SATI Beyond The Bunch 4th Quarter 2025

Releases must be calibrated to the pest pressure. For example, in blocks with severe vine mealy bug infestations, early-season releases of both Anagyrus vladimiri and Coccidoxenoides perminutus , followed by repeated releases of A. vladimiri , may need to be augmented with predators such as Cryptolaemus or lacewings. Additionally, shopping around for the cheapest predators or parasitoids could end up being extremely costly. Not all bio control agents are created equal. Some products contain poor-quality insects, a suboptimal male-to-female ratio, or even incorrectly identified species. Stick to repu table suppliers and, where available, regis tered products. Work with suppliers to ensure they can prepare the correct volumes of fresh insects at the right time. Supply bottlenecks are common, especially during the November to January peak demand period. This can result in delays if growers haven’t communicated their requirements. Lastly, remember that predator and parasitoid releases aren’t one-and-done. Just as conventional pesticides are applied multiple times, every season, releases must be repeated. But in both cases, a long-term commitment to integrated pest management will gradually reduce pest pressure and create more resilient vineyards.

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Ant control Sticky stem barriers are highly effective at excluding ants (and weevils) from the canopy. Some markets even require sticky stem barriers. Although labour-intensive to apply, the barriers are long lasting, provided they are checked to ensure they stay clean. Ants have been known to build bridges over sticky barriers. Stem barriers must also be applied to posts and wires. Ensure that ants can’t access the vines by climbing up weeds or other structures. Attract-and-kill products are already registered for ants in other crops, so could become an option for table grapes in future. If all else fails, ant nests can be sprayed. These must be spot applications using a backpack-sprayer.

Entomopathogens Entomopathogens are microorganisms that attack and kill insects. Two entomopathogenic fungi ( Beauveria bassiana and Metarhizium anisopliae ) are available as products registered for mealy bugs. Fungal spores are applied as full-cover sprays and are most effective against crawlers. They are less effective against older life stages. However, they help control other insects, including thrips and weevils. Spray applications must land the fungal spores on the pests, as spore survival can be short, especially when exposed to sunlight. Repeated applications are recommended. Entomopathogenic fungi can also be applied as a soil drench to control mealy bug adults on vine roots. The fungi may also help reduce the soil stages of other pests, such as false codling moths. The compatibility of entomopathogenic fungi with various fungicides differs. Consult your crop-protection adviser when incorporating these fungi into your programme. Furthermore, remember that fungal spores only work if they’re alive, so store and handle them with care, avoiding exposure to high temperatures.

Acknowledgements The following specialists provided technical inputs:

• De Wet Du Toit. Technical marketing specialist. InteliGro. • Desi Fourie. Technical Adviser. Viking.

• Brahm Jonker. Managing Director. Fieldbugs. • Robert Wilsdorf. Technical manager. Viking.

BEYOND THE BUNCH • 11 • QUARTER 4 • 2025