Screening Of Fungicides Research Articles

Diels‐alder reaction: New antimicrobial pyrazolo‐chroman derivatives

AbstractPyrazolo‐[2,3‐d]‐chroman dione derivatives were obtained via Diels‐Alder reaction of pyrazolone arylidenes and 1,4‐benzoquinone. The reaction rate and its yield have been found to be solvent and time dependent. The evaluation of the bactericidal and fungicidal screening showed significant inhibition effects against some thermophilic organisms grown and incubated at 55°C.

Screening of fungicides for the control of downy mildew on container-grown cabbage seedlings

Eleven fungicides were screened, over three seasons, for efficacy against crucifer downy mildew, Peronospora parasitica, on cabbage seedlings grown in 24-modular polystyrene trays. Starting 10 days after emergence, seedlings were treated with weekly foliar applications of fungicide formulations. Percentage disease severity was assessed weekly using a visual rating scale; the area under the disease progress curve (AUDPC) was calculated for each treatment. A single assessment of final disease severity was an inadequate parameter for comparison of fungicide efficacy. However, AUDPC facilitated clear separation of treatments and provided an integrated measure of disease control. The mixture of cymoxanil and mancozeb was consistently found to be the most effective fungicide against crucifer downy mildew. Other fungicides that provided control included systemics (oxadixyl as a mixture with mancozeb and propamocarb) and protectants (mancozeb, chlorothalonil and cupric hydroxide). All metalaxyl-based fungicides were ineffective.

Metal complexes of 1-hydroxy-2,3-dimethyl-4-(3?-methyl-4?-amino-5?-mercapto-1?, 2?, 4?-triazole)-1,4-diaza-1, 3-butadiene with manganese(II), cobalt(II), nickel(II) and copper(II)

Binuclear metal complexes of the type [M(HDDB)-(H2O)2]2: where HDDB=1-hydroxy-2,3-dimethyl-4-(3′-methyl-4′-amino-5′-mercapto-1′, 2′, 4′-triazole)-1,4-diaza-1, 3-butadiene and M=manganese(II), cobalt(II), nickel(II) and copper(II), have been prepared and characterised by elemental and thermal analyses, magnetic measurements, electronic and i.r. spectra. Octahedral geometry around the metal(II) ions is proposed and the crystal field parameters of the cobalt(II) and nickel(II) complexes are also calculated. Fungicidal screening of the complexes has been made aginstHelminthosporium oryzae andFusarium oxysporium.

Effect of Quintozen, Benomyl and Carbendazim On the Interaction Between the Endomycorrhizal Fungus Glomus Fasciculatum and the Root-Knot Nematode Meloidugyne Incognita On Cotton

The effect of Quintozen, Benomyl, and Carbendazim, applied as a drench, on the VA endomycorrhizal fungus Glomus fasciculatum, the root-knot nematode Meloidogyne incognita and on the interaction between the two was studied on cotton in the greenhouse. G. fasciculatum did not affect plant growth or nematode population density 30 days after simultaneous inoculation at planting, but caused significant increases in plant growth and a significant reduction in M. incognita population density and reproduction 50 days after inoculation. The fungicides did not alter nematode populations on nonmycorrhizal plants. Benomyl and Carbendazim, however, significantly reduced G. fasciculatum antagonistic activity toward M. incognita reproduction when applied at planting. The diminution of antagonism was stronger than the effect of the fungicides on symbiont root colonization of cotton. Carbendazim, which was less toxic to G. fasciculatum than Benomyl, did not influence mycorrhizal intensity when applied at planting or 25 days later. Nematode numbers increased significantly on mycorrhizal plants when Benomyl was applied at planting, but no significant change was noticed with similar applications of Carbendazim. Conversely, there were fewer nematodes in mycorrhizal plants when the fungicides were applied 25 days after planting. The results demonstrated that fungicide concentration and time of application are important factors influencing the antagonistic interaction between endomycorrhizal fungi and root-knot nematodes on cotton. Effective use of VA mycorrhizae in nematode control systems, therefore, will require proper screening of fungicides for fungicidal activity to endomycorrhizal fungi.

Coordination polymers of N,N′‐bis(8‐hydroxy‐5‐quinolinyl)‐terephthalamide

AbstractFe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the bisbidentate ligand N,N′‐bis(8‐hydroxy‐5‐quinolinyl)terephthalamide (1) were synthesized. All the metal complexes are characterized by elemental analyses, infrared spectra, electronic reflectance spectra, magnetic susceptibility measurements and thermogravimetry. All the complexes showed a polymeric nature with a octahedral stereochemistry at the coordinated metal atom. The fungicidal screening of the coordination polymers showed them to be antifungal against Penicillium islandicum, Rizopus nigricans and Botrydiplodia theobromae.

Method for in vitro screening of aquatic fungicides

Abstract. Methods were developed for in vitro screening of candidate aquatic fungicides for efficacy against Achlya flagellata, A. racemosa, Saprolegnia hypogyna and S. megasperma. Agar plugs containing fungal hyphae, removed from the edge of actively growing colonies, were placed in the depressions of spot plates containing 1.0, 10.0 and 100 mg/l of the candidate compounds for 15 or 60 min. After exposure, the plugs were transferred on to filter papers (0.45‐μm pore) in a holder, rinsed, and then placed on cornmeal agar medium in tri‐petri dishes. The plates were checked for mycelial growth after 48, 96 and 168 h of incubation in a lighted (400–800 μm) environmental control chamber at 20±2°C. Criteria for the acceptance or rejection of candidate aquatic fungicides for further study were based on the antifungal spectrum index (ASI) comparisons between respective compounds and malachite green after 48 h and the concentration level producing complete growth inhibition. Candidate compounds whose ASI was Jess than 50% that of malachite green after 48 h or did not inhibit growth at levels less than 100 mg/l were rejected. This method provides a base from, which in vivo and definitive test regimens can be developed. Preliminary in vitro screening of candidate fungicides reduces the need for costly in vivo tests on compounds that have low antifungal activity.

Studies on substituted aryloxyalkanols as potential fungicides

Abstract2‐(4‐Fluorophenoxy)ethanol and 2‐(4‐chloro‐m‐tolyloxy)ethanol, prepared by the reduction of appropriate esters with aluminium lithium hydride, have been found to be remarkably active against Aspergillus flavus, Helminthosporium oryzae, and four species of aquatic fungi that are responsible for fish mycoses. These chemicals were not lethal to fish even at the highest concentration used for fungicidal screening.

Complexes of N′-(4-phenyl thiazole-2-yl) thiourea with some first row transition metals

Metal complexes of N′-(4-phenyl thiazole-2-yl) thiourea (L) possessing the stoichiometry, [MLX 2] (M = Cu 2+; X = Cl −, Br −, NO 3 − and ClO 4 −), (M = Ni 2+; X = Cl −), (M = Co 2+; X = Cl −, NO 3 −) have been isolated and studied. Tentative geometry of the complexes has been deduced by elemental analyses, magnetic and spectroscopic techniques. Fungicidal screening of the complexes has been made against Helminthosporium oryzae, Fusarium oxysporium and Aspergillus niger.

Organotin developments in wood preservation and fungicidal screening

Research into various aspects of organotin compounds in wood preservation has continued.

A bioassay for systemic fungicides using axenic cultures of the carnation rust fungus, Uromyces dianthi

The inhibitory action of three systemic fungicides (Benlate, Hoe 6053, and Milstem) on the growth of axenic cultures of the carnation rust fungus, Uromyces dianthi, was assessed. The rust- and smut-specific fungicide (Hoe 6053) was found to inhibit growth when present in the agar medium in very low concentrations, while moderate concentrations of the wide range fungicide (Benlate), and high concentrations of the powdery mildew-specific fungicide (Milstem) were needed for inhibition. The results indicated the possible use of U. dianthi in future in vitro fungicide screening programs and mode-of-action studies.

EFFECT OF FUNGICIDES ON COCHLIOBOLUS SATIVUS AND OTHER FUNGI ON BARLEY SEED IN SOIL

Nineteen seed-treatment fungicides were tested for their effects on the microflora of barley seed. The barley seed, naturally infested with Cochliobolus sativus, Alternaria alternata and Streptomyces species, was treated, placed m soil for seven days at 20 °C, and then examined. The wide-spectrum fungicides Ceresan M, Panogen PX and Dithane M 45 provided the best control of C. sativus; the more selective fungicides provided little or no control. Alternaria alternata was controlled (P < 0.05) by all fungicides except SWF 850 and G 696. In contrast, growth of Streptomyces spp. was enhanced by Chemagro 4497, G 696, SWF 860, SWF 800, F 735 and SWF 850; the other chemicals had no effect. Because of general agreement between soil and filter paper techniques and the amount of work involved in the former, the filter paper technique is recommended for initial screening of fungicides.

Studies on screening of fungicides

Studies on screening of fungicides