A Guide to Grapevine Abnormalities in South Africa - P.G. GOUSSARD

of this pest phenomenon can also be confirmed by the holes/tunnels that are usually found close to established grapevines (Photo 383). White ants The incidence of white ants – which are prominently detectable during the phases when they actively use inter alia dry twigs, grasses and other plant material to cover nest openings before rain showers – requires no introduction (Photo 384). In this regard instances have been reported where – possibly due to shortages of the material mentioned above – young grapevine leaves and green shoots (or parts thereof) have been used for the above-mentioned actions. This practice nevertheless occurs almost exclusively among newly-planted grapevines and is considered minimally important in terms of serious feeding damage. Dassies Although feeding damage by dassies is considered to be a fairly uncommon phenomenon, incidents have been reported where grapevine leaves and young shoot sections have tempted their taste buds (Photos 385 & 386). Seeing that there are no characteristic feeding or damage patterns on affected grapevines, these culprits must be caught in the act to be positively associated with harmful interventions. Obviously such situations will be limited to areas where dassies are a common occurrence. Antelopes The sporadic incidence of feeding damage to grapevines caused by antelopes is not an exceptional phenomenon – especially so where the vineyards in question are not fenced to keep out game and the adjacent territory includes bushy and mountainous terrain. Given the situation that characteristic feeding patterns are often absent (Photo 387), identification procedures in respect of the specific cause are mostly based on particulars of tracks and excretions in the immediate vicinity of damaged grapevines. Serious damage can nevertheless also be inflicted on grapevines within fenced vineyards – as reflected in situations where gates are left ajar to grant unhindered access, inter alia to ordinary farm animals such as goats, cattle and sheep (Photo 388). Moths/butterflies During the growing season it is by no means uncommon to find moths and butterflies, sometimes displaying colourful patterns on their wings, in vineyards. Although direct damage per se cannot be ascribed to them, on the other hand serious feeding damage may be inflicted on specific organs of affected grapevines during the larval stages – a situation that may result in epidemic interventions under conducive/optimal environmental conditions (Photos 389 & 390).

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