Leaf Extension Rate May Help Determine When Low Wild Oat Herbicide Rates Will Be Effective<sup>1</sup>

Harker, K. Neil; Blackshaw, Robert E.

doi:10.1614/wt-03-004r1

Cited by 11 publications

(11 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent study measured the leaf extension rate of wild oat as an indicator of “active growth” and found that the efficacy of reduced doses of tralkoxydim and imazamethabenz was correlated with greater wild oat leaf growth (Fig. 1; Harker & Blackshaw 2003). Perhaps farmers could utilize this simple method of assessing weed growth in their decision‐making process when considering reduced herbicide doses.…”

Section: Enhancing the Successful Use Of Reduced Herbicide Dosesmentioning

confidence: 99%

Reduced herbicide doses in field crops: A review

Blackshaw

O’Donovan

Harker

et al. 2006

Weed Biology and Management

Self Cite

View full text Add to dashboard Cite

Farmers are becoming increasingly interested in more comprehensive weed management programs that reduce weed populations over time and in the use of reduced herbicide doses that lower their production costs. Research indicates that there is good potential to reduce the number of herbicide applications and utilize lower herbicide doses within competitive cropping systems. Diverse crop rotations, competitive cultivars, higher crop seed rates, reduced row spacing, specific fertilizer placement, and cover crops have been identified as integral components of competitive cropping systems. This review paper explores the potential for successful use of reduced herbicide doses within competitive cropping systems that have a multiyear approach to weed management. The utilization of decision support systems or new methods of assessing active weed growth are discussed in light of further enhancing the successful use of reduced herbicide doses and advising farmers on when (and when not) they might be a viable option.

show abstract

Section: Enhancing the Successful Use Of Reduced Herbicide Dosesmentioning

confidence: 99%

Reduced herbicide doses in field crops: A review

Blackshaw

O’Donovan

Harker

et al. 2006

Weed Biology and Management

Self Cite

View full text Add to dashboard Cite

show abstract

“…Several authors have suggested that environmental conditions before, during and after herbicide application are an important basis for determining the reduced dose rate (Caseley, 1987, 1989; Kudsk, 1989; Kudsk & Kristensen, 1992; Lundkvist, 1997a; Collings et al. , 2003; Harker & Blackshaw, 2003; Madafiglio et al. , 2006).…”

Section: Introductionmentioning

confidence: 99%

Are pre‐spraying growing conditions a major determinant of herbicide efficacy?

et al. 2007

View full text Add to dashboard Cite

Summary To evaluate the effect of pre‐spraying growing conditions on herbicide efficacy, two years of experimentation were conducted in which Persicaria maculosa plants were exposed to different light intensities for 1–4 days before metribuzin treatment. Specific leaf area, rather than plant growth rate or plant size, was the only parameter that correlated well with herbicide efficacy in both years of experimentation. The negative relationship between the ED50 and the specific leaf area indicates that leaf characteristics might be an important determinant of herbicide efficacy, for instance through an effect on herbicide uptake. In the third year of experimentation this hypothesis was further investigated by raising six cohorts of weed plants at a 1‐week interval and thus exposing them to a range of weather conditions. Clear relationships between uptake and herbicide efficacy were found for a combination of four plant species (Solanum nigrum, Senecio vulgaris, Chenopodium album and Brassica napus) and two herbicides (phenmedipham and bentazone). For phenmedipham, uptake was negatively correlated with global radiation and positively correlated with relative humidity. For the herbicide bentazone the opposite was found. These results were not species‐specific. This study shows the importance of the sensitivity of herbicide × species combinations and indicates that pre‐spraying weather information is relevant for the development of reduced dose rate recommendations.

show abstract

“…Many herbicide labels recommend application when weeds are actively growing and that efficacy can be reduced under poor growing conditions or when plants are stressed. As pointed out by Harker and Blackshaw (2003), none of the instructions indicate what good growing conditions are or how actively growing weeds can be identified. Those authors found that Avena spp.…”

Section: Discussionmentioning

confidence: 99%

“…, 1974) at the time of spraying. Leaf extension rates were also recorded in 2003 for a 24 h period around the time of spraying, as described by Harker and Blackshaw (2003). Analyses of the data collected in 2003 indicated that Avena spp.…”

Section: Methodsmentioning

confidence: 99%

“…In addition to studying the impacts of application and environmental factors on herbicide efficacy, attempts have been made to directly determine the rate of plant growth, and therefore the susceptibility of weeds to herbicides. For example, Harker and Blackshaw (2003) utilized a direct measure of Avena spp. growth in the hope that it might more accurately predict herbicide efficacy.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Field validation of the factors related to clodinafop efficacy on Avena species

et al. 2007

View full text Add to dashboard Cite

Previous research has shown that historical data and interpolated weather information can be used to correlate environmental and other variables with herbicide efficacy. This article examines this possibility using field experiments and on-site weather data. Clodinafop was applied to Avena spp. (wild oat) infestations on 46 occasions, in eight separate experiments, during 2003-2004 across the grain growing regions of New South Wales, Australia. Linear mixed models and covariate analyses were used to determine correlations of agronomic and environmental variables with clodinafop efficacy on Avena spp., as measured by plant mortality, panicle density and seed production. Clodinafop dose, maximum temperature on the day of spraying, spray water volume, the spray water volume by maximum temperature interaction and available soil moisture at spraying were correlated with mortality. Minimum temperatures prior to spraying, previously reported to be correlated with clodinafop efficacy, were not a significant factor in this study. On-site weather data were highly correlated with interpolated, generic weather data and thus there was little impact on which of these meteorological data sets were used to determine the correlations. This suggests that accessible, generic weather data could be used to develop and implement a predictive model for clodinafop efficacy. The relationship between the variables and Avena spp. mortality were generally supported when applied to panicle density and estimated seed production, with some exceptions.The results indicate that it should be possible to incorporate industry and field data to develop a robust predictive model for Avena spp. control with clodinafop.Keywords: wild oats, multi-site analysis, mixed models, temperature, soil moisture, spray water volume, dose rate. ANDREWSTS, MEDD RW, VAN DE VEN RJ & PICKERING DI (2007) Field validation of the factors related to clodinafop efficacy on Avena species. Weed Research 47, 15-24.

show abstract

Leaf Extension Rate May Help Determine When Low Wild Oat Herbicide Rates Will Be Effective¹

Cited by 11 publications

References 23 publications

Reduced herbicide doses in field crops: A review

Reduced herbicide doses in field crops: A review

Are pre‐spraying growing conditions a major determinant of herbicide efficacy?

Field validation of the factors related to clodinafop efficacy on Avena species

Contact Info

Product

Resources

About

Leaf Extension Rate May Help Determine When Low Wild Oat Herbicide Rates Will Be Effective1

Cited by 11 publications

References 23 publications

Reduced herbicide doses in field crops: A review

Reduced herbicide doses in field crops: A review

Are pre‐spraying growing conditions a major determinant of herbicide efficacy?

Field validation of the factors related to clodinafop efficacy on Avena species

Contact Info

Product

Resources

About

Leaf Extension Rate May Help Determine When Low Wild Oat Herbicide Rates Will Be Effective¹