Induction of resistance against Brevicoryne brassicae by Pseudomonas putida and salicylic acid in canola

The cabbage aphid, Brevicoryne brassicae L. (Hem: Aphididae), is one of the most serious pests of canola worldwide. In this research, the effects of Pseudomonas putida, salicylic acid (SA), and integrated application of both inducers were studied on the resistance of canola to B. brassicae. In free-choice situation, the number of B. brassicae attracted on canola plants under treatments containing P. putida and SA was significantly lower compared to control plants. In the life table study, pre-adult survival, longevity, reproductive period, and fecundity of this aphid were lowest on plants treated with P. putida + SA. The net reproductive rate (R0), intrinsic rate of population increase (r), and finite rate of increase (λ) of B. brassicae decreased significantly in the following order: control (47.19 offspring, 0.293 and 1.340 day−1), P. putida (16.7 offspring, 0.238 and 1.269 day−1), SA (6.37 offspring, 0.163 and 1.178 day−1), and P. putida + SA (3.24 offspring, 0.112 and 1.119 day−1). Moreover, the beneficial effect of the integrated application of P. putida and SA on plant growth parameters was significantly evident in our study. The highest values of glucosinolates, total phenol, and flavonoids were recorded in P. putida + SA treatment. We concluded that canola plants treated with P. putida + SA are more resistant to the cabbage aphid. These findings demonstrated that SA integrated with P. putida on canola plants act effectively for reducing the population of B. brassicae and can be used in integrated management programs of this pest.