m. bozorg-amirkalaee

Pistachio psylla Agonoscena pistaciae Burckhardt & Lauterer is Iran's most important pest of pistachio trees. Due to the negative effects of excessive use of chemical insecticides, alternative strategies are necessary to control this pest. In this research, some resistance-inducing compounds, including chitosan, gamma-aminobutyric acid (GABA), and potassium silicate in pistachio trees, were studied on the percentage of population growth and detoxifying enzymes of this psyllid. Based on the results obtained, 7 days after spraying, the lowest and highest population growth of pistachio psyllid nymphs were observed in chitosan treatment and control, respectively. Also, the average growth percentage of the nymph population after 14 days did not show a significant difference among GABA, chitosan and potassium silicate, but it significantly decreased on these treatments compared to the control. In this study, the highest and lowest activity levels of esterase enzyme in psyllid nymphs were achieved in the control and chitosan treatments, respectively.On the other hand, the highest level of glutathione S-transferase activity was obtained in chitosan and potassium silicate treatments, and the lowest one was found in the control. The study results revealed that the different inducers could reduce the A. pistaciae population growth by generating physiological changes in the host plant and, subsequently the pest insect. Therefore, these compounds could be considered in the integrated management of this pest.

Induced resistance in plants can be manipulated using the application of elicitors. In this study, the effects of Salicylic Acid (SA), chitosan, γ-Aminobutyric Acid (GABA), Serenad Aso (Bacillus subtilis QST713), and combined application of these elicitors were studied on the resistance of canola to cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae). The number of B. brassicae attracted to canola plants treated with different inducers was significantly lower compared to the control in the field experiments. The lowest population density of aphid was observed on plants treated with SA+GABA and SA+chitosan. Moreover, the highest amounts of glucosinolates in canola leaves were recorded in SA+GABA treatment. The contents of sugar, lipid, and glycogen of B. brassicae were lowest when fed on the plants treated with SA integrated with GABA or chitosan. Furthermore, the activity of catalase, esterase, peroxidase and glutathione S-transferase enzymes was the lowest in SA+GABA and SA+chitosan. These findings suggest that exogenous application of SA integrated with GABA or chitosan on canola plants are successful in suppressing the B. brassicae population and can be considered in integrated management programs against this and other aphids.