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Author: Brian Richardson Publisher: ISBN: Category : Herbicides Languages : en Pages : 302
Book Description
To improve the efficiency of herbicide applications, each stage of the spray application process must be considered. Two of these stages, the process of spray deposition within plant canopies and the influence of the form of the spray deposit on efficacy were investigated. The effect of droplet size, spray volume, and droplet trajectory on the vertical distribution of spray deposits was measured within canopies of bracken fern (Pteridium aquilinum L. Kuhn) and greenleaf manzanita (Arctostaphylos patula Greene). Spray containing a fluorescent tracer was applied using spinning disc and flat fan nozzles, and deposition was measured on horizontal strings placed at various levels in the canopy. Spray deposition profiles were not significantly affected by droplet size. With bracken, 50 1/ha application volumes gave greater deposition than at 100 1/ha. Spray deposition was increased, particularly with the vertically oriented manzanita foliage, when droplets entered the canopy with a significant horizontal component to their trajectory. The foliage structure of bracken and manzanita canopies was measured using a point quadrat vegetation sampling technique. A model to predict spray deposition profiles was then developed, and observed deposition profiles were compared to predicted profiles. With bracken, the modelled profile was close to, but underestimated, the measured deposit attenuation. With manzanita, the predicted deposit profile overestimated deposit attenuation, suggesting that the vertically moving droplets were reflected from the foliage inclined at 72° from the horizontal. The effects of droplet size, spray volume, and herbicide rate on phytotoxicity were also investigated. Glyphosate and fluroxypyr were applied to bracken fern and greenleaf manzanita, respectively, using spinning discs. Increasing glyphosate concentration or the area of foliage wetted were equally effective in enhancing efficacy on bracken fern. A smaller droplet size and higher spray volume increased the efficacy of fluroxypyr on manzanita. For both species and chemical combinations, the addition of a surfactant, L-77, showed the greatest potential for increasing the efficiency of spray applications. In general, using small droplets with a horizontal velocity component, and a suitable surfactant will increase spray efficiency. High herbicide concentrations may be beneficial if localized scorch does not occur.
Author: Brian Richardson Publisher: ISBN: Category : Herbicides Languages : en Pages : 302
Book Description
To improve the efficiency of herbicide applications, each stage of the spray application process must be considered. Two of these stages, the process of spray deposition within plant canopies and the influence of the form of the spray deposit on efficacy were investigated. The effect of droplet size, spray volume, and droplet trajectory on the vertical distribution of spray deposits was measured within canopies of bracken fern (Pteridium aquilinum L. Kuhn) and greenleaf manzanita (Arctostaphylos patula Greene). Spray containing a fluorescent tracer was applied using spinning disc and flat fan nozzles, and deposition was measured on horizontal strings placed at various levels in the canopy. Spray deposition profiles were not significantly affected by droplet size. With bracken, 50 1/ha application volumes gave greater deposition than at 100 1/ha. Spray deposition was increased, particularly with the vertically oriented manzanita foliage, when droplets entered the canopy with a significant horizontal component to their trajectory. The foliage structure of bracken and manzanita canopies was measured using a point quadrat vegetation sampling technique. A model to predict spray deposition profiles was then developed, and observed deposition profiles were compared to predicted profiles. With bracken, the modelled profile was close to, but underestimated, the measured deposit attenuation. With manzanita, the predicted deposit profile overestimated deposit attenuation, suggesting that the vertically moving droplets were reflected from the foliage inclined at 72° from the horizontal. The effects of droplet size, spray volume, and herbicide rate on phytotoxicity were also investigated. Glyphosate and fluroxypyr were applied to bracken fern and greenleaf manzanita, respectively, using spinning discs. Increasing glyphosate concentration or the area of foliage wetted were equally effective in enhancing efficacy on bracken fern. A smaller droplet size and higher spray volume increased the efficacy of fluroxypyr on manzanita. For both species and chemical combinations, the addition of a surfactant, L-77, showed the greatest potential for increasing the efficiency of spray applications. In general, using small droplets with a horizontal velocity component, and a suitable surfactant will increase spray efficiency. High herbicide concentrations may be beneficial if localized scorch does not occur.
Author: Chester L. Foy Publisher: CRC Press ISBN: 1351077953 Category : Technology & Engineering Languages : en Pages : 763
Book Description
Based on a conference, this book is intended to promote a better understanding of the effects of adjuvants on pesticide penetration, translocation, photodegradation and stability, spray deposition and dissipation, and the fate of herbicides in the environment.
Author: Barbara Houston Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Herbicide performance is directly related to the amount of active ingredient that has been deposited on the plant. Hence, spray solution characteristics and application parameters are crucial in determining the efficacy of an herbicide application. To maximize the effectiveness of chemical control, methods to deliver full chemical dose must be utilized: allowing the active ingredient to be readily absorbed once added to the carrier and mitigating off-target movement and low herbicide doses. Water is the most frequently used carrier in herbicide applications. Chemical parameters, such as water hardness and pH, can have a critical role in herbicide performance. It is generally believed that weak acid herbicides, such as glyphosate and 2,4-D, have higher dissociation in higher carrier pH, which leads to decreased uptake into plants. Moreover, increased concentration of hard water cations may have antagonistic effect on weak acid herbicide applications. To overcome the negative effect of water quality on weak acid applications, addition of water conditioning adjuvants is recommended. Carrier volume and droplet size are crucial parameters in application technology that can also impact herbicide performance. Nozzles and their spray characteristics have gone under significant development in past decades to enhance spray potential under a wide range of conditions. Introduction of air inclusion nozzles provided the ability to create larger droplets at the same pressure and flow rate as conventional nozzles, resulting in less drift. Controlling off target movement essentiality decreases the potential for herbicide resistance selection on weeds, as well as injury on sensitive crops. Hence, the objectives of this research were to investigate water quality, carrier volume and droplet size effects on herbicide efficacy and drift potential.
Author: J.J. Picot Publisher: Springer Science & Business Media ISBN: 9401156344 Category : Technology & Engineering Languages : en Pages : 225
Book Description
Introduced to the technical aspects of forestry aerial spraying in the mid-1970's, we were immediately impressed by the complexity of the process of delivering pesticide to foliage. At that time, there was a vigorous public debate in New Brunswick about the ecological and public h~alth impacts of the annual spray program for the control of defoliation of spruce and fir trees by the spruce budworm. The forest industry is important to the province and changes to the established procedures of budworm control could have major economic implications. A rational debate required reliable information about the mechanics of the spraying process. There was a need to supply missing information as to required pesticide application rates, atomizer performance, off-target drift and deposit, and the effects of weather and aircraft operating factors. We were invited to initiate a research program in this domain by New Brunswick forest management officials, and what follows in this book is a logical and quantitative description of the overall process based on our own research and that of others over the intervening years. After a short introduction to aerial spraying, we begin (Chapter 2) by describing forest stands in terms of their interaction with suspended atmospheric particulate material carried along by the wind and susceptible to deposition on foliage. We introduce foliage simulators and their use in measuring the deposit of sprayed pesticide on foliage, the "biological interface" between pest and pesticide.
Author: Jake McNeal Publisher: ISBN: Category : Languages : en Pages : 106
Book Description
The application of pesticides in agriculture production systems is a complex process and involves a series of factors that dynamically interact to impact overall pesticide application efficacy. Spray droplet formation, target impaction and deposition, plant uptake, and subsequent biological response are all functions of pesticide active ingredient, nozzle selection, application pressure, and carrier volume. Smaller spray droplets with a lower kinetic energy result in greater spray droplet retention on the leaf surface relative to larger droplets. Consequently, larger spray droplets with higher kinetic energy are poorly retained on the leaf surface and yield minimal coverage of leaf surface tissue. While smaller droplets maximize target coverage and spray droplet retention, larger spray droplets minimize off-target movement and agrichemical transport. Consequently, application factors that maximize pesticide efficacy and minimize off-target movement are often incongruous elements. Therefore, the objective of this research was to evaluate the impact of carrier volume and spray droplet size on the efficacy of various pesticide applications in Mississippi. These data indicate that 1) for thrips and tarnished plant bug control, acephate and sulfoxaflor are superior dicamba application partners relative to dimethoate and thiamethoxam, respectively, insecticide efficacy did not vary due to spray droplet size when applied without dicamba, and maximum efficacy was achieved with a carrier volume of 187 L ha-1; 2) dicamba + acephate and dicamba + thiamethoxam or sulfoxaflor are efficacious options to control Palmer amaranth relative to dicamba applied alone, and maximum Palmer amaranth control was achieved with a carrier volume of 187 L ha-1; 3) cotton defoliation efficacy is positively and negatively correlated with carrier volume and spray droplet size, respectively, and maximum efficacy was achieved with cotton defoliation programs consisting of two-applications, each with a carrier volume of 187 L ha-1 and 200 μm droplets; 4) soybean harvest aid efficacy is primarily a function of the harvest aid applied and that the impact of carrier volume and spray droplet size varies across harvest aids. However, when paraquat is applied, a carrier volume between 47 and 187 L ha-1 should be utilized with droplets of 200-500 μm to maximize harvest aid efficacy.
Author: Brian Richardson
Author: Brian Richardson
Author: Chester L. Foy
Author: Edward Fredrickson
Author: Barbara Houston
Author: William Harris Morris
Author: 
Author: 
Author: J.J. Picot
Author: Jake McNeal
Author: