The cotton industry in southern NSW has expanded from negligible areas less than a decade ago to 70,680 ha harvested in 2014, 44,201 ha in 2016, and predictions of 90,000 ha in the 2017/18 season, with plantings into Victoria. Three gins have opened in the south; one each at Whitton (2012), Carathool (2014) and Hay (2015). Since cotton production first moved to the south, growers have reported having to control thrips during establishment, and mirids and green vegetable bug (GVB) mid season.

We know that early sprays against thrips can disrupt the natural enemy complex, potentially leading to outbreaks of secondary pests such as spider mites, aphids and whiteflies and that thrips themselves are predatory on mites (Wilson et al. 1996, 1998; Milne and Walter 1998). The risk to reducing natural enemies is further increased if follow-up sprays are made targeting mirids or GVB.

Previous research has shown that cotton has high potential to recover from thrips damage (Wilson et al. 2003, 2009). However this is influenced by thrips density and duration of populations, with recovery poorer from high density populations that persist longer. Sufficient crop compensation is also less likely in shorter season regions, however, data was lacking for the southern regions, and growers and agronomists were unsure whether the Industry thrips thresholds based on data from the northern regions would hold in the south. Similarly, thresholds for mirids were based on data from the Darling Downs region and thresholds for shorter season cotton areas were half those of full season areas (Khan et al. 2004, 2006), but again data was lacking for southern regions.

Another concern for the southern cotton area was the relatively higher incidence of western flower thrips (WFT), Frankliniella occidentalis on a range of horticultural crops and the potential for it to be a larger component of the thrips species complex on cotton. WFT was first identified in Australia in 1993 (Malipatil et al 1993) and spread across Australia over the next decade. Given high levels of insecticide resistance for WFT (Herron and James 2005, Thalavaisundaram et al., 2008, Herron et al., 2010, Marshall and Herron 2016), there was concern that it could be a far more significant problem in the south than was experienced in the northern cotton production areas.

The significant expansion and investment in cotton in southern NSW (Hillston, Condobolin, Griffith, Coleambally and Berrigan) led to the commissioned project Moving in and out of cotton – Identifying farming systems issues in southern NSW irrigation areas (Sykes et al. 2013) and a subsequent extension think-tank held in Griffith in April 2013 identifying the need for southern research capacity and focusing on early crop establishment as priority issues. The rationale being that the shorter growing season allows for less leeway in crop establishment and harvest, and for higher crop establishment costs. Thrips is a key pest at crop establishment. Analysis of the crops that entered the Cotton Grower’s Association crop competition in 2013 highlighted that growers were applying at least 2 and up to 6 insecticides, largely to control sucking pests such as thrips, mirids, GVB and mites (O’Keeffe pers com).

The distances from the Australian Cotton Research Institute (ACRI) and other northern research centres preclude regular visits or high input research experiments, hence the need to develop some local cotton research capacity. NSW DPI has a major research station based at Yanco with researchers and research development officers with experience working in a range of irrigated cropping systems and available to work in cotton.