Jaspers, Marlene V.

Nielsen, M.-C.

Schmidt, Katrin

Teulon, D. A. J.

Wratten, Stephen D.

Lincoln University Research Archive

Phenology of New Zealand flower thrips (Thrips obscuratus) in vineyards Introduction The New Zealand fLower thrips (NZFT), Thrips obscuratus Crawford, is endemic to New Zealand and is widespread in vineyards at flowering (Fig. 1). During spring, thrips aduLts (1.5-2mm) are abundant on many flowering pLants and this species can achieve densities of up to 2 million per hectare of vines. Methods The first step in investigating the interactions between the fungus and the insect was to determine thrips abundance in vineyards. At a vineyard fieLd site in the Waipara Valley (Canterbury House Winery), aeriaL popuLations of aduLt thrips were monitored from three weeks before flowering untiL harvest (27.11.03 to 01.04.04) with white water traps (18 in totaL) placed at three different heights (15, 80 and 140 cm). K. Schmidt1, D.A.J. Teulon2, M-C. Nielsen2, S.D. Wratten1 and M.V. Jaspers! 1 NItIonel CentnI for AdVaIIced lIIo-PnItectlon Ted1no1o&fes, PO Box 84, Uncoln Unlvelslty. CanterbUIY. New Zealand 2 New Zealand In5lltute for Crop • Food R_h Umltecl. PrIvate Bas 4704. Chrlstcllurdl, New Zealand CorrespondInJ author. schmldtkOUncoln.ac.nz Results Fig. 1. Adult Thrips obscuratus on a grape flower In wine grapes, thrips are considered to cause LittLe direct economic damage. However, they have been shown to vector diseases of fruit crops and to carry conidia of Botrytis cinerea Persoon (Fig. 2). Since the incidence of B. cinerea at flowering is beLieved to influence the amount of disease at harvest, thrips may contribute to yieLd and quaLity Losses in New ZeaLand vineyards. Fig. 2. NZFT carrying spores of Botrytis dnerea (SEM) • Thrips numbers increased during flowering and decreased thereafter (Fig. 3). • Thrips identified were T. obscuratus, Limothrips cereaLium HaLiday, Thrips australis Bagnall and some species from the sub-order TubuLifera. 10000 1000 100 10 --+- 15 ern ___ 80 em ........ 140 em Fig. 3. Mean numbers (log scale) of thrips caught in a vineyard in water traps at 15, 80 and 140 cm above ground during the growing season Conclusion Since there were high Levels of NZFTin vineyards at flowering, thrips are LikeLy to pick up B. cinerea spores from infected flowers and couLd transfer them to uninfected flowers, causing Loss of flowers and Latent infection of ripening fruit. Acknowledgements This research is supported by the National Centre for Advanced Bio-Protection Technologies, a Centre of Research Excellence funded by the Tertiary Education Commission, New Zealand. We are grateful for the support of NeudorfVineyards and Canterbury House Winery by providing their vineyards for this work. Many thanks also to Virginia Marroni for providing the photographs. • During flowering and earLy berry deveLopment (18.12.03 to 22.01.04) NZFT was the most common thrips species in water traps at 80 and 140 cm height, whereas at ground LeveL (15 cm) other species were more common (Fig.4). • Towards the end of the growing season the percentage of NZFT caught in the traps steadily decreased, whereas subsequentLy the percentage of other thrips species increased (Fig. 4). 100 __ 15cm 80 60 40 20 o+-.:....-..---.------,...------,----'----r-----r----.----=----. Fig. 4. Mean percent ofT. obscuratus caughtin a vineyard in water traps at 15, 80 and 140 cm above ground during the growing season Future Research The overaLL goaL of this research is to improve understanding of the tritrophic dynamics and interactions between the grapevine Vitis vinifera, B. cinerea and T. obscuratus in vineyards. This wiLL include: • FieLd trials in two New Zealand wine regions with different microclimates to investigate the -bioLogy and popuLation dynamics of NZFT -effects of thrips on Levels of B. cinerea • Greenhouse and Laboratory studies on the mechanisms of the interaction. 

Phenology of New Zealand Flower Thrips (Thrips obscuratus) in vineyards

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