Ms Mary Retallack

Evaluating native insectary plants to boost the presence of predatory arthropods which may provide greater biological pest control options in vineyards.

Which species of Tortricidae leafrollers are key insect pests in South Australian vineyards?

Light brown apple moth, Epiphyas postvittana (Lepidoptera: Tortricidae) is regarded as the key insect pest in Australian vineyards and it is also an important pest of apples and citrus. E. postvittana is indigenous to Australia and has a wide geographical distribution. Recent observations suggest that leafroller species other than E. postvittana may be causing damage in grapevine canopies. A study of tortricids was undertaken in Adelaide Hills and McLaren Vale vineyards, South Australia. A total of 407 specimens of Tortricidae were collected from grapevine canopies. Molecular techniques were used to identify species. The mean prevalence of E. postvittana per sample was 91.0% in 2014/15 and 96.2% in 2015/16. Larval Acropolitis rudisana, lucerne leafroller, Merophyas divulsana and cotton tipworm, Crocidosema plebejana were also found on the grapevine canopy at much lower densities for the first time. The presence of leafroller species A. rudisana, M. divulsana and C. plebejana on grapevines confirms these species of Tortricidae may also be present in South Australian vineyards. This study confirms that E. postvittana is the most common tortricid pest in Adelaide Hills and McLaren Vale vineyards and also illustrates the utility of molecular methods in determining with confidence the species identity of larval Tortricidae.

Predatory arthropods associated with potential insectary plants for Australian vineyards

We evaluated three native plants to determine their capacity to provide insectary benefits to predatory arthropods in vineyards, and thereby to enhance biological control of insect pests. Establishing insectary plants could reduce the need for insecticides by boosting the abundance of predators. Native plants are preferred as supplementary flora, as they are naturally adapted to Australia’s climatic conditions. We looked at the potential for using these native insectary plants around Australia. Stands of mature Bursaria spinosa, Leptospermum continentaleand Rytidosperma ssp. located adjacent to or in the mid-rows of Adelaide Hills and Barossa vineyards were sampled in 2013/14. Vitis vinifera  was also sampled. We found that these native insectary plants are naturally adapted to all of the major wine growing regions within Australia. Bursaria spinosa and L. continentale have the potential to be used as insectary plants in association with Australian vineyards, as they support populations of predatory arthropods throughout the year. Rytidosperma ssp. could provide insectary benefits on sites where Ommatoiulus moreletiiis not considered to be a problem. This study confirms associations between predatory arthropods and three native plants. The opportunity to plant selected native insectary species could help wine grape growers produce fruit with lower insecticide inputs, while enhancing biodiversity and resilience of their vineyards.