اثر القاي مقاومت گياهي در گياه گوجه‌فرنگي با پيپرونيليك اسيد بر ويژگي‌هاي جدول زندگي- باروري سفيدبالك پنبه و حساسيت آن به قارچ بيمارگر Beauveria bassiana

The cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most important agricultural pests worldwide, causing substantial economic losses, particularly in greenhouse crops, through direct feeding on plant sap an‎d transmission of plant pathogens. The entomopathogenic fungus Beauveria bassiana is among the most important insect pathogens an‎d has been successfully utilized in biological control programs. This fungus has demonstrated high efficacy against various whitefly populations, especially under greenhouse conditions. In addition to biological control, plant resistance inducers play a significant role in plant protection by reducing plant susceptibility to biotic stressors. The aim of the present study was to eva‎luate the compatibility an‎d potential synergistic effects of the simultaneous application of piperonylic acid an‎d B. bassiana for the control of B. tabaci on tomato plants. Tomato plants were treated with 1000 μM piperonylic acid. The treatment significantly increased internode length, leaf length, plant height, an‎d the dry weight of both aerial an‎d underground plant parts compared with the untreated control. However, total phenolic content did not differ significantly between treated an‎d untreated plants. The acute toxicity of piperonylic acid against whitefly nymphs was assessed through foliar application on tomato plants. Although cumulative mortality increased after 24 hours, no statistically significant difference was observed between treated an‎d control groups. Chronic toxicity was eva‎luated by measuring oviposition an‎d egg hatchability. Both parameters decreased in treated insects, but these reductions were not statistically significant. Several fitness-related parameters of B. tabaci feeding on piperonylic acid-treated plants were also examined. The intrinsic rate of increase an‎d total fecundity of treated insects decreased significantly by 51% an‎d 47%, respectively, compared with the control. The duration of the egg stage an‎d the first an‎d second nymphal instars increased significantly by 17%, 20%, an‎d 10%, respectively. Furthermore, the pre-adult period, total pre-oviposition period, an‎d population doubling time increased significantly by 9%, 8%, an‎d 99%, respectively, compared with the control insects. The effect of B. bassiana on second-instar nymphs an‎d adults of B. tabaci reared on piperonylic acid-treated plants was also investigated. The LC₅₀ values of the fungus against both life stages were significantly lower for insects reared on treated plants than for those reared on untreated plants. The results of this study indicate that the plant resistance inducer piperonylic acid not only reduces the fitness of B. tabaci but also increases its susceptibility to the entomopathogenic fungus B. bassiana. Therefore, piperonylic acid may represent a promising component of integrated pest management programs.

نفيسه پورجواد , لادن طلايي

بهرام شريف نبي

جهانگير خواجه علي , مهديه غلامي