تاثیر اسانس فرموله شده بذر زنیان Trachyspermum ammi (L.) بر برخی ویژگی‌های زیستی و فیزیولوژیک کرم غوزه پنبه Helicoverpa armigera Hüb.

نوع مقاله : مقاله پژوهشی

نویسندگان

• داود محمدی ¹
• فاطمه رشکی هروان ²
• رضا فرشباف پورآباد ³

¹ گروه گیاه پزشکی، دانشکده کشاورزی، دانشگاه شهید مدنی آذربایجان، تبریز-ایران

² گروه گیاه‌پژشکی، دانشکده کشاورزی، دانشگاه شهید مدنی آذربایجان، تبریز، ایران.

³ گروه گیاه‌پزشکی، دانشکده کشاورزی، دانشگاه اگه، ازمیر، ترکیه

چکیده

کلیدواژه‌ها

• اسانس
• تیمول
• مرگ و میر
• مهارکننده آنزیم

موضوعات

• دیگر روشهای مرتبط با بیوکنترل

Extended Abstract

Introduction

The use of chemical pesticides as the most common method of pest control with less selective properties, has resulted in problems such as residual, development of resistance in pests, negative effects on natural enemies, and consequently pest outbreaks. These problems have led to develop alternative control methods with fewer adverse effects in recent years. Plant extracts and essential oils with acceptable insecticidal, antifeedant, repellent, attractant, lower cost and less environmental pollution properties can be used in pest management programs.

Cotton bollworm is one of the most important pests of agricultural crops, vegetables and even ornamentals. It is a polyphagous insect and the use of various pesticides in high concentrations has led to develop resistance to a wide range of chemical pesticides from different groups. Alternative methods for controlling this pest include agricultural methods, biological control, the use of resistant plants, the use of plant metabolites, and integrated pest management recommended by researchers in the field of plant conservation.

Trachyspermum ammi is an annual plant belonging to the apiaceae family which has a high percentage of essential oil in its seeds. Numerous studies have been conducted on the biological effects of this plant essential oil on insects, including the fumigant effect, repellency, digestive system disruption, physiology and other sublethal effects on biology of insects. In recent years, with the expansion of attention to biological pesticides, the insecticidal effects of this plant have also been well studied, including its fumigant, lethal effects, antifeedant, larvicidal, and repellent effects against various pests.

The present study aimed to investigate the various biological, behavioral, and physiological effects of T. ammi essential oil emulsion on cotton bollworm.

Material and Methods

Insects reared in controlled condition on artificial diet. The essential oil of T. ammi seeds was prepared by water distillation using Clevenger apparatus. To prepare the emulsion of EO, Tween 20 used as emulsifier.

Gas chromatography mass spectrometry (GC-MS) was used to identify the essential oil chemical composition.

Biological effects including ovicidal, repellent activity, fumigant toxicity and sublethal effects including larval life span, adults and pupa emergence, mortality during generation recorded. Inhibitory activity of essential oils in different concentrations on alpha-amylase, protease and acetylcholine esterase, carried out using standard protocols.

The data was analyzed using SPSS v: 26 software. In case of observing mortality in control treatments, the Abbot formula was used to correct the data. SPSS software and F-test were used for data analysis and mean comparisons.

Results and discussion

The main identified compounds of the T. ammi essential oil extract, using gas chromatography, include thymol, cymene, and terpinene, with percentages of 61.6%, 18.5%, and 14.4%, respectively.

The ovicidal assays indicate that, with increasing the concentration of the EO hatching rate decreased. the concentration of 2.5 percent showed up to 80% ovicidal toxicity. The LC₅₀ value obtained was 0.632 percent. The slope of the concentration-mortality line was calculated to be 1.36.

The highest concentration of the oil, 500 microliters per liter, caused 100% mortality of larvae, and after that, with a concentration of 250 µl/l air, 81.66% mortality recorded. The LC₅₀ and LC₇₀ values were calculated as 82.73 and 151.14 µl/l air, respectively. The slope of the concentration-mortality line was also calculated as 2.002.

About repellent activity of T. ammi essential oil, a repellency rate of 61 to 76 percent was observed for 3^rd and 64 to 76 percent for 6^th larvae instars at different time intervals of 6 to 16 hours.

with increasing the concentrations, the length of larval developmental period increased, and a direct relationship between the concentration of the essential oil and the length of the larvae developmental duration was recorded. At concentrations of 2.5 and 1.25 percent of T. ammi essential oil, the length of the larvae developmental period increased to 9 and 7 days, respectively, in comparing with the control.

About sublethal effects, the highest concentration of essential oil (5%) completely prevented the pupation and adult’s emergence. Even at the lowest concentration of T. ammi essential oils (0.039%), only 28% pupation and adult emergence appeared, indicating the significant effect of the essential oil on the population of cotton bollworm. Also some deformities were also observed in the emerged pupas.

The essential oil of T. ammi caused significant inhibition of alpha-amylase, protease and acetylcholinesterase enzymes activity in 6^th instar larvae of cotton bollworm.

Conclusion

According to the results of current research, the formulated essential oil of T. ammi has good potential to manage cotton bollworm. The observed biological and physiological effects indicate the significant impact of this essential oil in reducing the population of cotton bollworm.