ارزیابی آزمایشگاهی سمیت چند حشره‏ کش‏ شیمیایی روی شته مومی کلم Brevicoryne brassicae (Hemiptera: Aphididae) و بررسی انتخابی بودن آنها برای کفشدوزک شکارگر Hippodamia variegata (Coleoptera: Coccinellidae)

نوع مقاله : مقاله پژوهشی

نویسندگان

• حاصل مصری ¹
• اروج ولیزادگان ²
• اثمر سلیمان زاده ¹

¹ گروه گیاه پزشکی، دانشکده کشاورزی، دانشگاه ارومیه، ارومیه، ایران

² گروه حشره شناسی، دانشکده کشاورزی، دانشگاه ارومیه، ارومیه، ایران

چکیده

کلیدواژه‌ها

• اثر کشندگی
• اثر زیرکشندگی
• دینوتفوران
• فلوپیرادیفوران فلوکسامتامید

20.1001.1.20084781.1402.54.1.11.1

عنوان مقاله [English]

Laboratory assessment of some chemical insecticides toxicity on Brevicoryne brassicae (Hemiptera: Aphididae) and their selectivity for its predator, Hippodamia variegata (Coleoptera: Coccinellidae)

نویسندگان [English]

• Hasel Mesri ¹
• Orouj Valizadegan ²
• Asmar Soleymanzade ¹

کلیدواژه‌ها [English]

• Lethal effect
• Sub-lethal effect
• Dinotefuran
• Flupyradifurone
• Fluxametamide

Extended Abstract

Introduction

    The cabbage aphid, Brevicoryne brassicae L. is a serious pest of various crop plants from the family Brassicaceae, stunting plant growth, transmitting at least 20 viruses and causing 85% yield losses. The indiscriminate use of conventional insecticides has caused unwanted consequences, such as environmental pollution, harm to pests' natural enemies and insecticide residue. Accordingly, the development and use of insecticides that are  selective to pests have received more attention in recent decades. As part of integrated pest management (IPM) programs, choosing a selective insecticide with minimal effect on the natural predators and non-target insects, may be the most suitable option to control a pest. On the other hand, in addition to direct mortality induced by insecticides, insect pests that survive exposure to these products may experience behavioral and/or physiological modifications.  By life table analysis, it is possible to comprehend the overall toxicity of insecticides exactly on the pests. The variegated lady beetle, Hippodama variegata Goeze is considered one of the most active aphidophagous predators. Therefore, the current study aimed to evaluate the toxicity of insecticides flupyradifurone, fluxametamide and dinotefuran against adults of B. brassicae and adults and third instar larvae of H. variegata. Also, the sublethal concentration (LC₂₅) effect of the most effective insecticide was studied on B. brassicae population growth parameters.

Materials and Methods

   The trials were conducted in a completely randomized design, with five concentrations of treatment and three replications. Distilled water was used as control. Mortality was recorded after 24 hours. To estimate the toxicity of the tested insecticides on B. brassicae, the cabbage leaves were immersed in different concentrations of each of the chemical products for 10 seconds and then air-dried. These treated leaves were individually placed in a Petri dish (8 cm diameter) and 20 adult aphids were transferred to each leaf. The aphids were kept at 20 ± 1°C, 60% ± 5% RH, and a photoperiod of 16:8 h (L:D). Acute toxicity measurements for H. variegata were conducted using spray applications. The Petri dishes containing 10 adults or third instar larvae were sprayed with 1 mL of the toxic solution at different concentrations of each insecticide. Immediately after spraying, the excess run off solution was removed from the Petri dishes, and the dishes were then covered with mesh lids. The test predators were provided with cabbage aphids as a food source. To evaluate the sublethal effect of the most effective insecticide (flupyradifurone) on adult aphids, cabbage leaf discs were treated with LC₂₅ of insecticide for 10 seconds, following the above-mentioned method for lethal effect assessment. After the leaf discs dried, a total of 100 one-day-old adult aphids were placed on the treated leaf discs in individual Petri dishes. Distilled water was used as the control treatment. After 24-h exposure, the 55 surviving aphids were transferred to a new Petri dish without insecticide and were daily observed for progeny nymphs and parental aphid survival until the last aphid died.

Results and Discussion

    Probit analysis revealed flupyradifurone as the most effective insecticide against the pest, with an LC₅₀ value of 58.16 mg/L. The LC₅₀ values of fluxametamide and dinotefuran on B. brassicae were estimated at 173.98 and 415.54 mg/L, respectively. When compared to the control group, sublethal concentration (LC₂₅= 21.65 mg/L) of flupyradifurone treatment significantly reduced adult longevity from 17.65 to 13.87 days. The sublethal concentration of the insecticide also affected the progeny of treated adult aphids. The values of population growth parameters, including the intrinsic rate of increase, net reproductive rate, finite rate of increase and gross reproductive rate, were significantly lower with the LC₂₅ of flupyradifurone compared to the control. The 24h LC₅₀ values of flupyradifurone, dinotefuran and fluxametamide against adults and third instar larvae of H. variegata were determined as (1408.77, 427.79), (1005.17, 244.50) and (1287.21, 430.04) mg/L, respectively. The selectivity ratio and hazard quotient values indicated that all three insecticides are selective and safe for H. variegate.

Conclusion

    Selective chemical insecticides have become the dominant approach for the management of resistant insect pests. These chemical compounds, when used in combination with an effective natural enemy, may provide more effective control in the context of an integrated pest management program than either approach alone. In this study, results indicated that flupyradifurone had significant lethal and sublethal effects on B. brassicae. The obtained selectivity ratio and hazard quotient values showed that insecticides flupyradifurone, dinotefuran and fluxametamide are selective and safe for H. variegate. The information from this study will guide future studies and could be used as an effective tool for B. brrasicae management strategies.