Background and Objectives

Grapevine (Vitis vinifera L.) is one of the most economically important horticultural crops cultivated in the arid and semi-arid regions of Iran. In southeastern Iran’s Sistan region, viticulture plays an important socioeconomic role; however, vineyards frequently face severe environmental stresses, including arid winds and pest outbreaks. Among arthropod pests, vine leafhoppers (Hemiptera: Cicadellidae) are major limiting factors. Both nymphs and adults cause direct physiological injury by piercing leaf tissues and feeding on plant sap, resulting in characteristic chlorotic stippling, leaf curling, premature senescence, and substantial yield losses. Despite their prevalence, information on leafhopper species composition, dominant fauna, associated natural enemies, and varietal resistance mechanisms remains scarce in Sistan’s extreme desert agroecosystems. Therefore, this study aimed to (1) identify the leafhopper fauna of Sistan vineyards, (2) determine the relative abundance and dominance of the identified species, (3) survey and identify their associated biological control agents, and (4) evaluate the oviposition preference and host susceptibility of eight commercial grape cultivars to the dominant leafhopper species.



Materials and Methods

Field and laboratory investigations were conducted during two consecutive growing seasons (2019–2021) in representative commercial vineyards across the Sistan plain. Leafhopper populations were systematically monitored and sampled biweekly from April to October using a standard sweep net, a motorized D-Vac suction sampler, and handheld aspirators. Collected adults were preserved, cleared in 10% KOH solution, and identified to species level using diagnostic morphological keys and dissection of male genitalia. Natural enemies, including egg parasitoids, predators, and predatory mites, were simultaneously collected, reared under controlled laboratory conditions (25 ± 1°C, 65 ± 5% RH, 16:8 h L:D), and taxonomically identified. Host preference was assessed using a no-choice oviposition bioassay involving eight grape cultivars: ‘Yaghouti-e-Ghermez’, ‘Shahani’, ‘Askari’, ‘Perlette’, ‘Yaghouti-e-Sefid’, ‘Bidaneh-e-Qazvin’, ‘Cardinal’, and ‘Fakhri’. The experiment was arranged in a randomized complete block design (RCBD) with three replications. The mean number of endophytic eggs deposited per leaf was determined under a stereomicroscope. Data were tested for normality and subjected to one-way analysis of variance (ANOVA), and treatment means were compared using Tukey’s honestly significant difference (HSD) test at P ≤ 0.05 in SAS software (v9.4).



Results

Three leafhopper species were identified in Sistan vineyards: Arboridia kermanshah Dlabola, Empoasca decipiens Paoli, and Anaceratagallia laevis (Ribaut). Arboridia kermanshah was the eudominant pest species, accounting for 73.31% of all captured individuals, followed by E. decipiens (26.45%) and A. laevis (0.24%). Surveys of natural enemies identified a beneficial guild comprising the egg parasitoid Anagrus atomus (L.) (Hymenoptera: Mymaridae), Trichogramma sp. (Hymenoptera: Trichogrammatidae), the green lacewing Chrysoperla sp. (Neuroptera: Chrysopidae), and the predatory mite Anystis baccarum (L.) (Acari: Anystidae). Notably, A. atomus showed the highest emergence abundance, coinciding with peak oviposition periods of A. kermanshah. Oviposition preference differed significantly among grape cultivars (F7,14 = 45.41, P < 0.001). The locally prominent cultivar ‘Yaghouti-e-Ghermez’ was the most susceptible host, with the highest egg density (7.56 ± 0.28 eggs/leaf). In contrast, ‘Shahani’ (2.71 ± 0.18 eggs/leaf) and ‘Fakhri’ (2.84 ± 0.20 eggs/leaf) had the lowest egg densities, indicating marked antixenotic resistance. No significant linear correlation was detected between leaf trichome density and the oviposition preference of A. kermanshah. Host selection may therefore be influenced by other leaf anatomical characteristics or biochemical profiles, which warrant further investigation.



Discussion

The results indicate that A. kermanshah is the primary leafhopper pest in Sistan vineyards. The established presence and high natural activity of the egg parasitoid A. atomus indicate considerable potential for conservation biological control. In addition, the marked antixenosis observed in cultivars such as ‘Shahani’ and ‘Fakhri’ provides a potentially valuable cultural control strategy. Integrating host-plant resistance with the conservation of indigenous natural enemies may provide an ecologically sound and sustainable integrated pest management (IPM) framework for viticulture in arid regions.