Susceptibility to Arthropod Pests of Mildew-Resistant Grape Varieties: What Do We Know and Where Are We Going?

Abstract

Grapevine breeding has successfully developed mildew-resistant varieties, yet their susceptibility to arthropod pests remains largely unexplored. This review synthesizes current knowledge of arthropod pest interactions with mildew-resistant grapevines and compares them with those of conventional and parental varieties. Only a few studies have reported detailed information on arthropod pest susceptibility, covering 23 resistant varieties tested against seven species/groups, including Daktulosphaira vitifoliae, Lobesia botrana, Drosophila suzukii and eriophyid mites. About half of the available studies focused on berry pests—particularly the invasive D. suzukii—while leaf and root pests received little attention. In several cases, resistant varieties exhibited susceptibility levels comparable to those of their parental varieties, although the limited number of studies makes it difficult to draw clear conclusions. Overall, major knowledge gaps remain, highlighting the need for breeding programs that integrate mildew resistance with improved assessment of arthropod pest susceptibility, without compromising agronomic performance and wine quality.

1. Grapevine and Biotic Stresses

Biotic stresses in plants are caused by living organisms—vertebrates and invertebrates, weeds, and pathogens—and can reduce crop fitness, causing yield and quality losses [1,2,3,4]. These impacts extend beyond the field, affecting the social, economic and ecological sustainability of crop production [5,6,7,8]. Plant domestication has often reduced resilience, unintentionally increasing susceptibility to pests and pathogens. In grapevine, as in other perennial crops, the selection for traits such as yield, cluster compactness and berry quality during domestication has often been accompanied by a loss of natural defenses, including structural barriers and secondary metabolites that deter herbivores. Modern varieties of Vitis vinifera L. are particularly susceptible to both fungal pathogens and arthropod pests because this plant species evolved in environments where major biotic stressors—such as the grape phylloxera Daktulosphaira vitifoliae (Fitch) (Hemiptera: Phylloxeridae), the downy mildew Plasmopara viticola (Berk. & M.A. Curtis) Berl. & De Toni (Oomycetes: Peronosporaceae) and powdery mildew Erysiphe necator (Schwein.) Burrill (Leotiomycetes: Erysiphaceae)—were absent, and therefore it did not coevolve effective resistance to them [9]. Experimental evidence further shows that V. vinifera lacks effective defense responses against the root-feeding stages of D. vitifoliae, which can exploit infected tissues as nutrient reservoirs without triggering hypersensitive or structural reaction [10]. Consequently, the recovery and integration of traits associated with host plant resistance (HPR) is a desirable goal within Integrated Pest Management (IPM) strategies [11,12,13].

Grapevine is one of the world’s most important crops for wine and table grape production (about 7.3 million ha yielding >70 million tonnes of grapes, ~40% in Europe [14,15,16]). Grapevine production frequently depends on intensive insecticide and fungicide use; in table grapes, insecticide applications may reach 10 treatments per year [17]. Major pathogens causing economic losses in vineyards include downy mildew P. viticola, powdery mildew E. necator and gray mold Botrytis cinerea Pers. (Leotiomycetes: Sclerotiniaceae). Developing varieties resistant to downy and/or powdery mildews is a promising approach to reduce crop losses and pesticide use [17,18,19]. In addition to the loss of structural defenses, biochemical and signaling-based mechanisms also play a crucial role in shaping grapevine responses to biotic stress. However, the resistance mechanisms conferring protection against fungal pathogens, mainly mediated by salicylic-acid signaling and hypersensitive response genes (e.g., Rpv and Ren loci), may interact antagonistically with jasmonic-acid– and ethylene–dependent pathways that govern resistance to chewing or sucking arthropods. While this hormonal crosstalk is well-documented in model plants, recent transcriptomic and molecular studies in V. vinifera and Vitis hybrids confirm that this antagonism operates via a highly specific transcriptional reprogramming web. Specifically, when a vine perceives a biotrophic fungal pathogen, the activation of Rpv or Ren loci triggers a massive salicylic-acid-dependent signaling cascade, upregulating key regulatory genes in susceptive varieties, such as VvNPR1, specific VvWRKY transcription factors, and downstream pathogenesis-related proteins like VvPR1 [20,21]. This intense salicylic-acid-mediated transcriptional shift actively suppresses the lipoxygenase biosynthetic pathway—mirroring mechanisms observed in other plants [22,23,24]—and downregulates VvMYC transcription factors, which simultaneously impairs jasmonic acid-dependent defense responses including abiotic adaptations like cold tolerance [25]. Furthermore, this regulatory network intimately intersects with auxin signaling, a crucial driver of biotic stress homeostasis that regulates physical defense adaptations, including leaf trichome development [26,27]. This multi-hormonal cross-talk can potentially generate metabolic trade-offs by pleiotropically altering structural defenses or secondary metabolite profiles—such as flavonoids and protective phenolics—leading to unpredictable susceptibility patterns in newly bred resistant varieties [28,29,30,31]. Because modern PIWI varieties possess highly diverse genetic backgrounds depending on their unique wild parentage, these introgressed genomic fragments introduce highly variable baseline hormonal cross-talk and metabolic resource cross-allocation. This complex genomic friction may explain why final pest susceptibility patterns remain highly variable and unpredictable in newly registered resistant varieties [32]. Consequently, these hypotheses must be rigorously tested ad hoc within the pest–grapevine system.

Beyond pathogens, grapevine is attacked by numerous arthropod pests, including grape berry moths (Lepidoptera: Tortricidae), leafhoppers (Hemiptera: Cicadellidae), mealybugs (Hemiptera: Pseudococcidae) and mites (Acari: Eriophyidae, Tetranychidae) [17]. Arthropod pest and disease pressure forced growers to rely heavily on pesticides [33,34], which raise concerns for human health and the environment [17,35]. Intensive pesticide use also promotes resistance development and pest resurgence, e.g., [36,37,38,39,40,41]. The reduction or elimination of fungicide sprays in mildew-resistant vineyards can also influence arthropod communities, potentially favoring the non-target pests while enhancing populations of predators and parasitoids. Consequently, evaluating arthropod pest susceptibility in resistant varieties cannot be dissociated from the broader ecological context in which these grapevines are cultivated [42,43,44,45]. Despite significant progress in breeding mildew-resistant grapevine varieties, their interactions with arthropod pests remain poorly understood. Information on arthropod pest susceptibility is fragmented and often limited to a few species or varieties, leaving major gaps in our understanding of their broader resistance profile. This review summarizes current knowledge on the susceptibility of mildew-resistant grapevine varieties to invertebrate pests, comparing available data with those of conventional varieties and, where possible, their parental lines.

2. Methodology

Literature Research

The literature research was performed by searching in Google Scholar, Web of Science and Scopus, using a combination of the following terms:

“[variety name]” AND “resistan*” or “susceptib*” or “toleran*” AND “beetle*” or “leafhopper*” or “mite*” or “moth*” or “nematode*” or “pest*” or “phylloxera*” or “scale*”

all the terms were used in multiple logical combinations. The research was also conducted in Italian, German and French, and included articles in languages other than those listed above. As concerns mildew-resistant varieties, the list was retrieved from Pertot et al. [17] and Vitis International Variety Catalogue (VIVC; [46]); the varieties derived from the VIVC we have chosen are listed as resistant to P. viticola and/or E. necator.

For resistant varieties with at least one pest-susceptibility study, we also examined susceptibility traits of one or both parental varieties using VIVC data [46]. Because available information on arthropod pest interactions with mildew-resistant varieties is limited, we present results descriptively and discuss them in the context of existing knowledge gaps.

3. Where Do We Come from? Grape Varieties Resistant to Mildews

Grapevine breeding aims to modify key growing-season traits, including phenological timing, enhance tolerance to cold and drought stress, and improve resistance to diseases [47,48]. Historically, early hybrids between American Vitis species and V. vinifera often had agronomic drawbacks and off-flavors [17,49], reducing consumer acceptance [9]. Market and regulatory barriers further slowed adoption [17,18,50], as did the need for farmers to adapt agronomic and enological practices.

More recent HPR varieties—FRG (Fungus-Resistant Grapes) and PIWI (from the German “Pilzwiderstandsfähige”, meaning disease-resistant)—exhibit improved agronomic and enological traits without major wine-quality penalties [17,18,50]. Advantages include reduced fungicide and fuel use for their applications (up to 60–100%), reduced soil copper accumulation, improved biodiversity, lower costs and disease risk, reduced worker exposure, and smoother labor distribution [17,50]. In addition, reduced fungicide inputs may indirectly promote higher abundance and activity of natural enemies [38,42,51,52].

Modern breeding often uses marker-assisted pyramiding to introgress multiple resistance loci while preserving wine quality [9,17,47,53]. However, most varieties have not yet been systematically screened for arthropod pest susceptibility [54]. Marker validation across germplasm is required before varieties can be widely released for wine production [47,55,56]. In this context, recent breeding techniques (e.g., genome editing) may face social and regulatory challenges even when they do not introduce foreign DNA, thus having social acceptance and policy as crucial components of deployment.

4. What Are We? Grape Varieties and Interaction with Pests

Mildew-resistant grape varieties may exhibit varying susceptibility to arthropod pests, depending on environmental context and management practices [18]. Although most available evidence derives from V. vinifera varieties or interspecific hybrids not specifically bred for disease resistance, these examples illustrate the diversity of plant traits influencing arthropod pest interactions and are relevant when assessing newly developed resistant varieties. Resistance mechanisms are commonly linked to phenology, morphology and biochemical traits that affect pest preference, survival, development and fecundity. Smith & Clement [57] classify plant resistance as: (1) phenological resistance (timing mismatch between pest and vulnerable plant stages), (2) antixenosis (non-preference due to lack of stimuli), (3) antibiosis (adverse effects on pest fitness), and (4) tolerance (ability to withstand damage). However, these mechanisms are often poorly characterized in grapevines.

The host plant resistance—defined as genetically inherited traits that render one variety less damaged by a pest than a susceptible counterpart—offers economic and environmental benefits by reducing the number of insecticide applications and consequently their residues [58,59]. The economic injury level (EIL) provides a functional, threshold-based measure of plant resistance by representing the pest density at which the cost of control equals the value of crop yield saved. Because the EIL directly integrates management costs and market values, it can function as a confounding factor; shifts in labor, machinery, or pesticide pricing can alter this threshold independently of plant genetics. From a strictly biological perspective, however, host genotypes express distinct defense strategies. Resistant plants typically do not experience economic damage, whereas partially resistant plants sustain damage only at high pest densities. In contrast, tolerant plants are able to maintain higher yield and quality under comparable herbivore pressure, effectively elevating their economic injury level, while susceptible plants reach the economic injury level at lower pest population levels [11,60]. All these aspects are generally linked to plant defenses against herbivores that can involve various mechanisms including the structural barriers (e.g., tissue toughness, trichomes) and allelochemicals acting as antifeedants or toxins [57,59,61]. Indirect defenses such as volatile organic compounds that attract natural enemies also modulate herbivore impacts and may interact with pathogen-induced signaling pathways [57,62], and show that plant defense mechanisms can be both constitutive or induced by pest attack [63,64,65,66].

Rootstocks illustrate how genotype influences pest interactions. Rootstocks confer resistance to soil pathogens and improve abiotic stress tolerance [67]. The case of the grape phylloxera D. vitifoliae demonstrates the value of resistant American Vitis rootstocks for controlling this devastating pest introduced into Europe in the 1860s [59,68]. In addition, susceptibility to phylloxera is influenced by host–pest genotype interactions, which affect important biological traits of the pest such as feeding success, gall formation and development [69,70,71,72,73,74,75,76,77,78,79]. Similarly, rootstocks influence nematode susceptibility [80,81] and may reduce Colomerus vitis (Pagenstecher) (Acari: Eriophyidae) leaf infestation via altered enzyme activity or resveratrol levels [82].

Variability in disease incidence and recovery for phytoplasmas and xylem bacteria has also been observed among varieties [83,84,85,86,87,88]. Molecular and biochemical responses of grapevine to pests have been documented: vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) feeding elicits defense-related protein expression [89]. Single dominant alleles confer resistance to root-knot nematodes (‘MJR1’) or phylloxera (‘RDV2’), often involving hypersensitive responses and secondary metabolite production [90,91,92,93,94]. Mite feeding can trigger upregulation of genes related to cell-wall proteins and defensive enzymes [95,96].

Morphological traits such as cluster architecture influence pest pressure. For instance, highly compact bunches increase Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) infestation and facilitate the spread of secondary rots [97,98,99,100,101]. Berry traits (trichomes, epicuticular wax, skin thickness, pulp firmness) affect oviposition and larval success. In this context, the scarcity of pubescence on inflorescences positively affects the 1st-generation infestation levels of L. botrana and Eupoecilia ambiguella (Hübner) (Lepidoptera: Tortricidae) larvae, as does the earliness of inflorescence emergence [102]. The spotted wing drosophila Drosophila suzukii Matsumura (Diptera: Drosophilidae) preferentially oviposits in berries with thin skin and low pulp penetration force [103,104,105,106,107], although some variability among studies has been reported [108]. High berry wax reduces oviposition by L. botrana and E. ambiguella [109], while leaf waxiness and trichome density influence eriophyid mite settling and affect the efficacy of natural enemies, such as phytoseiid mites, e.g., [95,110,111].

Chemical traits, including volatiles and secondary metabolites, influence pest behavior and performance. Variation in infestation and oviposition across varieties has been reported for the brown marmorated stink bug Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the Japanese beetle Popillia japonica Newman (Coleoptera: Scarabaeidae), the leafhoppers Hebata vitis (Göthe) and Erythroneura spp. (Hemiptera: Cicadellidae) and the grape berry moth L. botrana [112,113,114,115,116,117]. Volatiles can attract or repel pests and influence berry moth oviposition via antennal and ovipositor responses, acting together with the physical features of the oviposition site [118,119,120,121,122,123,124]. For instance, on plants treated with resistance inducers, the planthopper Hyalesthes obsoletus Signoret (Hemiptera: Cixiidae)—the primary vector of ‘Candidatus Phytoplasma solani’ in grapevines—displayed variable responses to the volatiles emitted by the vines, showing either attraction or repellence [124]. Berry sugar content and larval host experience influence L. botrana oviposition preference [125,126], and leaf nitrogen can enhance larval performance in Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) [127]. Soluble solids and chemical cues mediate D. suzukii oviposition and probably similarly influence tephritid fruit flies (Diptera: Tephritidae) [105,108,128,129]. Furthermore, allelochemicals in grapevines alter immune responses in L. botrana and E. ambiguella larvae [130,131] and act as oviposition or feeding deterrents [132]. Unlike other berry parts, Cabernet Sauvignon seeds reduced L. botrana fitness in laboratory tests [133]. Phenolics and carbohydrates can reduce eriophyid mite density by inhibiting feeding [95], and mite abundance correlates with indole-3-acetic acid and inversely with salicylic and jasmonic acids [95,134]. Crucially, these downstream chemical defenses are initiated by early-stage reactive oxygen and nitrogen species (ROS/RNS) signaling. These molecules act as primary redox alarms that help the plant recognize attackers and activate defense genes, possibly making them essential to the long-term resilience of new breeding lines [26], though further evaluation on PIWI varieties is required.

Grapevine phenological resistance offers an effective strategy to reduce pest damage by using varieties that ripen before or after peak pest activity. For example, early- or late-ripening varieties significantly reduced attacks by the green June beetle Cotinis nitida (L.) (Coleoptera: Scarabaeidae) in the United States [135]. Similarly, infestations by L. botrana are strongly influenced by grapevine phenology [102,131,136,137,138], as are infestations by the invasive D. suzukii [107,139,140]. The European grapevine moth also tends to avoid ovipositing during the third or fourth generation on varieties that are close to harvest [101,141,142]. In addition, mite damage has been reported to decrease in varieties with fast-growing shoots [143], and D. vitifoliae root infestations differ between “fast-growing” rootstocks (1103P, Vitis berlandieri Planch. × Vitis rupestris Scheele) and “slow-growing” ones (101–14 Mgt, Vitis riparia Michx. × V. rupestris), with the former exhibiting lower survivorship of infested roots [144]. Grapevine vigor can also enhance tolerance mechanisms, as observed for Margarodidae (Hemiptera) infestations [145].

While plant-derived resistance and tolerance traits hold promise for pest management, strong selection for mildew resistance in cultivated grapes may exert evolutionary pressure on phytophagous insects, leading to shifts in feeding behavior [146]. A striking example is the emergence of D. vitifoliae populations capable of feeding on the leaves of previously resistant grape scions, possibly driven by combined local and global anthropogenic pressures [147,148].

5. Where Are We Going? Arthropod Pest Susceptibility of Mildew-Resistant Grape Varieties

Current knowledge on how mildew-resistant grape varieties interact with arthropod pests remains scarce and fragmented. While the foundational studies reviewed in the previous section demonstrate that grapevine defenses rely on a complex matrix of phenological, morphological, and chemical traits, it remains unclear how these defensive systems operate within modern, mildew-resistant varieties. Because breeding lines are primarily selected for localized pathogen resistance, the downstream effects on insect dynamics are often treated as secondary factors. New grape varieties are primarily evaluated for desirable agronomic and enological traits, as well as resistance to diseases [50], but their susceptibility to insect and mite pests has seldom been considered during the selection or registration processes. Research on arthropod pest susceptibility in mildew-resistant grape varieties has only recently gained attention. For instance, recent studies indicate that resistance to diseases does not automatically translate into resistance to specific phytoplasmas, with notable variability in susceptibility across different PIWI varieties [149,150]. To systematically assess how these breeding priorities alter pest dynamics in practice, a comprehensive compilation and analysis of the existing empirical literature was performed. Overall, we identified 23 mildew-resistant varieties across 11 studies [69,108,109,113,147,151,152,153,154,155,156] that evaluated susceptibility to seven pest taxa affecting leaves, fruits, or roots (Figure 1 and

Table A1. List of grape varieties with reference to arthropod pests including mildew-resistant ones, by published paper/report. The list of mildew-resistant-varieties (in bold) is retrieved from Pertot et al. [17] and Vitis International Variety Catalogue [46]. The varieties derived from the VIVC are listed as resistant to Plasmopara viticola and/or Erysiphe necator.

Plant Part	Pest	Varieties	Susceptibility *	Parameter	Notes	Reference(s)
Berries	Drosophila suzukii	IRAC 1999	A	Oviposition holes in berries	Laboratory	[151,152]
		Bronner	AB
		Cabernet Cortis	AB
		Seyval blanc	AB
		VB 91 26 04	ABC
		VB 32-7	ABCD
		Johanniter	BCD
		Solaris	BCD
		Blauburgunder	CDE
		Prior	DE
		Chambourcin	E
	Drosophila suzukii	Acolon	Very high	Infestation severity of berries	Field	[108]
		Regent	High to very high
		Pinot Noir	High
		Müller-Thurgau	Very low
		Pinot Blanc	Very low
		(other 34 varieties with no statistical analysis)	(variable)
	Drosophila suzukii	Acolon	High	Adult location preference	Laboratory, dual-choice assays	[108]
		Regent	High
		Pinot Noir	Low to high
		Müller-Thurgau	Low
		Pinot Blanc	Low
	Drosophila suzukii	Regent	High	Oviposition preference	Laboratory, dual-choice assays	[108]
		Acolon	Low to high
		Pinot Blanc	Low to high
		Müller-Thurgau	Low
		Pinot Noir	Low
	Drosophila suzukii	Acolon	A	Insect infestation	Field (samples studied in laboratory)	[152]
		Cabernet Dorsa	A
		Cornalin	A
		Divico	A
		Dornfelder	A
		Dunkelfelder	A
		Galotta	A
		Garanoir	A
		Humagne rouge	A
		Mara	A
		Regent	A
		Syrah	A
		Chasselas	B
		Cornalin	B
		Dakapo	B
		Diolinoir	B
		Gamaret	B
		Gamay	B
		Merlot	B
		Müller-Thurgau	B
		Muscat bleu	B
		Pinot Noir	B
	Drosophila suzukii and other Drosophilidae	Concord	A	Infestations of berries (adult emergence)	Field (samples studied in laboratory)	[153]
		Pinot gris	A
		Chardonnay	AB
		Marquette	AB
		Marquis	AB
		Niagara	AB
		Pinot Noir	AB
		Seyval blanc	AB
		Vanessa	AB
		Zweilgelt	AB
		Cabernet Franc	B
		Mars	B
		Merlot	B
		Noiret	B
		Regent	B
Traminette		B
Eupoecilia ambiguella	Regent	A	Oviposition preference	Laboratory, dual-choice experiment; influence of wax layer on berry	[109]
	Pinot Noir	A
	Müller-Thurgau	AB
	Riesling	B
Lobesia botrana	Regent	A	Oviposition preference	Laboratory, dual-choice experiment; influence of wax layer on berry	[109]
	Pinot Noir	A
	Müller-Thurgau	AB
	Riesling	B
Lobesia botrana	Chardonnay	A	Infestation (number of pupae per cluster)	Field	[154]
	Merlot	A
	Noah	AB
	Pinot	AB
	Chasselas	B
	Riesling	B
Leaves	Daktulosphaira vitifoliae	Léon Millot	High (11 out of 11)	Infestation, leaf galls (and no. of sub-plots with leaf galls)	Field	[147]
		Maréchal Foch	High (15 out of 19)
		Baco Noir	Medium to high (2 out of 3)
		Charmont	Medium to high (1 out of 1)
		Clinton	Medium to high (1 out of 1)
		Divico	Medium to high (1 out of 1)
		York Madeira	Medium to high (1 out of 1)
		Cabernet Jura	Medium to high (1 out of 1)
		Chasselas	Medium to high (1 out of 2)
		Chardonnay Blanc	Medium to high (2 out of 2)
		Seyval	Medium to high (2 out of 2)
		Triomphe d’Alsace	Medium to high (2 out of 2)
		VB 32-7	Medium to high (2 out of 2)
		Pinot Noir	No galls (0 out of 1)
		Cabernet Carbon	No galls (0 out of 1)
		Regent	No galls (0 out of 2)
	Daktulosphaira vitifoliae	Seyval	High (80.0%; 162)	Infestation (and % of leaves infested; no. of galls per leaf)	Field. Fluctuations in years	[69]
		Aurora	High (75.2%; 182)
		Rayon D’Or	High (43.2%; 155)
		Cascade	High (78.8%; 82)
		Villard Blanc	High (77.2%; 64)
		Chancellor	High (40.4%; 209)
		Delaware	Medium (27.2%; 140)
		Vignoles	Medium (28.4%; 98)
		Léon Millot	Medium (26.4%; 106)
		Vidal 256 [=Vidal Blanc]	Medium (34.8%; 68)
		Baco Noir	Medium (16.4%; 102)
		Chelois	Medium (27.6%; 82)
		Dutchess	Medium (13.2%; 94)
		Niagara	Medium (4.0%; 72)
		J. Riesling	Medium (9.2%; 34)
		Florental	Medium (8.0%; 20)
		Catawba	Medium (2.0%; 31)
		Maréchal Foch	Medium (8.8%; 16)
		Cabernet Sauvignon	Medium (9.2%; 11)
		Chardonnay	Medium (9.2%; 3)
		Steuben	Medium (1.2%; 2)
		DeChaunac	No galls (0%; 0)
		Gamay	No galls (0%; 0)
	Daktulosphaira vitifoliae	Cabernet Cortis	High	‘Resistance’ [other details not specified] (score 1 to 10)	Field	[155]
		Bronner	High
		Johanniter	High
		Helios	Low to medium
		Cabernet Carbon	Low
		Prior	Low
		Regent	Low
		Solaris	Low
		Souvignier Gris	Low
	Eriophyidae	Cabernet Cortis	High	‘Resistance’ (leaf galls; score 1 to 10)	Field	[155]
		Souvignier Gris	High
		Cabernet Carbon	Medium
		Regent	Medium
		Bronner	Medium
		Prior	Low
		Solaris	Low
		Helios	Low
		Johanniter	Low
	Hebata vitis	Regent	High	‘Resistance’ (score 1 to 10)	Field	[155]
		Prior	Medium
		Bronner	Low
		Cabernet Carbon	Low
		Cabernet Cortis	Low
		Souvignier Gris	Low
		Solaris	Low
Helios		Low
Johanniter		Low
Popillia japonica	Vidal Blanc	A	Incidence (% of damaged leaves)	Semi-field (cage experiment)	[113]
	Seyval	AB
	Rougeon	ABC
	St. Croix	ABC
	St. Vincent	ABC
	Vignoles	ABC
	Lemberger	ABC
	Chambourcin	ABC
	Glenora	ABC
	DeChaunac	ABC
	Maréchal Foch (Marshal Foch)	ABC
	Himrod	ABC
	Chardonel	ABC
	Delaware (Pr)	ABC
	Cayuga White	ABC
	Chardonnay (Pr)	ABC
	Chancellor	ABC
	Frantenac	ABC
	Lacrosse	ABC
	Cabernet Sauvignon (Pr)	BC
	Cabernet Franc	BC
	Vanessa	BC
	Jupiter	BC
	Reliance	BCD
	Catawba (At)	BCD
	Concord Seedless	BCD
	Concord	BCD
	Edelweiss	BCD
	3309 Couderc	BCD
	Einset	BCD
	Marquis	CD
	Mars	D
Roots	Daktulosphaira vitifoliae	Cabernet Cortis	High (mean mortality 17%)	Mortality rate	Laboratory, material from different field origin. Different phylloxera lineages and populations were used	[156]
		Cabernet Carbon	High (mean mortality 17%)
		Cabernet Dorse We750	High (mean mortality 17%)
		Cabernet Mitos We650	High (mean mortality 17%)
		125AA—Gm1	Medium (mean mortality 15%)
		125AA—Gm3	Medium (mean mortality 15%)
		125AA—Gm5	Medium (mean mortality 15%)

* Where available, different letters indicate statistically significant differences as reported in the cited studies, standardized to an A–Z order, with A denoting higher susceptibility for the trait under investigation. In studies without statistical groupings, susceptibility was evaluated according to the reported qualitative categories (very low to very high) from the published results.

). More than half the studies (53.3%) targeted pests attacking berries, primarily Drosophilidae (33.3%), followed by L. botrana (13.3%) and E. ambiguella (6.7%). Leaf-feeding arthropod pest studies accounted for 40.0%, with D. vitifoliae representing 20.0%; single studies examined Eriophyidae, H. vitis, and P. japonica (6.7% each), with D. vitifoliae also represented for roots in a study (Figure 2; Table A1). Measured parameters included infestation incidence, severity, oviposition preference (e.g., for D. suzukii, E. ambiguella, and L. botrana), and phylloxera mortality across genetic lineages (Table A1). Certain varieties, such as Regent and Seyval, were slightly more frequently represented in scientific publications (Figure 3).

Only a few records document pest susceptibility of the parental varieties, leaving it uncertain whether arthropod susceptibility is reliably heritable from parental lines or whether the introgression of resistance loci disrupts existing pest-defense mechanisms in unpredictable ways [157]. Cabernet Sauvignon—parent of Cabernet Cortis and Souvignier Gris (

Table 1. Resistant grapevine varieties for which studies on arthropod pests were conducted, and parental details as reported in the Vitis International Variety Catalogue [46].

Resistant Variety	Color of Berry Skin	Pedigree as Given by Breeder/Bibliography	Pedigree Confirmed by Markers
3309 Couderc	Noir	Vitis riparia (Riparia Tomenteux) × Vitis rupestris (Rupestris Martin)
Bronner	Blanc	Merzling × Geisenheim 64934
Cabernet Carbon	Noir	Cabernet Sauvignon × Bronner
Cabernet Cortis	Noir	Cabernet Sauvignon × Solaris
Cabernet Jura	Noir	Medina × Kaberne Severnyi	Medina × Kaberne Severnyi
Cascade	Noir	Seibel 7042 × Seibel 5409	[Parent 1 and parent 2 were not confirmed]
Chambourcin	Noir	Seyve Villard 12-417 [=Joannes Seyve 11369] × Seibel 7053	Joannes Seyve 11369 × Plantet
Florental	Noir	Seibel 8365 × Gamay N
Helios	Blanc	Merzling × Freiburg 986-60
Johanniter	Blanc	Riesling Weiss [=Renano] × Freiburg 589-54
Léon Millot	Noir	Millardet et Grasset 101 O.P. × ?	Millardet et Grasset 101 O.P. × Goldriesling
Maréchal Foch	Noir	Millardet et Grasset 101 O.P. × ?	Millardet et Grasset 101 O.P. × Goldriesling
Muscat bleu	Noir	Garnier 15-6 × Seyve Villard 20-347
Noah	Blanc	Taylor O.P.	Taylor × ?
Prior	Noir	Freiburg 4-61 × Freiburg 236-75
Rayon D’Or	Blanc	Seibel 405 × Seibel 2007 [=Aramon du Gard]	Seibel 405 × Seibel 867
Regent	Noir	Diana × Chambourcin
Seyval	Blanc	Seibel 5656 × Seibel 4986	Seibel 5656 × Rayon D’Or [=Seibel 4986]
‘’	Noir	Seibel 5656 × Seibel 4986	Seibel 5656 × Seibel 4986
Solaris	Blanc	Merzling × Geisenheim 6493
Souvignier Gris	Rose	Cabernet Sauvignon × Bronner	Seyval × Zaehringer
Triomphe d’Alsace	Noir	Millardet et Grasset 101 O.P. × Knipperle	Millardet et Grasset 101 O.P. × Knipperle
Vidal Blanc	Blanc	St. Emilion [=Ugni Blanc] × Seibel 4986	Ugni Blanc × Rayon D’Or
Villard Blanc	Blanc	Seibel 6468 × Seibel 6905

)—shows relatively high susceptibility to eriophyid mites [158], moderate to pronounced susceptibility to leaf and root phylloxera and H. vitis [70,71,73,74,75,76,116,159,160,161,162], and also susceptibility to D. suzukii [106,163]. These patterns partially align with the high susceptibility observed in Cabernet Cortis and Souvignier Gris (Table A1), although one study on H. vitis suggested that Cabernet Cortis may be less susceptible than other tested varieties [155], these results warrant further validation. Moreover, the PIWI variety Noah exhibited intermediate susceptibility to L. botrana infestation in the field (Table A1), while Taylor—one of its two parental lines (Table 1)—is reported among the varieties susceptible to this pest [159]. These observations suggest that susceptibility patterns in newly bred varieties often reflect the inherited genetic background of their parental lines due to additive gene action or stable metabolic resource allocation. However, physical introgression and downstream hormonal cross-talk can also introduce unpredictable phenotypic variations or disrupt structural defense mechanisms—a challenge further exacerbated by the complex phenotypic expressions typically encountered when evaluating Vitis hybrids under field conditions [164,165]. The present inconsistencies and severely limited data highlight a critical need for systematic, ad hoc evaluation of both parental and resistant lines within the pest–grapevine system.

6. Mildew-Resistant Grape Varieties and Susceptibility to Arthropod Pests—Where Should We Go?

Our review highlights a major knowledge gap, i.e., the susceptibility of mildew-resistant varieties to arthropod pests is poorly documented and insufficiently integrated into breeding pipelines. To bridge this gap, coordinated efforts are needed between breeders, entomologists and viticulturists to design multi-year, multi-site evaluations that explicitly include pest assessments during variety testing.

Arthropod pest and disease management strongly influence both the economic and environmental sustainability of viticulture. Mildew-resistant grapevine varieties have the potential to significantly reduce pesticide inputs, but their adoption depends on factors such as agronomic performance, wine quality, regulatory approval and consumer acceptance. Increasing societal concern regarding environmental and public health impacts associated with pesticide use may further accelerate the adoption of resistant varieties [19,166].

Nevertheless, the ecological consequences associated with reduced pesticide use require further investigation. In particular, greater attention should be devoted to the multitrophic interactions occurring within vineyard ecosystems, also in relation to resistant varieties, as these may influence not only phytophagous arthropods but also their natural enemies. For example, some grapevine varieties may deter key parasitoids of pest species, potentially affecting their diversity and abundance [167,168,169]. Reducing pesticide use may also reshape arthropod communities and encourage the emergence of new balances between pests and their natural enemies. Specifically, the reduction in traditional fungicide regimes (e.g., inorganic copper and sulfur, or synthetic systemic and contact fungicides) removes significant negative effects on non-target beneficials, allowing key natural enemies like predatory mites (Phytoseiidae) and parasitoids to recover and fortify top-down suppression, e.g., [42,170,171,172]. However, reducing fungicide applications can eliminate their concomitant suppression of secondary pests, potentially triggering resurgences of previously minor herbivore guilds once free from this unintended chemical control, e.g., [170,173,174,175,176,177,178,179]. This dual dynamic highlights the need for systematic monitoring of pest dynamics to ensure the long-term resilience of viticultural systems. Moreover, current knowledge regarding several important groups of phytophagous arthropods—such as thrips (Thysanoptera), mealybugs, spider mites (Acari: Tetranychidae), and leaf miners (Lepidoptera)—remains limited in evaluations of mildew-resistant grapevine varieties, thus warranting targeted investigations on these interactions.

Breeding strategies must balance crop quality, local breeding goals, germplasm exploration and biodiversity conservation [180]. New breeding techniques should meet scientific, social and cultural requirements. Given current knowledge gaps, research agendas should prioritize a sequential framework structured by immediate operational urgency and long-term ecological impact:

• Systematic pest screening of HPR varieties across phenological stages and at different field scales (laboratory and multi-site field trials). This baseline screening represents the most immediate, highest-impact prerequisite needed to map current vulnerabilities;
• Evaluation of parental lines and rootstocks to assess heritability and root-based vs. scion-based arthropod pest susceptibility through morphological, phenological and biochemical traits. This represents a crucial mechanistic parallel to baseline screening, establishing whether observed field traits are predictably heritable;
• Monitoring for pest adaptation to new mildew-resistant varieties, including potential shifts in host range or feeding/oviposition behavior. Importantly, this long-term tracking depends directly on the baselines established in items 1 and 2, shifting the focus from immediate mapping to future ecosystem resilience;
• Socioeconomic and regulatory analyses to foster adoption while maintaining wine quality and consumer confidence. While less biological, this final step represents the ultimate practical bottleneck governing whether these multi-resistant varieties can achieve widespread commercial deployment.

Integrating arthropod pest resistance into breeding programs will support sustainable viticulture. Future programs should aim to combine mildew resistance with reduced susceptibility to arthropod pests, thus producing varieties that reduce chemical inputs while maintaining product quality and ecosystem services.