Spraying broadcast

Spray nozzle type plays an important role in the success of agrochemical application. For broadcast applications to soil, flat fan nozzles should be used. Newer spray tips such as the DG TeeJet, XR TeeJet, Turbo TeeJet and similar nozzles supplied by Lechler and Hardy have provided acceptable results in a number of studies. For a given nozzle type, the lower the application pressure, the larger is the spray droplet size and the less potential for spray drift. Similarly, the closer the boom is positioned to the soil surface, the less is the potential for spray drift." Most applications are made with spray tips having 80° or 110° spray angles and boom heights of about 50 cm above the soil surface. 

Iwata, Y, Carman, G.E., Dinoff, T.M., and Gunther, F.A. Metaldehyde residues on and in citrus fruits after a soil broadcast of a granular formulation and after a spray application to ciUus Uees. J. Agric. Food Chem., 30(3) 606-608, 1982. 

Banding of herbicides is not a new practice. In fact, when herbicides were first introduced for com production, it was common to band herbicides in order to keep herbicide costs low. However, farmers have largely replaced banding of herbicides in corn with broadcast sprays over the entire field. In 1993 in the US Com Belt, 16% of the com acreage was banded (USDA ERS, 1994). The rate of banding was highest in Nebraska (50%) and lowest in Illinois (3%). 

If conservation tillage is practiced, leave at least 30% of the soil covered with plant residues at planting, apply a maximum of 21b a.i./A as a broadcast spray. If the soil coverage with plant residue is less than 30% at planting, a maximum of 1.61b a.i./A may be applied. 

Brush control in established pine stands is nearly always conducted with herbicides. As in site preparation, 2,4,5-T was the primary herbicide used until the injunction against its use in 1979. It was the only herbicide that controlled a variety of brush species without badly damaging pine when broadcast sprayed over plantations. Research has been conducted to establish other effective herbicides for this use. 

The 2,4-DP product is recommended for use in broadcast applications to be sprayed after pines have completed the first growth flush of the season. It is quite effective on oak species. At present another method of application involves directed sprays with knapsack sprayers. 

Figure 11. Carbofuran residue in high volume air samples taken above rice paddies treated by foliage spray (0) or by foliar spray followed by granular broadcast treatment (A) (51) (each point = 8 hr of sampling at 623 L/min)...

Granules are mostly used for application to soil and water. They are useful in variety of insect control situations. Examples include application to the seed bed for seed protection, broadcasting and tilling into the soil for soil insect control, application to growing crops for either foliar or soil insect control, and application to ponds for mosquito control. They are easy to apply and are not as likely to drift as dusts or spray. They have less tendency to adhere to foliage and can thus be applied to soil surface through a canopy of leaves. Researchers often find that when different formulations of a toxicant are compared, the granules perform better. 

The influence of the volatility of a pesticide on measurable indoor air levels is evident by comparing semivolatile chlorpyrifos with nonvolatile permethrin. Room-air concentrations of these two insecticides were found to be comparable (means of 30 and 42p.g/m, respectively) 0-2h after broadcast spraying, but the air levels of permethrin declined so rapidly that nothing ([Pg.109]

Patterson, 1991). Indoor air levels of chlorpyrifos applied as a microencapsulated formulation were measured at 3.1p,g/m 0-2 h after broadcast spraying and 5.2 p,g/m after 24h, compared to 30 and 15 p.g/m, respectively, for the emulsi-liable concentrate (Koehler and Moye, 1995a). After 48 h, levels were still about double for the emulsifiable concentrate application (8.5 p-g/m versus 4.0 pg/m ). 

Matoba, Y., I. Ohnishi and M. Matsuo (1995a). Indoor simulation of insecticides in broadcast spraying, Chemosphere, 30, 345-365. 

The regular flat fan nozzle tip makes a narrow oval pattern with tapered ends. It is used for broadcast herbicide and insecticide spraying at 15 to 60 psi. The pattern is designed to be used on a boom and to be overlapped 30 to 50 percent for even distribution. Spacing on the boom, spray angle, and boom height determine proper overlap and should be carefully controlled. Tips are available in brass, plastic, stainless steel, and hardened stainless steel. 

The flooding (net fan) nozzle delivers a wide-angle net spray pattern. It operates at very low pressure and produces large spray droplets. Its pattern is fairly uniform across its width but not as even as the regular net fan nozzle pattern. If used for broadcast spraying, it should be overlapped to provide double coverage. It is frequently used for applying liquid fertilizers, fertilizer-... 

How to Use You can buy avermectins in spray form to control leafminers and spider mites. Spray both upper and lower surfaces of leaves thoroughh to ensure good coverage. To control fire ants, broadcast the poison bait or apply it to individual ant mounds, according to label instructions. Placing the bait in... 

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