Carbofuran granule

CBs have been widely used in agriculture as insecticides, molluskicides, and aca-ricides. They have been applied as sprays and as granules or pellets. Highly toxic compounds, such as aldicarb and carbofuran, are usually only available as granules. 

Table 12.1 Carbofuran and Its Degradation Products (mg/kg dry weight) in Corn (Zea mays) at Silage Stage (117 days) and at Harvest (149 days) Following Application of Carbofuran (10%) Granules at 5.41 kg/ha...

Examples of risk hypotheses given by USEPA (1998) are textual (e.g., birds die when they consume recently applied granulated carbofuran ). Eor a quantitative risk assessment it will be preferable to express risk hypotheses using formal mathematical equations. 

Cultivation treatments of carbofuran (Furadan 15G, 1.12 kg Al/ha) were made four to six weeks after planting, when CRW larvae were actively feeding on corn roots. Plastic tubes, positioned directly in front of the cultivator sweeps, directed the insecticide to both sides of the corn row where soil was thrown over the granules to effect incorporation. For planting-time applications, Furadan 15G (1.12 kg Al/ha) was placed in an 18-cm band in front of the firming wheels and incorporated with a drag chain. 

Two types of carbofuran formulations were tested, a gypsum-based roll-compacted granule manufactured by Union Carbide (Res. Triangle Pk., N. Carolina) and a proprietary controlled-release granule manufactured by Sierra Chem. 

In a second laboratory experiment, the chemical persistence of carbofuran applied as Furadan 10G (the commercial sand-coated granule) and 2 Sierra controlled-release carbofuran formulations (samples no. 32-47-2, 9.1% AI and 32-48-2, 9.7% AI) were monitored for two months in three soil types, no. 29, 46, and 44 (Table I). Three-hundred forty-one grams (300 g oven-dry weight) of each soil were weighed into glass bottles and fortified with 1.5 g of one of the three formulations. The actual rates of application were 455 ppm (no. 32-47-2), 485 ppm (no. 32-48-2), and 500 ppm (Furadan 10G). The soils were thoroughly mixed and adjusted to 25% of MHC. The bottles were sealed with Parafilm and incubated at 25°C. At biweekly intervals, 20-g replicates of each soil were removed for quantitative analysis of carbofuran. 

Controlled-release formulations extended the persistence of carbofuran in soils exhibiting enhanced biodegradation. Owing to the comparatively low susceptibility of CRW larvae to carbofuran, and the apparently very slow release of carbofuran from the Sierra controlled-release granules, carbofuran efficacy at normal... 

Sporadic kills of migratory birds were associated with carbofuran formulations containing 3% a.i. For example, migratory sandpipers died after eating Furadan 3G granules (3% a.i.) applied to rice crops in Texas. The granules... 

Waterways and flood areas can be contaminated with pesticides, especially insecticides, and result in bird deaths (Hxmt et al., 1995 Elliott et al., 1996). Granules of carbofuran in flooded fields have been incriminated as the cause of duck deaths and the cause of death in raptors scavenging dead or debilitated ducks. Illegal use of insecticides resulting in the death of wildlife has also been reported (Allen et al., 1996). Rodenticides have been used to control unwanted rodents and caused collateral deaths (Ruder et al., 2011). The toxicology of pesticides has recently been reviewed (Poppenga, 2012 Gupta, 2012). 

A coated granule containing a solid (carbofuran) and a liquid (diazinon) insecticide is to be prepared. The solid inseeticide is ground to a fine powder the liquid inseeticide is sprayed onto an absorbent silica. A combination of two adhesives is used. Granular (0.4-0.8 mm) quartz is first sprayed with a liquid polyurethane while tumbling the quartz in a shell blender. Once the mass is wetted the inseetieide powders are added. After tumbling the mass to adhere the powders, an aqueous solution of polyvinyl alcohol is sprayed onto the surface. In order to set the adhesive the mass is transferred to a drier and heated to about 60°C. 

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