The culture of cashew (Anacardium occidentale L.) is increasing in the Far North Cameroon. But, the productivity is threatened by the development of diseases in orchads. Therefore, the aim of this study is to identify diseases and pathogens involved in cashew cultivation. The diseases were identified under the basis of the identification keys. The fungal structures were characterized using an optical microscope and the pathogenicity test were carried out. Incidence, severity and prevalence of diseases were assessed in the dry season and the rainy season. Seven diseases and seven pathogens have been identified: anthracnose (Colletotrichum gloeosporioides Penz), pestalotia leaf spot (Pestalotia heterocornis), alternaria (Alternaria solani), drying of buds (Colletotrichum gloeosporioides, Phomopsus anacardii and Curvularia lunata), dieback (Colletotrichum sp. and Lasiodiplodia sp.), blight of leaves (Pestalotia heterocornis and Colletotrichum gloeosporioides) and powdery mildew (Oidium anacardii Noack). Whatever the season; anthracnose, pestalotia leaf spot an drying of buds are diseases with higher incidence (more than 85, 60 and 75% respectively) and higher prevalence. The severity of the diseases varied according to the location and season. Pathogenicity test revealed that all the test fungi were pathogenic to their respective host parts except cashew powder mildew and alternaria. The results of this study represent database for implementation of integrated disease management approaches in Cameroon.

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In August 2020, a disease with symptoms identical to red rust caused by Cephaleuros virescens was found in orchards of mangoes besides orchards of Anacardium surveyed in Maroua and Garoua (Cameroon). The objective of this research was to study this disease with characterizing its causal organism using morphological methods. Mango leaves exhibiting clear symptoms of red rust with pathogen somatic and reproductive structures were used for morphological characterization and identification of the causal pathogen. Leaves were collected based on the symptoms, size and number of lesions associated. The survey results indicate that orange coloured,  small circular lesions were found on the upper leaf surfaces and coalescing in midrib were observed. Circular lesions on the leaves were of varied diameter from 1 to 5 mm with an average of 1.6 (coefficient of variation 34%). Among symptomatic leaves showing lesions, 60% were exhibiting lesions smaller than 2 mm in diameter.  The length and width of sporangiophores and sporangia were 237.62 - 4645.85 × 15.5 μm and 20.6 - 41.32 × 20.6 μm, respectively. Based on the symptoms observed and microscopic morphological studies, the recovered pathogen was identified as Cephaleuros virescens. This is the first report of algal leaf disease on M. indica in Cameroon.

Corn (Zea mays L.) is one of the most widely grown cereals in the world. However, in Cameroon, particularly in the Far North Region, yields remain low because of diseases increasing due to farming practices and climate change. This work aimed to characterize Brown Spot and Stalk Rot of corn and evaluate the susceptibility of two maize varieties to Physoderma maydis in field conditions. Two maize varieties, CMS9015, and CMS8704 were evaluated in a randomized block design. Disease symptoms were observed and described using identification keys. Microscopic characteristics of pathogens were performed using a microscope. Incidence, severity, and areas under disease curve progress (AUIPC and AUSiPC) were calculated.  Brown spot occurred 3 or 4 weeks after sowing (WAS) at the growing stage in CMS8704 variety first, and stalk rot 7 WAS. Brown spot appeared in leaves and is characterized by oval yellowish spots in the leaf blade and brownish spots in the midrid. Stalk rot infects stem nodes and is characterized by brownish spots, leading to the broken stem. The incidence of brown spot increased with time and environmental conditions (rainfall). The highest incidence of Physoderma Brown Spot was recorded with CMS8704 variety 53.06 % against 51.72 % with CMS9015. Severity was respectively 54.40 % and 47.12 % with CMS8704 and CMS9015. The incidence and severity of stalk rot were almost identical in both varieties. AUIPC of PBS and PSR was higher in CMS9015 than in CMS 8704, 63 DAS. PBS and PSR infect maize production, and both varieties are susceptible to P. maydis.

This study aims to evaluate the effect of ethanolic extracts of Balanites aegyptiaca, Melia azedarach and Ocimum gratissimum leaves as bioinsecticide in the preservation of cowpea seeds (Vigna unguiculata) against the pest Callosobruchus maculatus. The extracts were obtained by maceration of leaves powdersin ethanol (95%). These extracts were then used to achieve anti-insecticides tests in jars at doses of 10, 15, 25 and 50% compared to a reference compound (Stargrain). The weevils rearing and some biological tests were conducted in laboratory conditions at a temperature of 29.1°C and a relative humidity of 74%. The results showed that these extracts have anti-oviposition activity and ovicidal dose-dependent. Doses 25 and 50% of Melia azedarach and Ocimum gratissimum have completely inhibited the spawning activity of C. maculatus 24 h after treatment. There was significant difference (p<0.05) between oviposition due to the positive control (Stargrain) and that due to dose 50% of the three extracts. Compared to the negative control (ethanol 95%), all these plant extracts have significantly reduced (p<0.05) oviposition of C. maculates female (38 eggs per 100 seeds after 4 days). The dose 10% of B. aegyptiaca and 50% of O. gratissimum showed no weevil emergency. It have been also noticed a reduction in seeds depreciation and rate attack in all the treated settings compared to the control. So the rate attack and the mass loss were proportional to the doses of B. aegyptiaca leaves extract but conversely proportional to doses of Melia azedarach and O. gratissimum leaves extracts. No depreciation of seeds was recorded at doses 10 and 15% of B. aegyptiaca and 50% of O. gratissimum. The different treatments did not affect the germination of seeds; the highest germination rate (93.67%) was recorded with seeds treated with the dose 50% of O. gratissimum against only 65% with those treated with the positive control. These ethanolic extracts have shown insecticidal effect against C. maculatus and can alternatively use for the cowpea seeds preservation.