Evaluation of reported volatile components and blends on field trapping of leopard moth, Zeuzera pyrina L. (Lep.: Cossidae) in the Iranian walnut orchards‎.

Leopard moth, Zeuzera pyrina L. (Lep.: Cossidae), is a key pest of walnut in Iran. The pheromone of this pest can be used for controlling its damage. The commercially available pheromone of this pest is a blend of (E,Z)-2,13-octandecadienyl acetate (95%) and (E,Z)-3,13-octandecadienyl acetate (5%) does not always capture this pest. The same components, with similar ratios (97% and 3% respectively), are presented as the pheromone of currant clearwing moth, Synanthedon tipuliformis Clerk (Lep.: Sesiidae), which also attracts Leopard moth in Iran. On the other hand, some other blends with different components are mentioned in references as the leopard moth female-specific volatiles, causing behavioral response in males. In this study, the efficiencies of these reported molecules or blends were investigated in Iranian walnut orchards. The results showed that there were differences in capture rate of leopard moth by different molecules and blends. (E,Z)-2,13-octandecadienyl acetate and (E,Z)-3,13-octandecadienyl acetate (the components of commercial pheromones of leopard moth and currant clearwing moth) were not attractive or poorly attractive for leopard moth. But the blends of these two molecules with respectively 95:5 (leopard moth sex pheromone) and 97:3 (currant clearwing moth sex pheromone) were attractive. The results showed the synergic effect of these two components. The males of leopard moth were also attracted by the most of the blends (3 of 4 blends) containing (Z)-13-octandecenyl acetate confirming the role of this molecule as a minor component of Leopard moth sex pheromone. Only one of the blends containing (Z)-13-octandecenyl acetate didn't capture any male, probably due to the antagonistic effect of (E)-2-octandecenyl acetate, which was present in this blend. It seems that (Z,Z)-2,13-octandecadienyl acetate and octandecyl acetate didn't have any behavioral effect. It can be concluded that (E,Z)-2,13-octandecadienyl acetate, reported in all references with the highest quantity, is the major component; while (E,Z)-3,13-octandecadienyl acetate and (Z)-13-octandecenyl acetate, reported respectively in two and four of references with lower quantities, are the minor components of leopard sex pheromone. (E,Z)-3,13-octadecadienyl acetate or (E,Z)-2,13-octadecadienyl acetate and the blends of these two molecules (with trested amounts) were attractive for S. myopaeformis and they can be used for minitoring of this pest. (E,Z)-2,13-octadecadienyl acetate showed an additional effect on the attraction of (E,Z)-3,13-octadecadienyl acetate.