New Insights on the Role of Allyl Isothiocyanate in Controlling the Root Knot Nematode Meloidogyne hapla

Abstract

Biofumigation, although a well-known method, is still controversially debated as a management strategy for plant-parasitic nematodes (PPN). Its controlling effect is attributed to the production of isothiocyanates (ITCs) following the action of myrosinase on glucosinolates (GSLs). Different ITCs are formed from different GSLs, depending on the plant species. To better understand the potential of ITCs, eight cultivars from three Brassicaceae species were investigated as biofumigation crops to control the root knot nematode Meloidogyne hapla. Since results were inconsistent, the nematicidal effect of selected ITCs were further evaluated in vitro. Based on its nematicidal potential, allyl ITC (AITC) was specifically investigated under different soil:sand compositions. A significantly lower nematicidal activity was observed in soil compared to sand. AITC was also evaluated as an additive to the biofumigation in a greenhouse trial. Its supplementation to the biofumigation process with Brassica juncea cv. Terrafit controlled M. hapla, while no control was observed using Raphanus sativus cv. Defender. Thus, the success of biofumigation seems to be strongly dependent on the soil characteristics and the ITC produced during the biofumigation process. Therefore, the supplementation of AITC in combination with the right cover crop can improve the biofumigation process to control M. hapla.

Changes in the Plant β-Sitosterol/Stigmasterol Ratio Caused by the Plant Parasitic Nematode Meloidogyne incognita

“…ITCs are highly toxic, leading to a suppressive effect of Brassica species on soil-borne pathogens and herbivores [ 36 ]. Therefore, Brassica species including B. juncea are used as cover crops in PPN management via so-called bio-fumigation [ 37 , 38 ]. Nevertheless, B. juncea is a host of M. incognita [ 39 ].…”

Polysulfides Applied as Formulated Garlic Extract to Protect Tomato Plants against the Root-Knot Nematode Meloidogyne incognita

“…As soil can have a crucial effect on nematicidal activity [ 6 , 14 ], the controlling effect of NEMguard ® DE against M. incognita was further tested in small pots using silver sand:soil mixture. Our results revealed that the single application of NEMguard ® DE, as recommended by the supplier [ 14 ], reduced root galling on tomato plants, 31 days after M. incognita inoculation ( Table 2 ).…”

“…Although most chemical nematicides show high nematicidal efficacy under field conditions, their impact on human health and on the environment has resulted in enforced regulation or the total ban of the different products [ 3 ]. To control plant-parasitic nematodes, grafting, biofumigation, heat treatment, soil compost and crop rotation with poor hosts, catch crops or antagonistic microorganisms have been intensively studied [ 4 , 5 , 6 ]. However, further management methods, such as plant-based metabolites are being investigated to search for alternative human and environment friendly biopesticides [ 3 , 7 ].…”

Deciphering the Behavioral Response of Meloidogyne incognita and Fusarium oxysporum Toward Mustard Essential Oil

“…Lower values of all these parameters suggest better interactions. observation was made by Dahlin and Hallmann (2020) during an in vitro bioassay of various isocyanates against M. hapla, where the significant recovery of isocyanate-treated J 2 s from inactive states was observed at a lower concentration. The same study reported that the J 2 s exposed to a low concentration of AITC, after recovery, were still able to cause root galling in cucumbers.…”