© Dr Andre de Klerk Wineland
Margarode infestation can be recognised by curling leaves.
The margarode is a scale insect that attacks the roots of the vines, usually 40 to 60 cm deep. These insects, also known as ‘ground pearls’, can especially be seen in the soil from December to May and are distributed through soil cultivation implements and water. The first symptom of a margarode infection is poor growth, usually found in sections of the vineyard. Vine shoots become shorter and thinner with smaller leaves, curling downwards. However, there is no typical symptom of margarode contamination.
©Dr Andre de Klerk Wineland
Size difference of encysted larvae of two margarode species
Ten different species are found in South Africa, but only five of them can have an economic repercussion for a vineyard. A large number of plants, especially grasses, are damaged. With the development of especially new vineyards it is important to know which crops serve as natural host plants for margarodes. Thus, a possible natural contamination can be prevented. The camel-thorn tree (Acacia erioloba), widely found in the Orange River and Mpumalanga areas, has recently been identified as the natural host plant of one of the margarode species. The natural host plants of the other South African species are still unknown.
No registered chemical control of margarodes is currently available, but it is recommended that tractor tires and other tools be cleaned when moving from a contaminated vineyard block to uninfected blocks.