Effects of sugar-acetic acid-ethanol water solutions and sex pheromone on trapping Grapholitha molesta Busck in peach-apple neighbor orchards

Abstract: 【Objective】This study aimed to investigate the diurnal activity rhythm of Grapholitha moles-ta Busck (oriental fruit moth) and explore the effects of sugar-acetic acid-ethanol-water solution (SAEWS) and sex pheromone on trapping the oriental fruit moths in peach-apple neighbor orchards, soas to provide a theoretical basis for the effective and rational use of SAEWS and sex pheromone fortrapping the oriental fruit moths.【Methods】The occurrence dynamics of adult oriental fruit mothsthroughout the year were determined based on the number of adult moths trapped using sex pheromone.Five trap-hanging heights were designed within 0-2.5 m above ground: 0, 1.0, 1.5, 2.0 and 2.5 m. During the eclosion peak of each of the 4 observed generations, the number of adult moths trapped bySAEWS and sex pheromone was monitored every 2 hours at the 5 heights for the continuous 72 hoursto study the diurnal activity rhythm of the oriental fruit moth. Based on the number of adult mothstrapped, the effects of SAEWS and sex pheromone on trapping the oriental fruit moth were explored.【Results】The trends in the number of adult moths trapped by sex pheromone as well as the time and du-ration of peak trapping were basically identical for the peach or neighbor apple orchard, the duration oftrapping by sex pheromone was from early April to early October, with four obvious peaks in bothpeach and apple orchards. The peaks in the peach orchard were concentrated from late May to late Au-gust, and were from middle June to late September in the apple orchard. In the peach orchard, moth trap-ping by sex pheromone mainly occurred during 3 time periods: May 20-June 19, June 22-July 19 and Ju-ly 28-August 25, with the greatest trapping number of adult moths in July 1. In the neighbor apple or-chard, moth trapping by sex pheromone mainly occurred during 3 time periods: June 22-July 19, July28-August 25 and August 28-September 24, with the greatest trapping number of adult moths in August19. At the emergence peaks of each generation, the trends in the dynamics of each 24 hours based onthe number of adult moths trapped by SAEWS as well as the duration time of peak trapping were in con-sistent with those observed by sex pheromone in both the peach and apple orchards, although the dura-tion time and peak trapping of adult moths by SAEWS and sex pheromone differed during the 72-hourcontinuous monitoring periods. During these monitoring periods, the trapping occurred at 16:00―22:00 and 4:00―8:00, with a peak trapping appearing at 18:00―20:00 each day and a smaller peak appearingat 4:00―8:00 hours since the second monitoring period (July 2-5) . In the peach and neighbor apple or-chards, the number of oriental fruit moths trapped by SAEWS was 5.4 moths · trap^-1 and 4.0 moths · trap^-1 respectively, significantly lower than that by sex pheromone (35.4 moths· lure^-1 and 37.1 moths· lure^-1) (α = 0.01) . During the eclosion period of each generation, moths were trapped at all the designed hang-ing heights from 0-2.5 m above ground by the SAEWS and sex pheromone traps in the peach-appleneighbor orchards, with different trapping effects among the trap hanging heights. The greatest numberof moths was trapped at 2.5 m above ground for both the SAEWS and sex pheromone traps, theamounts of moths trapped by SAEWS and sex pheromone in the peach orchard were 12.4 moths· trap^-1 and 67.3 moths· lure^-1, and in the neighbor apple orchard they were 12.8 moths· trap^-1 and 79.44 moths·lure^-1, respectively, significantly higher than those at any other heights (α = 0.01) . The SAEWS and sexpheromone trapping methods showed different effects at the same hanging height, with greater numberof adult moths trapped found by sex pheromone than by SAEWS for each hanging height. However, thedifference in the number of adult moths trapped between SAEWS and sex pheromone decreased alongwith the trap hanging height increasing, with the smallest difference existing at 2.5 m above ground. Inthe peach orchard, the total number trapped by sex pheromone (177 moths· lure^-1) was 6.6 times morethan that by SAEWS (26.76 moths· trap^-1) . The numbers of adult moths trapped by sex pheromone at 0, 1, 1.5, 2 and 2.5 m above ground were 38.5, 26.6, 7.4, 6.4 and 5.4 times more than those by SAEWS atthe same height, respectively. In the neighbor apple orchard, the total number trapped by sex pheromone (185.8 moths· lure^-1) was 9.3 times more than that by SAEWS (19.9 moths· trap^-1) . The numbers of adultmoths trapped by sex pheromone at 0, 1, 1.5, 2 and 2.5 m above ground was 27.2, 27.0, 32.2, 10.2 and 6.2 times more than those by SAEWS at the same height, respectively.【Conclusion】The SAEWS andsex pheromone performed well in trapping oriental fruit moths, and the trapping peak occurred at 4:00―8:00 and 18:00―20:00 during the monitoring period. In a peach-apple mixed-planting orchard, the max-imum number of adult moths trapped by SAEWS and sex pheromone occurred at 2.5 m above ground.