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

Apart from the possible inclusion of individuals in picking crates during mechanical harvesting, no additional disadvantages associated with the incidence of chameleons could be stipulated (Photo 522). In the case of dragonflies (Photo 523) foliage wires are sometimes used to rest on without causing any damage to grapevines. Although wasps have no harmful characteristics in terms of general cultivation practices, they may cause great frustration among vineyard workers when nests are disturbed and stinging attacks launched in retribution (Photo 524). Similar tendencies apply to honeybees, which sometimes occur in caked format on bunches when the onset of noble rot during dry autumn conditions affects individual berries (Photo 525). Despite the fact that spiders may sometimes look creepy, their presence may have advantages and disadvantages – eating of moths/insects in the former and in the latter, the possibility that they may be crushed as ‘material other than grapes’ (Photos 526 & 527). Apart from proven harmful larvae/caterpillars, strange/unknown examples are often observed on grapevines on a sporadic basis (Photos 528 & 529) – in which case expert advice should be sought at all times to confirm possible harmful interventions that may apply. Although the incidence of birds’ nests (sometimes with chicks) is considered common, there are no real disadvantages, except for possibly being incorporated in picking crates (Photo 530). Unlike feeding damage such as that which may be caused by guinea fowl tucking into grape bunches, thick-knees show no appetite for grapes, despite the fact that chicks are often hatched in the shade of trellised grapevines in separate vineyard rows, whereafter the sites in question are soon vacated (Photo 531). Based on the benefits of mealybug control ascribed to the feeding activities of ladybirds, their presence is strongly encouraged (Photo 532). In addition to situations associated with the specific examples mentioned in the previous paragraph, several other examples relative to grapevines may be mentioned, to be respectively classified as either harmful, harmless, or merely interesting. Although widely divergent, some characteristic examples in this regard are highlighted, namely: (i) pearl glands (Photo 533); (ii) strangulation effects by tendrils (Photos 534 - 536); (iii) leaf yellowing in dense canopies (Photo 537); (iv) exudation of bleeding sap (Photo 538); (v) delayed bud burst (Photo 539); (vi) fungicide overdose (Photo 540) and (vii) bunches on trunks/cordon arms (Photo 541).

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