Onion (Allium cepa L.) purple blotch caused by Alternaria porri (Ellis) Cif. is a disease of world-wide importance. The aim of this study is to evaluate the effectiveness of treatment combinations with fungicides and plant-based pesticides in the control of A. porri, onion growth and bulb production. To do so, the effect of aqueous extracts (5%, 10%, 15%) of Lippia multiflora, Azadirachta indica and the fungicides Mancozeb 80 WP (1g/L) and Azoxystrobin 250 SC (0.2%) on the radial growth of A. porri on Potato Dextrose Agar (PDA) medium was assessed. Furthermore, the onion variety «Prema» was used in field in a Fisher block design with four replicates. The treatments included the following: (i) the application of foliar sprays with distilled water (control), Mancozeb at 2 kg/ha and Azoxystrobin (1L/ha); (ii) the ground application of plant leaf powder (400 g/m2) at seven days before transplanting, which was then followed by the application of aqueous plant extracts and fungicides as foliar sprays. Sprays were carried out at 60, 80 and 100 days after transplanting. The results show that treatments inhibited the growth of A. porri from 25.35 to 100%. Furthermore, bulb yields in the plots treated with plant powders, ranging from 35 to 43.25 t/ha, exceeded that of the fungicide Mancozeb, which was 28.75 t/ha. From these findings, soil and leaf treatments with plant extracts may be used in the control of onion purple blotch disease. Nevertheless, it is essential to study the effects of plant extracts on soil fauna and microorganisms.

The objective of this study was to evaluate, in a semi-controlled environment, the resistance of twelve (12) new rice genotypes (KBR2, KBR4, KBR6, KBR8, KBR9, KBR11, KBR12, KBR13, KBR15, KBR17, KBR28, KBR42) to rice blast caused by Magnaporthe oryzae in Burkina Faso. The experimental design used was a randomised block with three (03) replications. The parameters assessed were leaf and panicle severity, leaf and panicle incidence, yield per pot and percentage yield loss. The results showed that genotypes KBR11, KBR15 and KBR42 were resistant to medium resistance to blast, with values ranging from 7.7% to 15% of leaf area diseased and from 14% to 24.07% of panicles diseased. These genotypes recorded the best yields per pot of 60.32g/pot, 65.97g/pot and 60.43g/pot respectively, with relatively low yield losses. Genotypes KBR11, KBR15 and KBR42 were resistant to medium resistance to leaf and panicle blast with high yield performance and relatively low yield loss rates. These genotypes can be used to control rice blast in rice fields in Burkina Faso. They therefore need to be improved and made more widely available. This will require the support of agricultural research, extension services and farm advisory services.