Essential Oils and Volatiles as Nematodicides against the Cyst Nematodes Globodera and Heterodera

The cyst nematodes of the genera Heterodera (HET) and Globodera (GLO) are among the most damaging obligate plant parasitic nematodes (PPNs) that parasitize cereals, rice, potatoes and soybean. In the absence of resistant crops, soil fumigation of pesticides provides a good strategy for population control. However, synthetic nematicides can cause negative environmental and public health impacts and are feared to lead to the development of resistance and immunity. The use of essential oils (EOs) could be a viable environmentally friendly alternative, which has been poorly explored on cyst nematodes but has shown very good results on other PPNs. The present work reviews the existing bibliography on the biological activity of EOs against GLO and HET. EOs from Allium sativum, Eucalyptus globulus, and Salvia officinalis were the most active against GLO egg hatching. The EOs extracted from Hyssopus cuspidatus, Kaempferia galanga, Mentha canadensis, Ocimum basilicum, and Valeriana amurensis had the highest activity against HET J2 juveniles. Ethyl p-methoxycinnamate, a phenylpropanoid ester, was the EO volatile with the highest toxicity against HET, showing lower EC50 values than the nematodicide fosthiazate. The study of EOs against cyst nematodes is still preliminary in comparison to other PPNs. Future works must expand this line of research and explore greener practices in cyst nematode pest management