Life Cycle and Development of Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae), a pest of balsa

Novel Symbiotic Association Between Euwallacea Ambrosia Beetle and Fusarium Fungus on Fig Trees in Japan

Ficus carica plantations in Japan were first reported to be infested by an ambrosia beetle species, identified as Euwallacea interjectus, in 1996. The purpose of this study was to determine the symbiotic fungi of female adults of E. interjectus emerging from F. carica trees infected with fig wilt disease (FWD). Dispersal adults (51 females) of E. interjectus, which were collected from logs of an infested fig tree in Hiroshima Prefecture, Western Japan, were separated into three respective body parts (head, thorax, and abdomen) and used for fungal isolation. Isolated fungi were identified based on the morphological characteristics and DNA sequence data. Over 13 species of associated fungi were detected, of which a specific fungus, Fusarium kuroshium, was dominant in female head (including oral mycangia). The plant-pathogenic fungus of FWD, Ceratocystis ficicola, was not observed within any body parts of E. interjectus. We further discussed the relationship among E. interjectus and its associated fungi in fig tree.

A revision of the Neotropical genus Coptoborus Hopkins (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

The Neotropical xyleborine ambrosia beetle genus Coptoborus Hopkins is reviewed. The following 40 Coptoborus species are described: C. amplissimus sp. nov. (Peru), C. asperatus sp. nov. (Ecuador), C. barbicauda sp. nov. (French Guiana), C. bettysmithae sp. nov. (Ecuador), C. brevicauda sp. nov. (Ecuador), C. brigman sp. nov. (Ecuador), C. busoror sp. nov. (Ecuador), C. capillisoror sp. nov. (Brazil), C. chica sp. nov. (Suriname), C. crassisororcula sp. nov. (Peru), C. doliolum sp. nov. (Ecuador), C. erwini sp. nov. (Ecuador), C. furiosa sp. nov. (Ecuador), C. galacatosae sp. nov. (Ecuador), C. hansen sp. nov. (Brazil), C. incomptus sp. nov. (Peru), C. janeway sp. nov. (Peru), C. katniss sp. nov. (Ecuador), C. leeloo sp. nov. (Ecuador), C. leia sp. nov. (Ecuador, Suriname), C. leporinus sp. nov. (Peru), C. martinezae sp. nov. (Ecuador), C. murinus sp. nov. (Ecuador), C. newt sp. nov. (Peru), C. osbornae sp. nov. (Ecuador), C. panosus sp. nov. (French Guiana), C. papillicauda sp. nov. (Suriname), C. pilisoror sp. nov. (Ecuador), C. ripley sp. nov. (Ecuador), C. sagitticauda sp. nov. (Guyana), C. sarahconnor sp. nov. (Brazil), C. scully sp. nov. (Ecuador), C. sicula sp. nov. (Ecuador), C. sororcula sp. nov. (Peru), C. starbuck sp. nov. (Ecuador), C. trinity sp. nov. (Brazil), C. uhura sp. nov. (Peru), C. vasquez sp. nov. (Panama), C. vrataski sp. nov. (Brazil), and C. yar sp. nov. (Ecuador). Seventeen new combinations are given: Coptoborus amazonicus (Petrov, 2020) comb. nov., C. atlanticus (Bright & Torres, 2006) comb. nov., C. bellus Bright & Torres, 2006 comb. nov., C. coartatus (Sampson, 1921) comb. nov., C. crinitulus (Wood, 1974) comb. nov., C. exilis (Schedl, 1934) comb. nov., C. incultus (Wood, 1975) comb. nov., C. magnus (Petrov, 2020) comb. nov., C. micarius (Wood, 1974) comb. nov., C. obtusicornis (Schedl, 1976) comb. nov., C. paurus (Wood, 2007) comb. nov., C. pristis (Wood, 1974) comb. nov., C. pseudotenuis (Schedl, 1936) comb. nov., C. puertoricensis (Bright & Torres, 2006) comb. nov., C. ricini (Eggers, 1932) comb. nov., C. semicostatus (Schedl, 1948) comb. nov., C. tristiculus (Wood, 1975) comb. nov., and C. villosulus (Blandford, 1898) comb. nov. Two new synonyms are proposed: Coptoborus Hopkins, 1915 (= Theoborus Hopkins, 1915 syn. nov.) and Coptoborus villosulus (Blandford, 1898) (= Theoborus theobromae Hopkins, 1915 syn. nov.). Xyleborus neosphenos Schedl, 1976 comb. res. is removed from Coptoborus. The revised genus now contains 77 species and a key to their identification is provided.

Effects of Climate and Host Age on Flight Activity, Infestation Percentage, and Intensity by Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae) in Commercial Balsa Plantations of Ecuador

Coptoborus ochromactonus (Smith and Cognato) is one of the most common and important pests of balsa, Ochroma pyramidale (Cav. Ex Lam. Urb.), an economic pillar of the wood industry in Ecuador. Commercial balsa plantations have been expanded from humid to dry climate areas to limit insect damage, but basic knowledge is still lacking on the interaction of C. ochromactonus activity with variation in climate and plantation age. We investigated the effects of climate and host age on the seasonal flight activity of C. ochromactonus and its infestation rate and intensity, as well as the effect of age and individual infestation intensity on balsa dieback. Experiments were conducted in 1-, 2-, and 3-yr-old commercial balsa plantations located in areas of humid or dry climates. Seasonal flight activity (monitored with baited traps) differed between study sites and seasons. Increased flight activity was significantly correlated with higher relative humidity, higher mean temperature, and reduced precipitation during the dry season in the humid site and with increased mean and minimum temperature and increased precipitation during the rainy season in the dry site. Infestation rates by C. ochromactonus significantly increased with plantation age, especially in the humid site. Intensity of individual infestations (measured as number of successful insect entry holes per tree) was significantly influenced by both climate and plantation age, and it was particularly severe on 3-yr-old trees in the dry site. Percentage of foliage loss significantly increased with infestation intensity. Overall, our results can be relevant for devising preventive measures and suitable management strategies for this emerging pest in Ecuadorian wood plantations.