There’s no silver bullet to control the passionvine hopper (PVH) in kiwifruit, but growers now have several proven tactics to reduce crop losses. A Zespri / Bioeconomy Science Institute – Plant and Food Research project, aligned with A Lighter Touch, brought together researchers, growers and technical experts to test IPM tactics not reliant on agrichemicals to manage PVH.
The integrated pest management approach developed from the project has three components:
» reducing PVH populations at source
» reducing migration of PVH adults into the block
» managing PVH populations within the block
Jessie Fea, Zespri Innovation Leader for Crop Protection Market Access, says multiple tactics were identified to reduce PVH at the source including application of a well-timed pyrethrin plus 0.5 percent oil spray on gully borders to target and kill nymphs, reducing the number of adults emerging and migrating into the block early on. “The project also identified some native plants which are a poor host of PVH and are suitable for use in revegetation of orchard boundaries,” Jessie says. “Another method growers tested involved clearing an area between any gullies and their kiwifruit blocks. PVH disperse by moving across adjacent plants, so creating a barren area effectively reduced PVH migration into the block.” The project also assessed the efficacy of shelterbelts in reducing migration and found dense natural shelters are more effective than porous shelters.
An artificial shelter with no gap can reduce PVH migration by over 90 percent. For orchards with resident populations of PVH, a single bifenthrin spray during dormancy or pre-flowering was shown to effectively kill the eggs. Zespri Orchard Quality Services Manager Melanie Walker says this should not be necessary every year, as infestations on orchard take time to build up and kiwifruit is not a preferred host. If good border management is taking place, infestations on orchards should remain low. For growers who don’t spray and have lots of dock plants under the canopy, sward mowing once or twice in late October or November could reduce the PVH nymph populations.'
