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Abstract

The effects of application of an artificial honeydew mixture of glucose, fructose and trehalose (GFT), honey and Bemisia tabaci nymph-extract as kairomonal sources in enhancing the foraging efficiency and performance of Eretmocerus sp. near furuhashii on cucumber plants were studied. Experiments were conducted in small greenhouses (4×3×3 m) using life table methods. Life table data indicated that the total mortality in B. tabaci immature cohorts in all treatments was in the order of fourth instar > first instar > second = third > egg > pupa cohorts. The tested kairomonal materials had a significant effect on the rate of parasitism (p > 0.0415) with 13.23, 9.04 and 10.54% higher than that of control in artificial honeydew of GFT, nymph-extract and honey treatments, respectively. B. tabaci egg/adult survival ratio was also significantly affected (p > 0.0001) by the tested kairomonal sources being lowest (22.91%) in nymph-extract treatment. Moreover, the tested kairomonal materials arrested significantly more parasitoids to colonize the treated plants comparing to control. Apparently, the tested materials were significantly effective in attracting the parasitoids up to 3 days after applications then significant difference was not found between treatments.

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Authors and Affiliations

Nasser Said Mandour
Shun-xiang Ren
Bao-li Qiu
Felix Wäckers
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Abstract

The green peach aphid, Myzus persicae (Sulzer), is a polyphagous and holocyclic aphid which significantly damages agricultural crops. In the current study, the effects of micronutrients on some secondary metabolites of bell pepper (Capsicum annum L.) leaves and their subsequent influence on the life table parameters of M. persicae were investigated under greenhouse conditions. The flavonoid content in bell pepper leaves significantly changed following micronutrient treatments in the wavelength of 270 nm while there were no significant differences in the wavelengths 300 and 330 nm. The highest anthocyanin content was recorded after Fe treatment (3.811 mg ⋅ ml–1) while the total phenolic content in the bell pepper leaves increased after Mn (541.2 mg ⋅ ml–1) treatment compared to Fe (254.5 mg ⋅ ml–1) and control (216.33 mg ⋅ ml–1), respectively. The highest values of intrinsic (r) and finite rates of population increase (λ) of M. persicae were gained with Zn (0.320 and 1.377 day–1, respectively) treatment although the highest and the lowest values of the mean generation time (T) were found with Fe and Zn (14.07 and 12.63 days, respectively) treatments, respectively. Our findings suggest that Mn, more than Zn micronutrients, decreased ecological fitness of green peach aphid and may help enhance the efficiency of pest control techniques.

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Authors and Affiliations

Tayebeh Alizamani
Jahanshir Shakarami
Mozhgan Mardani-Talaee
Arash Zibaee
Jose Eduardo Serrão
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Abstract

The current survey was carried out to evaluate the effect of different nitrogen levels (0, 2.1, 3.0, 3.9 g ∙ pot–1 nitrogen as urea 46%) on tomato fruit worm Helicoverpa armigera on six common tomato cultivars (e.g., Kingston, Riogrand, Earlyurbana, Redston, Superstrain-B and Primoearly) under laboratory conditions [25 ± 1°C, 60 ± 5% RH, 16 : 8 (L : D) h]. The mortality, developmental period of immature stages as well as the longevity and fecundity of adult stages were recorded. Data were analyzed based on the age-stage, two-sex lifetable theory. The longest (24.21 ± 0.59 days) larval developmental period was recorded in Earlyurbana variety with zero nitrogen level and the shortest (15.44 ± 0.36 days) in Superstrain-B variety with the highest nitrogen level. Consequently, the net reproductive rate (R0) ranged from 35.7 ± 7.06 to 62.16 ± 18.9 offspring/female/individual in Redston variety with zero nitrogen level and in Superstrain-B variety with the highest nitrogen level, respectively. The lowest and highest values of the intrinsic rate (r) and finite rate of increase (l) were estimated for Redston variety with zero level of nitrogen (0.0712 ± 0.0065 and 1.0732 ± 0.0069 day–1) and Superstrain-B variety with the highest nitrogen fertilizer (0.1507 ± 0.0057 and 1.1629 ± 0.0066 day–1), respectively. The results demonstrated that nitrogen fertilizer influenced nearly all the life parameters of the pest which depended on the cultivars. Finally, it could be concluded that Kingston and Superstrain-B were suitable and Earlyurbana and Redston were unsuitable host plant cultivars for H. armigera.

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Authors and Affiliations

Fereshteh Salehi
Gholamhossein Gharekhani
Jalal Shirazi
Nahid Vaez

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