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Wood and bark borers comprise some of the most serious pests of forestry trees worldwide. These insects use the inside of bark and / or the wood to feed on and to make a home. Damage by these insects includes under bark girdling, extensive tunneling which weakens the tree, and / or the introduction of symbiotic fungi that weaken or kill the host. Although some wood boring beetles (such as Apate indistincta and Sinoxylon bellicosum) have been reported as minor pests of A. mearnsii, the current major wood and bark boring pests infest Eucalyptus and Pinus.

Wood borers of eucalypts

The cossid moth (Coryphodema tristis) is a major pest of Eucalyptus. This insect is reported to be native to South Africa with a wide range of native and introduced host plants, including grape vines (Vitis vinifera), quince (Cydonia oblonga) and bushwillows (Combretum sp.). It was first recorded infesting Eucalyptus in 2004. Strangely, despite its broad host range, the cossid moth has only been reported to infest E. nitens. No other Eucalyptus species has been infested, even when planted adjacent to highly infested E. nitens stands. The adult female cossid moth lays her eggs under the branches or in bark cracks. Emerging larvae first feed under the bark, but later instars bore into the sapwood. This insect is gregarious (feeds in groups) and causes extensive tunneling. Characteristic symptoms include large amounts of frass protruding from holes in the trunk, sawdust at the base of the trunk and a blackening of the trunk. The moths are also known as goat moths because of the unpleasant smell associated with their infestations. Trees often survive infestation by more than one generation of the cossid moth. But, in time trees weakened by the extensive tunneling are likely to be blown over by the wind. The tunneling also affects the quality and volume of the wood. The cossid moth has been reported to infest trees four years and older (Gebeyehu et al. 2004).

The Eucalyptus longhorn beetles (Phorocantha recurva and P. semipunctata) were accidentally introduced from Australia, and first recorded in South Africa in 1906. The adult female lays eggs under loose bark and the emerging larvae feed on the cambium and phloem layers. Fully grown larvae bore directly into the heartwood where they later pupate. The tunneling of the larvae can cause under bark girdling and reduce the value of the timber. However, these beetles are currently not considered major pests as they primarily infest dying trees.

Wood borers of pine

The Sirex woodwasp (Sirex noctilio) is one of the most serious pests of Pinus in South Africa (Hurley et al. 2008). This insect is native to Eurasia, but has been accidentally introduced to various southern hemisphere countries, and more recently to North America. In South Africa, the Sirex woodwasp was first detected in 1994 in Cape Town. It has since spread to the majority of pine growing areas in the country. The Sirex woodwasp has a symbiotic association with a fungus (Amylostereum areolatum). The adult female wasp places this fungus, together with its eggs and a toxic mucous, into the wood of pine trees. The fungus and mucous together overcome the defense of the tree and block the tracheids and thus nutrient transport. Attack by this insect usually results in tree death. Trees that survive the attack are usually attacked again the next year and killed. Importantly, the Sirex woodwasp primarily attacks stressed trees. Consequently, the most severe damage of this insect has been reported in areas where trees are stressed by factors such as drought and high stocking. The larvae tunnel in the wood, feeding on the fungus. Pupation occurs in the wood. The adult wasps do not feed and only live for one to two weeks.

The ambrosia beetles (Xyleborus and Xyleborinus spp.) also bore into the wood of Pinus. Unlike the Sirex woodwasp, these beetles are considered a minor pest. Infestations are often associated with cut or burnt trees. The beetles have a symbiotic association with fungi. The tunnels of these beetles and the staining of the wood from the fungi can make infested trees unsuitable for use as saw timber. Both the larvae and adults feed on the fungi.

Bark borers of pine

There are three species of bark beetles that are recorded to infest Pinus in South Africa. All three of these species have been accidentally introduced from the northern hemisphere. Bark beetles are considered as some of the most serious pest threats to forestry worldwide, but fortunately the three species currently in South Africa are only minor pests.

The Mediterranean pine engraver beetle (Orthotomicus erosus) feeds on the inner bark, generally on the main trunk. It attacks dead and dying trees, and can accelerate the death of dying trees by under bark girdling. It is also know to be associated with the fungus Ophiostoma ips that causes bluestain of the wood, thus decreasing its value as saw timber. The adults are dark brown and about 3 mm long. The pine bark beetle (Hylastes angustatus) feeds on the roots and stumps of dying trees. It is generally considered a secondary pest, although it has been known to kill seedlings by feeding on their roots and root-collars, thereby causing under bark girdling. In such cases, the pine bark beetle can become a serious pest. The adults are dark brown and about 4 mm long. The red-haired bark beetle (Hylurgus ligniperda) infests stumps or the base of weakened trees. The adults are dark brown and about 6 mm long (Tribe 1992).

Another bark borer on Pinus is the deodar weevil (Pissodes nemorensis). This insect breeds in dead or dying trees, but also infests the leaders of young healthy trees. The adult beetle lays its eggs under the bark and the larvae feed on the inner bark. When feeding occurs on the leaders of young trees, the leader is often killed from under bark girdling. This results in double leaders and malformation of the tree. It has been observed that such double leaders are more susceptible to infestation by the Sirex woodwasp. Pupation occurs in a chip-cocoon under the bark. Emerging adults are about 7 mm long with two creamy-white spots on their elytra (hind wings) (Gebeyehu and Wingfield 2003).

New Publications

Ramaswe JB, Steenkamp ET, De Vos L, Fru FF, Adegeye OO, Wingfield BD. (2024) Sex pheromone receptor Ste2 orchestrates chemotropic growth towards pine root extracts in the pitch canker pathogen Fusarium circinatum. Pathogens 13:425. 10.3390/pathogens13050425
Marais I, Buitendag C, Duong TA, Crampton BG, Theron J, Kidanemarium D, Berger DK. (2024) Double-stranded RNA uptake for the control of the maize pathogen Cercospora zeina. Plant Pathology Online first:1-11. 10.1111/ppa.13909
van Heerden A, Pham NQ, Wingfield BD, Wingfield MJ, Muro Abad JI, Durán A, Wilken PM. (2024) LAMP assay to detect Elsinoë necatrix; an important Eucalyptus shoot and leaf pathogen. Plant Disease 10.1094/PDIS-01-24-0086-RE
Silva GA, Oliveira MES, Rêgo GMS, Wingfield BD, Wingfield MJ, Ferreira MA. (2024) Chrysoporthe brasiliensis sp. nov. pathogenic to Melastomataceae in southeast Brazil. Fungal Biology 10.1016/j.funbio.2024.04.001
Fick A, Swart V, Bombarely A, van den Berg N. (2024) Comparative transcriptional analysis of Persea americana MYB, WRKY and AP2/ERF transcription factors following Phytophthora cinnamomi infection. Molecular Plant Pathology 25(4):e13453. 10.1111/mpp.13453 PDF
Van Lill M, Venter SN, Muema EK, Palmer M., Beukes CW, Chan WY, Steenkamp ET. (2024) SeqCode facilitates naming of South African rhizobia left in limbo. Systematics and Applied Microbiology 47(2-3):126504. 10.1016/j.syapm.2024.126504 PDF
Visagie CM, Meyer H, Yilmaz N. (2024) Maize–Fusarium associations and their mycotoxins: Insights from South Africa. Fungal Biology 10.1016/j.funbio.2024.03.009
Elisa P, Allison J, Hurley BP, Slippers B, Fourie G. (2024) Lethal and sublethal effects of insecticides on Bathycoelia distincta (Heteroptera: Pentatomidae). African Entomology 32: e16992:1-9. 10.17159/2254-8854/2024/a16992
Pietersen G, Morgan S, Read DA. (2024) First report of Citrus concave gum-associated virus (CCGaV) on apple (Malus spp.) in South Africa. Journal of Plant Pathology 10.1007/s42161-024-01629-9
Gush S, Lebre P, Coutinho TA, Cowan DA, van der Waals JE. (2024) Disentangling shifts in the soil microbiome of potatoes infected with Rhizoctonia solani Anastomosis Group 3-PT in search of potential biocontrol agents. Phytobiomes Journal 10.1094/PBIOMES-06-23-0046-R
Dankie VN, Steenkamp ET, De Vos L, Swalarsk-Parry BS, Dewing C, Fru F, Wilken PM, Mchunu NP, Wingfield BD, Wingfield MJ, van der Nest MA. (2024) Growth, pathogenicity and sexual fertility of the African tree pathogen Ceratocystis albifundus. Journal of Plant Pathology :1-11. 10.1007/s42161-024-01634-y
Bornman S, Thomas C, Ntladi S, Wilken PM. (2024) Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot on peanut (groundnut) in South Africa. Australasian Plant Disease Notes 19 10.1007/s13314-024-00537-2
Abkallo HM, Arbuthnot P, Auer TO, Berger DK, Burger J, Chakauya E, Concordet J-P, Diabate A, Di Donato V, Groenewald J-H, Guindo A, Koekemoer LL, Nazare F, Nolan T, Okumu F, Orefuwa E, Paemka L, Prieto-Godino L, Runo S, Sadler M, Tesfaye K, Tripathi L, Wondji C. (2024) Making genome editing a success story in Africa. Nature Biotechnology :1-4. https://rdcu.be/dBJUa
Robert R, Robberste N, Thompson GD, Read DA. (2024) Characterization of macadamia ringspot‑associated virus, a novel Orthotospovirus associated with Macadamia integrifolia in South Africa. European Journal of Plant Pathology 10.1007/s10658-024-02832-1 PDF
Hiroyuki S, Marincowitz S, Roux J, Paap T, Wingfield BD, Wingfield MJ. (2024) A new genus and species of Cryphonectriaceae causing stem cankers on plantation eucalypts in South Africa. Plant Pathology :1-14. 10.1111/ppa.13883 PDF
Strydom RF, Wilson CR, Tegg RS, Balendres MA, van der Waals JE. (2024) Advancements in Spongospora subterranea: Current knnowledge, management strategies, and research gaps. Potato Research 10.1007/s11540-024-09701-8
Mapfumo P, Buthelezi S, Archer E, Swanevelder DZH, Wilken PM, Creux N. (2024) In-field climatic factors driving Sclerotinia head rot progression across different sunflower planting dates. Plant Pathology 10.1111/ppa.13873
Price J-L, Visagie CM, Meyer H, Yilmaz N. (2024) Fungal species and mycotoxins Associated with Maize ear rots collected from the Eastern Cape in South Africa. Toxins 16:95. 10.3390/toxins16020095
Tarigan M, Wingfield MJ, Jami F, Marpaung YMAN, Duran A, Pham NQ. (2024) Pathogenicity of Chrysoporthe deuterocubensis on eucalypts in Indonesia. Southern Forests: a Journal of Forest Science 10.2989/20702620.2023.2279054
Caballol M, Serradó F, Barnes I, Camarero JJ, Valeriano C, Colangelo M, Oliva J. (2024) Climate, host ontogeny and pathogen structural specificity determine forest disease distribution at a regional scale. Ecography :e06974. 10.1111/ecog.06974 PDF
MISEV Consortium, Motaung T. (2024) Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches. Journal of Extracellular Vesicles 13(2):e12404. 10.1002/jev2.12404
Pham NQ, Suzuki H, Duong TA, Wingfield BD, Barnes I, Duran A, Wingfield MJ. (2024) Cryptic sexual reproduction in an emerging Eucalyptus shoot and foliar pathogen. Plant Pathology 10.1111/ppa.13876
Francinah M. Ratsoma, Nthabiseng Z. Mokoena, Quentin C. Santana, Brenda D. Wingfield, Emma T. Steenkamp, Thabiso E. Motaung. (2024) Characterization of the Fusarium circinatum biofilm environmental response role. Journal of Basic Microbiology 00(00):1-16. 10.1002/jobm.202300536
Morrison EW, Duong TA, Garnas JR. (2024) A high-quality draft genome sequence of Neonectria faginata, causative agent of beech bark disease of Fagus grandifolia. Microbiology Resource Announcements 10.1128/mra.01048-23
Roberts E, Paap T, Roets F. (2024) Chemical control of the Polyphagous Shothole Borer beetle (PSHB, Euwallacea fornicatus) and Fusarium euwallaceae in American sweetgum (Liquidambar styraciflua). Journal of Plant Pathology 10.1007/s42161-023-01583-y
Fitza KNE, Allison J, Slippers B, Chingandu N, Reed SE. (2024) Diversity and potential sources of introduction of the Beech leaf nematode (Litylenchus crenatae< mccannii) to Ontario, Canada. Canadian Journal of Plant Pathology
Engelbrecht K, Raubenheimer I, Paap T, Neethling E, Roets F. (2024) Detection of Fusarium euwallaceae and its vector Euwallacea fornicatus on Pear (Pyrus communis) and in deciduous fruit orchards in South Africa. Australasian Plant Disease Notes 19(1) 10.1007/s13314-023-00524-z PDF
Visagie CM, Meijer M, Kraak B, Groenewald M, Houbraken J, Theelen B, Vorst Y, Boekhout T. (2024) Blastobotrys nigripullensis, a new yeast species isolated from a fungal outbreak on an ancient Roman shipwreck in the Netherlands. Antonie Van Leeuwenhoek 117:22. 10.1007/s10482-023-01898-x
Hlongwane NL, Dzomba EF, Hadebe K, van der Nest MA, Pierneef R, Muchadeyi FC. (2024) Identification of signatures of positive selection that have shaped the genomic landscape of South African pig populations. Animals 14:235. 10.3390/ani14020236
De Vos L, van der Nest MA, Santana QC, van Wyk S, Leeuwendaal KS, Wingfield BD, Steenkamp ET. (2024) Chromosome-level assemblies for the pine pitch canker pathogen Fusarium circinatum. Pathogens 13(1):70. 10.3390/pathogens13010070