Lethal and sublethal effects of thiodicarb and hexaflumuron on egg parasitoid, Trichogramma brassicae Bezdenko under laboratory conditions
Article Type:
Research/Original Article (دارای رتبه معتبر)
Background And Objectives
Conservation of the natural enemies is an important approach to develop a biological control program. Knowledge of the side-effects of insecticides on parasitoids and using reduced-risk chemicals is a principal tool for integrating biological and chemical methods to pest management in agricultural ecosystems. Because of the important role of Trichogramma brassicae in lepidopteran pests control in agricultural ecosystems of Iran, this study was carried out to investigate lethal and sublethal effects of three concentrations of two insecticides, thiodicarb and hexaflumuron on this parasitoid under laboratory conditions.
Materials And Methods
Thiodicarb was prepared at three concentrations of 250, 500 and 1000 ppm and hexaflumuron was prepared at concentrations of 250, 500 and 750 ppm, and their effects were assessed through three exposure methods, including contaminating adult’s food (honey solution 10%) with insecticides, adult’s residual contact, and dipping parasitized (in prepupa stage of parasitoid) and unparasitized host eggs into insecticide solutions. Lethal effects on adult and immature stages of parasitoid and some sublethal effects such as male and female longevity and mean of daily oviposition were assessed for each insecticide/concentration.
Thiodicarb at all three concentrations and in both oral and contact exposure method caused 100% mortality in both male and female adults. Dipping parasitized host eggs in 1000 ppm concentration of thiodicarb caused 87.3% mortality in wasp prepupa population. In contrast, 750 ppm hexaflumuron in oral and contact exposure methods caused 30.2 and 30.54% mortality in adult female population, respectively and 60.55% mortality in wasp prepupa. Dipping unparasitized host eggs in highest concentration of thiodicarb and hexaflumuron resulted in 55.8 and 43.6% reductions in parasitism rate, respectively. Dipping unparasitized host eggs into both insecticide solutions reduced their parasitism significantly. Hexaflumuron in both oral and contact bioassay tests reduced significantly male and female longevity and mean of oviposition, but there was no significant difference among three concentrations of this insecticide.
According to the "total effect" and IOBC categories of toxicity, thiodicarb was found to be a "harmful" insecticide in both oral and contact exposure methods. Therefore, its application is not recommended in fields. Lethal effect of hexaflumuron was significantly lower than thiodicarb, categorized as a "slightly harmful" and "moderately harmful" insecticide in oral and contact exposure methods, respectively. However, because of high total effect of hexaflumuron on T. brassicae, using other less-toxic insecticides is recommended in IMP programs of lepidopteran pests, especially cotton boll worm.
Journal of Plant Protection, Volume:41 Issue: 1, 2018
75 to 89
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یک‌ساله به مبلغ 990,000ريال می‌توانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
  • حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران می‌شود.
  • پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانه‌های چاپی و دیجیتال را به کاربر نمی‌دهد.
In order to view content subscription is required

Personal subscription
Subscribe magiran.com for 50 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!