Diallyl disulfide is a reduction decomposition product of allicin (known also as garlicin) and is a major component of garlic, as well as wasabi. It has pesticidal applications in organic farming.
The U.S. Environmental Protection Agency has approved of branded products (which diallyl disulfide as a major ingredient) for the treatment of white rot in onions, garlic, and leek crops, with no "unreasonable adverse effects to humans or the environment" from accumulated exposure.  However it was not recommended for usage on surface soil, but instead a shanking method was recommended "inject the product directly into the soil at a low use rate" to prevent exposure. It has been suggested that diallyl disulfide potentially has a much wider array of antimicrobial, nematicidal, insecticidal, fungicidal, and other diverse anti-pathogenic activity as well.    
Studies on diallyl disulfide usage in crops with sprinkler irrigation systems found that the diallyl disulfide had limited soil mobility due to its volatility and liability to decompose rapidly (into byproducts like allyl methyl sulfide) when exposed to the elements. Its efficacy in avoiding unwanted environmental exposure was superior to the organic pesticide cinnamaldehyde by this measure. 
For agricultural application it is recommended not to use pure diallyl disulfide, due to its volatility in concentrated form, but rather to dilute it in a solution for usage. This compound is sold in volumetric units of measurement and comes as a liquid in a vial. For reference, the density of this chemical is 1.01 g/mL. This product is not for human consumption and is strictly for research purposes only.
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 - López-Serna, Rebeca, et al. “Analysis of cinnamaldehyde and diallyl disulfide as eco-Pesticides in soils of different textures—a laboratory-Scale mobility study.” Journal of Soils and Sediments, vol. 16, no. 2, Feb. 2015, pp. 566–580., doi:10.1007/s11368-015-1249-5.