Synthetic Nematicides in Italy: Past and Present Role in the Management of Plant Parasitic Nematodes and Future Perspectives of Control

Although plant damages caused by phytoparasitic nematodes has been known at world level since the second half of the 19th century, the most effective methods for their management were discovered only in the past century. At first, plant parasitic nematodes (PPN) were controlled by the same products used against insect pests (carbon disulfide, chloropicrin, methyl bromide), but since 1940, with the discovery of the nematicide activity of the soil fumigant DD (dichlopropane-dichloropropene), chemical nematicides played a pivotal role in increasing the yield of many agricultural crops. In the second half of the past century and especially during its last two decades, the high demand from the farmers for chemical products having immediate nematicidial activity stimulated the interest of many chemical companies in patenting and marketing an increasing number of new chemical products. They were both fumigants (methyl bromide, chloropicrin, dibromoethane, bromochloropropane, dichloroethane, dichloropropane, dichloropropene, dazomet, metam sodium, metam potassium, methyl isothiocyanate, dimethyldisulfide) and non-fumigants (aldicarb, abamectin, benfuracarb, cadusaphos, carbosulfan, carbofuran, benfuracarb, fosthiazate, fluopyram, fenamiphos, ethoprophos, oxamyl, iprodione, thionazin). In the meantime, awareness increased about the negative impact of plant protection products were having on the environment and the need to regulate their approval and use in the European Union (EU). This resulted in a number of EU decrees adopted by all member States to restrict the marketing and use of these products. This led to a drastic reduction in p.a. nematicides on the market, which are already in limited numbers compared to fungicides and insecticides. In this phase of transition towards eco-sustainable agriculture, as alternative products are not yet available for all crops and for all the different species of parasitic nematodes, agricultural operators are having considerable difficulties. The future of the market for synthetic nematicides is not promising. Today, only a handful of active ingredients (dazomet, metam sodium, metam potassiium fenamiphos, fosthiazate, fluopyran, abamectin) are registered in EU. However, studies are underway to search for less polluting products, such as plant extracts, volatile organic compounds, and nano-formulations. The use of these products should be integrated with the implementation of appropriate crop systems, the use of cover crops, soil amendments, rigorous sanitation practices, and resistant planting material, obtained both by conventional and modern technique, for a sustainable control of PPN. Key Words: nematicides, nematode control, chemical products