Leptocybe invasa National Monitoring Programme: 2018 results and 2-year trends

Germishuizen (d'Inzillo Carranza) I
Publication Type
Technical Note
Publication Year
TN 01/2019

The second national monitoring survey of the blue gum chalcid wasp, L. invasa, in the eucalypt plantations of the summer rainfall region of South Africa was conducted between February and November 2018. One hundred and thirty-four sites were surveyed for the presence of L. invasa induced damage, damage intensity and presence of other insect pests and diseases. L. invasa was present in 24.7% of sites sampled. This result shows a slight reduction in the presence of L. invasa’s induced damage from the previous survey conducted in 2017, when damage was observed in 27% of sites. When present, damage was predominantly of low intensity and uniformly spread, affecting most trees in the stand. The higher susceptibility of E. grandis and its hybrids was evident. An important result was the increase of damage induced by Gonipterus sp. 2, which rose from 5.9 % in 2017 to 16% in 2018; the leaf spot disease caused by T. destructans was observed in 7% of sites (2017: 4%) and is no longer confined to coastal Zululand.