**1. Introduction**

Green peach aphid, *Myzus persicae* (Sulzer) (Hemiptera: Aphididae), is one of the most damaging insect pests throughout the world, with more than 800 host plant species [1]. Its feeding on the sap leads to chlorosis and necrosis spots, honeydew production, and a dramatic reduction in the marketability of crops [2]. Along with direct losses due to nutritional activities, *M. persicae* can indirectly impair the host plants by the transmission of pathogenic viruses as an efficient vector [3,4]. As a holocyclic species, *M. persicae* can produce both the sexual population with the ability of genetic adaptation against environmental pressures and asexual generations to create large populations [5]. These characteristics have made *M. persicae* a very harmful pest on a wide range of crops, orchards, and greenhouses [6].

Although the chemical control is the main method in the managemen<sup>t</sup> of aphids, overuse of synthetic insecticides has led to various side effects, including insecticide resistance, the outbreak of secondary pests, negative effects on beneficial organisms, and dangerous residues on foods [7–9]. Therefore, the application of chemical insecticides must be replaced by eco-friendly and efficient methods, such as resistant host plants [10].

**Citation:** Raeyat, Z.; Razmjou, J.; Naseri, B.; Ebadollahi, A.; Krutmuang, P. Evaluation of the Susceptibility of Some Eggplant Cultivars to Green Peach Aphid, *Myzus persicae* (Sulzer) (Hemiptera:Aphididae). *Agriculture* **2021**, *11*, 31.https://doi.org/10.3390/ agriculture11010031

Received: 23 November 2020 Accepted: 21 December 2020 Published: 4 January 2021

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The use of resistant plants, as one of the most prominent pest managemen<sup>t</sup> tools, is an effective way to reduce the utilization of chemical pesticides [11,12]. Due to differences in food quality, morphological characteristics, and other host-dependent factors, the performance of aphids may change on plant cultivars (CVS) [13–15]. In general, the plant resistance is classified into three categories, including tolerance, antibiosis, and antixenosis. Tolerance is defined as the ability of a plant to diminish or to recover from herbivore damage. Tolerance mechanisms may be associated with increases in photosynthesis, compensatory growth, and utilization of stored materials [16,17]. For instance, in the study of Nampeera et al. [2], the production of large leaves and/or the repair of leaves of *Amaranthus* sp. were considered as tolerance mechanism evidence against *M. persicae* damage. Antixenosis, as an insect-preferred reaction, is the genetic resistance of a plant. Antixenosis represents specific morphological and chemical characteristics of the host plant that adversely affect the behavior of the insect, and lead to the selection of another host by the pest [18–20]. Antibiosis resistance is formed in plants based on biological traits of insects, such as survival, longevity, and fertility. It pronounces the inefficiency of a plant as a host, leading to select another host plant by the pests [21]. The importance of host plant resistance in integrated pest managemen<sup>t</sup> strategies has led many researchers to study its categories in different crops for various insect pests, including aphids [22–24]. For example, resistance of seven cabbage CVS and six potato CVS against *M. persicae* was documented [25,26].

Eggplant, *Solanum melongena* L. (Solanaceae), with grea<sup>t</sup> morphological and genetic diversity is renowned as an economically important vegetable crop, especially in Asia and the Mediterranean regions [27]. After potato and tomato, eggplant is the third-largest crop of the Solanaceae family [28]. In terms of nutritional value, eggplant is one of the valuable vegetables for human health due to its high content of vitamins, minerals, and biologically active compounds [29–31]. Due to the economic importance of eggplant and detrimental side effects caused by the use of synthetic insecticides, it is necessary to introduce its resistant CVS against pests. Therefore, the main objective of the present study was a) to identify possible resistance and susceptibility of eggplant cultivars and b) to determine the type of possible resistance categories, including antixenosis, antibiosis, and tolerance, against *Myzus persicae*. Hence, the results of the present study may provide useful information for the integrated managemen<sup>t</sup> of *M. persicae* on eggplant.

#### **2. Materials and Methods**

#### *2.1. Collecting and Breeding Aphid Colonies*

About two-hundred apterous female adults of aphids were collected from the research greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. After collection, apterous female adults of aphids were transferred to the four-leaf stage of the pepper (*Capsicum annum* L.: 'California wonder' cultivar (CV.)). Aphids was reared for three generations on all fourteen CVS of eggplant and pots were kept in the greenhouse at 25 ± 5 ◦C, 60 ± 10% Relative Humidity (RH), and a natural photoperiod.

#### *2.2. Cultivation of Eggplant Cultivars*

Seeds of 14 eggplant cultivars, including 'Bianca-Tonda', 'Black-Beauty', 'Calliope', 'Florida-Market', 'Long-Green', 'Green-Oblong', 'Pearl-Round', 'Purple-Violetta', 'Purple-Panter', 'Ravaya', 'Red-Round', 'Rosa-Bianca', 'White-Casper' and 'White-Eggplant' were obtained from Johnny's seeds, (Larosa, Reimerseeds Company, Maryland, USA). Before planting, the seeds were soaked for 12 h in the paper towel. The seeds were then planted in the cultivated tray with coco peat and perlite in equal proportions as a growing medium. When seedlings reached the two-leaf stage, they were transferred to plastic pots (20 cm diameter and 14 cm height) with a mixture of soil, sand, and manure (1:1:2). The pots were kept in the greenhouse at 25 ± 5 ◦C, 60 ± 10% RH, and a natural photoperiod.
