The invention generally relates to mixtures of cinnamaldehyde (cinnamic aldehyde) and allicin (10%) in emulsifiable suspension formulations at ratios ranging from 1:1 to 20:1 for protecting plants from damage by nematodes, fungal pathogens, insects and mites. The nematicidal compositions described are easily flowable, easily mixable in water and have low volatility and exhibit no phytotoxicity. Methods of applying the compositions for agriculture use are disclosed.