A Model for Spray Droplet Adhesion, Bounce or Shatter at a Crop Leaf Surface

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.

Download Full-text

SPRAY DROPLET/CHEMICAL DEPOSIT INTERACTION WITH LEAF SURFACES

HortScience ◽

10.21273/hortsci.25.9.1146a ◽

1990 ◽

Vol 25 (9) ◽

pp. 1146a-1146

Author(s):

M.J. Bukovac ◽

D.L. Reichard

Keyword(s):

Fine Structure ◽

Growth Regulators ◽

Leaf Surface ◽

Crop Protection ◽

Chemical Deposition ◽

Lateral Diffusion ◽

Tween 20 ◽

Spray Droplet ◽

Leaf Surfaces ◽

Droplet Drying

Most growth regulators and crop protection chemicals are delivered to the plant as aqueous sprays. Spray droplet:plant surface interaction is central to establishing spray and, hence, dose retention by the plant. Further, the nature of chemical deposition from spray droplets plays an important role in determining the efficiency of the active ingredient (a.i.). Using scanning electron microscopy and dispersive x-ray analysis, we investigated chemical deposit formation of selected growth regulators (e.g. ethephon, 2,4, 5-TP, TIBA) on leaf surfaces differing in wettability and surface fine-structure. The a.i. frequently deposited in the form of an annulus on droplet drying, and the degree of spreading was related to surface tension of the spray solution, and wettability, fine-structure and morphology of the leaf surface. Marked differences were observed in spreading following impaction on veins vs. interveinal areas of leaves of Prunus and Pyrus sp. The epidermis over veins was more readily wetted leading to rapid lateral diffusion along veins. Surfactants (e.g. Tween 20, Regulaid) altered the deposition pattern, expanding the annulus and increasing spreading on the leaf surface.

Download Full-text

Spray droplet impaction models and their use within AGDISP software to predict retention

New Zealand Plant Protection ◽

10.30843/nzpp.2012.65.5393 ◽

2012 ◽

Vol 65 ◽

pp. 85-92 ◽

Cited By ~ 6

Author(s):

W.A. Forster ◽

G.N. Mercer ◽

W.C. Schou

Keyword(s):

Leaf Surface ◽

Simulation Software ◽

Surface Adhesion ◽

Physical Processes ◽

Spray Droplet ◽

Retention Models ◽

Crucial Effect ◽

Model Predictions ◽

Spray Formulation ◽

Droplet Impacts

The retention and distribution of spray droplets within the plant canopy have a crucial effect on the biological efficacy of pesticides To maximise spray retention droplets that impact a leaf must remain on the plant Three outcomes are possible when a droplet impacts a leaf surface adhesion bounce or shatter Those droplets that bounce or shatter can continue their journey through the canopy depositing at lower levels in the canopy or on the ground Mathematical models based on the physical processes involved in the bounce/ adhesion and shatter of droplets have been developed improved and described These processbased retention models have recently been implemented within an experimental build of the spray application simulation software AGDISP This has allowed differences in total spray retention to plants due to the spray formulation used or vegetative species studied to be predicted This paper discusses these new tools illustrates the effect different spray formulations and application parameters have on predicted retention and compares model predictions with measured retention

Download Full-text

DESIGN AND TEST OF SELF-PROPELLED STRADDLE-TYPE LYCIUM BARBARUM L. SPRAYING MACHINE

INMATEH Agricultural Engineering ◽

10.35633/inmateh-65-36 ◽

2021 ◽

pp. 345-354

Author(s):

ZeNing Gao ◽

QingYu Chen ◽

GuangRui Hu ◽

Chao Chen ◽

ChuanLin Li ◽

...

Keyword(s):

Environmental Pollution ◽

Leaf Surface ◽

Coverage Rate ◽

Lycium Barbarum ◽

Spray Droplet ◽

Droplet Distribution ◽

Shortest Distance ◽

Labor Requirements ◽

Natural Wind ◽

Liquid Medicine

According to the planting agronomy of Lycium barbarum L. in Ningxia, a self-propelled straddle-type sprayer was designed. The aim was to reduce the labor requirements, improve the spraying effect to the middle and lower parts of the canopy, reduce the influence of natural wind on droplet drift, and recycle excess liquid medicine to reduce environmental pollution. Tests showed that the coverage rate of liquid medicine on the leaf surface and back of the leaf peaked at 84.2% and 48.3%, respectively, when spraying pressure was high. Under different spraying distances, the coverage rate of liquid medicine on leaf surface and back of leaf reached 73.3% and 38.3% at the shortest distance. The uniformity of the spray droplet distribution was good, the use error was less than 10%, and the excess liquid was effectively recovered.

Download Full-text

Leaf characteristics and surfactants affect primisulfuron droplet spread in three broadleaf weeds

Weed Science ◽

10.1614/ws-05-019r.1 ◽

2006 ◽

Vol 54 (1) ◽

pp. 16-22 ◽

Cited By ~ 16

Author(s):

Debanjan Sanyal ◽

Prasanta C. Bhowmik ◽

Krishna N. Reddy

Keyword(s):

Leaf Surface ◽

Epicuticular Wax ◽

Distilled Water ◽

Weed Species ◽

Spray Droplet ◽

Common Lambsquarters ◽

Leaf Surfaces ◽

Droplet Behavior ◽

Wax Content ◽

Common Purslane

Laboratory studies were conducted to examine the leaf surface, epicuticular wax content, and spray droplet behavior on common lambsquarters, common purslane, and velvetleaf. Adaxial and abaxial leaf surfaces were examined using scanning electron microscopy, and leaf wax was extracted and quantified for all three weed species. The spread of 1-μl droplets of distilled water, primisulfuron solution (without surfactant), primisulfuron solution with a nonionic low foam wetter/spreader adjuvant (0.25% v/v), and with an organosilicone wetting agent (0.1% v/v) was determined on the adaxial leaf surfaces of each of the weed species. Glands and trichomes were present on both the adaxial and abaxial leaf surfaces of velvetleaf. Common purslane had neither glands nor trichomes on either side of the leaf. Common lambsquarters did not have any glands or trichomes, but it had globular bladder hairs on both adaxial and abaxial leaf surfaces. Stomata were present on both adaxial and abaxial leaf surfaces in all three weed species. Common purslane had a much lower number of stomata per unit area of leaf as compared with velvetleaf or common lambsquarters. Common lambsquarters had the highest epicuticular wax content on the leaf surface (274.5 μg cm−2), followed by common purslane (153.4 μg cm−2) and velvetleaf (7.4 μg cm−2). There were no significant variations in the spread of the 1-μl droplet of distilled water and primisulfuron (without adjuvant) among the species. Spread of primisulfuron droplets with surfactant was highest on the leaf surface of velvetleaf that had the lowest wax content. Droplet spread was greatest with organosilicone surfactant followed by the nonionic surfactant.

Download Full-text

Spray Droplet Residual of Glyphosate in Various Carriers

Weed Science ◽

10.1017/s0043174500058161 ◽

1992 ◽

Vol 40 (4) ◽

pp. 576-589 ◽

Cited By ~ 27

Author(s):

John D. Nalewaja ◽

Robert Matysiak ◽

Thomas P. Freeman

Keyword(s):

Calcium Chloride ◽

Leaf Surface ◽

Chloride Salt ◽

Scanning Electron Micrographs ◽

Spray Droplet ◽

Residue Contact ◽

Physical Entrapment ◽

Diammonium Sulfate ◽

Chloride Salts ◽

Crystal Content

Scanning electron micrographs of spray droplet residual on wheat, sunflower, and kochia indicated that salts and various adjuvants applied with glyphosate affected deposit crystal content, thickness, and contact with the leaf surface. Spray deposits of glyphosate applied with diammonium sulfate contained distinct crystals, which related to enhanced toxicity of glyphosate applied alone, or to overcoming antagonism of glyphosate toxicity by calcium chloride, when applied to wheat. In general, glyphosate applied with antagonistic calcium chloride salt formed spray deposits that were amorphous, thick, and without crystals. Glyphosate sprayed with nonantagonistic diammonium sulfate and ammonium chloride salts had deposits with crystals and an evenly spread residue beneath the crystals. The various micrographs indicate that the antagonism of glyphosate phytotoxicity by salts may be in part from physical entrapment of glyphosate in the spray deposit. Glyphosate spray droplet residue contact with wheat, sunflower, and kochia surfaces related to observed differences in glyphosate toxicity to these species.

Download Full-text

SOOTY MOULD DISEASES OF SOME TREES FROM AURANGABAD DISTRICT, MAHARASHTRA (INDIA)

FLORA AND FAUNA ◽

10.33451/florafauna.v23i2pp351-354 ◽

2017 ◽

Vol 23 (2) ◽

Author(s):

NAVALSINGH J. TODAWAT

Keyword(s):

Surface Area ◽

Fungal Pathogens ◽

Leaf Surface ◽

Severity Of Disease ◽

Sooty Mould ◽

Leaf Surface Area

Sooty mould diseases of Tress from Aurangabad district were surveyed. During the survey of tress, 5 species were found infected by fungal pathogens causing sooty mould diseases. Disease is easily identifiable by the presence of a black, velvety growth covering the leaf surface area. The fungus produces mycelium which is superficial and dark grows on the flowers, leaf, stem and sometime on fruits also. The severity of disease depends on the honeydew secretions by insects. The diseases were found to be caused by 5 species of fungi viz. Capnodium anonae, C. ramosum, Capnodium sp., Meliola bangalorensis and Meliola ranganthii.

Download Full-text