Beaches are major sites of microbiological pollution. Assessment of the abundance of resistant forms of enteric protozoa on these recreational waters is important for the prevention and management of health risks. Based on sedimentation and flotation methods, this study found that Kribi beach waters concentrate considerable amounts of enteric protozoa, which are potentially pathogenic. They include Coccidia (Cryptosporidium sp. and Cyclospora cayetanensis), Amoebae (Endolimax nana, Entamoeba histolytica and Entamoeba coli) and Flagellates (Giardia intestinalis). In general, seasonal changes and tidal cycles have significantly impacted the spread of these parasites along Kribi beaches. Thus, at all sites surveyed (Mpalla, Ngoyè and Mboamanga), maximum protozoan abundances were recorded at low tide and during the rainy seasons. It should also be noted that at each sampling site, significant correlations were recorded between certain protozoa and certain physico-chemical variables (p < 0.05). At Mboamanga, for example, Cryptosporidium sp. and Endolimax nana were positively correlated during the Short Rainy Season with temperature (r = 0.601, p = 0.044 and r = 0.632, p = 0.042). At Mpalla, a positive and significant correlation was observed during the Short Rainy Season between Entamoeba coli and pH (r = 0.605, p = 0.033). The high concentration of resistant forms of these enteric protozoa at Kribi beaches is a real public health threat for bathers. Therefore, in this tourist town, it is urgent to put in place an effective plan for the collection and sustainable treatment of solid and liquid waste, which are the main sources of contamination.

The present study aims to determine the effect of harvest date on the germination of rice seeds. The experiment was carried out at Nkol bisson, a locality within the forest agro-ecological zone characterized by a bimodal rainfall pattern. Four varieties of NERICA: NERICA 3, NERICA 8, NERICA 9 and 13 NERICA widely grown in Cameroon were used and planted in a completely randomized block design. Rice seed was produced according to the standards of its production and were harvested at six different dates: 20, 25, 30, 35, 40 and 45 days after heading. The harvested seeds were dried at 13% moisture content.The results showed that the harvest dates have a significant effect on the latency, the time corresponding to 50% sprouted grains (T50), the number of sprouted grains, number of dead seed and the number of non-sprouted grains. There was significant difference between rice varieties evaluated and the different harvesting date. The germination rates 98.88%, 99.44%, 99.75% and 97.00% were obtained respectively for the harvest dates of 30, 35, 40 and 45 days after 50% heading. The harvest dates 20 and 25 days after 50% heading presented low germination rates. With these early harvesting dates, the mean percentages of dead seeds ranged between 18.25% and 55.25%. Too early harvest had a negative impact on rice seeds germination. To obtain good germination rate, it is recommend harvesting rice between the ranges of 30 to 40 days after 50% of heading.

The study compares the impact due to rice stem borers in two sites (Yaoundé and Ntui). It also shows the diversity of the African Rice Gall Midge (AfRGM) biotypes in southern Cameroon (Santchou, Ndop, Tonga, Ebolowa, Baïgom, Yaoundé and Ntui). The New Rice for Africa (NERICA) varieties 3, 8, 9 and 13 sown in Ntui were less attacked than those sown in Yaoundé. At both sites, damages ranged from 0.78% to 2.7%. In terms of diversity, the main stem-borer species were O. oryzivora, Diopsis apicalis, D. longiconis and Chilo zacconius. Molecular analyses of Orseolia oryzivora larvae collected in the localities of Santchou, Ndop, Tonga, Ebolowa, Baïgom and Yaoundé showed the existence of more than one O. oryzivora biotype in southern Cameroon's rice basins.