Galls are abnormal growths on a plant that can have various causes, including viruses, nematodes, bacteria, fungi, mites and insects. Aphids, flies and wasps are some of the insects known to cause galls. Generally plants can tolerate galls with no obvious injury. However, a very high incidence of galls can damage and even kills plants.

Gall formers on eucalypts

The Eucalyptus gall wasp (Leptocybe invasa) is currently the only gall forming insect in South Africa which is considered a serious pest of plantation forest trees. This insect, which infests Eucalyptus, was accidentally introduced from Australia. It was first detected in South Africa in 2007 (and only in 2009 in forestry areas). The Eucalyptus gall wasp causes galls on the stems, petioles and midrib of leaves. Damage by this insect is particularly severe on younger trees, where the majority of leaves can have galls, resulting in severe leaf drop. In such cases, stunting of growth and possibly tree death can occur. The adult wasp is minute (about 1.4 mm), but the galls, which often contain multiple eggs of the Eucalyptus gall wasp, are easily visible. Severely infested trees have a gnarled appearance.

New Publications

Jami F , Marincowitz S, Slippers B, Wingfield MJ. (2018) New Botryosphaeriales on native red milkwood (Mimusops caffra). Australasian Plant Pathology 10.1007/s13313-018-0586-4 PDF
Estrada-de los Santos P, Palmer M, Chávez-Ramírez B, Beukes C, Steenkamp ET, Briscoe L, Khan N, Maluk M, Lafos M, Humm E, Arrabit M, Crook M, Gross E, Simon MF, Bueno dos Reis F, Whitman WB, Shapiro N, Poole PS, Hirsch AM, Venter SN, James EK. (2018) Whole Genome Analyses Suggests that Burkholderia sensu lato Contains Two Additional Novel Genera (Mycetohabitans gen. nov., and Trinickia gen. nov.): Implications for the Evolution of Diazotrophy and Nodulation in the Burkholderiaceae. Genes 9(8):389. 10.3390/genes9080389
Naalden D, Haegeman A, de Almeida‐Engler J, Eshetu FB, Bauters L, Gheysen G. (2018) The Meloidogyne graminicola effector Mg16820 is secreted in the apoplast and cytoplasm to suppress plant host defense responses. Molecular plant pathology 10.1111/mpp.12719https://onlinelibrary.wiley.com/doi/abs/10.1111/mpp.12719
Marin-Felix Y, Hernandez-Restrepo M, Wingfield M, Akulov A, Carnegie A, Cheewangkoon R, Gramaje D, Groenewald J, Guarnaccia V, Halleen F, Lombard L, Luangsaard J, Marincowitz S, Moslemi A, Mostert L, Quaedvlieg W, Schumacher R, Spies C, Thangavel R, Taylor P, Wilson A, Wingfield B, Wood A, Crous P. (2018) Genera of phytopathogenic fungi: GOPHY 2. STUDIES IN MYCOLOGY 92:47 - 133. 10.1016/j.simyco.2018.04.002
Burgess TI, Tan YP, Garnas J, Edwards J, Scarlett KA, Shuttleworth LA, Daniel R, Dann EK, Parkinson LE, Dinh Q, Shivas RG, Jami F. (2018) Current status of the Botryosphaeriaceae in Australia. Australasian Plant Pathology 10.1007/s13313-018-0577-5 PDF