A barcode database for insects associated with the spread of the Cocoa Swollen Shoot Virus Disease in Côte d’Ivoire
Authors: Koffi Kouakou Alain Deron , Babin Régis , Delvare Gérard , Chérasse Sarah , Ouvrard David , Shimbori Eduardo , Koigny Kouadio Juslin , Kpangui Serge , Benoit Laure , Galan Maxime , Yodé Christine , Ouali N'goran Mauricette , Haran Julien 
Published: December 2024

Swollen Shoot is a viral disease affecting cocoa trees, transmitted by several species of mealybugs (Insecta: Hemiptera: Sternorrhyncha: Pseudococcidae). These insects maintain trophobiotic relationships with a complex and species-rich assemblage of ants protecting them and natural enemies controlling their populations. Here, we provide a curated DNA barcode database to characterize this insect community. Systematic observation of 7,500 cocoa trees was conducted coupled with the collection of mealybug colonies and associated insect communities (parasitoids, predators, and ants). Natural enemies were reared from mealybug colonies collected from 1,430 cocoa trees. Specimens were identified morphologically and sequenced for fragments of the standard DNA barcode region of the COI. We recovered 19 species of mealybugs and giant scales: 17 species from the Pseudococcidae family, and two from the Monophlebidae family. Among these species, eight are new to the Ivorian cocoa orchard: Dysmicoccus neobrevipes Beardsley, Ferrisia dasylirii (Cockerell), Maconellicoccus ugandae (Laing), Paracoccus marginatus Williams & Granara de Willink, Phenacoccus solenopsis Tinsley, Planococcus minor (Maskell), Pseudococcus concavocerarii James and Pseudococcus occiduus De Lotto. Five of these species were identified for the first time in cocoa orchards in Africa: Dysmicoccus neobrevipes Beardsley, Ferrisia dasylirii (Cockerell), Paracoccus marginatus Williams & Granara de Willink, Phenacoccus solenopsis Tinsley and Planococcus minor (Maskell). A total of 54 ant species were identified for the first time in cocoa mealybug colonies in Côte d’Ivoire. Among the mealybug natural enemies, 23 primary parasitoids, seven hyperparasitoids, 11 ladybirds, seven species of predatory gall midges, one predatory lepidopteran species, and four spider species were identified. Twelve species of mealybug parasitoids are new to the African cocoa orchards: Acerophagus aff. dysmicocci, Anagyrus kamali, Anagyrus aff. pseudococci, Anagyrus aff. subproximus, Aenasius advena, Clausenia corrugata, Clausenia aff. corrugata, Gyranusoidea aff. tebygi, Zaplatycerus aff. natalensis (Encyrtidae); Coccophagus pulvinarea (Aphelinidae) and Pachyneuron muscarum (Pteromalidae). For Côte d’Ivoire in particular, besides the previously mentioned 12 parasitoids, four additional species are recorded for the first time, including two primary parasitoids, Blepyrus insularis (Encyrtidae), Coccidoctonus pseudococci (Encyrtidae), and two hyperparasitoids, Cheiloneurus cyanonotus (Encyrtidae), and Prochiloneurus aegyptiacus (Encyrtidae). The genus Nephus (Coccinellidae) was identified for the first time as a predator of mealybugs in West Africa. These results significantly enhance the knowledge of the diversity of the entomofauna associated with Swollen Shoot disease and pave the way for developing control methods based on the natural regulation of its mealybug vectors.