scholarly journals Herbicide-Resistant Weed Seeds Contaminate Grain Sown in the Western Australian Grainbelt

Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 466-472 ◽  
Author(s):  
Pippa J. Michael ◽  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Farming Systems ◽  
Wild Oat ◽  
Wild Radish ◽  
Crop Species ◽  
Weed Seeds ◽  
Rigid Ryegrass ◽  
Western Australian ◽  
Crop Seed

Preventing the introduction of weeds into the farming system through sowing of clean seeds is an essential component of weed management. The weed seed contamination of cleaned grain and herbicide resistance levels of the recovered weed seeds were examined in a study conducted across 74 farms in the Western Australian grainbelt. Most farmers grew and conserved their own crop seed. The majority of cleaned samples had some level of seed contamination from 11 foreign weed and volunteer crop species, with an average of 62 seeds 10 kg−1grain, substantially higher than the 28 seeds 10 kg−1grain expected by farmers. The most common weed contaminants across all samples were rigid ryegrass, wild radish, brome, and wild oat. When categorized by crop type, rigid ryegrass was the most frequent contaminant of cereal crops (barley and wheat), however wild radish was the most frequent contaminant of lupin crops. Uncleaned crop seed samples had almost 25 times more contamination than cleaned crop seed. Herbicide resistance was highly prevalent within rigid ryegrass populations recovered from cleaned grain except for glyphosate, which controlled all populations tested. Some resistance was also found in wild radish and wild oat populations; however, brome was susceptible to fluazifop. This study has shown that farmers are unknowingly introducing weed seeds into their farming systems during crop seeding, many of which have herbicide resistance.

The nature and consequence of weed spread in cropping systems

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Donald C. Thill ◽  
Carol A. Mallory-Smith
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Short Distance ◽  
Crop Production ◽  
Cropping Systems ◽  
Weed Seed ◽  
Management Options ◽  
Crop Species ◽  
Weed Seeds ◽  
Pollen Movement

Weeds spread through movement of seeds and vegetative reproductive propagules. Pollen movement can spread weedy traits, such as herbicide resistance, between related weed and crop species. Weed seeds can spread short or long distances by natural plant dehiscence mechanisms, wind, water, animals, and man&s activities. This symposium paper is a practical review of short-distance spread of weed seeds in and between nearby arable fields and noncrop lands, examining some of the causes of spread and subsequent effects on crop production. Pollen movement, as it affects the spread of herbicide resistance, also is considered a component of short-distance weed spread. Specific weed management options can be used to reduce man-caused weed seed spread within and between nearby fields, thus reducing potential crop yield losses. Long-term management will be more difficult for weed seed spread by natural dispersal mechanisms.

ACCase-Inhibiting Herbicide-ResistantAvenaspp. Populations from the Western Australian Grain Belt

2012 ◽  
Vol 26 (1) ◽  
pp. 130-136 ◽  
Author(s):  
M. S. Ahmad-Hamdani ◽  
Mechelle J. Owen ◽  
Qin Yu ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Dose Response ◽  
Resistance Index ◽  
Wild Oat ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Grain Crops ◽  
High Level ◽  
Western Australian

Avenaspp. are world weeds with many cases of evolved herbicide resistance. In Australia,Avenaspp. (wild oat and sterile oat) are a major problem, especially in grain crops. Acetyl-CoA carboxylase (ACCase)–inhibiting herbicides have been used extensively since the late 1970s forAvenaspp. control. However, continued reliance on these herbicides has resulted in the evolution of resistantAvenaspp. populations. Resistance across many ACCase-inhibiting herbicides was characterized in fourAvenaspp. populations from the Western Australian grain belt. Dose–response experiments were conducted to determine the level of resistance to the aryloxyphenoxypropionates and cyclohexanediones and to the phenylpyrazoline herbicide pinoxaden. On the basis of resistance index values, all four resistant populations exhibited high-level diclofop resistance but varied in the level of resistance to other ACCase-inhibiting herbicides tested. It is evident thatAvenaspp. populations from the Western Australian grain belt have evolved resistance to a number of ACCase-inhibiting herbicides.

The economic value of haying and green manuring in the integrated management of annual ryegrass and wild radish in a Western Australian farming system

2004 ◽  
Vol 44 (12) ◽  
pp. 1195 ◽  
Author(s):  
M. Monjardino ◽  
D. J. Pannell ◽  
S. B. Powles
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Weed Management ◽  
Integrated Management ◽  
Farming System ◽  
Integrated Weed Management ◽  
Annual Ryegrass ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Green Manuring

Most cropping farms in Western Australia must deal with the management of herbicide-resistant populations of weeds such as annual ryegrass (Lolium rigidum) and wild radish (Raphanus raphanistrum). Farmers are approaching the problem of herbicide resistance by adopting integrated weed management systems, which allow weed control with a range of different techniques. These systems include non-herbicide methods ranging from delayed seeding and high crop seeding rates to the use of non-cropping phases in the rotation. In this paper, the Multi-species RIM (resistance and integrated management) model was used to investigate the value of including non-cropping phases in the crop rotation. Non-crop options investigated here were haying and green manuring. Despite them providing excellent weed control, it was found that inclusion of these non-cropping phases did not increase returns, except in cases of extreme weed numbers and high levels of herbicide resistance.

Weed management in wide-row cropping systems: a review of current practices and risks for Australian farming systems

2009 ◽  
Vol 60 (5) ◽  
pp. 395 ◽  
Author(s):  
S. C. Peltzer ◽  
A. Hashem ◽  
V. A. Osten ◽  
M. L. Gupta ◽  
A. J. Diggle ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Precision Agriculture ◽  
Weed Management ◽  
Cropping Systems ◽  
Farming Systems ◽  
Crop Damage ◽  
Species Dominance ◽  
Pests And Diseases ◽  
Management Technology

Growing agricultural crops in wide row spacings has been widely adopted to conserve water, to control pests and diseases, and to minimise problems associated with sowing into stubble. The development of herbicide resistance combined with the advent of precision agriculture has resulted in a further reason for wide row spacings to be adopted: weed control. Increased row spacing enables two different methods of weed control to be implemented with non-selective chemical and physical control methods utilised in the wide inter-row zone, with or without selective chemicals used on the on-row only. However, continual application of herbicides and tillage on the inter-row zone brings risks of herbicide resistance, species shifts and/or changes in species dominance, crop damage, increased costs, yield losses, and more expensive weed management technology.

The economic value of pasture phases in the integrated management of annual ryegrass and wild radish in a Western Australian farming system

2004 ◽  
Vol 44 (3) ◽  
pp. 265 ◽  
Author(s):  
M. Monjardino ◽  
D. J. Pannell ◽  
S. B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Integrated Management ◽  
Economic Value ◽  
Farming System ◽  
Integrated Weed Management ◽  
Continuous Cropping ◽  
Annual Ryegrass ◽  
Wild Radish ◽  
Raphanus Raphanistrum

Most cropping farms in Western Australia must deal with the management of herbicide-resistant populations of weeds such as annual ryegrass (Lolium rigidum Gaudin) and wild radish (Raphanus raphanistrum�L.). Farmers are approaching the problem of herbicide resistance by adopting integrated weed management systems, which allow weed control with a range of different techniques. One important question in the design of such systems is whether and when the benefits of including pasture in rotation with crops exceed the costs. In this paper, the multi-species resistance and integrated management model was used to investigate the value of including pasture phases in the crop rotation. The most promising of the systems examined appears to be so-called 'phase farming', involving occasional 3-year phases of pasture rather than shorter, more frequent and regular pasture phases. This approach was competitive with the best continuous cropping rotation in a number of scenarios, particularly where herbicide resistance was at high levels.

Lessons learnt: crop-seed cleaning reduces weed-seed contamination in Western Australian grain samples

2020 ◽  
Vol 71 (7) ◽  
pp. 660
Author(s):  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Growing Season ◽  
Annual Ryegrass ◽  
Weed Seed ◽  
Cleaning Method ◽  
Crop Type ◽  
Weed Seeds ◽  
Soil Seedbank ◽  
Contamination Levels ◽  
Western Australian ◽  
Crop Seed

Weeds are a major contributing factor to crop yield loss. Weed control is regularly practiced during the growing season, with many growers making a conscious effort to minimise weed-seed return to the soil seedbank during the cropping program. However, growers may be unintentionally introducing weed seeds through sowing of contaminated crop seed. Using samples of crop seed obtained from 29 growers across two Western Australian grain-growing regions, 81 samples were hand-cleaned to determine weed-seed contamination levels. Of those samples, 41% were weed-free, and in the remaining 59%, the main contaminant was Lolium rigidum (annual ryegrass), occurring in 49% of contaminated samples. Crop type and cleaning method had significant effects on the level of weed-seed contamination, with barley having higher levels of contamination than other crops, and professional contractors providing lower contamination than other methods of cleaning. However, any seed-cleaning method provided significantly cleaner grain samples than no seed cleaning. This study established that crop-seed contamination was evident on Western Australian farms and that growers may be unintentionally sowing weed seeds with their crops. Seed cleaning combined with judicious paddock selection and weed-seed removal during the growing season can lead to weed-free crop seed.

Distribution and frequency of herbicide-resistant wild oat (Avena spp.) across the Western Australian grain belt

2009 ◽  
Vol 60 (1) ◽  
pp. 25 ◽  
Author(s):  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Wild Oat ◽  
Cultural Management ◽  
Herbicide Resistant ◽  
Low Level ◽  
Resistance Evolution ◽  
Modes Of Action ◽  
Random Survey ◽  
Herbicide Use ◽  
Western Australian

In 2005, a random survey was conducted across 14 million hectares of the Western Australian grain belt to establish the frequency and distribution of herbicide-resistant wild oat (Avena spp.) in cropping fields. In total, 677 cropping fields were visited, with wild oat populations collected from 150 fields. These wild oat populations were screened with several herbicides commonly used to control this weed. Most of the wild oat populations (71%) were found to contain individuals resistant to the ACCase-inhibiting herbicide diclofop-methyl. Resistance to other ACCase-inhibiting herbicides was markedly lower. Herbicides of alternative modes of action were effective on all wild oat populations. Overall, wild oat resistance to diclofop-methyl was found to be widespread across the Western Australian grain belt, but resistance to other herbicides was relatively low. Therefore, through diversity in herbicide use and with cultural management, it is possible to maintain wild oat populations at a low level and/or minimise herbicide resistance evolution.

Herbicide Resistance in Rigid Ryegrass (Lolium rigidum)Has Not Led to Higher Weed Densities in Western Australian Cropping Fields

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Rick S. Llewellyn ◽  
Francis H. D'Emden ◽  
Mechelle J. Owen ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Resistance Management ◽  
Multiple Resistance ◽  
Harvest Time ◽  
Lolium Rigidum ◽  
Herbicide Resistant ◽  
Rigid Ryegrass ◽  
Susceptible Populations ◽  
Western Australian ◽  
Very High

The aim of this study was to test whether herbicide resistance in rigid ryegrass has led to increased densities of this weed in Western Australian (WA) cropping fields. A total of 503 wheat fields with previously unknown management history and weed status were visited prior to harvest across 15 agronomic areas of the central WA cropping belt in 1998 and 2003. Rigid ryegrass density was visually assessed and, where possible, seed was collected from the population. Ryegrass was found in 91% of the wheat crops sampled. Ryegrass populations were tested in the following year for resistance to chlorsulfuron, sulfometuron, diclofop, and clethodim. With the use of nonparametric and regression statistical methods, resistance status, including multiple-resistance status, was not found to be associated with higher weed density. The results show that growers are generally maintaining low densities in fields with herbicide-resistant rigid ryegrass. The most common rigid ryegrass density at harvest time was less than 1 plant m−2in both resistant and susceptible populations. Field and model-based studies of weed and herbicide resistance management that allow populations to continue at very high densities are unlikely to reflect common grower practice.

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