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Fruit flies are significant insect pests, worldwide. Tephritid species diversity and their seasonal abundance were investigated over 2 yr (May 2017 to May 2019) in Western Burkina Faso. A mass trapping experiment consisting of 288 Tephri Trap types, operating with four types of parapheromones comprising methyl eugenol, terpinyl acetate, trimedlure, and cue lure and an insecticide (Dichlorvos), was used for attracting and killing insects. Plant formations including natural fallows, mango orchards, and agroforestry parks in each of the six study sites were selected for data collection. Twenty-nine tephritid species belonging to 10 genera were identified. Fourteen fruit fly species were identified for the first time in Burkina Faso. The genera Ceratitis MacLeay (Diptera : Tephritidae) and Dacus Fabricius (Diptera: Tephritidae) with, respectively, 14 and 7 species recorded were the most represented. The dominant species caught was the invasive Bactrocera dorsalis Hendel (Diptera: Tephritidae) followed by Ceratitis cosyra Walker (Diptera: Tephritidae) and Ceratitis silvestrii Bezzi (Diptera: Tephritidae). The fruit fly population density was very high during the rainy season, with peaks occurring in June or July. The fruit fly species were generally more abundant during the hot and rainy seasons than during the cold and dry seasons. The highest diversity was recorded in natural fallows, as compared with the mango orchards and agroforestry parks. Tephritid species found refuge in the mango orchards during the dry and cold periods. The results of that investigation may be used for developing a sustainable pest management strategy for commercial orchards.

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In Western Burkina Faso, the host range of fruit flies was evaluated in three plant formations between May 2017 and April 2019. Samples of 61 potential hosts were collected and incubated for fruit fly emergence. Twenty-seven hosts including cultivated and wild fruit were identified. Among cultivated fruit species, mango, and guava were the most infested while high infestation incidences were observed in the fruit of the indigenous plants Vitellaria paradoxa, Annona senegalensis, Sarcocephalus latifolius, and Saba senegalensis. Low infestation rates were observed in Anacardium occidentale, Citrus species, Opilia celtidifolia, and Cissus populnea. The highest infestation index (1648.57 flies kg−1) was observed from V. paradoxa. Eleven new host fruit infested with many fruit fly species are reported in Burkina Faso. A total of 18 fruit fly species were reared; Bactrocera dorsalis (42.94%), Ceratitis cosyra (29.93%), and Ceratitis silvestrii (22.33%) dominated those that emerged. Four fruit fly species have been detected for the first time in Burkina Faso. The main suitable fruit hosts are abundant and available from May through August during the rainy season and become rare and have low infestation from November to April during the dry season. This is the first study of its kind in the region. This study shows that the three plant formations had an impact on population dynamics of the three tephritid species of economic importance in Western Burkina Faso. This information should be integrated into the development of a fruit fly pests management strategy.

Fruit flies (Diptera: Tephritidae) are one of the insect groups that menace the horticultural sector in sub Saharan Africa. The main fruit fly species that caused mango fruits (Mangifera indica L.) damage in Western Burkina Faso include Bactrocera dorsalis Hendel and Ceratitis cosyra Walker. This work was carried out in Western Burkina Faso to study the relationships between these two insect pests on mango fruits in mango orchards. Thirty mango fruits per variety were sampled in six mango orchards every two weeks during two consecutive mango seasons (2017 and 2018). Each mango fruit was incubated individually for the emergence of adult fruit flies. Bactrocera dorsalis accounted for 66.30% of fruit flies reared from mango fruits and C. cosyra was represented by 33.52% of adult flies. Among mango fruits infested by fruit flies, 53.50% were attacked only by B. dorsalis, 22.14% by C. cosyra and 20.35% were infested by both species. In the mango fruits co-infested, 54.03% of adults belonged to B. dorsalis and 45.96% of adults were individuals of the C. cosyra species. The infestation rates of C. cosyra were higher at the beginning of the mango season while those of B. dorsalis were zero, and vice-versa at the end of mango season. This study highlights the relatively stable coexistence between these two major insect pests of mango fruits in mango orchards in Western Burkina Faso.

Vitellaria paradoxa, known as Shea tree or karité, is one of the dominant trees of agroforestry parklands in Sahelian region with an immense commercial value. In this study, we examined infestation of fruit-bearing shoots and fruits on two sites in western Burkina Faso across different reproductive phenophases, crown heights and aspects. The number of infested and healthy shoots and fruits were counted on 60 reproductively active trees randomly selected from on-year shea trees in each site, using a metal frame (0.5 · 0.5 m) to mark a fixed area of the canopy for sampling. The shoot and fruit borer was identified as Salebria sp. (Lepidoptera:Pyralidae), which was not reported earlier. The proportion of infested trees and shoots varied significantly between sites and among reproductive phenophases (P \ 0.0001). The site close to the natural forest had the highest infestation rate than distantly located site. Among reproductive phenophases, the proportions of infested trees and shoots were the highest during flowering and fruit set, respectively. Fruit infestation also varied significantly between sites, crown heights and aspects (P \ 0.001). The site close to the natural forest and the crown with north-east aspect were heavily infested while the bottom part of the crown had the lowest infestation. As a whole, 49-80% of trees, 24-31% of shoots and 4-15% of fruits were found infested, depending on the site. These infestation levels combined with precocious flower and fruit abscissions would pose serious economic losses that justify a call for immediate pest control initiatives.

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The effect of the hyphomycete Paecilomyces fumosoroseus (Wise) Brown & Smith on the predatory and parasitic activity of Aphelinus asychis Walker, a common parasitoid of the Russian wheat aphid, Diuraphis noxia (Mordvilko), was investigated under three different humidities. Three cohorts of 20 female A. asychis were treated with 5.2 x 10(4) spores/cm² (twice the LD95 for D. noxia). Each female was then individually maintained in a ventilated Petri dish in which were placed three barley leaves and 20 third-instar D. noxia. Cohorts of 20 treated females were each held at one of the following relative humidities along with an equal number of untreated control insects: 67-73%, 85-89%, and 94-98%. Every 24 hours over a period of one week, the surviving parasitoids were transferred into a new Petri dish provided with fresh leaves and 20 aphids. After each 24-hour period of exposure and for each parasitoid, dead aphids were counted and the leaves with live aphids were transferred to barley plants to permit the re-establishment of the aphids. Nine days after the transfer of aphids, the mummies were counted. The total number of aphids consumed and mummies originated from the treated parasitoids incubated at 94-98% RH was significantly lower than in the control group. There was a significant decline in predation and parasitism per treated female per day and a progressive reduction in the number of treated parasitoids surviving each day. The death of all treated parasitoids incubated for 7 days at 94-98% RH after treatment and the high level of mycosis in cadavers demonstrate the susceptibility of adult A. asychis to P. fumosoroseus at high relative humidity. However, the reduced suceptibility of parasitoids at lower humidities means that may still be possible to construct an integrated program of pest management using parasitoids and pathogens.