Applications of some compounds to induce resistance against cereal aphids (Hemiptera: Aphididae) in wheat fields

Among the different pests of wheat, cereal aphids are considered important pests that cause economic damage at high densities. Induced resistance by using some chemical and natural products can be an effective tool to control these pests in an integrated pest management (IPM) program. In this study, the effects of some potential resistance inducers, salicylic acid (SA), calcium silicate (CaSi), potassium silicate (PSi), and tea aquatic extract, on some cereal aphid populations were investigated under field conditions. Based on the results, almost no significant difference was observed between the potential resistance inducer treatments and the control on most sampling dates. The obtained results showed that there was no significant difference between the yield parameters, e.g., wheat spike length, spike numbers/m², seed numbers/m², seed numbers/spike, 1000 seed weight, wheat plant length, total spike weight/m² and total seed weight/ha, between the potential resistant inducer treatments and the control. The analysis of defensive compounds like hydrogen peroxide and flavonoids, along with the activities of defensive enzymes peroxidase and catalase, showed that there is no significant difference in the flavonoid and peroxide contents of plants treated with CaSi, PSi, SA, and tea extract. The peroxidase activity assay also indicated no significant difference among the treatments. Furthermore, although plants treated with PSi showed the lowest catalase activity compared to the other treatments, there was no significant difference in peroxidase activities among plants treated with the resistance inducers and control. Therefore, the study indicated that resistance inducers are not significantly effective in pest control.