Crop spraying

Uses. Tetrahydrofurfuryl alcohol is of interest in chemical and related industries where low toxicity and minimal environmental impact are important (134). For many years tetrahydrofurfuryl alcohol has been used as a specialty organic solvent. The fastest growing appHcations are in formulations for cleaners (135) and paint strippers (136), often as a replacement for chlorinated solvents (137). Other major appHcations include formulations for crop sprays, water-based paints, and the dyeing and finishing of textiles and leathers. Tetrahydrofurfuryl alcohol also finds appHcation as an intermediate in pharmaceutical appHcations. 

Approximately 5% of the U.S. consumption of is in agriculture. Boron is a necessary trace nutrient for plants and is added in small quantities to a number of fertilizers. Borates are also used in crop sprays for fast rehef of boron deficiency. Borates, when apphed at relatively high concentration, act as nonselective herbicides. Small quantities of borates are used in the manufacture of alloys and refractories (qv). Molten borates readily dissolve other metal oxides usage as a flux in metallurgy is an important apphcation. Other important small volume apphcations for borates are in fire retardants for both plastics and ceUulosic materials, in hydrocarbon fuels for fungus control, and in automotive antifreeze for corrosion control (see Corrosion and corrosion inhibitors). Borates are used as neutron absorbers in nuclear reactors. Several borates, which are registered with the Environmental Protection Agency (EPA) can be used for insecticidal purposes, eg, TIM-BOR. 

Studies of carrot and tomato crops sprayed with endosulfan 2 to 8 days prior to harvest showed that more pesticide remains in the pulp than in the juices of these vegetables. Washing and peeling the vegetables lowered the endosulfan concentration considerably (Burchat et al. 1998). 

The first commercially available HCH insecticide sometimes misleadingly called benzene hexachloride (BHC) was a mixture of isomers, principally alpha HCH (65-70%), beta HCH (7-10%), and gamma HCH (14-15%). Most of the insecticidal activity was due to the gamma isomer (Figure 5.1), a purified preparation of which (>99% pure) was marketed as lindane. In Western countries, technical HCH was quickly replaced by lindane, but in some other countries (e.g., China) the technical product, which is cheaper and easier to produce, has continued to be used. HCH has been used as a seed dressing, a crop spray, and a dip to control ectoparasites of farm animals. It has also been used to treat timber against wood-boring insects. 

Crop Spray - Applying Agricultural Chemicals - Spray Irrigation... 

Mercury amalgam, crop spraying, and an ancient electrical fire extinguisher these are some of my top sus-... 

These devices usually are used to apply contact herbicides to weeds which are taller than the crop in which they are growing. Solid streams of highly concentrated herbicides are directed across rows above the crop. Spray material which is not intercepted by the weeds is caught in a box or sump on the opposite side of the row and is recirculated. 

Halterman. D.R. (1994a). Piperonyl Butoxidc Analytical Phase for Pyrcnone Crop Spray (Pyiethrin + Piperonyl Buioxide) Field Dissipation - Terrestrial Trial Applied to Bare Ground in California, Georgia and Michigan. Landis International Inc., PO Box 5126, 3025 Madison Highway. Valdosta. GA 31603-5126, USA. 

HsULermann. D.R. (1996). Amended Piperonyl Butoxide Analytical Phase on [he Raw Agricultural Commodity Residue Evaluation of Piperonyl Butoxide Pyrclhrins Applied As Fyrenone Crop Spray to Leafy Vegetables, Biological lest Center Pharmaaj LSR International Inc., vol. II. (Protocol No. L8G09A003). Undertaken for the PBO Task Force, Washington IX . USA-... 

Hislop EC, 1983, Crop spraying the need for scientific data, SPAN, 26, 53-55. 

Coffee RA Electrodynamic crop spraying, Outlook on Agriculture, 1 350-356 (1981). 

Militarily, the nerve agents can be delivered as droplet clouds either by bombs from aircraft or by using shells. It would also be possible to deliver them with crop spraying equipment or something similar. 

Pollen ball samples were extracted from nests 5,10, and 27 days following sprays, for residue analysis. No residues of the pyrethroid could be detected and phosalone concentration decreased from 1 to O.lmg/kg within the 3-week sampling period. Larval mortality was very stable in the four cell samples collected when the larval development was completed before treatment 3.5 and 4.8 percent of larvae died in alphamethrin and phosalone samples versus 3.5 and 4.8 percent after treatment, respectively. No residues were detected in live larvae, which means that both molecules were metabolized [36]. Residues of deltamethrin were determined in leafcutting bee provisions collected in a field shelter placed in an alfalfa crop sprayed at the recommended rate. The maximum concentration was... 

The DDT found in the U.S. comes in on fruits and vegetables from Mexico. Sometimes it drifts across the border from Mexican crop spraying or is in the water supply in the border states. Mexico continued to use this chemical to kill mosquitoes that cause malaria. They have now agreed to phase out its use over the next ten years. 

I 6 Genetically Modified Herbicide Resistant Crops Spray atomization... 

Not all constituents of cereals are advantageous for health. Although many nutritionally beneficial components are concentrated in the outer layers of the grain, it may also happen that residues from crop sprays such as pesticides or fumigants from stored grain may remain. This may pose a problem for processors, who must also ensure that these residues do not become concentrated in the products. Other hazards include mycotoxins, which can be dangerous at low levels. 

In describing a solution, it is necessary to do so qualitatively, that is, to specify what the solvent is and what the solutes ate. For example, it has just been seen that HCl gas is the solute placed in water to form hydrochloric acid. It is also necessary to know what happens to the material when it dissolves. For instance, one needs to know that hydrogen chloride molecules dissolved in water form H+ ions and Cl" ions. In many cases, it is necessary to have quantitative information about a solution, that is, its concentration. The concentration of a solution is the amount of solute material dissolved in a particular amount of solution, or by a particular amount of solvent. Solution concentration may be expressed in a number of different ways. Solutions used in technical applications, such as for cleaning, are often made up of a specified number of grams of solute per 100 mL of solvent added. On the other hand, a person involved in crop spraying may mix the required solution by adding several pounds of pesticide to a specified number of barrels of water. 

The behavior of fertilizers in relation to crop-spraying aircraft is examined by Marshall and Neubauer (1955), who rate copper or cobalt sulfides (either on their own or in superphosphates) as unsuitable for use with galvanized steel equipment. Ammonium phosphate (measured corrosion rate 250 p,m/year) and nitrolimes (corrosion rate 300 p,m/year) can be used only with care, for short times. Salt (100 p,m/year) is better, as is calcium phosphate, while chalk and bone meal have little effect on galvanized steel. 

Other common apphcations of colloidal liquids include liquid aerosols, such as those occurring in the areas of environment (fog, mist, cloud, smog), agriculture (crop sprays), manufacturing (paint sprays), medicine (nasal sprays), and personal care (hair spray). 

In crop sprays applied to plants or weeds it is essential that the spray solution wets the substrate completely and in many cases rapid spreading may be required. Again the dynamics of wetting becomes a very important factor. 

The spreading of liquids on substrates is also an important industrial phenomenon, e.g. with crop sprays, which need to spread spontaneously on leaf surfaces to maximise the biological effect. A useful concept introduced by Harkens [1] is the spreading coefficient, which is simply the work done in destroying a unit area of solid/liquid and liquid/vapour interface to produce an area of solid/air interface. The spreading coefficient is simply determined from the contact angle d and the liquid/vapour surface tension lv ... 

DS] Quinn, P.J., Perrett, S.F. and Arnold, A-C. (1986). An evaluation of soya lecithin in crop spray performance- Atomisation. Spray Tech. 235-246. 

Following some evidence that commercial emulsifiers used in crop spraying enhanced the sensitivity of a variety of cultured mammalian cells to some but not all viral infections, Lee et ai [89] studied the phenomenon in more detail. Enhanced sensitivity is not due to increased adsorption of virus it is specifically related to single-stranded RNA viruses and not to double-stranded viruses. The optimum concentration of surfactant is just sub-toxic . The mechanism eluded Lee and his co-workers who conclude it appears probable that the enhancing property is due to some intracellular activity of the emulsifier which either makes successful infection more likely. .. or allows a virus replicative mechanism some additional selective advantage in treated cells as compared to untreated . 

---