Biological Activity of Capsicum annuum Extracts on the Developmental Stages of Mango Fruit Fly Bactrocera dorsalis (Egg and Pupa)

Bactrocera dorsalis and Ceratitis cosyra are the major constraints of the mango sector in Burkina Faso. Various methods are used to control these insect pests, including the use of chemical pesticides, which are expensive for farmers. The overuse of these chemicals leads to environmental pollution, food poisoning and resistance among insects. For this reason, research is increasingly focusing on plant derivatives as an alternative. A study of the biological activity of fractions of organic extracts of one plants, Capsicum annum on the development of B. dorsalis, was carried out under laboratory conditions in Burkina Faso. The plant fractions were extracted using solvents of increasing polarity: n-hexane, ethyl acetate and methanol. The biological activity test on the development of B. dorsalis was carried out in a randomised Fisher block design with 25 treatments in 10 replicates. The active extracts were fractionated using the Nair method and the fractions obtained were tested on the development of B. dorsalis. The highest yield (77.42 %) was observed with toluene and the lowest was observed with methanol (11.70 %). The highest yield (59.44%) was observed with C. annuum in chloroform and the lowest was observed with C. annuum in ethyl acetate (0.13%). The fractionation of the most active extracts (hexanic and ethyl acetate) of C. annum made it possible to obtain fractions which were the subject of insecticidal tests. The methanol and chloroform fractions of C. annuum resulted in the highest hatching rates with respectively 27.1% and 23.02%, i.e. inhibition rates of 67.5% and 72.27% respectively for effects of natural substance fractions on Bactrocera dorsalis eggs after 48 hours of exposure. The methanol fraction of C. annuum resulted in a higher hatching rate of 63.5%, i.e. an inhibition of 36.5%, followed by the toluene fraction of C. annuum (41%), i.e. a reduction 59% compared to the untreated control for effects of natural substance fractions on Bactrocera dorsalis eggs after 72 hours of exposure. The methanol fraction of C. annuum resulted in higher hatching rates of 94%, i.e. a reduction of 6.00%, followed by the methanol fraction of the toluene fraction of C. annuum (80.5%), i.e. reductions of 19.50% compared to the untreated control for effects of natural substance fractions on Bactrocera dorsalis eggs after 96 hours of exposure. The methanol fraction of C. annuum resulted in a higher hatching rate with respectively 99.50%, i.e. a reduction of 0.50%, followed by the toluene fraction of C. annuum 96.00%, i.e. a reduction of 0.50% reduction of 4.00% compared to the untreated control for effects of natural substance fractions on Bactrocera dorsalis eggs after 120 hours of exposure. The toluene, chloroform and methanolic fractions of C. annuum are 100% inhibitors of Bactrocera dorsalis pupation. No pupation took place. So, no emergence of adults was recorded. The toluene, chloroform and methanolic fractions of C. annuum are total inhibitors of B. dorsalis pupation. The fractions tested could be used to combat fruit flies, which are responsible for major economic losses in the mango sector in Burkina Faso.