تاثیر برخی ارقام خیار روی پارامترهای زیستی و رشد جمعیت شته‌ی جالیز aphis gossypii glover و واکنش تابعی بالتوری سبز (stephens) chrysoperla carnea

در این پژوهش، پارامترهای زیستی و رشد جمعیت شته‌ی جالیزglover  aphis gossypii پرورش یافته روی چهار رقم خیار شامل عرشیا، تاروم، کاسپین و دانیتو و واکنش تابعی لارو سن سوم بالتوری سبز chrysoperla carnea (stephens) در دمای 2±25 درجه ی سلسیوس، رطوبت نسبی 5±55 درصد و دوره‌ی نوری 16 ساعت روشنایی و هشت ساعت تاریکی مورد بررسی قرار گرفت. بیشترین مقدار نرخ ذاتی افزایش جمعیت (rm) و نرخ خالص تولیدمثل (r0) شته روی رقم تاروم (به‌ترتیب 0.009 ± 0.443 و 2.05 ± 30.14) و کمترین مقادیر آن‌ها روی ارقام کاسپین (به‌ترتیب 0.009 ± 0.297 و 1.55 ± 16.78) و دانیتو (به‌ترتیب 0.011 ± 0.305 بر روز و 1.60 ± 16.62 بر نسل) به‌دست آمد. واکنش تابعی لارو سن سوم شکارگر نسبت به شته‌ی جالیز روی هر چهار رقم خیار از نوع سوم به‌دست آمد. ضریب ثابت b برای لارو شکارگر در رقم‌های مورد بررسی بین 0.00121 تا 0.00168 و زمان دست‌یابی (th) آن بین 0.3145 تا 0.4596 ساعت متغیر بود. نتایج نشان داد رقم‌های تاروم و کاسپین به‌ترتیب میزبان‌های نسبتاً مطلوب و نسبتاً نامطلوب برای نشو و نما و تغذیه‌ی شته‌ی جالیز به‌حساب می‌آیند. همچنین با توجه به پارامترهای واکنش تابعی، به‌نظر می‌رسد ارقام کاسپین و دانیتو نسبت به دو رقم دیگر از کیفیت مناسب‌تری برای اعمال کنترل بیولوژیک این آفت برخوردار می‌باشند. با این‌حال، برای به‌دست آوردن اطلاعات بیشتر از برهم‌کنش‌های بین ارقام مختلف گیاه خیار، شته‌ی جالیز و بالتوری سبز نیاز است تا مطالعات بیشتری در شرایط گلخانه‌ای انجام گیرد.

effect of some cucumber cultivars on biological and population growth parameters of aphis gossypii (glover) and functional response of chrysoperla carnea (stephens)

extended abstract introduction: the melon aphid, aphis gossypii glover is a polyphagous pest that causes serious damage to various crops including vegetables. this insect is one of the most important pests of cucumber plant in greenhouses throughout the world. biological control is one of the alternative or complementary methods for chemical control that can be used in ipm programs. the use of natural enemies can be very effective in reducing the population of invasive pests. among biological control agents, chrysoperla carnea (stepehns) has attracted the most attention as an effective pest control agent. also, using resistant cultivars is one of the important methods for pest control management. therefore, the use of resistant cultivars with effective biological control agents plays an important role in pest control. the aim of this study was to investigate the effect of some cucumber cultivars on biological and population growth parameters of a. gossypii and the functional response of c. carnea. materials and methods: four cucumber cultivars including arshia, caspian, danito and tarom were used in this study. life table experiments were performed using 50 first instar nymphs (< 24 h old) for each cucumber cultivar. the nymphs were separately reared on the leaves of each cultivar. after emergence of adults, their fecundity and survival were recorded daily until all of them were dead. the parameters were estimated using twosex-ms chart, life table procedure. in the functional response experiment, different densities (2, 4, 8, 16, 32, 64 and 128) of 3- and 4-d- old aphid nymphs were separately offered to the third instar larvae of c. carnea, which were starved for 16 h before the test. the number of consumed preys was recorded after 24 h. the experiment was repeated 10 times for each aphid density and cucumber cultivar. logistic regression analysis and nonlinear least square regression procedure were used to determine the type of functional response and estimate the parameters, respectively. the experiments were carried out in a greenhouse at 25±2 °c, 65±5% rh and a photoperiod of 16:8 (l: d) h. results and discussion: based on the results, the highest values of intrinsic rate of increase (rm) and net reproductive rate (r0) of the aphid were estimated on tarom (0.443 ± 0.009 and 30.14 ± 2.05, resp.) and the lowest values were on caspian (0.297 ± 0.009 and 16.78 ± 1.55, resp.) and danito (0.305 ± 0.011 d-1 and 16.62 ± 1.60 per generation, respectively). the finite rate of increase (λ) ranged from 1.346 ± 0.013 on caspian to 1.557 ± 0.015 d-1 on tarom. the lowest values for mean generation time (t) and doubling time (dt) of the aphid were estimated on arshia and tarom cultivars. in the second experiment, the predator exhibited functional response type iii on all cucumber cultivars. the attack constant (b) for the third instar c. carnea varied from 0.00121 to 0.00168 and its handling time (th) ranged from 0.3145 to 0.4596 h on different cucumber cultivars. conclusion: comparison of the biological parameters showed that tarom cultivar with the highest values of rm and λ is a relatively desirable cultivar for the growth and feeding of a. gossypii. in contrast, caspian cultivar is less desirable for a. gossypii. also, according to the parameters of attack constant (b) and handling time (th), it seems that caspian and danito are more suitable cultivars for biological control of a. gossypii than other two cultivars. however, additional studies under greenhouse conditions are needed to provide further details of different cucumber cultivars, a. gossypii and c. carnea.