamyl and similar nematicides and to the use of controlled-release formulations as a means of increasing their efficacy.