Natural mollusc repellents and molluscicides based on Somali oleoresins

Abstract: The Somali oleoresins, commonly known as frankincense (Boswellia carteri), myrrh(Commiphora molmol) and opoponax (Commiphora guidotti), were evaluated for their potentialas natural slug control agents. Split substrate assays were used to compare the effect of variousvarnish paint formulations, containing Somali oleoresins and a chemical component, onDeroceras reticulatum slugs. Paints containing frankincense or a chemical component fromopoponax (CDF1) demonstrated high incidences of slug death or paralysis. In contrast, varnishpaint containing opoponax oleoresin showed no molluscicidal or sub-lethal activity but displayedsignificant slug repellence properties. Myrrh, formulated as a topical foliar spray, was applied atvarious application rates to a field planted with a crop of pansy flowers. The optimum application(20ml/L), significantly reduced the feeding activities of Deroceras spp. and Arion spp. slugs. Thespray also significantly reduced plant damage to levels comparable to those observed withcommercial Metaldehyde based pellets. After fourteen days, no signs of phytotoxicity andnegligible levels of slug mortality were observed. This study validates the use of Somalioleoresins as an alternative means of controlling slugs both in home and garden and fieldsituations.