Manganese Ethylene Research Articles

Reactions of [(dmpe)2MnH(C2H4)] with hydrogermanes to form germylene, germyl, hydrogermane, and germanide complexes.

Reactions of the ethylene hydride complex trans-[(dmpe)2MnH(C2H4)] (1) with secondary hydrogermanes H2GeR2 at 55-60 °C afforded the base-free terminal germylene hydride complexes trans-[(dmpe)2MnH(GeR2)] (R = Ph; 2a, R = Et; 2b). Room temperature reactions of 2a or 2b with an excess of the primary hydrogermanes H3GeR' (R' = Ph or nBu) afforded trans-[(dmpe)2MnH(GeHR')] (R' = Ph; 3a, R' = nBu; 3b) in rapid equilibrium with small amounts of 2a/b, as well as the digermyl hydride complex mer-[(dmpe)2MnH(GeH2R')2] {R' = Ph (4a) or nBu (4b)} and the trans-hydrogermane germyl complex trans-[(dmpe)2Mn(GeH2R')(HGeH2R')] {R' = Ph (5a) or nBu (5b)}. Pure 3b was isolated from the reaction of 2b with H3GenBu, whereas 3a decomposed readily in solution in the absence of free H3GePh, and a pure bulk sample was not obtained. Reactions of 1 with H3GeR' (R' = Ph or nBu) also proceeded at 55-60 °C to afford mixtures of 3a/b, 4a/b and 5a/b, accompanied by remaining 1. However, upon continued heating to consume 1, various unidentified manganese-containing intermediates were formed, ultimately affording the germanide complex [{(dmpe)2MnH}2(μ-Ge)] (6) in 17-49% spectroscopic yield. Pure trans,trans-6 was isolated in 27% yield from the reaction of 1 with H3GenBu, and it is notable that this reaction involves stripping of all four substituents from the hydrogermane. Complexes 2a, 3a, and 6 were crystallographically characterized, and the nature of the MnGe bonding in these species (as well as in 2b and 3b) was probed computationally.

Mancozeb selectively induces mitochondrial-mediated apoptosis in human gastric carcinoma cells through ROS generation

Mancozeb (Manganese ethylene bis-dithiocarbamate with zinc salt) is a dithiocarbamate fungicide used to control fungal disease in many fruit plants, flowers and the maintenance of field crops. The effect of mancozeb on cell viability of human gastric adenocarcinoma AGS, SNU-1 cells and human normal FHs 74 Int cells were investigated. This study demonstrated that mancozeb was able to inhibit cell proliferation by 56–82% at 5–10 μM concentrations after 48 h. Mancozeb treatment for 48 h resulted in 33% (P < 0.05) and 61% (P < 0.001) increase in apoptotic cells at 5 and 10 μM concentrations in AGS cells, respectively. Treatment with mancozeb did not cause cell cycle arrest, while modulated the expression level of cleaved caspase-3, and cleavage of poly-(ADP-ribose) polymerase. Furthermore, treatment with mancozeb caused a rapid stimulation of reactive oxygen species (ROS) and loss of mitochondrial transmembrane potential. The results also showed that mancozeb-induced apoptosis was accompanied by up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL. Overall, our data suggested that mancozeb caused ROS generation which induced significant (P < 0.05) apoptosis in AGS cells that was attenuated with pretreatment of NAC. More importantly, same concentration of mancozeb did not show any considerable effect on cell growth, death, cell cycle arrest and ROS generation in normal FHs 74 Int cells. Overall, for the first time these results suggest that mancozeb has selective anticancer activity at lower concentrations against gastric cancer cells.

Microglial Activation Induced by Neurodegeneration

Neuroinflammation mediated by microglial activation appears to play an essential role in the pathogenesis of Parkinson disease; however, the mechanisms by which microglia are activated are not fully understood. Thus, we first evaluated the effects of two parkinsonian toxicants, manganese ethylene bisdithiocarbamate (Mn-EBDC) and 1-methyl-4-phenylpyridine (MPP+), on microglial activation as well as associated dopaminergic (DAergic) neurotoxicity in primary cell culture systems. The results demonstrated that, when rat primary mesencephalic neuron-enriched or neuron-microglia mixed cultures were treated with Mn-EBDC at 2-8 microm or MPP+ at 0.25-5 microm, respectively, for 7 days, both toxicants were capable of inducing DAergic neurodegeneration as well as activating microglia via a mechanism secondary to DAergic neurodegeneration. Furthermore activated microglia subsequently enhanced DAergic neurotoxicity induced by Mn-EBDC or MPP+. Detailed scrutiny of neuron-microglia interactions identified a fraction of the conditioned media derived from a DAergic cell line treated with Mn-EBDC or MPP+ that potently activated microglia. To further define potential mediators leading to microglial activation secondary to neurodegeneration, we utilized a quantitative proteomic technique termed SILAC (for stable isotope labeling by amino acids in cell culture) to compare the protein profiles of MPP+-treated cellular fraction that mediated microglial activation as compared with controls. The search revealed numerous novel proteins that are potentially important in neurodegeneration-mediated microglial activation, a process believed to be critical in Parkinson disease progression.

Proteasomal inhibition induced by manganese ethylene- bis-dithiocarbamate: Relevance to parkinson′s disease

Maneb, a widely used fungicide, has been associated with Parkinsonism in humans. In experimental models, maneb and its major active element, manganese ethylene- bis-dithiocarbamate (Mn-EBDC) cause selective nigrostriatal neurodegeneration in mice and in rats, respectively. To investigate the mechanisms underlying this neurodegeneration, we studied the effects of Mn-EBDC on proteasomal function, which is decreased in patients with Parkinson's disease (PD), in a dopaminergic neuronal cell line (MES 23.5 or MES). The results demonstrated that exposure of MES cells to 6 μM Mn-EBDC for 7 days produced not only significant neurotoxicity but also inhibition of proteasomal chymotrypsin-like and postglutamyl peptidase activities. Proteasomal dysfunction was accompanied by formation of cytoplasmic inclusions that were positive for α-synuclein immunostaining and significantly increased sodium dodecyl sulfate-insoluble α-synuclein aggregation seen by Western blot analysis. In addition, there was a significant increase in oxidative stress, evidenced by elevated total protein carbonyl content, in cells treated with Mn-EBDC. Manipulation of intracellular reduced glutathione levels with N-acetyl- l-cysteine or l-buthionine sulfoximine pretreatment to modulate Mn-EBDC-mediated oxidative stress altered Mn-EBDC-mediated neurotoxicity, proteasomal dysfunction, and α-synuclein aggregation in these cells. These data suggest that neurotoxicity-induced by Mn-EBDC is at least partially attributable to Mn-EBDC-mediated proteasomal inhibition, and that the proteasome may be an important target by which environmental exposure modifies the risk for developing PD in vulnerable populations.

015 Evaluation of Fungicides for Use with TOM-CAST on Fresh-market Tomatoes in Northern New Jersey

A research trial evaluation of fungicides and fungicide combinations in conjunction with weekly or TOM-CAST (an early blight forecast system) spray schedules was conducted in 1998. Fungicide regimens were: Quadris (alternating with Bravo Weatherstik); Bravo Weatherstik; Manzate followed by Bravo Weatherstik; Champ; Champ and Bravo; Nu-Cop; NuCop and Bravo The weekly schedule resulted in 15 fungicide applications; the TOM-CAST schedule required five applications. Foliar disease was rated weekly. Mature fruit were harvested weekly to obtain total and marketable yields. All fungicide treatments reduced foliar disease compared to the untreated control. Quadris alternating with Bravo Weatherstik on a weekly or TOM-CAST schedule provided better disease control than any other material on either schedule. There were no significant differences in disease control among the other materials applied weekly. Disease control achieved with the TOM-CAST schedule was somewhat less than with the weekly schedule for all materials. Quadris/Bravo or Bravo provided the best control and Champ or Nu-Cop alone provided the least control on the TOM-CAST schedule. Total yield was not affected by fungicide or schedule. Marketable yield was reduced by weekly applications of copper fungicides compared to most other treatments. Chemical names used: tetrachloroisophtalonitrile (chlorothalonil); [methyl (E)-2-{2-[6-(2-cyanophenoxy) pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate (asoxystrobin); copper hydroxide; manganese ethylene bisdithiocarbamate and zinc.

Manganese Ethylene Bis(Maneb)-Induced Degeneration of Hair Follicle Epithelia in the Dosal Skin of WBN/ILA-Ht Rats.

The dorsal skin topically treated wiht 0.5 and 30% solution of manganese ethylene bis (Maneb), a kind of dithiocarbamate fungicides, for 7 consecutive days was examined histopathologically in Wistar-derived inbred hypotrichotic WBN/ILA-Ht rats (HtRs). At day 1 after cessation of the treatment, except for slight inflammatory cell infiltration around hair follicles, no prominent histopathological changes were found. At 2 weeks after cessation of the treatment, prominent degeneration of epithelial cells characterized by pyknosis or karyorrhexis was found in the epithelial root sheath of hair follicles, and the nuclei of such epithelial cells were strongly stained by the TUNEL method. Thus, Maneb caused delayed-type lesions in the epithelial root sheath of hair follicles due to apoptosis.

THE EFFECT OF FUNGICIDE ON THE GROWTH OF APPLE BITTER ROT PATHOGENS

Bitter rot, an economically important disease of apples in the southeastern U.S., is caused by a complex of plant pathogenic fungi. Fruit infection can result in large yield losses. Control of this disease is contingent upon the effectiveness of several commonly used fungicides. Two fungal species, Colletotrichum gloeosporioides (C.g.) and C. acutatum (C.a.), cause bitter rot. Isolates of both species also show a large degree of genotypic variation. The objective of this study was to determine the effect of several fungicides: benomyl (Benlate), Captan, Mancozeb (a combination of zinc ion and manganese ethylene bisdithiocarbamate, Dithane), and zinc dimethyldithiocarbamate (Ziram). Four concentrations (0, 0.5, 1, and 2 ppm) of each fungicide were used. Fungal growth was quantified by measuring colony diameters 3 and 6 days after incubation. Among the fungicides tested, only Benlate and Ziram significantly reduced fungal growth. Average growth reductions of C. gloeosporioides with Benlate and Ziram were 87% and 29%, respectively. In contrast, average growth reductions of C.a. with Benlate and Ziram were 60% and 52%, respectively. In conclusion, Benlate was the most effective fungicide in reducing overall fungal growth, while Ziram was more effective in reducing the growth of C.a.

Combination studies of selected acaricides with zineb, mancozeb, or carbamate for mite control on citrus

Abstract Field experiments were conducted between 1981 and 1988 to evaluate the potential of zineb (zinc ethylene bisdithiocarbamate), mancozeb (a coordination product of zinc ion and manganese ethylene bisdithiocarbamate) and carbamate (ferric dimethyldithiocarbamate) in combination with one or more of the following acaricides: ethion, chlorpyrifos, dicofol, chlorobenzilate, propargite or formetanate for the control of the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari:Eriophyidae). Treatments were applied to replicated single tree plots using a handgun from a truck-mounted sprayer or to replicated nine tree plots using an airblast sprayer during the postbloom, summer or supplemental fall spray periods. Mancozeb alone was slightly better than zineb alone in the suppression of P. oleivora. However, neither compound demonstrated sufficient activity to justify its use alone as an acaricide on citrus. The combinations of ethion, chlorpyrifos, dicofol or propargite with either mancozeb or zineb sh...

Phosphine Fumigation Influence on Rice Seed Germination and Vigor

Fumigation of seeds is one of the quarantine precautions directed against the international spread of pests. Seed treatment should ward off the pests without hampering seed germination and vigor. A study was conducted to evaluate the effect of fumigation with phosphine at different doses, exposure times, and seed moisture contents, and after the seed has been treated with fungicides on seed germination and seedling vigor in rice (Oryza sativa L.). The fumigated seed was evaluated for germination and vigor, initially and after 90 d of storage. At the normal recommended dose of 3 g m−3, fumigation did not affect germination or vigor. At 6 g m−3, vigor decreased. The effect became more perceptible after 90 d of storage. Long exposure time (6 d) showed deleterious effects. Entry differences were not significant under any of the treatments with respect to germination percentage, shoot length, root length, and seedling dry weight. However, such differences were evident in the degree of seed leaching as measured by the electrical conductivity of the leachates, and dehydrogenase activity, when seed was fumigated with a higher dose (6 g m−3) of phosphine and evaluated after 90 d of storage. There were no interaction effects between fungicidal treatment with Benlate [methyl l‐(butylcarbamoyl)‐2‐benzimi dazole carbamate] or Dithane M‐45 (zinc ion and manganese ethylene bisdithio carbamate) and fumigation on seed germination and vigor.

Effects of Timing of Nitrogen Fertilization and a Fungicide on Soft Red Winter Wheat1

AbstractSplit spring N applications and fungicides are important components of proposed intensive management systems for soft red winter wheat (Triticum aestivum L.). Six experiments at two locations were conducted on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf) soils to evaluate the responses of wheat to a fungicide and delayed or split N applications. Delayed N treatments consisted of a single application of 100 kg ha−1 at either growth stage (GS) 5 or 8. Seven split N treatments consisted of two or three applications made at GS 3, 5, or 8, totaling 100 kg N ha−1. Split and delayed N responses were compared to those resulting from four rates of N applied at GS 3. Average grain yields for the experiments ranged from 3.2 to 5.9 Mg ha−1. Yields from split and delayed N were greater than the maximum achieved with GS 3 N applications in only one of the six experiments. In this experiment, the greatest yield increase due to split N, 0.7 Mg ha−1, occurred when a fungicide was used. A large amount of precipitation (219 mm) at that location between GS 3 and GS 5, and a high fertilizer N requirement apparently contributed to the response to split N. Yield responses to fungicides (triadimefon [l‐(4‐chlorophenoxy)‐3,3‐dimethyl‐l‐(lH‐l,2,4‐trizol‐1‐yl)‐2‐butanone] or triadimefon + mancozeb [zinc ion and manganese ethylene bisdithiocarbamate)) varied between years and ranged from 0 to 0.9 Mg ha−1. Decisions to use split N and fungicides should be based on factors such as disease severity, rainfall, and anticipated soil N supplying capability.

Population Trends of Selected Phytophagous Arthropods and Predators Under Different Pesticide Programs in Virginia Apple Orchards

Population trends of selected pests in Virginia apple orchards [ Panonychus ulmi (Koch), Aculus schlechtendali (Nalepa), Aphis citricola Van der Goot, Dysaphis plantaginea (Passerini), Platynota . spp.] and predators [ Leptothrips mali (Fitch), Haplothrips subtilissimus Haliday, Orius insidiosus Say, Stethorus punctum (LeConte), Deraeocoris nebulosus (Uhler), Chrysopa spp.] were monitored during 1977 and 1978 under three reduced-pesticide programs. The pesticide program with phosalone and Dikar® [a blend of Dithane® M-45 (coordination product of zinc ion and manganese ethylene bisdithio=carbamate) and technical Karathane® (2,4-dinitro-6-octylphenyl crotonate, 2,6-dinitro-4 octylphenyl crotonate, and nitro-octyl-phenols)] as its major components allowed the largest number of predators to remain in the orchard and controlled most pests. Platynota spp. caused economic damage during August and September, regardless of the pesticides used or the number of predators in the orchards. L. mali and H. subtilissimus were the most abundant predators and probably responded numerically to densities of A. schlechtendali . The presence of this mite species may aid the development of large numbers of thrips within an apple orchard. O. insidiosus and D. nebulosus usually increased too late in the season to reduce aphid populations, but aphids may be important in attracting these general predators into the orchard. S. punctum ’s response to densities of P. ulmi was inconsistent, but together with other predators it may have had an important role in reducing P. ulmi populations. Chrysopa spp. remained at consistently low levels throughout the study under all pesticide programs.

Cucumber Pollen Germination and Tube Elongation Inhibited or Reduced by Pesticides and Adjuvants

Commercial formulations of 5 insecticides: diazinon, dicofol, endosulfan, malathion, and Pyrenone* (6% pyrethrins and 60% piperomyl butoxide); 2 fungicides: captan and Manzate* (zinc and manganese ethylene bisdithiocarbamate); and 9 adjuvants: Fomex*, Multi-Film X-77*, Nu-Trex*, Dupont Spreader Sticker*, Bio-88*, Target-E*, Bio-Film*, Dupont Surfactant F*, and Regutaid* severely reduced germination of cucumber pollen on an artificial medium. A lesser degree of reduction in germination was caused by the insecticides carbaryl and methoxychlor, the fungicide benomyl, and the adjuvants Regulaid*, Triton B-1956* and Chevron Spreader Sticker*. Carbaryl, methoxychlor and benomyl were used at spray concentrations of active ingredients recommended on the labels in 100 gal (378.5 liters) of water. The remainder of the pesticides was used at concentrations below label recommendations. Diazinon applied under controlled conditions to hand-pollinated pistillate flowers of cucumbers in greenhouse caused parthenocarpy and fruit abortion.

Cytotoxicity studies on dithiocarbamate fungicides

The cytotoxicity of selected metal-containing dithiocarbamate fungicides was determined using Chinese hamster ovary cells (CHO-K1) in culture. Bis(dimethylthiocarbamoyl)disulfide (thiram) and ferric dimethyldithiocarbamate (ferbam) were more toxic, having LC50 values of 5 × 10 −7 and 7 × 10 −7 m, respectively, whereas manganese ethylene bisdithiocarbamate (maneb) and zinc ethylene bisdithiocarbamate (zineb) were less toxic, having LC50 values of 3 × 10 −6 and 6 × 10 −6 m, respectively. Analysis of the data using “target theory” showed that ferbam, thiram, maneb, and zineb have a common hit number. These studies suggest that these fungicides have a common mechanism of toxicity.

A Rapid Method for the Determination of Manganese Ethylenebisdithiocarbamate and its Residues on Grains

A method has been developed, based on the periodate oxidation of the manganese in the coordination product of zinc ion and manganese ethylene bisdithiocarbamate to permanganic acid, to determine DithaneM-45. The relationship between the intensity of color and the concentration of manganese obeys Beer's law up to 100 mug at 540 nm. The method can be easily applied to the determination of the active ingredient in formulations and also for residue analysis. The method is sensitive to 0.6 mug and can be used to determine 6 mug fungicide at the 20 g sample level.

Título en español.

Durante 18 meses se estudiaron, en condiciones de laboratorio, los cambios producidos en los microorganismos presentes en el suelo arcilloso ácido laterítico Humatas y en el alcalino y fértil San Antón lómico, ambos incubados a 23° ± 1° C. después de haber recibido aplicaciones de 2,4- dicloro-(o-cloroaniline)-s-triazina (Dyrene) y etileno bisditiocarbamato de manganeso (Maneb) en concentraciones de 0, 60, 240 y 960 p.p.m. En general, el número de bacterias aumentó y el de actinomicetos y hongos disminuyó, especialmente a las concentraciones más altas de los agentes químicos. El aumento en el número de bacterias cesó a los 10 meses, excepto en el caso del Maneb a 960 p.pm., cuando el incremento persistió por más tiempo. Parecen ser las bacterias los principales microorganismos responsables de la degradación de estos fungicidas en el suelo. El Maneb produjo cambios cuantitativos y cualitativos en la población de hongos. En cuanto a la reacción al tratamiento químico, se notaron diferencias entre los microorganismos de uno y otro suelo. La inoculación con suelo fresco neutralizó la inhibición de los microorganismos.

Codling Moth and Pear Psylla: Evaluation of Insecticides for Control on Pears in California12

Pesticides were evaluated for control of Laspeyresia pomonclla (L.) and Psylla pyricola Foerster on pears at San Jose, Calif, during 1971. Leptophos (16 oz AI/100 gal) was significantly more effective against L. pomonclla than were phosalone (8 oz), Imidan® (O, O-dimethyl S-phthalimidomethyl phosphorodithioate) (4 oz), Imidan + Volck Supreme oil, and azinphosmethyl (2 oz) + Volck Supreme oil. Pirimiphos-methyl® (2-diethylamino-6-methylpyrimidin+yl dimethyl phosphorothionate) (8 oz) was only moderately effective while Dithane M-45® (coordination product of zinc ion and manganese ethylene bisdithiocarbamate) (16 oz.) was ineffective, Suppression of P. pyricola was greatest in treatments with oil included, however Imidan and phosalone were relatively effective when used alone, Dithane M-45 was not very effective and Pirimiphosmethyl was ineffective, Leptophos appeared to be nontoxic to P. pyricola and, in addition, was very disruptive to the natural population regulation of this insect, resulting in a ten-fold increase in numbers of adults during the summer.

Thatch Accumulation in Bermudagrass Turf in Relation to Management1

AbstractThatch accumulation and decomposition in a ‘Tifgreen’ bermudagrass [Cynodon dactylon (L.) Pers.] putting green was studied in relation to fertility, fungicides, and clipping management. The effects of these practices were evaluated by measuring total thatch accumulation, lignin content of thatch, and soil microbial activity.Two sources of N, (NH4)2SO4 and activated sewage sludge (Milorganite), were applied at rates 0.25 and 0.75 kg/100 m2 every 2 weeks. Potassium was applied at two rates, 0 and 0.75 kg/100 m2, to each N treatment at 4‐week intervals. Fungicide treatments consisted of 0.18 kg/100 m2 of Manganese ethylene bisdithiocarbamate (Fore) and 0.12 kg/100 m2 of Tetramethythiuram disulfide (Tersan OM) applied alternately at 2‐week intervals. For the clipping management treatments, grass clippings were collected from some plots and left on others during each mowing.The high level of N increased thatch accumulation 30% and lignin content 15% and decreased microbial activity 6% as compared to the low level of N. The Milorganite treatments decreased thatch accumulation and lignin 12% and increased microbial activity 3% as compared to the (NH4)2SO4 treatments. Differences may largely explained by influence of N on growth rates. Application of K had no influence on any of the parameters measured. Fungicide treatments decreased thatch accumulation 16% and lignin content 20% and increased microbial activity 30%; these treatments may have inhibited plant growth. Clipping residue treatments increased lignin 7% and decreased microbial activity 7% as compared to a control. This study suggests that the use of a slow‐release N fertilizer applied at a level that maintains acceptable aesthetic turf quality may reduce thatch accumulation, whereas high rates of soluble N fertilizers accelerate thatch accumulation.

European red mite control with some new acaricides.

In 1970 and in 1971, 15 and 18 acaricidal treatments, respectively, were compared for effectiveness in controlling Panonychus ulmi (Koch) on apple trees. A comparison of the results for the 2 years indicates that populations of 10 to 20 mites per leaf may be brought under control with several of the tested acaricides almost as quickly as populations ranging from 0.80 to 5.5 mites per leaf. Only Stauffer R-10044 (N-[(1,1,2,2-tetrachloro-2-fluoroethyl)thio] methanesulfonanilide) caused serious injury to foli-age of ‘Golden Delicious’ and ‘York Imperial’ trees, the apple cultivars in the test. Formetanate monohydro-chloride caused slight yellowing of the leaves of Golden Delicious trees. In 1970, Bay 37344 (4-(methylthio)-3,5-xylyl methylcarbamate) did not control P. ulmi effectively. In 1971, dinocap and Dikar® (74% a coordinated product of zinc ion and manganese ethylene bisdithio-carbamate plus 6% dinocap) exhibited only mite population suppression activity. In both years, of the rest of the acaricides tested, Acarol® (isopropyl 4,4-dibromo-benzilate), Acaralate® (isopropyl 4,4' dichlorobenzilate), and Shell SD-17250 ( N -[ (methylcarbamoyl) oxy]thioacetimidic acid ester with 3-mercaptopropionitrile) exhibited the least residual toxicity to P. ulmi . There were some indications in 1971 that some of the acaricides tested may be less toxic than others to the predatory mites Zetzellia mali (Ewing) and Amblyseius fallacies (Garman).

Grain and Flour Quality Factors of Spring Wheat Treated with Dicamba and RH 5391

Quality analyses were made on grain and flour from two hard red spring (Tritirum aestivum L. em Thell.) and two durum (Triticum durum Desf.) wheat cultivars treated in the field with 3,6‐dichloro‐o‐anisic acid (dicamba) and a coordination product of zinc ion and manganese ethylene bisdithiocarbamate‐plus anhydrous nickel sulphate (RH 539). Dicamba treatments caused the following changes. Protein percentage of wheat and flour increased by as much as 17% over the mean of untreated checks. Sulfhydral (—SH) concentration increased up 13.8% over the checks and in proportion to the increased protein content. Diastatic activity of whole wheat increased markedly (28.5% higher than the checks) from treatments, but endosperm tissue represented by flour and semolina was not affected. Mixogram scores of samples from treated wheat were significantly lower than check sample scores. Neither baking quality ratings of the hard red spring wheats nor macaroni performance scores of the durums were changed. Grain from treated plots averaged lower in flour yield than grain from untreated plots. Interactions between varieties and treatments were found for protein percentage, diastatic activity, and mixogram score.RH 539 did not significantly alter product quality, milling, dough‐mixing properties, or other quality factors evaluated.

Effect of Dyrene and Maneb on Nitrification and Ammonification, and Their Degradation in Tropical Soils

AbstractThe effect of 2,4‐dichloro‐6‐(o‐chloroanilino)‐s‐triazine (dyrene) and manganese ethylene bisdithiocarbamate (maneb) at 0, 15, 60, 240, and 960 ppm on nitrification of 100 ppm applied NH4‐N, and on ammonification of soil nitrogen, and the degradation of these fungicides, were studied in a lateritic clay and a fertile loam incubated at 24C for 16 weeks.Inhibition of nitrification by the fungicides was lesser and of shorter duration in the rapidly nitrifying loam than in the slow nitrifying lateritic soil. The chemicals inhibited the ammonia oxidizing bacteria but not the nitrite oxidizing bacteria. Maneb was several times more toxic to the nitrifying organisms than dyrene, and its effect lasted even after the chemical was degraded. Ammonification was inhibited only at 960 ppm of the fungicides. There was no synergistic effect with regard to inhibition of nitrification or ammonification when the soil received both the fungicides. The fungicides were degraded faster in the rapidly nitrifying soil than in the slow nitrifying soil. Maneb was decomposed earlier than dyrene.