Small holes indicative of oviposition are present on young shoots of black wattle trees. Swelling of the shoots starts around the oviposition hole due to the growing larva and its feeding. Feeding within the shoots leads to cracking, yellowing, and dieback. Much larger holes can also occur around the time of emergence of the mature larva when it is ready to pupate in the soil.
Thus far, aside from minor damage, no detrimental effects have been observed to plantation health due to infestation by the weevil. We are continuing to monitor its presence and determine if it will have any detrimental effects in the long term.
Small black snout weevil of about 3-5mm in size
Melanterius weevils are seed feeders that lay their eggs and develop in wattle seed. However, M. inconspicuus forms part of a unique groups of these insects that have also been found to infest wattle vegetative tissues in the presence of Uromycladium infection (Pinzón-Navarro et al. 2017). In the case of M. inconspicuus in South Africa, it infests and develops within shoots and twigs in the absence of Uromycladium infection. Immature adult weevils have been observed to congregate around wounds induced by hail damage.
Pinzón-Navarro SV, Jennings D, Oberprieler RG. 2017. Host associations of Melanterius Erichson (Coleoptera: Curculionidae: Cleogonini), with a diagnosis and delimitation of the genus and description of five new species. Zootaxa. 4298(1): 1-77. doi: 10.11646/zootaxa.4298.1.1
