Nematicidal activity of a biopolymer chitosan at different molecular weights against root-knot nematode, Meloidogyne incognita

Abstract

Khalil M.S., Badawy M.E.I. (2012): Nematicidal activity of a biopolymer chitosan at different molecular weights against root-knot nematode, Meloidogyne incognita. Plant Protect. Sci., 48: 170-178.The nematicidal activity of four molecular weights (2.27 × 10 5 , 3.60 × 10 5 , 5.97 × 10 5 , and 9.47 × 10 5 g/mol) of a biopolymer chitosan was assayed against the root-knot nematode, Meloidogyne incognita, in vitro and in pot experiments. In laboratory assays, the nematode mortality was significantly influenced by exposure times and chitosan molecular weight. Low molecular weight chitosan (2.27 × 10 5 g/mol) was the most effective in killing the nematode with EC 50 of 283.47 and 124.90 mg/l after 24 and 48 h of treatment, respectively. In a greenhouse bioassay, all the compounds mixed in soil at one-and five-fold concentrations of the LC 50 value significantly reduced population, egg mass, and root galling of tomato seedlings compared with the untreated control. In general, the nematicidal activity of these compounds was increased dramatically with a decrease in the molecular weight. The results suggest that the chitosan at low molecular weight may serve as a natural nematicide.

Potential of chitosan alone and in combination with agricultural wastes against the root-knot nematode, Meloidogyne incognita infesting eggplant

“…Nematicidal concentrations of ammonia in association with newly formed chitinolytic microflora are believed to cause nematode suppressiveness . The application of chitosan seemed therefore to decrease the severity of the disease, probably due to the impairment of nematode reproduction and/or to the induction of physiological alterations in both nematodes and plants (Khalil and Badawy 2012), which did not allow successful reproduction of the nematodes. Chitosan provides possible resistance to plants by exhibiting the elicitor activity through inducing the local and systemic resistance of tomato to the root-knot nematode, M. incognita.…”

Chitosan as a biocontrol agent against the pinewood nematode (Bursaphelenchus xylophilus)

“…For all MWs, the application of chitosan seemed therefore to decrease the severity of the disease, probably due to the impairment of nematode reproduction and/or to the induction of physiological alterations in both nematodes and plants (Khalil and Badawy ), which did not allowed the successful reproduction of the nematodes. In fact, Khalil and Badawy () reported that chitosan treatments as soil amendments against M. incognita reduced the extent of nematode invasion in tomato and eggplant and affected the morpho‐physiological and populational parameters of M. incognita itself. Thus, treatment of PWN‐inoculated P. pinaster plants with chitosan could have impaired the ability of the nematode population to migrate within the plant and to reproduce, resulting in the reduction of nematode numbers, comparing with untreated plants.…”

“…). Moreover, Khalil and Badawy () evaluated the nematicidal activity of different molecular weight (MW) chitosans against M. incognita infecting tomato seedlings and reported that its low MWs had the highest efficiency. Nevertheless, no data regarding the nematicidal activity of chitosans against stem infesting nematodes, such as the pinewood nematode, is available.…”

Effects of the Applications of Chitin and Chitosan on Soil Organisms

“…키틴은 토양 미생물상을 변화시켜 토양 병원균을 억 제하고 (Cretoiu et al, 2014), 키틴분해효소를 분비하는 미 생물을 촉진하여 식물기생성 선충을 감소시키는 효과도 있 다 (Sarathchandra et al, 1996). 키토산도 식물병원성 세 균과 곰팡이를 억제하고 (Cheah et al, 1997;Rabea and Steurbaut, 2010), 식물기생성 선충의 피해를 감소시킨다 (Khalil and Badawi, 2012). 또한, 키토산을 식물에 처리하 면 병원균을 억제하는 물질의 생성을 유도하는 효과가 있다 (Walker et al, 2003).…”