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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Background: Late blight caused by Oomycete Phytophthora infestans remains a huge problem in potato production and one of the most severe crop diseases worldwide. In Cameroon, the populations characterization of this pathogen remain very little known. Aims: This study aims to characterize isolates of P. infestans collected in twelve localities of Highlands zone of Cameroon. Study Design: Twelve localities in three main potato production areas of the Highlands agro-ecological zone (HAZ) in Cameroon were selected for sample collection. The phenotypic parameters of sporangia were measured. The presence of mating types and pathogenicity tests on detached leaflets of two potato varieties (MANATE and CIPIRA) were assessed. Results: A total of 36 isolates were collected. Height (08) Sporangia shape of P. infestans were obtain and 02 new different shape were pip form and oval to ellipsoid. Sporangia length/width ratio ranged from 1.62 to 2.18. Mating types A1 and A2 were present in the studied areas. Pathogenicity test on detached potato leaflets was positive with all the 36 isolates. The isolate HPBT02 from Tsela locality was more aggressive (P<0.05). MANATE variety was more susceptible. Conclusion: The study shows that mating types A1 and A2 of P. infestans exit in Cameroon and the morphology of sporangia varies according to the localities. Molecular characterization is needed.

In the perspective of effective control of diseases and pests of potatoes (Solanum tuberosum), a study carried out in the Highland West Region of Cameroon permitted to evaluate the effect of aqueous extracts of Thevetia peruviana seeds (AETPS) on the development of late blight caused by Phytophthora infestans and the population of insect pests. Two potato varieties (local (V1) and one improved variety "Cipira" (V2) were used. Five treatments: AETPS (T1), Bravo 720 fungicide (T3), Decis 5 EC insecticide (T4), mixture of the three substances (T2) and the control (T0) were tested using a double factorial system with completely randomized blocks. The evolution of the disease, insect population and tuber yield were evaluated and compared according to different treatments. The results show that a main disease identified in field and laboratory was mildew. 88 pests were collected and 9 pest families were identified. The Coccinelidae family was most represented (23, 86%). The incidence and severity of late blight in the field were respectively reduced to 22.77 and 76.05 % by the AETPS at 50 g/l, as the synthetic fungicide (T3). The number of insects decreased after treatment but remained relatively stable in control. The insecticidal power was maximum 1 h after application of the decis contrary to the AETPS of with maximum was between 24 and 48 h. The commercial yields obtained in the AETPS treatment were greater than 7.5 t/ha compared to 0 t/ha obtained in the controls (T0). Extracts of T. peruviana can therefore be used as anti-parasite substances in crop protection.