Granular Nematicides Research Articles

土壌消毒用粒剤を利用した線虫防除 ガス拡散型粒剤の施用法について

The purpose of this study is to establish the best method for applying granular nematicides to control nematodes. Four common methods of applying granular nematicides into the soil (the reader may refer to table 1) were adopted for the upland field to find out the best way to apply. The results were as follows:1) As it is desirable for the soil clods to be smaller than 10mm diam. to improve the efficiency, the application methods II and IV were necessary to pulverize the soil more.2) Though the moisture of the subsoil (15-40cm depth) was increased by the rainfall, that of the topsoil (0-5cm depth) was always constant and there was almost no recognizable difference of the water retentivity among the methods I-IV.3) There were some differences of the bulk density in the upper layer soil (0-20cm) depending on the methods till a week after applying, but after a month, there was no difference among the methods II-IV. It became clear that the effect of the nematodes control was influenced significantly by the soil condition just after applying nematicide.4) The peak of the nematodes vertical distribution in the soil agreed with the application depth 15-20cm of granular nematicide on using the methods II-IV. It was proved that it was very important to obtain a close agreement between the vertical distribution of the nematodes and the nematicide on using the gas diffusion type nematicides.5) The decrease rate of nematodes was from -7% (the application method I) to -17.5% (the method IV) at a week after applying granular nematicide, and it became clear that the nematicides which have a low vapor pressure were unable to control the nematodes in an early stage.6) The nematodes density of the test field of the method IV was 2-3 times as many as the other one, but that of the method IV decreased slowly and certainly from -17.5% to -30%, and then to -46.8% for two months. The method IV seemed to be an effectual method for the gas diffusion type of the granular nematicides.7) As the results of comparing the efficiencies of the four application methods at a month and two months after applying granular nematicide, the duration of the effect of the method IV was longer than the other methods and valued high entirely.8) The ratio accounting for the application times of the applications methods II-IV were 35-65% of total work time. It was considered that the improvement of the granular applicator based on the physical properties of granular nematicides was needed to improve the work efficiency.9) Though the effect of the method IV was better than the other ones, the work efficiency of this method was very much lower. This was because in the application method IV, the tilling process, the ditching process, the applying process, the covering process and the pressing process were independent of each other. It is necessary to unify those independent processes into one working process for improving work efficiency.

Causes of differences in growth pattern, yield and quality of potatoes (Solanum tuberosum L.) in short rotations on sandy soil as affected by crop rotation, cultivar and application of granular nematicides

A crop rotation experiment was carried out on a light sandy soil in 1979–1986 to study the effects of the frequency of potato cropping on yield, quality and on the occurrence of soil-borne pathogens other than potato cyst nematodes.

Effects of crop rotation and granular nematicides on the incidence ofVerticillium dahliae Kleb. andColletotrichum coccodes (Wallr.) Hughes, in potato

The incidence ofVerticillium dahliae andColletotrichum coccodes was studied in a crop rotation experiment on sandy soil from 1983 to 1986. Early in the growing season the percentage of stems infected byV. dahliae increased with increasing cropping frequency of potato, depending on the cropping sequence, and decreased with the application of granular nematicides. However, later in the growing season the initial differences decreased.C. coccodes infections of stems were not affected by these factors. The percentage of plants infected byV. dahliae closely correlated with the percentage of plants with wilt symptoms but this relationship was absent forC. coccodes.

Infection process of Rhizoctonia solani on Solanum tuberosum and effects of granular nematicides

The infection process ofRhizoctonia solani AG-3 was studied on potato sprouts, cv. Bintje, in growth chamber trials at 15 °C. Initially hyphae ofR. solani grew predominantly in the longitudinal direction of the sprouts (runner hyphae). They tended to follow the junctions between epidermis cells as was observed by SEM. The hyphae formed side-branches mainly half-way of the subterranean parts of the sprouts. They branched several times with short swollen cells to form infection cushions. Lesions developed only underneath the infection cushions and were first observed five days after inoculation. The necrotic area was proportional to the area covered with infection cushions on the sprouts. Depth of the lesions could extend up to the vascular bundle. Sprouts were colonized only in healthy tissue in the epidermal layer underneath the infection cushion and in necrotic tissue. A few days after appearance of the lesions,R. solani formed brown, uninfective mycelium on and in the circumference of these lesions.

A vertical band‐Dutch harrow technique for incorporating granular nematicides in soil to control potato cyst‐nematodes, Globodera rostochiensis and G. pallida

SUMMARYIn lightly infested silt loam, aldicarb at 3·3 kg ha‐1in 1985 or oxamyl at 4·5 kg ha‐1in 1986, applied to the top 12 – 15 cm of the soil by a 5 m wide Dutch harrow fitted with vertical band granule outlets 15 cm apart, increased yields of King Edward or Romano potatoes and effectively controlled increase of potato cyst‐nematodes. Carbofuran at 5 kg ha‐1in 1986 was less effective.This new vertical band‐Dutch harrow technique has the advantage over the vertical band‐rotary harrow technique in that lateral mixing of the vertical bands of granules is not required. It is especially useful for poorly structured soils, which will not tolerate powered harrowing, and could also prove beneficial on other soils of low organic matter content.

Management of the yellow beet cyst nematode with crop rotation, soil fumigation and granular nematicides

A trail field was managed for six years to test effects of short crop rotations, soil fumigation and granular nematicides on the population dynamics of the yellow beet cyst nematode (Heterodera trifolii f. sp.beta) and sugar-beet yields.

Effects of granular nematicides on growth and microbial antagonism to Rhizoctonia solani

Effects of nematicides on growth and microbial antagonism toRhizoctonia solani were investigated as part of a study on the mechanisms involved in the increased incidence of this pathogen in nematicide-treated potato crops.

Effects of potato genotype, oxamyl and the numbers of potato cyst‐nematodes, Globodera rostochiensis or G. pallida on tuber yields and nematode increase

SUMMARYA new technique is described for establishing different numbers of the potato cyst‐nematode Globodera rostochiensis in field soil, which leaves the soil homogeneous in nutrient status. Field plots established in this way were used to compare yield losses in four potato cultivars (Maris Piper, Pentland Crown, Pentland Dell and Désirée) associated with different numbers of G. rostochiensis. Over the range of 7.4 to 148.4 eggs g‐1 soil at planting, yield losses were 18.7% (Maris Piper), 53.2% (Désirée), 55.7% (Pentland Crown) and 63.5% (Pentland Dell). Similar results were obtained in another experiment on the same field in a different year using only lightly and heavily infested plots. Treating the seedbed soil with oxamyl before planting prevented significant injury to potatoes by G. rostochiensis but increased the yield of Pentland Dell and perhaps Désirée (but not Maris Piper or Pentland Crown) more than expected from nematode control alone. Treating heavily infested soil with such a nematicide cannot therefore be recommended as part of a valid procedure for establishing lightly and heavily infested plots for comparing tolerances of attack by potato cyst‐nematodes in a range of potato genotypes.In peaty loam soils moderately or heavily infested with G. pallida, oxamyl at 5.6 kg a.i. ha‐1 incorporated into the seedbed before potatoes were planted generally increased tuber yields, though the effects varied considerably with the cultivar grown. Increase of G. pallida in these soils was controlled better by growing potatoes bred for resistance to it (ZB 35 – 29, Caxton, Santé, Morag, 11233 ab 22, Fingal, A27/23, Cromwell). Increase of G. pallida on susceptible cultivars varied greatly and Romano increased G. pallida no more than the resistant Morag. G. pallida is probably controlled best in peaty loam by growing a resistant cultivar in soil treated with a granular (non‐fumigant) nematicide.

The effect of crop rotation and granular nematicides on the incidence ofRhizoctonia solani in potato

The incidence ofRhizoctonia solani in potato was studied in two crop rotation experiments from 1981 to 1985 inclusive. The greater the frequency of potato cropping, the more severe the attack on stems and stolons byR. solani. Severity of black scurf on progeny tubers and cropping frequency were also correlated, but less significantly. In fields with antagonists toR. solani, continuous potato cropping caused less black scurf on tubers than did 1∶2 rotations.

Pratylenchus penetrans(root lesion nematode)—cause of patch chlorosis ofPinus radiataseedlings

Summary The root lesion nematode Pratylenchus penetrans was recovered from the roots of stunted, chlorotic, wilting and recently dead Pinus radiata seedlings growing in a forest nursery located on deep sands in south-western Victoria adjacent to the South Australian border. Although specimens of the genus Pratylenchus were recovered from P. radiata nursery soils in this region about 20 years ago, this is the first record of the species P. penetrans parasitising P. radiata in Australia. Greenhouse and phytotron tests showed that P. penetrans could, by itself, cause the disease symptoms observed in the nursery and that other soil pathogens, which produce similar symptoms, contributed insignificantly. P. penetrans was controlled by a single application of readily available proprietary brands of either liquid or granular nematicides shortly after seedling germination. A 10–15% improvement in seedling height was obtained even in healthy-looking seedlings infested with nematodes.

Título en español

Se realizaron dos pruebas de campo para evaluar el efecto de oxamyl 24 L para combatir nematodos e incrementar la producción de ñames, Dioscorea rotundata Poir de alta calidad. Este nematicida se evaluó como tratamiento de inmersión para la semilla, tratamientos al surco y al follaje y combinaciones del tratamiento al follaje con los tratamientos a la semilla y al surco. Al aplicar oxamyl 24L al follaje en combinación con el tratamiento de la semilla y con el tratamiento a la semilla solamente se obtuvieron aumentos significativos en el rendimiento de ñames de alta calidad. Si se logrará conseguir una autorización para usar oxamyl 24 L para ñames en Puerto Rico se proveería al agricultor con otro producto eficaz contra los nematodes, además del producto granulado (aldicarb 10G) que actualmente puede usarse.

Título en español

Se hicieron tres experimentos de campo para evaluar el efecto de nematicidas no volátiles en ñame (Dioscorea rotundata Pair). Los nematicidas se aplicaron al sembrar, o al sembrar y después de la siembra. El aldicarb fue más eficaz que el carbofuran y el fensulfothion en el control de nematodos y aumento de tubérculos de alta calidad. No se encontró diferencia significativa entre los tratamientos en los que el nematicida se aplicó en una sola aplicación al sembrar y en los que la dosis se dividió para efectuar una segunda aplicación más tarde. Los resultados dejan por sentado la importancia de controlar los nematodos en la producción de ñames.

NONFUMIGANT NEMATICIDES FOR CONTROL OF NORTHERN ROOT-KNOT NEMATODE IN MUCK-GROWN CARROTS

Field experiments were conducted to determine the effects of rate and application method on the effectiveness of nonfumigant nematicides to protect carrot roots (Daucus carota L.) against Meloidogyne hapla, Chitwood, in organic soil. Carbamate compounds, aldicarb and oxamyl, provided better protection to carrot roots than organophosphorus, phenamiphos and terbufos compounds. In-furrow application of granular nematicides at the rate of 1.5 kg a.i./ha was more effective than band and broadcast incorporation at a rate of 6 kg a.i./ha. The standard control method with the fumigant, 1,3-dichloropropene, offered the best nematode control and the highest marketable yields.Key words: Daucus carota, Meloidogyne hapla

Effects of granular nematicides on Valencia orange trees infested with Tylenchulus semipenetrans

Three granular nematicides were applied at six-seven week intervals to soil around Valencia orange trees infested with the citrus nematode, Tylenchulus semipenetrans. Fenamiphos [two and three applications of 10 kg active ingredient (a.i.)/ha] and aldicarb (three applications of 8 kg a.i./ha) temporarily reduced populations of T. semipenetrans in roots, but fruit yields did not increase in the two subsequent harvests. 1,2-dibromo-3-chloropropane (D.B.C.P.) (two applications of 40 kg a.i./ha) had no effect on either nematode populations or yield. The nematicides did not affect the percentage of California red scale parasitized by biological control agents. Aldicarb residues were found in orange pulp, juice and rind eight months after application, but low residues of D.B.C.P. were found only in rind, and no fenamiphos residues were detected.

Effect of two granular nematicides on growth and nodulation ofArachis hypogea L.

The effect of two granular nematicidesviz. oxamyl and fenamiphos, on the nodulation and growth of Rhizobium inoculatedArachis hypogaea L. was studied in glasshouse and field trials. In the glasshouse trial at the suggested rates of application shoot fresh weight was significantly reduced by oxamyl whilst root fresh weight was similarly affected by fenamiphos. In the field trial vegetative growth and plant emergence were significantly reduced by both nematicides. Nodulation at the higher rates of application was increased by both oxamyl and fenamiphos whilst oxamyl caused a significant increase in pod number at the highest rate of application.

Population estimates of cereal cyst nematode and response of wheat to granular nematicides

Response of vegetative growth and grain yield of wheat Triticum aestivum cv. Condor to the control of cereal cyst nematode Heterodera avenae by nematicides applied with the seed, in the drill row was assessed in twenty field trials. These trials were conducted in 1978 on three soil types near Coonalpyn, South Australia. Aldicarb was used at all sites and fosthietan and terbufos at four sites. Significant grain yield increases to aldicarb were obtained at 12 sites while yields were increased by the three nematicides at three sites. Numbers of eggs of H. avenae were determined in soil taken in January 1978, and these counts showed that all sites were infested over the range 0.03-8.5 eggs/g soil. Plant assays of the soils assessed the reduction in the length of seminal root axes (range 0-45%) and the severity of the root knotting caused by H. avenae. The egg densities in the soil, reduction in the length of the seminal root axes and disease ratings in the plant assay were highly correlated with each other (r = 0.75; P< 0.001 to 0.91, P< 0.001). These variables were not significantly correlated with grain yield increase due to aldicarb on the two major wheat soils studied, although a correlation, explaining 32-42% of the increase, existed when all sites were considered. A mathematical model based on cropping history and an estimated annual hatch of eggs of H. avenae failed to show a relation between these variables and the yield increase from nematicide. H. avenae caused severe disease and yield loss on calcareous loams and red duplex soils but had only minimal effects at the sites on siliceous sands.

CARROT YIELD INCREASES AFTER CHEMICAL CONTROL OF ROOT-KNOT NEMATODE IN ORGANIC SOIL

In root-knot nematode-infested soil, post-treatment effects of nematicides on duration of acceptable yields of marketable carrots (Daucus carota L.) and on nematode population dynamics were determined. These studies included a comparison of the efficacy of granular nematicides and soil fumigants. Surviving nematodes multiplied and caused unacceptable losses 2 yr after fumigation. Fumigation with Telone, D.D. or Vorlex gave the best nematode control and the highest marketable yield. Oxamyl, aldicarb and fosthietan gave a significant protection of carrots at doses of 3 and 6 kg a.i./ha. Bunema, phenamiphos and carbofuran were the least effective.

Efficacy of Nematicides in Corn in Western Kansas

Efficacy of Nematicides in Corn in Western Kansas

Control of stem nematode (Ditylenchus dipsaci) in strawberry by granular nematicides

SUMMARYIn an attempt to find a control for stem nematode (Ditylenchus dipsaci (Kühn) Filipjev) on strawberry crops in south‐west England, aldicarb, ethoprophos, oxamyl, terbufos, thionazin and Tirpate were tested on severely damaged plants in pots. All treatments, except terbufos, decreased the number of infested plants; aldicarb and thionazin gave the best control. Fewer infested runner plants were found when the mother plant was grown in soil treated with aldicarb or thionazin. Soil treatment with ethoprophos, oxamyl or Tirpate was less effective or inconsistent in reducing spread of nematodes to the runners. Leaf treatment of the mother plants with ethoprophos or oxamyl reduced the number of infested runners.In a field trial in 1973/74, aldicarb, oxamyl and thionazin were compared with soil fumigation with dichloropropane‐dichloropropene mixture (D‐D). Aldicarb applied at planting decreased the number of plants damaged by stem nematode and increased the number and yield of fruits. Oxamyl granules at planting followed by a spray in February also increased the number and weight of fruits harvested compared with D‐D treated plots. A single application of oxamyl at planting, with or without previous D‐D soil fumigation, or a thionazin drench in February did not reduce damage.In three subsequent field trials in 1974–76, amounts and methods of application of aldicarb were compared with D‐D treatment. Spot applications of aldicarb to plants in heavily infested soil 15 weeks after planting reduced the rate of spread of stem nematode damage but treatment at 30 weeks had little effect. In a less severely infested plot, spot and band treatments of aldicarb, applied 10 and 21 days, respectively after planting, gave good control. Treatment with aldicarb 21 days after planting decreased the number of plants with severe symptoms, whereas serious damage was not prevented by treatment with D‐D in October or May.

Control of stem nematode, Ditylenchus dipsaci, in onions, by granular nematicides applied to the soil

SUMMARYAldicarb at 1.4–5.6 kg a.i. ha‐l or oxamyl at 1.3–5.2 kg a.i. ha‐1 applied over the seed furrows during sowing prevented much of the damage resulting from stem nematode attack in spring‐sown onions. Rotting of bulbs in store due to stem nematode infestation was sometimes lessened by these treatments. Neither sowing onion seeds on soil ridges, nor applying aldicarb in two equal doses, one over the seed furrows during sowing, the other over the plants mid‐season, controlled the nematode better or increased onion yields more than a single equivalent dose over the seed furrows. Applied as two doses in this way, aldicarb was sometimes more effective against the nematode in summer‐sown onions than was an equivalent amount applied over the seed furrows during sowing. Only 2.5 kg or less aldicarb ha‐1 can be applied to onions without leaving unacceptable residues (>0.15 μg g‐1) in the harvested bulbs.