Chitosan as Source for Pesticide Formulations

Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium solani f. sp. eumartii, respectively, are severe diseases in Solanaceae crops worldwide. Although traditional approaches to control plant diseases have mainly relied on toxic chemical compounds, current studies are focused to identify more sustainable options. Finding alternatives, a low molecular weight chitosan (LMWCh) obtained from biomass of Argentine Sea’s crustaceans was assayed. In an attempt to characterize the action of LMWCh alone or in combination with the synthetic fungicide Mancozeb, the antimicrobial properties of LMWCh were assayed. In a side-by-side comparison with the SYTOX Green nucleic acid stain and the nitric oxide–specific probe, diaminofluorescein-FM diacetate (DAF-FM DA), yielded a similar tendency, revealing LMWCh-mediated cell death. The efficacy of LMWCh, Mancozeb, and the mixture LMWCh–Mancozeb was in turn tested. A synergistic effect in the reduction of F. eumartii spore germination was measured in the presence of subinhibitory dosis of 0.025 mg ml−1 LMWCh and 0.008 mg ml−1 Mancozeb. This mixture was efficient to increase the effectiveness of the single treatments in protecting against biotic stress judged by a drastic reduction of lesion area in P. infestans–inoculated tissues and activation of the potato defense responses

Fundamentals and Applications of Chitosan

International audienceChitosan is a biopolymer obtained from chitin, one of the most abundant and renewable material on Earth. Chitin is a primary component of cell walls in fungi, the exoskeletons of arthropods, such as crustaceans, e.g. crabs, lobsters and shrimps, and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians. The discovery of chitin in 1811 is attributed to Henri Braconnot while the history of chitosan dates back to 1859 with the work of Charles Rouget. The name of chitosan was, however, introduced in 1894 by Felix Hoppe-Seyler. Because of its particular macromolecular structure, biocompatibility, biode-gradability and other intrinsic functional properties, chitosan has attracted major scientific and industrial interests from the late 1970s. Chitosan and its derivatives have practical applications in food industry, agriculture, pharmacy, medicine, cos-metology, textile and paper industries, and chemistry. In the last two decades, chito-san has also received much attention in numerous other fields such as dentistry, ophthalmology, biomedicine and bio-imaging, hygiene and personal care, veterinary medicine, packaging industry, agrochemistry, aquaculture, functional textiles and cosmetotextiles, catalysis, chromatography, beverage industry, photography, wastewater treatment and sludge dewatering, and biotechnology. Nutraceuticals and cosmeceuticals are actually growing markets, and therapeutic and biomedical products should be the next markets in the development of chitosan. Chitosan is also the N. Morin-Crini (*) · Laboratoire Chrono-environnement, UMR 6249, UFR Sciences et Techniques