Novel Encapsulated Herbicide Delivery Mechanism: Its Efficacy in Mimosa Bush (Vachellia farnesiana) Control

Mimosa bush (Vachellia farnesiana) is an invasive woody weed widely distributed in Australia. While it can be controlled using several mechanical and chemical techniques, this study evaluated a novel herbicide delivery mechanism that minimizes the risk of spray drift and potential non-target damage. This method, developed by Bioherbicides Australia, involves the implantation of encapsulated granular herbicides into the stem of intact plants or into the stump after cutting off plants close to ground level (cut stumps). Trials were implemented near Moree (New South Wales, Australia) on intact (two experimental runs) plants and cut stumped (two experimental runs) plants. For each trial, an untreated control plus the conventional basal bark application of a liquid formulation of triclopyr + picloram mixed with diesel was included for comparison. Encapsulated glyphosate, aminopyralid + metsulfuron-methyl, hexazinone and clopyralid were also tested in all trials. In addition, encapsulated triclopyr + picloram, and metsulfuron-methyl were included in one of the intact plant trials. Aminopyralid + metsulfuron-methyl was consistently most effective on cut stump and intact plants, whilst clopyralid provided highest mortality when applied to cut stumps and single-stemmed intact plants. Particularly for multi-stemmed intact plants, clopyralid should be applied to each stem. Overall, the highest efficacy was achieved on single stemmed plants, but with further refinement of the technique, it should be possible to achieve similar results for multi-stemmed individuals. This method resulted in a reduction in the use of herbicide and environmental contamination while significantly improving speed of treatment.

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Subtle Changes or Dramatic Perceptions of Air Pollution in Sydney during COVID-19

Environments ◽

10.3390/environments8010002 ◽

2021 ◽

Vol 8 (1) ◽

pp. 2

Author(s):

Peter Brimblecombe ◽

Yonghang Lai

Keyword(s):

Air Pollution ◽

Air Quality ◽

New South ◽

Human Mobility ◽

Ground Level ◽

Physical Reality ◽

Social Perceptions ◽

Search Terms ◽

South Wales ◽

Significant Difference

The COVID-19 pandemic made it critical to limit the spread of the disease by enforcing human isolation, restricting travel and reducing social activities. Dramatic improvements to air quality, especially NO2, have often characterised places under COVID-19 restrictions. Air pollution measurements in Sydney in April 2019 and during the lockdown period in April 2020 show reduced daily averaged NO2 concentrations: 8.52 ± 1.92 and 7.85 ± 2.92 ppb, though not significantly so (p1~0.15) and PM2.5 8.91 ± 4.94 and 7.95 ± 2.64 µg m−3, again a non-significant difference (p1~0.18). Satellite imagery suggests changes that parallel those at ground level, but the column densities averaged over space and time, in false-colour, are more dramatic. Changed human mobility could be traced in increasing times spent at home, assessed from Google Mobility Reports and mirrored in decreased traffic flow on a major road, suggesting compliance with the restrictions. Electricity demand for the State of New South Wales was low under lockdown in early April 2020, but it recovered rapidly. Analysis of the uses of search terms: bushfires, air quality, haze and air pollution using Google Trends showed strong links between bushfires and pollution-related terms. The smoke from bushfires in late 2019 may well have added to the general impression of improved air quality during lockdown, despite only modest changes in the ground level measurements. This gives hints that successful regulation of air quality requires maintaining a delicate balance between our social perceptions and the physical reality.

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Effects of herbicides on wallaby grass (Danthonia spp.) 1. Establishment

Australian Journal of Experimental Agriculture ◽

10.1071/ea9940753 ◽

1994 ◽

Vol 34 (6) ◽

pp. 753 ◽

Cited By ~ 9

Author(s):

GM Lodge ◽

MG McMillan ◽

AJ Schipp ◽

AS Cook

Keyword(s):

Dry Matter ◽

New South ◽

Stem Elongation ◽

New South Wales ◽

Growth Stages ◽

Dry Matter Yield ◽

Metsulfuron Methyl ◽

Tiller Stage ◽

South Wales

Two experiments were conducted at Tamworth, New South Wales, to assess the effects of herbicides applied post-sowing pre-emergence, and at 2 post-emergence growth stages, on Danthonia (wallaby grass) dry matter yield, plant number, and plant phytotoxicity. Phytotoxicity was scored visually on a 0-5 scale (0, no phytotoxicity; 5, 100% phytotoxicity). In the post-sowing pre-emergence study, no Danthonia plants survived on plots sprayed with metribuzin (375 g a.i./ha), chlorsulfuron (45 g a.i./ha), or simazine (750 and 1500 g a.i./ha). Phytotoxicity was also high at lower rates of metribuzin (187.5 g a.i./ha) and chlorsulfuron (22.5 g a.i./ha). Dry matter yields and plant numbers on 2,4-D amine and ester treatments were not significantly different from those of unsprayed controls. On metsulfuron-methyl (3 and 6 g a.i./ha) and triasulfuron (21.4 g a.i./ha) treatments, plant numbers were similar to the controls, but Danthonia yields were lower (P<0.05). In seedling stands, the only herbicide that reduced (P<0.05) Danthonia dry matter yield compared with the unsprayed control plots was metsulfuron-methyl applied at 6, 12, and 18 g a.i./ha at the 2-4 tiller stage, and at 12 and 18 g a.i./ha at early stem elongation. At both times of application, Danthonia plant numbers were lowest (P<0.05) on the metsulfuron-methyl 12 and 18 g a.i./ha treatments. Phytotoxicity scores were >2 and highest (P<0.05) on all metsulfuron-methyl plots. These studies indicated that a range of chemicals could be used to control broadleaf weed seedlings, without damaging Danthonia seedlings.

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Banana plant growth. 1. Gross morphology

Australian Journal of Experimental Agriculture ◽

10.1071/ea9720209 ◽

1972 ◽

Vol 12 (55) ◽

pp. 209 ◽

Cited By ~ 8

Author(s):

DW Turner

Keyword(s):

New South ◽

Ground Level ◽

Banana Plant ◽

Root Numbers ◽

South Wales ◽

Lateral Buds ◽

Lateral Bud ◽

Phases Of Development ◽

Bud Growth ◽

Sigmoid Growth Curve

Bananas plants (CV. Williams) at Alstonville, New South Wales, were sampled every two weeks from planting in November 1967 until early post emergence of the fruit in Map 1969. Records were kept of sucker, root, and inflorescence growth. On morphological grounds, the life of one apex was divided into five stages. The end points of these stages were : corm formation, commencement of lateral bud growth, floral initiation, bunch emergence, and harvest. Lateral buds, or suckers, commenced to grow after twelve foliate leaves were produced. Lateral bud development on the parent decreased as it commenced on the ratoon 1 crop. A total of 25 lateral buds showed some swelling but only 13 grew above ground level. All but one of these were removed when the plants were desuckered. After 19 months of growth, half of the live roots arose from gouged sucker remains. No decrease in root numbers was observed on the parent after bunch emergence. The first desuckering, nine months after planting, reduced the total number of roots on the plant by about 50 per cent. The young fruit underwent a sigmoid growth curve during the pre-emergence and early post-emergence phases of development. The most rapid growth of the fruit in terms of fresh weight increase occurred during the five to six weeks before emergence of the bunch.

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Influence of grazing and herbicide before sowing on establishment and survival of surface sown pasture species on the Northern Tablelands of New South Wales

Australian Journal of Experimental Agriculture ◽

10.1071/ea9830146 ◽

1983 ◽

Vol 23 (121) ◽

pp. 146

Author(s):

PM Dowling ◽

AR Gilmour

Keyword(s):

Relative Humidity ◽

Festuca Arundinacea ◽

New South ◽

New South Wales ◽

Trifolium Subterraneum ◽

Ground Level ◽

Seedling Development ◽

Vegetation Height ◽

South Wales ◽

Herbicide Mixture

The effect of surface sowing into different levels of native and naturalized vegetation, both herbicide treated and untreated, was evaluated in terms of seedling numbers and development at three sites on the Northern Tablelands of New South Wales during 1970-71. The herbicide mixture (2,2-DPA + Amitrole: 11.0 + 1.1 kg a.i./ha, respectively) was applied eight weeks before sowing with Trifolium subterraneum, Medicago sativa, Festuca arundinacea, Dactylis glomerata and Phalaris aquatics. Seedlings were counted 2, 6 and 11 months after sowing, and seedling development was assessed at the two initial samplings. Relative humidity and temperature 0.5 cm above ground level were measured with thermocouples for two months after sowing. Mean seedling numbers over all sites increased from 18.8 to 47.3; 5.2 to 30.2; and 5.5 to 12.1 /m2 for samplings 1,2 and 3, respectively, as level of vegetation increased. In particular, seedling numbers responded to height of vegetation rather than weight. Relative humidity increased and temperature decreased as vegetation height increased, but regressions of seedling numbers against relative humidity and temperature were not significant and indicated that vegetation height influenced seedling numbers by some means other than relative humidity and temperature. Application of herbicide to control the resident vegetation increased mean seedling numbers over sites for sampling times 1,2 and 3, from 30.8 to 36.4; 8.8 to 26.6; and 3.9 to 14.1 seedlings/m2, respectively, and also accelerated seedling development.

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