New reduced-risk agricultural nematicides - rationale and review

Abstract

The last decade has seen a sharp increase in nematicide research in the agricultural industry. As a result, several new synthetic nematicides have become available to growers, and several more are expected in the near future. This new interest in nematicides is directly related to the growing demand for safer and more selective products, and the increasing regulatory pressure on many of the traditional nematicides. This has led to a ban of several widely used fumigant (e.g. methyl bromide) and non-fumigant (e.g. aldicarb) nematicides. The loss of traditional nematicides, combined with a lack of replacement products and awareness of the damage that nematodes can cause, has not only raised concern among growers, but has also created new opportunities for the crop protection industry. Nematicides have become a priority, and many companies are now allocating significant research dollars to discover new nematicides. The new nematicides are very different from previous products: (i) they are more selective, often only targeting nematodes, and (ii) they are less toxic, and safer to use. This review article describes these new developments by discussing the challenges that are associated with finding new nematicides, reviewing the nature, characteristics, and efficacy of new nematicides, and discussing the impact they could have on future nematode management.

Impacts of Root-Lesion Nematode (Pratylenchus thornei) on Plant Nutrition, Biomass, Grain Yield and Yield Components of Susceptible/Intolerant Wheat Cultivars Determined by Nematicide Applications

“…The most effective oxime carbamate and organophosphate nematicides tested in this study have been largely withdrawn from world markets. Relatively effective new nematicides with greater specificity to nematodes are being tested for various world markets, among which the most promising are fluensulfone, fluopyram and fluazaindolizine [17,18]. These, and other next-generation nematicides, require thorough testing under field conditions in the environment of the subtropical grain region for effectiveness against P. thornei in wheat and other vulnerable crops.…”

“…Nematicides that are the most water soluble and mobile in soil will likely have the greatest chance of success in this environment. Next-generation nematicides have been selected for low solubility to satisfy regulatory requirements of no leaching [17], and this may result in low efficacy against P. thornei in this region. Similarly, systemic nematicides will have a greater chance of protecting crop root systems against P. thornei than non-systemic nematicides.…”

“…Following this exploratory work with two nematicides at high rates [15], experiments were conducted to test a wide range of nematicides at various rates to assess if economic control of P. thornei in this region is feasible. Many nematicides tested in these experiments have since been withdrawn from world markets for environmental concerns [16][17][18]. In this paper, the comprehensive experimental data collected in association with these experiments are examined to investigate in more detail the effects of P. thornei on nutrient concentrations, uptakes, growth and yield, and yield components of wheat in the environment of the Australian subtropical grain region.…”

“…The results provide new information on the impact of the nematodes on uptake of N and P by young wheat plants and effects on the subsequent wheat growth and components of grain yield. This information is valuable (a) for designing strategies for integrated management of P. thornei on farms, (b) for modifying crop growth models in order to simulate the effects of P. thornei on wheat production in this environment, and (c) for guidance in assessing next-generation nematicides [17][18][19] for potential responses in wheat under field conditions appropriate to the region.…”

Tomato Divinyl Ether-Biosynthesis Pathway Is Implicated in Modulating of Root-Knot Nematode Meloidogyne javanica's Parasitic Ability

“…Root knot nematodes (RKNs) are devastating pathogens of a wide variety of plants, causing substantial annual losses in yield worldwide (McCarter, 2009 ). They also incur the intensive use of toxic nematicides that pose a great threat to human and environmental health (Hague and Gowen, 1987 ; Johnson and Feldmesser, 1987 ; Thomason, 1987 ; Desaeger et al, 2020 ). The consequent withdrawal of frontline nematicides has put a significant dent in our ability to control RKNs, as well as all other plant-parasitic nematodes.…”