Spray deposition on plant surfaces: a modelling approach

2008 ◽  
Vol 35 (10) ◽  
pp. 988 ◽  
Author(s):  
Gary Dorr ◽  
Jim Hanan ◽  
Steve Adkins ◽  
Andrew Hewitt ◽  
Chris O'Donnell ◽  
...  

For pesticides to effectively manage pests, they must first be deposited on the target (typically a plant surface) in a manner in which the active ingredient(s) can be readily taken up by the target organism. A plant architectural model that enables the location of various plant components in 3-D space combined with a particle trajectory model has been used to study the interception of spray droplets by various vegetative elements. Results from the simulation are compared with wind tunnel studies of glyphosate deposition on cotton (Gossypium hirsutum L. var. Sicala), sow thistle (Sonchus oleraceus L.) and wild oats (Avena ludoviciana Durieu). An air induction flat fan nozzle (AI110015 at 500 kPa pressure) and an extended range flat fan nozzle (XR11002 at 280 kPa pressure) were predicted to have similar glyphosate deposition on cotton and sow thistle plants, whereas the extended range nozzle resulted in higher deposit on wild oats. Spray deposition (µg cm−2) on wild oat plants at the 5-leaf stage was more than double the amount of deposition on sow thistle or wild oat plants at the 2-leaf stage. The model was in good agreement with the experimental data except that it tended to over predict deposition on sow thistle plants.

1988 ◽  
Vol 68 (3) ◽  
pp. 823-827 ◽  
Author(s):  
D. H. WILCOX ◽  
I. N. MORRISON ◽  
G. MARSHALL

In controlled environment experiments diclofop methyl, difenzoquat, flamprop methyl, fluazifop-P and seythoxydim were applied to wild oat at the three-leaf stage at recommended rates 10 h before or after a single night of freezing (−4 °C) temperature. Herbicide efficacy, as determined by the change in post-treatment dry weight accumulation of treated wild oats during the ensuing 3 wk period, was unaffected by the freezing temperature. The dry matter accumulation of wild oat exposed to the −4 °C temperature was reduced by 10–20% compared to plants which were grown under a constant 15/5 °C day/night regime.Key words: Oat (wild), frost, diclofop methyl, flamprop methyl, difenzoquat, fluazifop-P, sethoxydim


1983 ◽  
Vol 63 (2) ◽  
pp. 503-507 ◽  
Author(s):  
M. P. SHARMA ◽  
W. H. VANDEN BORN

Field experiments were conducted over a 2-yr period to evaluate the need for competition by crop plants along with the application of postemergence herbicides for wild oat (Avena fatua L.) control in barley and wheat. Barban, difenzoquat, and barban plus difenzoquat were used in barley and barban, benzoylprop ethyl, diclofop methyl, flamprop methyl, and barban plus benzoylprop ethyl were used in wheat, at the two-leaf stage and the four-leaf stage of wild oats seeded alone or in a crop. Barban and diclofop methyl were effective for wild oat control at both the two-leaf and four-leaf stage of wild oats. Benzoylprop ethyl, difenzoquat and flamprop methyl alone or in combination with barban were more effective at the four-leaf than at the two-leaf stage of wild oats. Herbicide treatments increased barley yield up to 84% and wheat yield up to 177%. In the absence of herbicide treatments, crop competition from barley or wheat reduced the wild oat dry weight by about 50%. Competition by crop plants was essential for effective wild oat control with all foliage-applied wild oat herbicides included in this study.Key words: Competition, crop, wild oat, herbicides, wheat, barley


1985 ◽  
Vol 65 (4) ◽  
pp. 1101-1106 ◽  
Author(s):  
A. L. DARWENT ◽  
J. H. SMITH

In a 4-yr study, rapeseed (Brassica campestris L.) was seeded where wild oats (Avena fatua L.) had been controlled either by various delayed seeding procedures or by an early spring application of trifluralin at 1.1 kg a.i./ha. The trifluralin treatment provided the best wild oat control. However, allowing wild oats to grow to the two-leaf stage, destroying them with cultivation and then seeding rapeseed resulted in commercially acceptable control (70% or more) with little or no loss of crop yield. Postponing cultivation until the wild oats reached the three- to four-leaf stage provided control that was almost equivalent to that attained with cultivation at the two-leaf stage but resulted in reduced crop yields. Destruction of wild oat seedlings at the two-leaf stage by paraquat or glyphosate did not improve the level of control over that provided by cultivation.Key words: Oat (wild), delayed seeding, rapeseed, trifluralin


1987 ◽  
Vol 67 (1) ◽  
pp. 271-274
Author(s):  
G. H. FRIESEN

The efficacy of flamprop methyl and its active isomer (WL43423) on wild oats (Avena fatua L.) in field corn (Zea mays L.) was studied in field plots at Morden, Manitoba from 1983 to 1985. The herbicides were applied at recommended rates at the two-leaf, four-leaf and six-leaf stages of field corn. Spraying at the four-leaf stage consistently provided maximum wild oat control with acceptable field corn tolerance. When 2,4-D amine was applied at the same time as flamprop methyl, reduced wild oat control and field corn tolerance was observed.Key words: Oat (wild), Avena fatua, corn (field), Zea mays, flamprop methyl, WL43423


1976 ◽  
Vol 16 (80) ◽  
pp. 402 ◽  
Author(s):  
DW McNamara

The effects of removing wild oats (Avena spp.) from wheat (cv. Gamut) at different stages of wheat growth were investigated in three replicated factorial field experiments at the Tamworth Agricultural Research Centre. In addition, two wild oat densities were compared in the first experiment, and handpulling wild oats was compared with cutting and a shielded paraquat spray in the second experiment. Wheat yield was linearly reduced by up to 1.025 g m-2 day-1 for the duration of wild oat competition. Reductions in tiller number and dry matter yield measured at maturity and the number of tillers per plant recorded at the 5-6 leaf stage were also proportional to the time wild oats were allowed to compete with the wheat. This competitive effect of wild oats increased with increasing weed density. Handpulling and cutting wild oats gave similar measured competitive effects whereas the paraquat spray applied at the 2-3 leaf stage of wheat reduced wheat density.


Weed Science ◽  
1974 ◽  
Vol 22 (5) ◽  
pp. 476-480 ◽  
Author(s):  
Robert W. Neidermyer ◽  
John D. Nalewaja

The response of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.) to barban (4-chloro-2-butynyl-m-chlorocarbanilate) was studied as influenced by plant morphology and air temperature after application. Growth of wheat and wild oat seedlings was reduced by barban at 0.3 μg and 0.6 μg applied to the first node, respectively. Barban application to the base and midpoint of the first leaf blade required a lower dose to reduce wild oat growth than wheat growth. Increased tillering occurred from barban injury to the main culm in wheat. Wheat and wild oat susceptibility to barban increased as the post-treatment temperature decreased from 32 to 10 C. Barban selectivity for wild oats in wheat was greater at 27 and 21 C than at 16 and 10 C.


1979 ◽  
Vol 59 (1) ◽  
pp. 93-98 ◽  
Author(s):  
F. A. QURESHI ◽  
W. H. VANDEN BORN

Uptake of 14C-diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy propanoate]} by leaves of wild oats (Avena fatua L.) was reduced significantly in the presence of MCPA {[(4-chloro-o-tolyl)oxy]acetic acid]}, especially the dimethylamine formulation. If the herbicides were applied separately, the degree of interference with uptake depended on the extent of overlap of droplets of the two spray preparations on the leaf surface. Spray volume and direction of spray application were important factors in minimizing the mixing of spray droplets on the leaves if the two herbicides were applied separately with a tandem arrangement of two sprayers. Such a sequential application of MCPA ester and diclofop-methyl in a field experiment provided significantly greater wild oat control than could be obtained with a tank mix of the same two herbicides, but the results were not consistent enough to recommend the procedure for practical use.


1963 ◽  
Vol 43 (1) ◽  
pp. 64-69 ◽  
Author(s):  
J. J. Sexsmith ◽  
G. C. Russell

Spring wheat, with fertilizer applied in the drill rows, was grown in wild-oat-infested stubble on a Shallow Lethbride loam soil for 4 years, Phosphorus had no measurable effect on the height, straw weight, seed yield, or number of wild-oat plants. In contrast, nitrogen increased the number of seed-bearing stems, plant height, straw weight, and seed yield, but did not change the wild-oat stand. Wheat yields were increased by nitrogen and further increased by the addition of phosphorus at the rate of 20 pounds of P2O5 per acre in 3 of the 4 years. Measured bushel weight of the wheat increased with nitrogen fertilizer additions and was further increased by phosphorus except at the high rate of both materials. Fertilizer applications, under conditions similar to those encountered in this test, may be useful for increasing wheat production, but only at the expense of producing increased quantities of wild-oat seed.


1987 ◽  
Vol 1 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Stephen D. Miller ◽  
Harold P. Alley

In the field, eight barley (Hordeum vulgare L.) cultivars tolerated postemergence applications of AC 222,293 [a mixture of methyl 6 and 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) m- and p-toluate] at 0.4 to 1.4 kg/ha. AC 222,293 at 0.4 kg ai/ha applied at the 1.5- to 2-leaf stage controlled wild oats (Avena fatua L. # AVEFA) 96%, whereas 0.7 kg/ha applied at the 3.5- to 4-leaf stage controlled wild oats only 93%. Sugarbeets (Beta vulgaris L.) but not alfalfa (Medicago sativa L.), corn (Zea mays L.), pinto beans (Phaseolus vulgaris L.), or sunflower (Helianthus annus L.), were injured when planted 6 to 8 months after fall applications of AC 222,293 at 0.4 to 1.1 kg/ha.


1994 ◽  
Vol 8 (4) ◽  
pp. 673-678 ◽  
Author(s):  
David A. Wall

Field studies were undertaken in 1992 and 1993 to investigate the control of wild oat and green foxtail in flax with reduced rates of fluazifop-P and clethodim applied as tank-mixtures. Fluazifop-P plus clethodim at 50 + 18 g ai/ha controlled wild oat and green foxtail and was as effective as full rates of either herbicide applied alone. These rates represent a 20% reduction in total amount of active ingredient required to control wild oat and green foxtail. Application of fluazifop-P, and/or clethodim prior to the 3- to 4-leaf stage failed to control late emerging grass weeds. Application of graminicide mixtures at or after the 3- to 4-leaf stage controlled late emerging grass weeds and did not affect flax yield. When applied late, fluazifop-P at 175 g/ha tended to reduce flax yield, although weed control was acceptable and no foliar injury was observed following treatment. The efficacy of graminicide mixtures was reduced by addition of bromoxynil plus MCPA to the spray mix.


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