Studies on the fate in plants of ethylenebisdithiocarbamate fungicides and their decomposition products

A study was made of the fate in plants of ethylenebisdithiocarbamate fungicides and their decomposition products. Nabam (disodium ethylenebisdithiocarbamate) is known to decompose rapidly in aqueous environment, mainly to ethylenethiourea and ethylenethiuram monosulphide. Only ethylenethiourea was taken up by the roots and leaves of cucumber seedlings and by the roots of wheat seedlings. It was converted to a slight extent into an unknown compound. The fate of maneb (manganese ethylenebisdithiocarbamate) and zineb (zinc ethylenebisdithiocarbamate) does not differ essentially from the fate of nabam.     

A Comparison of the Hatching of Juveniles from Cysts of Heterodera schachtii and H. trifolii

The effects of root diffusates of selected plants within the families Chenopodiaceae and Cruciferae and the hatching agent zinc chloride were tested for their effects on hatching and emergence of juveniles from cysts of Heterodera schachtii and a race of H. trifolii parasitic on Chenopodaceae and Cruciferae in The Netherlands. Although all diffusates strongly stimulated hatching of juveniles of H. schachtii, their effects on H. trifolii were less evident.     

In-Vitro and In-Vivo Effects of Aldicarb on Survival and Development of Heterodera schachtii

Aqueous solutions of 5-500 μg/ml aldicarb inhibited hatching of Heterodera schachtii. Addition of hatching agents, zinc chloride, or sugarbeet root diffusate, to the aldicarb solutions did not decrease the inhibition of hatching. When cysts were removed from the aldicarb solufions and then treated for 4 wk in sugarbeet root diffusate, larvae hatched and emerged. Treatments of newly hatched larvae of H. schachtii with 5-100 μg/ml aldicarb depressed later development of larvae on sugarbeet (Beta vulgaris). Similar treatments with aldicarb sulfoxide had less effect on larval development, and aldicarb sulfone had no effect. Numbers of treated larvae that survived and developed were inversely proportional to concentration (0.1-5.0 μg/ml) and duration (0-14 days) of aldicarb treatments. Development of H. schachtii on sugarbeet grown in aldicarb-treated soil was inversely proportional to the concentration of aldicarb in the tested range of 0.75 - 3.0 μg aldicarb/g of soil. Transfer of nematode-infected plants to soil with aldicarb retarded nematode development, whereas transfer of plants first grownin treated soil to nematode-infested soil only slightly suppressed nematode development. Development of H. schachtii was inhibited in slices of storage roots of table beet (B. vulgaris), sugarbeet and turnip, (Brassica rapa), that had grown in soil treated with aldicarb.     

Inorganic ions and the hatching of Heterodera spp

Of various inorganic ions tested for their ability to stimulate hatching of eggs of the cyst nematodes of cereals (Heterodera avenae Woll), carrot (H. carotae Jones), cabbage (H. cruciferae Franklin), soybean (H. glycines Ichinohe), pea (H. goettingiana Liebs.), potato (H. rostochiensis Woll.), beet (H. schachtii Schm.), tobacco (H. tabacum Lownsbery & Lownsbery) and clover (H. trifolii Goffart), some were active. Zn²⁺ hatched many eggs of seven species and some of H. goettingiana, but inhibited hatch of H. avenae to below that in water. Zinc salts are the first recorded very active hatching stimulants for H. glycines in vitro. Many other metal ions stimulated hatching of H. schachtii eggs to varying extents; these also hatched some but not all of the other species. Vanadate ions were particularly effective for H. rostochiensis, more so than Zn²⁺. No ion increased the hatch of H. avenae to above that in water. The most active ions were not those most abundant in soil. The behaviour of different ions with different species did not suggest any obvious affinities between species, but the differences between the hatching of H. tabacum and H. rostochiensis add weight to the view that, despite morphological similarities and overlapping host ranges, they are distinct species rather than pathotypes of a single species. Ions and other hatching agents may be absorbed by materials within the egg or larva and alter the structure and function of these materials. The lack of correlation between the hatching of H. schachtii by ions and the known stability sequences of various biological metal-binding systems suggests that there may be several sites of action that differ in their response.     

Effect of certain inorganic chemicals on growth and spore germination of Alternaria tenuis auct., the fungus causing core rot of mandarin oranges in India

Summary Laboratory studies to determine the tolerance of an isolate ofAlternaria tenuis causing a black core rot of mandarin oranges (Citrus reticulata) have shown that presence of low amounts of manganese, zinc, iron, copper, boron, and molybdenum in a synthetic medium stimulated growth and sporulation of the fungus. Concentrations of 20 ppm or more of copper sulphate, boric acid, and ammonium molybdate, however, caused significant reduction of growth. Conidia of the fungus were very sensitive to even low amounts of copper, zinc, and iron. Copper sulphate was most toxic to spore germination followed, in order of inhibitory effect, by zinc sulphate, ferrous sulphate, and boric acid. Ammonium molybdate and manganese sulphate were stimulatory to spore germination at 5 ppm. There was a positive correlation between percentage of spore germination and average length of germ tubes in different concentrations of various chemicals. The possibility of using copper sulphate, zinc sulphate, and ferrous sulphate as spray materials for trees and as dip for ripe fruits to prevent black core rot are discussed.Assoc. Professor and Research Assistant, respectively. Publication under journal series No. 27 from Experiment Station, U.P. Agricultural University.     

Hatching agents for the potato cyst-nematode, Heterodera rostochiensis Woll

Of 444 compounds tested for their ability to stimulate eggs of Heterodera rostochiensis to hatch, forty-five did so to varying extents. Many compounds that hatched H. schachtii Schm. eggs did not hatch H. rostochiensis eggs. The most effective compounds with H. rostochiensis were picrolonic acid, anhydro-tetronic acid and vanadates. Tests with analogues of picrolonic and anhydro-tetronic acids suggested some structures that may be concerned in hatching H. rostochiensis and H. schachtii. The simple analogues hatched the eggs of H. schachtii but not those of H. rostochiensis. Suitably placed polarisable atoms seemed to be an essential feature. Picrolonic acid contains pairs of polarizable atoms, about 4 and 6·7 Å apart, that may respectively be associated with the hatching of H. schachtii and H. rostochiensis. Other features of the more active hatching agents were a cis and co-planar arrangement of the two polarizable atoms with respect to the rest of the molecule. The function of hatching agents is discussed.     

Effects of Aldicarb on the Behavior of Heterodera schachtii and Meloidogyne javanica

The toxic effects of sublethal concentrations ofaldicarb were studied on eggs and second-stage larvae and males of Heterodera schachtii and second-stage larvae only of Meloidogyne javanica in a quartz sand substrate. Aldicarb was more toxic to eggs of H. schachtii than to those of M. javanica. Complete suppression of hatching occurred between 0.48 and 4.8 μg/ml aldicarb for H. schachtii whereas 100% inhibition of hatch of M. javanica occurred between 4.8 and 48.0 μg/ml. M. javanica hatch was stimulated at 0.48 μg/ml aldicarb. Migration of second-stage larvae of H. schachtii and M. javanica in sand columns was inhibited under continuous exposure to 1 μg/ml aldicarb. Infection of sugarbeet and tomato seedlings by larvae was inhibited at 1 μg/ml. H. schachtii males failed to migrate toward nubile females at 0.01 μg/ml aldicarb. This was partially confirmed in a field study in which adding aldicarb to soil resulted in fewer females being fertilized.     

The in vitro Germination of Pollen of Setaria sphacelata

The effects of various substances upon germination and tube growth of pollen of Setaria sphacelata were investigated in hanging-drop culture. Both sucrose (0.6–0.7 M) and boron (1–5 ppm, as borate) are essential for germination. Comparable results were obtained with boric acid, sodium tetraborate and tri-n-butyl borate as boron sources, but sodium tetraphenylboron was inhibitory. Good germination and growth were obtained with raffinose and cellobiose, alone or in combination with sucrose (total 0.5 M); 0.25 M rhamnose, lactose and glycerol were without effect, and xylose, galactose and glucose were slightly inhibitory in the presence of 0.25 M sucrose; 0.25 M arabinose, fructose, mannose, sorbose, maltose, mannitol and sorbitol completely inhibited germination, even in the presence of 0.25 M sucrose. IAA and GA (0.01–10 ppm) could not replace or supplement the effects of borate on germination and growth, indicating the pollen to be self-sufficient in this respect. Riboflavin (0.1–10 ppm) and calcium pantothenate (1–100 ppm) stimulated germination and growth, whereas 0.01–10 ppm of thiamine, pyridoxine, nicotinic acid and ascorbic acid were generally without effect. Although copper sulphate, manganese sulphate, zinc sulphate and ammonium molybdate could not replace boric acid, 1.0 ppm of copper, manganese and zinc stimulated germination and growth in the presence of boron. In no instance were tubes found comparable in length to those required for fertilisation in vivo. It was concluded that the pollen probably requires a complex mixture of substances, including sucrose and borate, before this can be achieved in vitro.     

Effect of Liquid Nutrient Culture,Vacuum Distillation and Dialysis on Hatching Activity of Sugar Beet Root Diffusate for Heterodera schachtii

Roots of sugar beets grown in liquid culture excrete substances that stimulate egg hatch and emergence of larvae from cysts of Heterodera schachtii. Their hatching effect is comparable to that of sugar beet root diffusate leached from soil-grown sugar beet plants. Consequently, liquid culture provides a way of obtaining H. schachtii hatch-stimulant free of contaminants from soil. Root diffusate, concentrated 50-fold or dried by vacuum distillation, retained hatching activity. The active principle of diffusate is dialyzable with a diffusion rate between those of inorganic salts and compounds with molecular weights greater than 15,000.     

外来入侵甜菜孢囊线虫在新疆的适生性分布及风险评估

[目的] 甜菜孢囊线虫是世界性的重要进境检疫性有害生物,每年造成严重的经济损失。甜菜是新疆重要的优势经济作物,总产量占全国总产量一半以上。对新疆开展甜菜孢囊线虫适生性分析及风险评估,旨在为我区重大外来有害生物的科学预警及防控提供指导。[方法] 采用BIOCLIM模型对甜菜孢囊线虫在新疆的具体潜在分布区进行预测,并采用多指标赋值运算,对其入侵的风险进行定量分析。[结果] 甜菜孢囊线虫在新疆荒漠绿洲区的适生区域主要集中在阿勒泰市、塔城、博乐市、伊犁州、乌鲁木齐市、昌吉州、库尔勒市、阿克苏乌什县和拜城县和哈密市的巴里坤哈萨克族自治县。甜菜孢囊线虫的危险性综合评估风险值R为2.397,属于高度危险等级。[结论] 新疆主要甜菜种植区为甜菜孢囊线虫的高度适生区,需要高度重视,其预测结果为建立甜菜孢囊线虫长效预警与防控机制提供必要的理论基础。     

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.     

Dose effect relationship for some specific effects of dithiocarbamates

The effect of zinc ethylenebisdithiocarbamate (zineb) and manganese ethylenebisdithiocarbamate (maneb) has been studied in a chronic experiment (4.5 months) on albino rat thyroid gland and gonads. A complex of biochemical, morphological (histological, histochemical and electronmicroscopic), radiological, functional and biological methods has been employed. Different groups of rats were subjected to inhalatory poisoning with zineb in concentrations 110, 50, 10 and 2 mg.m-3 and maneb in concentrations 135, 12 and 2 mg.m-3. It was established that both compounds provoke toxic irritative changes in the lung and the trachea, more strongly expressed with maneb. A correlation of the dose and the effect was determined. At a zineb dose 0.1 LD50 and 0.01 LD50 applied twice weekly an increased 131l uptake (rebound phenomenon) was found and signs of increased activity of the thyroid gland. At doses 0.1, 0.02 and 0.01 LD50 both for zineb and maneb and an additional dose 0.002 LD50 for maneb, a decrease in the fertile capacity resulting from the damage of the germinative was determined (atrophic changes in Sertoli cells, deserted tubuli seminiferi because of disturbed maturation of the spermatozoa; small number or lack of differentiated forms of spermatogenesis; suppressed ovopoiesis, increased number of atretic follicles, with the domination of the relative part of the growing follicles) and endocrinoactive structures (destruction to disappearing of Leydig's cells; injured cells of Theca interna, granulosa and interstitium). These data as well as the data for teratogenicity give us grounds to recommend a higher security coefficient in hygiene standardization.     

A comparative study of the tolerance of salt marsh plants to manganese

Summary Salicornia europaea, Puccinellia maritima, Triglochin maritima, Aster tripolium, Plantago maritima, Armeria maritima, Juncus gerardii andFestuca rubra, collected as seed from a salt marsh at Portaferry, County Down, were grown on saline (340 mM NaCl) and non saline nutrient solutions at five concentrations of manganese sulphate (0.025–10.0 mM). After an eight week growing period, shoot and root yields and the concentrations of sodium, potassium, calcium and manganese in the shoots were determined.Except forS. europaea the saline treatments had a strongly limiting effect on plant growth. Each of the species investigated showed a degree of tolerance to high concentrations of manganese which was similar to that of calcifuge species and plants characteristic of waterlogged sand dune slack communities, but which was very much greater than that ofArrhenatherum elatius a species usually excluded from acidic soils. There was little evidence to support the hypothesis that tolerance of high manganese concentrations was correlated with the position of the experimental plants in the salt marsh ecotone or that the manganese nutrition of halophytic and glycophytic marsh species differs. Whilst manganese uptake increased proportionally with solution manganese concentration, there were few other major effects of manganese on the balance of shoot cation concentrations in the plants investigated. Both antagonistic and synergistic effects of sodium on manganese uptake were recorded for different species.     

Glasshouse evaluation of systemic compounds, derivatives of dithiocarbamic acid and other fungicides for the control of clubroot

Seventy-one fungicides were mixed with an artificially infested soil/peat mixture in which cabbage seedlings were subsequently grown in pots in a glasshouse. The incidence and severity of clubroot and any toxic effects on the plants were recorded. Carbendazim, chloraniformethan, maneb, ferbam, zinc N-methyl dithiocarbamate, zinc diethanolamine dithiocarbamate and ziram were selected as suitable for further evaluation as they gave disease control as good as the standard calomel treatment and were of comparably low phototoxicity.     

Biomineralisation of carbonate and sulphate by the halophilic bacterium Halomonas maura at different manganese concentrations

The ability of Halomonas maura to bioprecipitate carbonate and sulphate crystals in solid media at different manganese concentrations has been demonstrated in this study for the first time. The precipitated minerals were studied by X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The precipitated minerals were different based on the manganese concentration present in the medium and the incubation time. In the absence of manganese, H. maura formed pseudokutnahorite crystals; in the presence of manganese, the concentration in the culture medium determined the precipitation carbonates, such as rhodochrosite and dolomites. However, in the presence of low concentrations of manganese chloride (MnCl₂) (5 g/l), kutnohorite crystals were also formed. Finally, when H. maura was grown in the presence of manganese, small amounts of sulphate crystals (such as bassanite and gypsum) were detected. Our study of the precipitated minerals showed an active role of H. maura in the biomineralisation process, but the geochemical conditions, and the manganese concentrations in particular, were clearly influential.

     

Investigations on organic fungicides

Summary l-Histidine was found to antagonize the toxicity of the fungicides tetramethylthiuram disulphide (T.M.T.D.), tetramethylthiuram monosulphide (T.M.T.M.) and sodium dimethyldithiocarbamate towardsBotrytis cinerea, Penicillium italicum, Aspergillus niger and, in the cases studied, towardsRhizopus nigricans. The antagonism showed a competitive character but as yet no definite conclusion could be drawn whether these compounds interfere with histidine synthesis or rather with some essential reaction in which histidine is involved. At high pH values histidine proved to be more effective than at low pH values. The histidine effect is restricted to the process of spore germination: this process is far more sensitive to the toxicants mentioned than mycelial growth. The inhibition of the latter process is not counteracted by histidine. With increasing concentration of the fungicides an inversion of their toxic effect was observed for certain of the test moulds under specified conditions. This inversion phenomenon too is connected with the process of spore germination and shows a close relationship with the histidine antagonism in so far as histidine is only effective at concentrations below those at which inversion becomes manifest. Histidine cannot antagonize the action of the fungicides disodium ethylenebisdithiocarbamate (“dithane”) and tetramethylene diisothiocyanate. This supports the view that the mode of antifungal action of these compounds is different from that of the chemically related lower thiuram sulphides and dimethyldithiocarbamates. I: Antonie van Leeuwenhoek16, 45, 1950; II: Antonie van Leeuwenhoek16, 282, 1950; III: Antonie van Leeuwenhoek17, 58, 1951; IV: Rec. trav. chim.70, 917, 1951; V: Rec. trav. chim.70, 949, 1951.     

THE TOXICITY OF ZINC SULPHATE TO RAINBOW TROUT

The toxicity of zinc sulphate to rainbow trout ( Salmo gairdnerii Richardson) has been investigated in waters of different chemical and physical properties.
Zinc sulphate was less toxic to rainbow trout in hard water than in soft water; when the log concentration of zinc was plotted against log median period of survival of the fish the dose response curve was linear in a very soft water, and curvilinear in a hard water, approaching an apparent threshold concentration. Solutions of zinc sulphate containing calcium chloride were less toxic than those containing an equivalent concentration of calcium as bicarbonate.
An increase in temperature decreased the survival time of rainbow trout in solutions of zinc sulphate in a hard water, but the threshold concentration was not appreciably affected by changes in temperature.
A reduction in the dissolved oxygen concentration of the water increased the toxicity of zinc sulphate, but the effect was reduced when the fish were previously acclimatized to the lower oxygen concentration of the test.
The cause of death of fish in solutions of zinc sulphate was not by the precipitation of mucus on the gills but probably by damage to the gill epithelium.     

Heterodera glycines Cyst Components and Surface Disinfestants Affect H. glycines Hatching

We investigated the effects of Heterodera glycines cyst components and surface disinfestants on hatching of H. glycines eggs in vitro. Eggs were incubated in either H. glycines cyst wall fragments, cyst wall and egg rinsate, egg homogenate, or control solutions of soybean root diffusate, sterile distilled water, or zinc sulfate. Hatch in cyst wall and egg rinsate, and egg homogenate, was greater (α = 0.05) than hatch in sterile distilled water; however, it was not different from hatch in zinc sulfate according to Dunnett''s test. Hatch in cyst wall fragments was similar to hatch in sterile distilled water. To determine whether surface disinfestants affected hatch, eggs were treated first with chlorhexidine diacetate, mercuric chloride, sodium hypochlorite, or streptomycin sulfate and then incubated in H. glycines egg homogenate, soybean root diffusate, sterile distilled water, or zinc sulfate. Hatch of eggs treated with chlorhexidine diacetate, mercuric chloride, and streptomycin sulfate was reduced (α = 0.05), and hatch of eggs treated with sodium hypochlorite was increased (α = 0.05) relative to hatch of nontreated eggs in all incubation solutions except zinc sulfate according to Dunnett''s Test. Hatch in zinc sulfate was similar among all surface disinfestants except mercuric chloride, where hatch was reduced relative to hatch of nontreated and other surface disinfestant-treated eggs.     

Sulphur requirements of certain isolates ofAlternaria tenuis Auct

The sulphur nutrition of three isolates ofAlternaria tenuis Auct., isolated from the diseased leaves ofMangifera indica L.,Musa paradisiaca L. andPsidium guajava L., was studied. They were grown on the medium devoid of sulphur as well as on media containing various sources of sulphur viz., ammonium sulphate, sodium hyposulphite, sodium thiosulphate, magnesium sulphate, potassium sulphate, potassium metabisulphite, zinc sulphate and thiourea. Sodium hyposulphite, sodium thiosulphate, magnesium sulphate, potassium sulphate and zinc sulphate were generally found to be satisfactory sources for the growth of all the isolates under study. Poor growth of the different isolates was observed on the medium devoid of sulphur.     

Sulphur and phosphorus requirements of Curvularia pallescens Boed

The effect of different sulphur and phosphorus compounds on the growth and sporulation ofCurvularia pallescens Boed. has been studied. Nine different sulphur sources were tried but among them only magnesium sulphate yielded the best dry weight of the fungus. Zinc sulphate, sodium sulphate, sodium thiosulphate, potassium sulphate and calcium sulphate supported good growth. Poor growth was recorded on sodium bisulphite, ammonium sulphate, sodium sulphide and control. Sporulation was excellent on magnesium sulphate. It was good on zinc sulphate, sodium sulphate and potassium sulphate. On sodium thiosulphate, calcium sulphate, sodium bisulphite and control it was fair. Sodium sulphide and ammonium sulphate had inhibitory effect as sporulation was poor and nil on these two compounds respectively.Six phosphorus compounds were studied. Tripotassium phosphate gave best growth and excellent sporulation. Good growth and excellent sporulation was recorded on monobasic potassium phosphate and magnesium phosphate. Growth and sporulation were good on dibasic potassium phosphate and sodium dihydrogen phosphate. Ammonium phosphate was poorly utilized.