Effect of ryegrass root residues, knockdown herbicides, and fungicides on the emergence of barley in sandy soils

1987 ◽  
Vol 27 (6) ◽  
pp. 785 ◽  
Author(s):  
WM Blowes

Poor seedling emergence of 30 000 ha of winter crops occurred in Western Australia in 1984 after herbicides were used to kill weeds prior to sowing. In pot experiments to determine the possible cause(s), the emergence of barley seedlings was reduced by the presence of both herbicide treated and untreated ryegrass root residues in the soil. Fumigation of the soil with methy1 bromide or the application of a fungicide soil drench restored seedling emergence in the presence of ryegrass root residues, but benomyl drench was less effective than methyl bromide fumigant or furalaxyl soil drench. The effects of the residue, fumigant and furalaxyl were consistent in the 3 soils used but soif type affected the severity of the problem. In the presence of ryegrass root residues, Pythim species colonised the large roots and subsurface hypocotyl of barley seedlings. Metalaxyl seed dressing reduced the colonisation of barley seedlings by Pythim species and restored seedling emergence.

1988 ◽  
Vol 28 (6) ◽  
pp. 765 ◽  
Author(s):  
MDA Bolland ◽  
MJ Baker

Seed of 2 cultivars of wheat (Triticum aestivum) and 1 burr medic (Medicago polymorpha) with increasing phosphorus (P) concentrations (wheat 1.4-3.7 g P/kg dry matter, medic 3.3-7.9 g P/kg dry matter) were collected from field experiments with variable levels of applied superphosphate (wheat 0- 577 kg P/ha, medic 0-364 kg P/ha) in south-western Australia. These seeds were used in further experiments to examine the effect of seed P concentration on the subsequent dry matter (DM) production of seedlings and plants in 3 glasshouse pot experiments and 1 field experiment. Seed of the same size (wheat, 35 mg/seed; medic, 3.6 mg/seed) but with increasing P concentration produced substantially higher DM yields in the absence or presence of freshly applied superphosphate P up to 28-35 days after sowing in the pot experiments and 67 days after sowing in the field experiment.


1970 ◽  
Vol 10 (45) ◽  
pp. 493 ◽  
Author(s):  
JW Meagher ◽  
PT Jenkins

In a field experiment with strawberries, pre-plant treatments with broad-spectrum fumigants methyl bromide-chloropicrin (450 kg/ha) or methyl isothiocyanate-dichloropropene (500 l/ha) (and 300 l/ha) controlled wilt caused by Verticillium dahliae Kleb and resulted in increased yields. Soil fumigation with the nematicide ethylene dibromidz (105 l/ha) also improved yields. It controlled the root-knot nematode (Meloidogyne hapla Chitwood), delayed the onset of wilt symptoms and reduced the severity of disease. This indicated a nematode-fungus interaction and is the first report of a Meloidogyne-Verticillium interaction in strawberry.


1989 ◽  
Vol 29 (2) ◽  
pp. 223 ◽  
Author(s):  
GR Stirling ◽  
LL Vawdrey ◽  
EL Shannon

Options for the control of Paralongidorus australis on paddy rice in northern Queensland were evaluated in a series of field and pot experiments. Soil fumigation with 1,3-dichloropropene at 220 and 358 kglha gave excellent control in the field and increased grain yields by more than 40%. In pots, carbofuran (5, 10 and 20 kg a.i./ha) applied to soil prior to sowing or in water at the time of permanent flooding gave good control but fenamiphos and CuSO4 did not. These results suggested that the amounts of 1,3-dichloropropene or carbofuran needed to control the nematode were too high for annual treatment with nematicides to be economic. Carbofuran and oxamyl applied as seed dressings at 0.75% and 0.36% a.i. respectively were much cheaper treatments, but failed to control P. australis or reduce nematode damage to root tips. P. australis was eliminated from moist soil by air-drying, but this effect could not be reproduced in the field by deep ripping followed by cultivation to break up clods. Amendment of nematode-infested soil with straw and various sulfur-containing compounds and flooding for 6 or 12 weeks, failed to reduce nematode numbers in the subsequent rice crop, indicating that products of anaerobic decomposition did not control the nematode. However, there was a marked reduction in the percentage of root tips damaged by the nematode in the straw + sulphur treatment. Additional pot experiments investigated practices that reduced losses from P. australis but did not necessarily control the nematode. When rice was flooded 1, 2, 3, 5 or 7 weeks after sowing, the degree of nematode damage was reduced as flooding was delayed, possibly because P. australis remained inactive during the period prior to flooding. Of the 14 rice cultivars and breeding lines tested for tolerance to P. australis, several cultivars were more tolerant than Starbonnet and Lemont, the cultivars currently being grown commercially in northern Queensland. Both delayed flooding and the use of tolerant varieties showed enough promise to warrant further testing in the field.


1993 ◽  
Vol 90 (18) ◽  
pp. 8420-8423 ◽  
Author(s):  
K. Yagi ◽  
J. Williams ◽  
N. Y. Wang ◽  
R. J. Cicerone

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 867-872 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Gurjeet Gill ◽  
Christopher Preston

Threehorn bedstraw is an important dicotyledonous weed of winter crops in southern Australia, which can be difficult to control in some field crops. Knowledge of the germination ecology of this weed would facilitate development of effective weed control programs. Seed germination in the laboratory was greater for seeds that after-ripened while buried in the soil relative to those that after-ripened on the soil surface. The timing of greatest seed germination in the laboratory was found to coincide with the period of low temperature in the field. Seed germination of threehorn bedstraw was moderately sensitive to salt stress but moderately tolerant to osmotic stress. Seeds of threehorn bedstraw germinated over a broad range of pH from 4 to 10. No seedlings emerged from seeds placed on the soil surface. Maximum seedling emergence occurred at depths of 1 to 2 cm (89 to 91%) and declined at greater depths.


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