Invertebrate pests update
A suite of pests, differing in their severity across regions, have been important this season. These include:
- Garden weevil was generally considered to be important but reasonably well managed. Under vine cultivation seems to be having a positive effect in reducing numbers. With the cooler season, the weevil was present in greater numbers later in the season.
- Mealybugs were important enough to warrant treatment in some vineyards, and control with insecticides seems to have been effective.
- While grapevine moth was considered less important this season compared to the previous one, heliothis caused some concern, especially in newly planted vines. Mature larvae are voracious feeders and can easily attack growing tips which has a severe impact on the growth and vigour of young plants.
- Snails, both garden snail and small pointed snail were important. Early season baiting of garden snail did not do as good a job as expected, despite the theory that this is the most strategic time to limit populations for the following spring bud burst. Small pointed snail is always a challenge to control and a few more of them around contributed to contamination in harvested crops.
- Grapeleaf rust mite was notable in some crops to the extent that spraying with a miticide was considered.
- European earwig was around but not in significant numbers to cause major concern.
- One surprise was the presence of Portuguese millipede that managed to finish up in harvested grapes. With unseasonal summer rain, these invertebrates will be driven to higher ground and in the case of millipedes in a vineyard, this means climbing into the canopy.
- Wingless grasshoppers were reported in high numbers and further into the season than usual in some areas, requiring targeted sprays where necessary.
- Other surprises included what appears to have been vegetable beetles damaging young vines. The use of grow guards appears to have been an attraction in some instances with the beetles climbed onto the young vines and proceeding to defoliate them within the guards.
- There was one other case of an unidentified tiny weevil attacking buds in grafted vines. We hope to get specimens of this weevil to have it identified.
As usual, it was a case of expect the unexpected. Comments by vignerons on their experiences to complement this report are welcomed.
A big thanks to consultants and vignerons across the WA regions for sharing their experiences this season upon which this summary is based.
For more information, contact Manjimup based Senior Entomologist Stewart Learmonth.