A Tillage-Dependent System of Arable Pests: How Soil Condition and Prevailing Climate Influence Pest Occurrence?

Abstract

Conventional and conservation tillage systems are applied differently in agricultural practices. Considering the current trends, the spread of tillage before denser crop cultures can also be observed in the case of other crops. These systems alter microclimatic conditions in the cultivated layer, soil surface, and crop canopy by physically modifying the soil environment. This greatly influences the occurrence and success of microbiome, plant, and animal organisms. At the same time, it has a decisive influence on the occurrence and damage caused to crops by harmful microorganisms and herbivorous pests. This review investigates how tillage systems influence the emergence and mass propagation of herbivores, based on their soil dependency. The impact of soil as a medium on pests will be analysed by grouping them according to their soil attachment and providing cultivation and agro-zoological examples. We highlight that selecting a tillage system should consider soil-dwelling pest ecology, as this knowledge is critical for optimizing both soil health and crop protection.

1. Introduction

The application of different tillage systems is driven by well-established arguments, among which, the preservation of soil moisture, optimisation of pore volume, and maintenance of soil humus content are particularly noteworthy [1,2,3].

However, interventions in soil, as a complex system, affect not only its abiotic components, such as moisture, temperature, pH, and mineral content [4,5], but also exert a significant influence on the living components of agroecosystems through these factors. The impact of tillage systems on pests can be elucidated by examining the abiotic alterations induced by tillage implements on the soil surface and the cultivated layer. The triggered alteration in this way can determine the life activities, occurrence, or even population growth of microorganisms [6,7], plants [8], and animal species [9,10,11,12].

Various soil physical interventions can form disparate microclimates within the cultivated layer, on the surface, and in the developing crops [13,14]. In conventional tillage systems, the relative humidity is typically lower, and temperature fluctuations are more extreme between crop rows than in areas with plant residue cover. Similarly, fundamental abiotic changes occur at the soil surface. As a direct consequence of these factors, the risk of desiccation is significantly higher in conventional tilled soils [15]. Additionally, notable physical distinctions are evident within the cultivated layer. Soils tilled annually and ploughed to a consistent depth may develop a plough pan (a compacted layer below the ploughing depth), which partitions the soil vertically into different sections [15,16]. Soils cultivated in this manner exhibit thinner soil profiles, which are more susceptible to air temperature fluctuations, resulting in greater temperature variability (i.e., they warm up or cool down more rapidly). As a result, their water infiltration and retention capacity decrease, while the likelihood of surface waterlogging (or standing water) increases [4].

In contrast, no-till systems have been demonstrated to increase moisture levels and humidity within the crop stand and on the soil surface [13,14]. In soil that has reached a state of equilibrium and is undergoing gradual compaction, the temperature gradient with depth is typically linear, contingent on the degree of compaction. However, fluctuations in soil moisture levels are directly proportional to precipitation and groundwater conditions, with most fluctuations occurring vertically [17,18]. The life activities and biological characteristics of various pests determine their interaction with the soil as a medium and the soil’s physical and chemical parameters significantly influence the presence and success of certain species.

The occurrence of soil-dwelling organisms is primarily influenced by soil structure but also correlates with the type of tillage used. No-till or reduced-till systems, including the use of cover crops and mulch, stimulate the enrichment of soil life over successive years. Additionally, the longer a field remains undisturbed, the more pronounced the benefits become, such as an increase in the diversity of the agrobiotope, including a rise in microbial decomposer species and their population density [19]. These biological processes culminate in the accumulation of organic matter in these fields, which is reflected in increased specific crop yields [20].

The tillage system also indirectly affects the pest fauna of a given field, including the species composition and diversity of soil-associated organisms. The presence or absence of weeds in the area determines the appearance of a given pest, which can be an alternative host for the species, in addition to the cultivated field crop [21]. The use of an intensive, conventional tillage system reduces the emergence of some Therophyta weeds, thanks to the soil rotation elements implemented throughout the year [22]. In contrast, in the case of a crop sown in a weedy, settled seedbed, the probability of occurrence of specific pests increases. These plants play a so-called maintenance, reservoir role. An example of this is the heavy infestation of a given area with Setaria spp. and other monocotyledons, which predispose the plant-hosting Phyllotreta vittula, Redtenbacher, to damage on cereals. Weed infestations can also act as reservoirs for certain polyphagous viruses [23]. In this case, the vector role of the feeding aphid species is decisive, as it transmits the virus to the crop plant. Among the many examples, the spread of the Turnip yellow virus, which infects rape by Myzus persicae Sulzer, can be mentioned. This agent is perfectly preserved by cruciferous weeds [24].

Global warming is a decisive factor influencing agricultural productivity in our time. A clear indicator of this is the north–south shift in the cultivation limits of crops [25,26]. Among other things, this induces changes in the composition of cultivated crops in the Carpathian Basin and the herbivore community that depends on them [27]. This also has a significant impact on the spread of invasive pest species, which conquest and expansion can be linked to this combination of factors. The correct choice of soil cultivation system can be approached from the perspective of ensuring healthy plant development [28]. If the soil cultivation system used ensures the healthy development of the plant (e.g., through moisture preservation), then the healthy plant population that develops in this way is better able to tolerate damage from arthropod species, even if they are invasive pests.

So far, the effects of different soil cultivation systems have been analysed mainly from the perspective of changes in the physical state of the soil. The changes in the diversity of organisms living there—more specifically, the effects of these changes on harmful animal organisms and their attachment to the soil—have not been fully classified. This study explores, for the first time, the effects of conventional and conservation tillage practices on herbivorous animal species. Moreover, the study further aims to provide a summary and categorisation of various pests based on their relationship to the soil as a habitat and medium for development, illustrated with examples from Central European agricultural systems. Overall, the displayed pest categorisation system helps to understand the consequences of soil cultivation on living organisms and thus supports the creation of good soil cultivation practices that can be adapted to a given area.

2. The Effects of Physical and Chemical Parameters of the Soils on the Presence of Pests

The physical and chemical properties of soil play a pivotal role in determining the occurrence of specific pests, limiting their appearance, and influencing their success or potential for mass propagation in a given location. These influencing parameters include soil temperature, humidity and moisture content, pH, light transmission, humus and organic matter content, porosity, and soil structure.

The duration of metamorphosis is directly affected by the soil temperature [29]. For example, Johnson et al. [30] demonstrated that the embryonic development of Sitona lepidus Gyllenhal eggs placed in the soil is 3.5 times faster at 25 °C compared to 10 °C. Additionally, soil temperature influences the spring emergence of overwintering adult insects, with most species emerging when the soil temperature reaches approximately 10.5 °C [31]. Furthermore, it affects the seasonal vertical migration of long-developing, so-called semivoltine soil-dwelling organisms [32]. Some species insulate their overwintering burrows with silk or hibernate in plant tissues, reducing exposure to unfavourable temperature fluctuations [33].

The presence of water is a crucial aspect for insect development. However, a distinction must be made between humidity and soil moisture, which is crucial from the perspective of insects developing [34]. Soil moisture refers to the amount of water vapour present in the soil and affects soil fertility, vegetation development, and various other geographical processes [9,17]. This is why females of the Agriotes species (Coleoptera: Elateridae) are inclined to select moist patches of soil for egg laying [35,36], as this ensures their progeny’s survival and optimal living conditions. The development of eggs placed in the soil during the embryonic phase [37], or the pupal stages of holometabolous species undergoing histolysis and histogenesis, is contingent upon the absorption of water or the presence of moisture [38]. This is why, in arid soils, desiccation and the death of eggs are probable outcomes, whereas excessive moisture levels are conducive to the life condition of entomopathogenic microorganisms [39].

In exceptional cases, the immediate environment of the cultivated soil layer can also induce the mass propagation of certain pests. Of course, numerous factors influence changes in pest populations [40]. However, the combination of moisture and temperature isotherms in the edaphic environment can have a decisive influence on the mass reproduction of specific pests, regardless of other factors. In particular, the high relative humidity prevailing in plant stands created by regenerative agriculture and no-till practices may favour the mass reproduction of particular snail species (Arion fasciatus Nilsson, Deroceras reticulatum Müller, etc.) and their aggressive damage at the field level [41]. The females of various Agriotes species (Col.: Elateridae) may react similarly to the presence of moist soil covered with vegetation, and their propagation may indicate a severe shortage of food [42].

The role of light in the life and ecology of soil-dwelling insects is of great importance, influencing their behaviour, physiology, and interactions within ecosystems. Soil-dwelling species frequently demonstrate negative phototaxis, evincing a proclivity for light avoidance and a preference for dark, moist environments that afford protection from predators and desiccation [43]. Furthermore, light and temperature regulate circadian rhythms, affecting activities such as foraging, mating, and emergence [44]. Some species rely on the photoperiod for the timing of developmental stages, such as metamorphosis, by environmental conditions [45]. Furthermore, light intensity, wavelength, and photoperiod influence habitat preferences and predator–prey interactions [43].

Soil pH significantly influences the diversity of soil-dwelling arthropods. Milosavljević et al. [46] demonstrated that alkaline soils enhance the biological diversity of Limonius wireworm (Coleoptera: Elateridae) communities, particularly facilitating the proliferation of Limonius californicus Mannerheim. In contrast, Staudacher et al. [36] found that acidic soils (pH 4–5.2) positively affected the presence of Agriotes species, including A. obscurus L., A. lineatus L., and A. proximus Schwarz. These species demonstrated a positive correlation with the soil humus content.

Therefore, the soil humus and organic matter content are crucial determinants of the presence or absence of particular species. It is well documented that many polyphagous larvae (e.g., grubs and wireworms) feed on organic matter in the soil. Without soil organic matter, these species do not thrive [35]. The presence or absence of Gryllotalpa gryllotalpa L. is an excellent indicator of the soil organic matter content, as this species causes significant damage primarily in home gardens with organic fertilisation. This is because its prey is more abundant in areas enriched with organic manure. However, its harmfulness also stems from its omnivorous nature, as it consumes plant parts encountered while searching for prey. Regardless of this, the physical parameters and higher water retention capacity of the soil with a high organic matter content support the individual development and developmental stage changes of the organisms living there, including G. gryllotalpa [47].

The composition of soil air, particularly that of carbon dioxide, is also of importance for the survival of particular species. Carbon dioxide (CO₂) is present in relatively high concentrations in most soils, primarily resulting from plant and microbial respiration. Microbial respiration often contributes significantly to CO₂ levels due to decomposition processes [48]. Some soil-dwelling species are highly adapted to anaerobic conditions. Fidler [49] demonstrated in laboratory experiments that larvae of the scarab beetle Serica brunnea L. can survive in a CO₂-rich atmosphere for 5–8 days. Conversely, numerous pathogens and pests are killed when they are buried in deeper, oxygen-poor soil layers due to ploughing.

The soil’s physical texture can influence the development of particular arthropod species. It has been demonstrated that Anisoplia spp. and Polyphilla spp. (Coleoptera: Scarabaeidae) exhibit reduced larval mortality in moderately cohesive soils [50]. The larvae of Diabrotica v. virgifera LeConte demonstrate reduced developmental success in sandy soils, a phenomenon attributed to the damaging effects of quartz crystals on their cuticle [37,51]. Similarly, Zabrus tenebrioides L. exhibit suboptimal growth in loose-structured soils, where the larvae cannot create burrows near developing plants [52].

3. Characteristics of Central European Arable Crop Production and Tillage Systems in the Light of the Attachment of Pests to the Soil

Central Europe’s continental sub-humid climate zone provides excellent natural conditions, climate, topography, and good-quality soils for arable cultivation [53] and serves as a reasonable basis for diversified farming [54]. Agricultural production is mainly influenced by precipitation (600–800 mm), of which the southwestern parts benefit the most. In contrast, the central part of the Great Plain mostly lacks precipitation. The hours of sunshine in the Southern Great Plain can exceed 2000 h yearly. Based on these conditions, the share of crop production in the country’s total agricultural activity is still higher than the EU average. The diversity of the crops grown underlines this fact. Looking at the arable plant ecosystems, which cover some 4.2 M ha, the dominant crops are cereals—mainly winter wheat, maise, and winter barley—and industrial crops such as sunflowers and oilseed rape. Besides them, there is a smaller area of leguminous crops, and the areas of potatoes and sugar beet fields can also be mentioned [55]. In these predominantly arable areas, ploughing systems typically dominated tillage from the mid-1700s to the mid-1950s [56], and this tillage system is still dominating in several areas in Europe. Changes in soil that are important to tillage systems have occurred only in the past 50 years. However, a significant change has only occurred in the last 50 years from the point of view of the tillage systems. The first mention of the mitigation of ploughing pan inevitably associated with ploughing was in 1900 [57]. Nowadays, preserving and improving soil quality has been complemented by reducing the severity of climatic damage [58,59,60]. These facts call for adopting cultivation systems that lose the least moisture and preserve crop safety, and the role of stubble residues is becoming increasingly important. Conservational tillage provides excellent topsoil protection, higher soil water content, and favourable soil physical conditions, generally characterised by lower compaction than uncovered ploughed soils [57,61,62]. Overall, the developed soil condition determines the diversity and number of animal organisms living there. Similarly, it fundamentally affects the development of similar values of damaging herbivorous organisms.

Field crop production is threatened by long day insects, most of which, due to seasonal climate change, go into a state of hypometabolism in search of a protected place (such as the soil) at a particular stage or stages of the year [63]. With this ecological feature, they survive unfavourable climatic periods, such as those dominated by frost in the winter (hibernation or overwintering) or extreme heat (aestivation), which are often coupled with a lack of host plants. These dormant states can be further classified into subtypes, such as quiescence, which is present depending on the presence of a triggering factor, and diapause, which occurs independently of the triggering factor [64]. Therefore, applying different tillage systems in the upper productive layer of the soil will affect the life activity and success of the pest that is currently wintering or feeding there.

4. Main Groups of Herbivores by Their Attachment to the Soil

From a physical perspective, soil serves the ecological needs of various pests in several other ways. For certain soil-dwelling arthropods, it provides a medium for development and ontogenetic progression. Other species or species groups use the soil for ecological reasons, such as during dormancy in unfavourable winters or summers.

In addition, in the case of a much smaller group of species, based on species-specific ecological criteria, the individual species/groups of species can be classified into the groups shown in Figure 1a based on their relationship with soil or near-soil elements. The attachment of pests to the soil can basically be ontogenetic, ecological, and social/behavioural in origin. Based on these, eight different groups can be distinguished: long-term developers (1), short-term developers (2), overwinters in the soil (3), aestivators in the soil (4), overwinters in plant remains (5), or among plant remains (6), colony/nest formators (7), and finally, shelter seekers (8).

Figure 1b illustrates the seasonal periods of stay in the soil as a medium for groups of arable pests, classified according to their attachment to the soil, based on the ecological and climatological conditions recorded in the Carpathian Basin. It can be seen that species belonging to the long-term developers (1) and colony/nest formators (7) groups are capable of endangering the plant health of crops throughout the entire vegetation period of arable crops (even over several years) by inhabiting the soil. This primarily takes the form of soil-borne root damage or direct damage to the root collar, located above the plant surface [65]. The short-term developers (2) are pests that threaten the juvenile development of autumn and spring crops, causing damage that is often root-borne and may even manifest later. Members of the group that overwinters in the soil (3), in plant remains (5) above the soil surface, and among plant remains (6) are bound to the soil as a medium during their winter dormancy [66,67]. In the case of species that aestivate in the soil (4) in the summer, various forms of damage can be mentioned, the damage patterns of which appear in the later phenology of the plant, even on the generative parts. The attachment of species in the shelter-seekers group (8) to the soil as a shelter is random (depending on climate and agrotechnology) and lasts throughout the entire vegetation period.

4.1. The Group of Pests That Develop in the Soil for Years—Long-Term Developers

These are typically semivoltine (multi-year development) terricolous insects which development cycle is strictly tied to the soil and consistently exceeds one year [68]. The most notable groups include the cockchafers (Melolontha spp. and Anisoplia spp.) and the click beetles (Agriotes spp.) [69]. The damage caused by the larvae of cockchafers (grubs) and click beetles (wireworms) is soil-originated and persists due to the extended development of these insects [69]. Click beetles have a preference for ovipositing in undisturbed, vegetated areas. However, higher soil organic matter and moisture levels have been observed to increase the likelihood of damage [70,71]. Cockchafers select humus-rich, well-warmed soils near forests or tree lines for oviposition. The larvae are sensitive to changes in physical parameters, exhibiting horizontal and vertical movement within the soil [71]. However, their seasonal movements are predominantly vertical.

Berezina [72] corroborated the assertion that the upward migration of larvae that have survived the winter is influenced by soil temperature and humidity in the upper layers. However, high humidity in deeper, water table-adjacent layers has been demonstrated to significantly accelerate the movement of these overwintering stages. It was observed that the number of larvae in the upper layers decreased with the rising temperatures and falling humidity during June and July. Vertical migration factors include food availability, soil compaction, and pore volume. Consequently, forecasting their movement is contingent upon the rate of warming and plant cover. Continuous ploughing at the same depth annually can create a plough pan. This low permeability layer can result in a rapid increase in surface soil temperatures during the spring season. This, in turn, can accelerate the vertical movement of larvae towards the surface [15,16]. Agrotechnical failures under the same cultivation can result in saturated, soggy patches in the near-surface layers. These areas are considered attractive patches on the field, favoured by females of pre-laying click beetles (Elateridae) for egg-laying (Figure 2). Thus, more extensive wireworm damage can be expected on these patches [69].

4.2. The Group of Pests Which Developmental Stages Are Soil-Bound—Short-Term Developers

These pests are typically economically significant, and their development is characterised by bi- or multivoltine. The diapause stage is followed by one or two generations that develop without the diapause period. A developmental stage always detects diapause induction before the actual diapausing stage. This is a facultative diapause. These pests develop in the soil from eggs to pupae. A common characteristic is that they typically cause root damage (rhizophagous pests), which presents a significant challenge for expected control. The presence and extent of damage caused by these pests is highly dependent on the host plants. Notable examples include the cabbage root fly (Delia radicum L), which causes damage to oilseed rape, and the Western corn rootworm (Diabrotica v. virgifera LeConte), which attacks maise roots. The larvae of these species inflict damage upon the outer surfaces of plant roots, at times creating burrowing channels within them [73,74]. The affected plants experience difficulties absorbing water and nutrients, which can result in wilting in juvenile crops and, in extreme cases, the drying up of the plant [75]. The cereal ground beetle (Zabrus tenebrionides L.) develops in soil burrows in proximity to its food source, feeding on leaves that it drags into its burrow and gnawing them into fine pieces [76].

It is of the utmost importance to implement an effective soil management strategy to control these pests and influence the mass emergence of adults [77]. To illustrate, in the case of the monophagous Western corn rootworm, D. v. virgifera, the selection of tillage methodology following the cultivation of maise determines the concentration and timing of adult flights (Figure 3).

Autumn deep ploughing after successive maise crops results in the mixing of egg masses deposited by females in the top 5 cm of soil to depths of 28–32 cm [78]. The development of eggs in the upper layers is accelerated due to their earlier exposure to the requisite heat sum. In contrast, those situated at greater depths develop at a slower rate. Consequently, the period during which adult flights occur, generally confined to a single generation per year, is extended from mid-June to late summer under conventional tillage [79]. In contrast, in no-till fields, the egg masses reach the requisite heat sum for adult development at nearly the same time, resulting in a markedly shorter but more concentrated flight period [80,81].

4.3. The Group of Pests That Are Hibernating in the Soil—Overwinters in Soil

Species in this group spend the cold continental winters in the soil in the adult stage, entering dormancy (diapause and quiescence). These species can typically be univoltine (one generation per year) pests [82]. Diapause induction of these species is genetically determined, independent from outside influencing factors, and they are characterised by so-called obligated diapause [33,83].

The physical condition of the soil resulting from different tillage tools does not significantly affect the success of their overwintering or spring emergence. These pests, independent of tillage methods, threaten spring-sown crops. In the early stages of seedling growth (e.g., maize, sugar beet, oats, spring barley, and mustard), leaf damage caused by these pests can lead to water balance issues in the host, stunted growth, and, in severe cases, even the plant can perish [84]. Often, pests emerge and become active before their primary host plants germinate [85]. In such cases, they gather in different crop fields before launching a frontal attack on their primary host plants [86,87]. Historically, insecticides generating steam in shallow trenches were used against such pests. The pests overwintering in soil are primarily from the families of the leaf beetle (Coleoptera: Chrysomelidae) and weevil (Coleoptera: Curculionidae). For example, the mass emergence of corn and stem weevils along field edges of winter cereals in mid-March is typical. Such pests include the Colorado potato beetle (Leptinotarsa decemlineata L.) and the sugar beet weevil (Asproparthenis punctiventris Germar). Species that overwinter as adults often appear in fields early in the spring, immediately after the winter, and begin feeding [88].

4.4. The Group of Pests That Spends the Summer Drought in the Soil—Aestivators in Soil

In the temperate zones during the summer and in the dry seasons of tropical regions, insects are subjected to prolonged periods of dry, water-deficient conditions. In order to survive these conditions, some insects enter aestivation, a process whereby they temporarily cease their metabolic activities to conserve water. During aestivation, insects undergo a series of molecular and biochemical changes that result in the cessation of development, a reduction in metabolism [89], the capacity to tolerate high temperatures, and an enhancement of their ability to maintain water balance [90]. The development of these pests is invariably completed within a year, and a considerable number of species belong to oilseed rape pests. These pests attempt to survive the summer heat, lack of precipitation, and the absence of host plants by spending the summer in the soil [91]. The appearance of these species is most limited by the presence or absence of the host plant due to their narrow host plant selection, which results from evolutionary development. Moreover, the prevailing climate after the harvesting of the host plant is also of significant consequence. A climate typified by elevated summer temperatures and a paucity of precipitation is inimical to these species’ survival and reproductive activities. Consequently, they respond to these unfavourable factors with a hypometabolic response, which involves a reduction in metabolic processes [92]. This aestivation is primarily characteristic of species native to our region or have already been successfully settled. Furthermore, these adverse effects during the summer months can also impede the spread of certain invasive species currently expanding in our region. If the summer temperature exceeds 35 °C for an extended period, it can have a detrimental impact on survival, particularly in the case of eggs and early larval stages. This is exemplified by the fall armyworm (Spodoptera frugiperda J.E. Smith), a dangerous corn pest which invasion into the Carpathian Basin has been limited by this climatic conjunction (and not by winter frost or cold). The species can tolerate high temperatures. However, extreme heat and drought can create unfavourable conditions for its development [93,94,95]. Nevertheless, this pest, which possesses remarkable adaptive capabilities, is only temporarily constrained by unfavourable climate conditions.

The appearance and successful survival of the pests attacking crucifers (Brassicaceae), particularly oilseed rape, following their summer dormancy are greatly supported by the second crop crucifers. This increases autumn pest damage [96]. The life activities of the members of these groups, which are seasonally tied to the soil, are not influenced by the applied tillage methods or tools, as this summer dormancy can occur even in areas independent of agricultural cultivation.

4.5. The Group of Pests Hibernating on the Soil Surface in Plant Tissues—Overwinters in Plant Remains

The members of this group are frequently characterised by their hidden lifestyles. The damage caused by these insects, which depends on the presence of their host plants, manifests in mining roots, stems, leaf blades, or petioles. Additionally, their damage is often accompanied by the colonisation of parasitic microorganisms, including species such as Fusarium spp., Penicillium spp., and Aspergillus spp. [97,98]. Notable members of this category include the European corn borer (Ostrinia nubilalis Hbn.) (Figure 4), the turnip sawfly (Athalia rosae L.), and the potato tuber moth (Phthorimaea operculella Zeller). The selection of appropriate fundamental tillage techniques to eradicate the overwintering habitats of the European corn borer has been a significant concern for experts in plant production and protection. The main objective in the fight against this serious pest is to contribute to a reduction in the following year’s population by eliminating the overwintering population [99].

Scientific studies have shown that the overwintering larvae of the European corn borer can survive in stalks left on the surface and do not perish even in the face of direct frost. This resilience to frost is a notable adaptation that enables the larvae to persist despite the adverse effects of direct exposure to freezing temperatures [100]. The lethality caused by contact frost can be attributed to the formation of ice crystals that damage tissue and cell membranes. The overwintering insect can respond to this cell-destroying effect with a physiological transition (resulting in the uptake of sugars and the formation of a protein network) [101]. In conclusion, the mortality of insect populations overwintering in stalks left on the surface is not anticipated, given the mild winter climate. Therefore, the reduction of the overwintering population can only be expected from the physical impacts caused by operations such as crushing the stalks (e.g., stubble cut low during harvesting, finely chopped corn stalks, or stalk crushing performed in a separate operation) (Figure 4). Crushing corn stalks is only effective in destroying European corn borer larvae if the size of the shreds is sufficiently small, because, in this case, the larvae are most affected [102,103]. In the absence of expected effectiveness, the most effective agronomic thinning of the overwintering European corn borer population known today is expected only from ploughing, which ensures airless conditions and soil pressure [104].

4.6. The Group of Pests Hibernating on the Soil Surface Among Plant Residues—Overwinters Among Plant Remains

Members of this group overwinter in leaf litter in forests, sometimes on ditch banks, grasslands, or pastures, and emerge early in the spring to cause damage in arable fields, representing a significant threat [105,106]. Notable examples of these pests include pollen beetles (Brassicogethes spp.), which are particularly important in oilseed rape. Various cereal pests (Aelia spp. and Eurygaster spp.) can be mentioned here, threatening grain crops. Furthermore, numerous species that cause damage in arable fields also utilise this overwintering strategy.

Most of these pests belong to the Coleoptera order and undergo complete metamorphosis, overwintering in adult stages. Other groups, such as certain thrips and heteropteran species, also exhibit this overwintering strategy. A common feature of these species is that they emerge in the early spring, lay eggs after a brief feeding period, and reproduce. The overwintering period typically occurs in deciduous forests [106,107], although some species are known to overwinter in coniferous forests [108]. As a consequence of this biological imperative, the spring immigration of these species into arable fields is expected from the direction of forest habitats. From this point of view, the risk to plant health posed by this group of species is heightened in arable crops situated close to forested areas, particularly in the case of winter oilseed rape and cereals [105]. Concerning these pests, the impact of different soil tillage techniques is inconsequential. However, there is a risk that their overwintering sites may transfer to areas with no-till methods due to previous plant residues or mulch (Figure 5).

4.7. The Group of Pests That Build Nests and Colonies in the Soil—Colony/Nest Formators

Social and eusocial organisms, such as the common vole (Microtus arvalis L.) and the pavement ant (Tetramorium caespitum L.) species complex, a caste-structured ant species known to damage crops in fields, can be mentioned here [109,110]. The colonies, distributed across vegetation, with nests that harbour successive generations over several years, can threaten the economic viability of crop production in the affected areas. These species cause patchy destruction of vegetation, gnawing on developing plant populations in the vicinity of their colonies and nests [111]. In contrast to these social species, the solitary pest European field cricket, Gryllus campestris L., inhabits self-dug burrows in the soil.

The damage caused by this orthopteran is also seen to be patchy, particularly in grasslands and pastures [112]. The members of this group are polyphagous, with a generalist status as pests.

The selection of an appropriate soil tillage method is considered crucial in controlling these pests, particularly the common vole. Tillage methods that involve turning and loosening the soil can potentially disrupt vole colonies, destroying their colonies [113]. It is evident, however, that technology that retains cover crops or plant mulch from the previous year on the surface and employs minimum, no-tillage, or zero-tillage practices significantly contributes to the proliferation of these members of the pest group. The presence of plant residues on the soil surface, which may form thick layers, provides ideal concealment and creates a microclimate conducive to pests’ survival and colonies’ establishment [114]. This explains the significant damage caused by these species in cultivated areas using conservation tillage methods.

Conventional tillage is undoubtedly effective in mitigating field common vole damage, but some argue that it does not destroy colonies but results in their translocation to adjacent fields [113,114]. Among the tools employed for eradicating nests of pavement ants in crop fields, preventive soil cultivation methods are crucial (Figure 6a). In the case of dense crop systems, mainly rapeseed, where the damage is especially significant, the presence of active ant colonies observed before planting makes it worthwhile to consider, including deep soil operations in the cultivation process or even pre-sowing ploughing to destroy existing nests. This would prevent the colony from restoring the damaged nests and broods by the time the rapeseed germinates, thereby reducing the potential damage [115]. Similarly, disrupting the burrow of European field crickets destroys their habitat and living conditions, and thus, their presence is not expected in regularly cultivated fields [112].

4.8. The Group of Pests That Find Shelter in the Soil Between Soil Clods—Shelter-Seekers

These species hide in the lower soil layers to escape wind, drought, and light and return to the host plants when these factors subside [116]. Such pests include slug species (Arion spp., Deroceras spp., Limax spp., etc.), which typically live on the soil surface in wet environments but retreat to deeper soil layers in response to unfavourable conditions such as drought and heat by forming an epiphragmatic layer [117] (Figure 6b,c). During periods of rainfall, however, they emerge and resume feeding. This biological character of snails explains the aggressive infestation observed in areas cultivated with mulch cover and cover crops. These systems ensure a well-balanced wet microclimatic environment above the tillage layer [118]. Proper soil management, such as creating a sufficiently compact seedbed, can mitigate the surface damage caused by slugs [119]. A study by Bayer CropScience [120] suggested the field risk posed by slugs and offered agrotechnical and chemical control methods for farmers in the UK and North America. This study examined how slug pellet applications can be effectively implemented through careful seedbed preparation. According to the survey, shallow sowings can reduce slug damage by creating a firm seedbed, while loose seedbeds predispose to realising slug damage. However, a different approach is required for large-seeded crops. Slugs can penetrate deeper soil layers but do not reach the depth of the seed, so a loose soil structure is preferable, and a compact seedbed is unnecessary.

The larvae of noctuid moths (Lep.: Noctuidae: Scotia spp., Euxoa spp., Mammestra spp., Amathes spp., etc.) follow a similar strategy [121]. However, light intensity is the limiting factor for these species, not moisture. These larvae, which become active at dusk, are nocturnal and hide in clods of soil near their host plants during the day. Their presence is indicated by the damage they cause to plants. Similarly, the maize leaf weevil (Tanymecus dilaticollis Gyllenhal) (Figure 6b,c), which is diurnal, seeks shelter among soil clods to escape the drying effects of the wind [122].

The most complex example of behaviour driven by soil shelter-seeking is found in the adults of the Colorado potato beetle (Leptinotarsa decemlineata, Say). The activity of this leaf-feeding beetle is influenced by temperature and relative humidity. Under dry conditions (high temperature paired with low humidity), the beetle responds with positive geotaxis (moving into soil clods). In contrast, it exhibits negative geotaxis under humid conditions, moving into the canopy to feed and cause damage [123].

5. Comprehensive Dominance and Taxonomic Analysis of Herbivorous Groups Bound to Soil as a Medium

A list of pests registered in arable crops in the Carpathian Basin is presented in Supplementary Table S1, organised by their association with specific soil types. Among the discussed groups, the most populous group overwinters among plant remains (Figure 7). Short-term developers follow them. In contrast, the long-term developers (100 percent of the species) overwinter in the soil (40 percent of the species), and short-term developers (33.96 percent) are responsible for causing the actual soil-derived damage (which occurs while feeding there, not merely dormant or seeking shelter). Also included are colony/nest formators, four species of which (100%) are also soil-induced damage factors.

The majority of pests associated with soil as a medium in the Hungarian arable ecosystems under analysis belong to the order of beetles (Coleoptera) (57.6%) (Figure 8), followed by flies (Diptera) (14%) and moths (Lepidoptera) (12.8%). For some strategies, the representation of a particular insect order is dominant, such as the representation of Coleoptera in the long-term and aestivator groups or Hemiptera in overwinters among plant remains groups. From a taxonomic point of view, the most diverse groups are short-term developers and aestivators in the soil, each containing members of six different pest orders.

The soil, as a medium, is dominated by plant cover that is infested with pests possessing chewing mouthparts and, to a lesser extent, those with hook-like mouthparts (Chloropidae and Anthomyiidae). The overwintering places of piercing-sucking mouthpart pests (Thysanoptera and Hemiptera) are never spread to arable ecosystems. They can only be mentioned in relation to ground surface vegetation and wintering at the forest floor level. The only soil-derived pests known to occur as hemipteran species are two aphidiid pests belonging to the colony/nest formers group.

6. Conclusions

Soil-dwelling herbivores can be divided into groups based on their attachment to the soil, highlighting similarities of some group members and differences among the groups. The main differences among these groups lie in their developmental cycles and ecological strategies for survival, while they all share an attachment to the soil for development or survival. Long-term developers are semivoltine with multi-year life cycles, while short-term developers are uni-, bi-, or multivoltine. The long-term developer insects cause prolonged damage to roots. These insects are highly dependent on soil conditions for successful development. In contrast, short-term developers complete their life cycle within a year and often cause significant economic damage by feeding on roots. Both groups share a common dependence on soil for development but differ in their life cycle duration and severity of induced damage.

Another group consists of insects that use the soil for ecological purposes, such as overwintering or aestivation during unfavourable conditions. These insects, applying a dormant strategy, use the soil to remain protected during cold periods, while aestivators attempt to endure the hot and dry seasons. The common trait here is dormancy, though the timing and reason for dormancy differ depending on environmental conditions.

Finally, some insects seek shelter in the soil. These insects use the soil to escape environmental stressors such as light, drought, or wind. Shelter-seekers are often more solitary and polyphagous or omnivorous organisms.

Proper soil management is critical, as it directly alters pest habitats. Interference in the tilled soil layer will trigger a rapid and short-term response in these species. Conventional rotational tillage and its various physical consequences on the soil create favourable living conditions for the long-term developers’ group members. On the other hand, the colony/nest formators species cannot survive. The type of soil cultivation system does not directly affect the habitat of short-term developers and overwinters in the soil. However, it does influence their adults’ damage and flight period, either in the present or future.

The occurrence and subsequent damage of species of the overwinters in and among the plant remains group will be influenced by the cultivation practices associated with the soil tillage practices (stem crushing) and the residual cultural condition of the site (presence/absence of cover crops or mulch and weed cover).

Overall, conventional tillage destroys habitats by mechanically rotating soil layers, thereby eliminating overwintering sites for many pests. Thus, in ploughed areas, solitary species that overwinter or seek shelter in or among plant remains left on the soil surface, or associated pests living in colonies or nests, lose their habitat. Their presence may thus spread to other unrotated areas. The success of long-developer soil pests under conventional tillage is attributed to the formation of waterproof layers that introduce favourable abiotic conditions to these pests. However, their presence is not solely dependent on the type of tillage used but rather on the physical properties of the soil itself. It is known that the silica crystal particles of loose-textured sandy soils can penetrate the waterproof layer of the insect cuticle, leading to dehydration and, ultimately, death of the soil-dwelling organisms. This explains the severe phytosanitary importance of wireworms in high-quality soils.

Significant differences in floristic and faunal composition arise from different tillage practices. The expected pest composition is generally known in conventionally tilled fields, and appropriate countermeasures can be planned and timed. In contrast, the species composition, pest activity, and economic impact of pest damage in conservation tillage systems must be better understood. Thus, effective technological responses need to be satisfiable or entirely unknown. Consequently, the most urgent task for decision-makers is developing and approving sustainable pesticide assortments and effective technological responses to support farmers practising these methods.

Conservation tillage has different physical consequences in the immediate crop production environment, which has a decisive impact on the composition of the pest spectrum. In Central Europe, particularly in the Carpathian Basin, conventional tillage has been the dominant practice for decades. As a result, farmers can respond to this soil cultivation practice with almost formulaic technological solutions. There is no previous practical experience with the occurrence of pests caused by any conservation tillage. Thus, the presence of pests and damage caused by this method of soil cultivation often occurs without a technological response, resulting in significant damage. Of course, over time, other players in the ecosystem, such as natural enemies, will begin to colonise the area, ultimately creating a self-regulating system. Until then, the primary task facing researchers is to investigate effective practical measures aimed at curbing the new pest complex associated with conservation tillage and the damage it causes.

To summarise, the choice of the tillage method must be based on several considerations and conditions. Still, an essential aspect of maintaining the health of our crops is knowing the presence of soil-dwelling pests, their association with the soil, and their membership in the ecological groups outlined. This knowledge is essential for the farmer to achieve the desired plant health status and the expected soil conditions.