Background: Insect damage induces chemical changes in plants, and frequently these changes are part of a defensive response to the insect injury. Induced resistance was activated in winter wheat using a foliar application of synthetic jasmonic acid. Field trials were conducted to observe effects of jasmonic acid application on some wheat insects. Two wheat cultivars (Cubus and Tommi) were sprayed twice at growth stages (GS) 41 and 59 with two concentrations of jasmonic acid, along with control plots that were sprayed with water.
Results: There was a significant difference in the number of thrips and wheat blossom midges (WBM) among treatments in both cultivars. Plants in control plots had higher numbers of thrips and midges than in treated plots. There were higher numbers of thrips in the Tommi cultivar than in the Cubus cultivar, while the latter had higher numbers of WBM larvae than the Tommi cultivar. There was a positive correlation between WBM numbers and infested kernels in both cultivars. This study also indicated that jasmonic acid enhances the wheat yield in sprayed plots compared with control plots.
Conclusions: The results indicate that jasmonic acid induced pest resistance in wheat plants and may act as a resistance mechanism of wheat against insect herbivores.