The Normandy cliffs studied in this paper correspond to the north-western termination of the Paris sedimentary basin. The latter is characterized by the existence of more or less high, undulating and sometimes faulted plateaus, explaining the lithostratigraphic diversity of the outcrops, and the variety of types of cliff falls and gravitational landslides encountered. These plateaus are carved into cliffs with much faster retreat due to the outcropping of sedimentary formations (from the Jurassic to the Upper Cretaceous) favorable to weathering. Spatial and temporal variations of Norman sedimentary cliff retreat rates over multi-temporal data are examined. Data are derived from historical maps and air photographs but also from recent lasergrammetric and photogrammetric monitoring. These latter measures are on specific sites monitored at high frequency and resolution. The diachronic analysis of all these data gives retreat rates in line with the international literature, 0.2-0.3 m/yr. The spatial variations of the cliff retreat rates, at the Normandy scale, can be explained by geological structure, especially at the cliff foot, but also by the influence of cliff collapses or anthropogenic obstacles that disrupt the longshore drift (rates can be multiplied by 2). The contribution of the recent lasergrammetric and photogrammetric techniques shows along the Norman cliffs (1) the spatial distribution of the retreat or evolution rates on the cliff face. For chalk cliff of Seine Maritime, the ablation rate evaluated by TLS (Terrestrial Laser Scan) on active cliffs over a period of 7 years corroborates that established by photo-interpretation (observed over nearly 50 years), i.e. around 36 cm/year for the cap d'Ailly and almost zero for the abandoned cliffs of Dieppe; scree movements (debris falls) represent 100% of the evolution of the abandoned cliff faces while they account for 2% of the total retreat of the active cliff of cap d'Ailly. About the rhythms, multi-temporal data shows that the temporalities evolution of cliff extends from 1 to 7 decades according to the lithology. The high resolution and frequency monitoring provide also some information about the factors responsible for triggering gravitational landslides (rockfall, slide, debris fall). For the cliff characterized by landslides (Villerville et Vaches Noires), which are under the dominating influence of the rainfall and the groundwater level evolution, the study proposed a regional warning, especially in cases in which the piezometer of the site exceed a depth of 11m (Groundwater Level) and the effective rain on a 4months-period is over 250 mm. In this respect, and for chalk and limestone cliffs, the monitoring is inconclusive, because the origin of evolutions is more multifactorial.

Sheath blight caused by Rhizoctonia solani Kuhn [Thanatephorus cucumeris (Frank) Donk], occurs throughout the temperate and tropical rice growing regions. Rice sheath blight was considered as a minor disease in earlier days, but now it is regarded as an internationally important disease second only to rice blast. Use of fungicides with a broad spectrum of activity against more than one disease is common in rice. The foliar spray of fungicides is the single most effective method for the management of sheath blight disease. The bio efficacy of various fungicides like Carbendazim 50 per cent WP, Mancozeb 50 per cent WP, Benomyl 50 per cent WP, Copper oxychloride 50 per cent WP, Edifenphos 50 per cent EC, Iprobenphos 50 per cent EC and Hexaconazole 5 EC were used to test against the R. solani by Poisoned food technique and Mycelial dry weight is analyzed. All the tested fungicides registered appreciable inhibition in colony growth and mycelia dry weight. Among the eight fungicides, Hexaconazole 200 ppm and 400 ppm were completely inhibiting the mycelial growth of R. solani. Among the fungicides, Hexaconazole showed the highest level of inhibition and recorded 49.3 mg mean of mycelial dry weight. The result of the experiment revealed the superiority of Hexaconazole in the control of R. solani, hence the same was used for further studies.

Plasmopara viticola and Uncinula necator are the causative agents of downy mildew and powdery mildew diseases, respectively, which become a major problem in grape crop (Vitis vinifera L.). The use of natural products such as seaweed provides a rich source of structurally diverse and biologically active secondary metabolites; and is the ultimate way of combating these diseases. In this context, six different seaweed algae such as; Sargassum wightii, Padina gymospora, Caulerpa peltata, Halimeda gracilis, Acanthophora spicifera and Gracilaria opuntia; were used to control the downy and powdery mildew diseases of grapes. Enzymatic studies were carried out during two growing seasons 1 and 2 on peroxidase; polyphenol oxidase, phenylalanine ammonia lyase and β-1,3glucanase. During season 1; in grape plants treated with Sargassum wightii, the four enzymes raised the glucose concentration to 60.79µg, 3.87µg, 5.20µg and 225.5µg; respectively, and then these plants were treated with Bordeaux mixture at 1%. After seaweed application; enzymes raised the glucose level to 59.83µg, 3.57µg, 5.17µg, 221.7µg. During season 2; when plants were treated with Sargassum wightii, the enzymes raised the glucose concentration to 62.48µg, 5.93µg, 7.25µg and 226.2µg, and then these plants were treated with Bordeaux mixture at 1%. After application; the enzymes raised the glucose level to 61.92µg, 3.57µg, 7.21µg and 224.2µg, respectively. During both seasons; β-1,3-glucanase released more amounts of glucose in both normal plants and those treated with Bordeaux mixture. The present study was undertaken to evaluate whether various extracts of seaweeds algae such as; brown, red, and green seaweeds along with the defence enzymes studied, would increase the resistance of grapes to downy and powdery mildews.

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