Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 4212 IREC Farmers' Newsletter No. 196 — Summer 2016 VALIDATING THRIPS THRESHOLDS FOR SOUTHERN COTTON Commercial-scale trials are testing the industry-wide threshold for controlling thrips in southern cotton production systems. l  Thrips, an early season pest of cotton crops, were predicted to have a greater effect in southern growing regions than in the north because early crop establishment is strongly linked to yield. l  Four trials conducted on commercial-scale cotton crops tested the current industry spray threshold of 10 thrips/plant against a lower threshold of 1 thrips/plant. l  Trials were conducted at Whitton and Darlington Point over two seasons in 2014–15 and 2015–16. l  No yield difference was observed between sprayed and unsprayed plots in the two seasons. l  The dominant thrips species in the trial crops was onion thrips, making up 80% of the population. Cotton crops in southern Australia have a shorter growing season than northern crops, giving them less opportunity to recover from early season crop damage and stress. Sandra McDougall, Sarah Beaumont, Jianhua Mo, Alicia Ryan, Scott Munro and Mark Stevens NSW Department of Primary Industries, Yanco Agricultural Institute THE length of the growing season for cotton crops is important because links have been made between early crop establishment and high yields. Thrips are sucking pests of cotton seedlings and where their pressure is high, they can cause cupping of leaves up to the 6-leaf stage of cotton development. This results in reduced leaf surface area during the establishment phase. Insecticides are commonly used to control thrips in the southern cotton production region, averaging two sprays per season. The industry-wide spray threshold is 10 thrips per plant and more than 80% leaf area loss for seedlings up to the 6-leaf stage. Due to the shorter growing season in the south, we wished to test if this threshold was sufficient to minimise yield losses from thrips damage. QUICK TAKE