A Forest Soil Suppressive to Phytophthora cinnamomi and Conducive to Phytophthora cryptogea. I. Survival, Germination and Infectivity of Mycelium and Chlamydospores.

1982 ◽  
Vol 30 (1) ◽  
pp. 11 ◽  
Author(s):  
DM Halsall
Keyword(s):  
Forest Soil ◽  
Recovery Rate ◽  
Phytophthora Cinnamomi ◽  
Field Trials ◽  
Chemical Characteristics ◽  
Subsequent Recovery ◽  
Suppressive Soil ◽  
Phytophthora Cryptogea ◽  
Physical And Chemical ◽  
Conducive Soil

The physical and chemical characteristics of a forest soil suppressive to P. cinnamomi are compared with those of other, previously described, suppressive soils. Recovery of P. cinnamomi chlamydospores from the suppressive soil was reduced to 51% of recovery from condilcive soil when the chlamydospores were mixed through the soil immediately prior to sampling. The subsequent recovery rate decreased more rapidly in the suppressive soil than in the conducive soil. Germination of chlamydospores by the formation of a terminal sporangium and zoospores was inhibited in the suppressive soil. Degeneration of mycelium was more rapid in the suppressive than in the conducive soil. Glasshouse tests showed infection of seedlings growing in the suppressive soil could occur when a zoospore inoculum was used. Infection was greatly reduced when a chlamydospore inoculum was used. Field trials in Tallaganda State Forest, N.S.W., indicated that P. cinnamomi introduced into this habitat rarely caused infection and was unlikely to spread.

Behaviour of Phytophthora cinnamomi in soils suppressive and conducive to root rot

1974 ◽  
Vol 25 (1) ◽  
pp. 121 ◽  
Author(s):  
P Broadbent ◽  
KF Baker
Keyword(s):  
Organic Matter ◽  
Forest Soil ◽  
Root Rot ◽  
Rain Forest ◽  
Phytophthora Cinnamomi ◽  
Nutrient Level ◽  
Soil Leachate ◽  
Suppressive Soil ◽  
Isolation Frequency ◽  
Calcium And Magnesium

Suppression of root rot in avocados caused by Phytophthora cinnamomi was demonstrated in soil from a grove at Tamborine Mt., Queensland. The addition of P. cinnamomi inoculum in amounts sufficient to cause severe root rot of plants in other soils, untreated or steam-air treated at 60°C for 30 min, produced little or no damage in the suppressive soil. Suppressive soil was found to have higher populations of bacteria and actinomycetes than soils conducive to root rot. Few sporangia were formed by P. cinnamomi and P. citrophthora in suppressive soil or soil leachate. The suppression of sporangium formation was found to be microbial and not related to the nutrient level of the soil leachate. Mycelium of P. cinnamomi grew through untreated conducive soils, but developed poorly in untreated suppressive soils. The fungus grew readily through all soils steam-air treated at 49, 60 and 100�C for 30 min. After 6 weeks the isolation frequency of P. cinnamomi had declined in the suppressive soil treated at 49 or 60°C for 30 min. Exchangeable calcium and magnesium, nitrogen, and organic matter were higher in soils suppressive to root rot than in conducive soils. Rain-forest soil, where the pathogen is not damaging, was comparable in this respect to the suppressive soil.

Correlation Between Physical Properties and Field Performance of Insecticidal Emulsion Sprays

1975 ◽  
Vol 58 (1) ◽  
pp. 35-39
Author(s):  
Abd R El-Refai ◽  
Zakaria M El-Attal ◽  
Ali A A Said
Keyword(s):  
Physical Properties ◽  
Droplet Size ◽  
Laboratory Tests ◽  
Emulsion Stability ◽  
Field Performance ◽  
Field Trials ◽  
Chemical Characteristics ◽  
Extensive Field ◽  
Leaf Surfaces ◽  
Physical And Chemical

Abstract Commercial and laboratory-prepared insecticide emulsiliable concentrates were tested in the laboratory and in the field to study their physical and chemical characteristics. Distribution of spray emulsion and retained deposits of active ingredients on leaf surfaces are directly related to emulsion stability, amount of emulsifier, and droplet size of spray emulsion. Thus the laboratory tests described for the measurement of the latter 3 properties can be performed before extensive field trials are conducted.

A Forest Soil Suppressive to Phytophthora cinnamomi and Conducive to Phytophthora cryptogea. II. Suppression of Sporulation.

1982 ◽  
Vol 30 (1) ◽  
pp. 27 ◽  
Author(s):  
DM Halsall
Keyword(s):  
Microbial Population ◽  
Phytophthora Cinnamomi ◽  
Soil Extract ◽  
Aerobic Bacteria ◽  
Suppressive Soil ◽  
Eucalypt Forest ◽  
Inhibitory Compounds ◽  
Soluble Components ◽  
Conducive Soil ◽  
Suppressive Action

Extracts of soil from a wet sclerophyll eucalypt forest suppressed the formation of Phytophthora cinnamomi sporangia but facilitated production of P. cryptogea sporangia and zoospores. This suppressive action was shown to be associated in part with the microbial components of the extract and in part with the soluble components. The microbial population of the suppressive soil contained significantly greater numbers of actinomycetes than the conducive soil tested at the same time. All Streptomyes isolates from the suppressive soil were shown to be antagonistic to certain of the aerobic bacteria from the same soil and to directly inhibit mycelial growth of P. cinnamomi. The soluble component of the soil extract inhibited growth of P. cinnamomi to a greater extent than P. Cryptogea. Interactions between soil microorganisms and inhibitory compounds in the soil are considered to be the cause of the suppressive action of the soil against P. cinnamomi whilst facilitating sporulation of P. Cryptogea.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

Study of Structural, Physical and Chemical Characteristics of Marshmallow Without Gelatin

Food Industry ◽  
2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Nataliia V. Nepovinnykh ◽  
Yuri A. Kodatsky ◽  
Oksana N. Klyukina ◽  
Nataliia M. Ptichkin ◽  
Samira Yeganehzad
Keyword(s):  
Chemical Characteristics ◽  
Physical And Chemical Characteristics ◽  
Physical And Chemical

Effects of Chlormequat-Uniconazole 30% Micro-Emulsion on Stem Physical and Chemical Characteristics of Rice

2013 ◽  
Vol 39 (6) ◽  
pp. 1089
Author(s):  
Qian ZHANG ◽  
Ming-Cai ZHANG ◽  
Hai-Yan ZHANG ◽  
Wei-Ming TAN ◽  
Zhao-Hu LI ◽  
...  
Keyword(s):  
Chemical Characteristics ◽  
Physical And Chemical Characteristics ◽  
Micro Emulsion ◽  
Physical And Chemical
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