International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.4, 196-205 http://ecoevopublisher.com/index.php/ijmec 20 1 leaving only the remaining plants. The damage caused by African land snails to crops is both broad-spectrum and destructive. The forms of damage to different crops vary slightly, but the common consequence is a decline in yield and deterioration in quality. For small-scale growers, snail invasion often means a devastating blow: In small-scale farming regions such as Cuba and Thailand, snail outbreaks have led to many farmers losing their harvest or even giving up farming (Thiengo et al., 2007; Cazarin-Oliveira et al., 2021). 5.2 The impact of planting systems and facility agriculture African land snails not only harm open-field farmlands, but also have an impact on facility agriculture and urban greening systems. Moreover, they are more likely to cause disasters due to their closed environment. Greenhouse and other facility agricultural systems provide A constant-temperature and high-humidity environment, which is almost a "paradise" for A. fulica. In terms of urban green Spaces and horticulture, A. fulica is often seen in urban parks, campuses, and community gardens. They hide during the day and feed at night, gnawing on the leaves and flowers of ornamental plants, which damages the landscape and pollutes the lawns and walkways, affecting citizens' activities. The impact on the planting system is also reflected in the disruption of the agricultural ecological balance. The massive feeding and excretion of snails alter the microenvironment in the field, leading to an increase in some secondary pests (such as slugs and subterranean termites) due to ecological interaction, or causing a decline in plant resistance and making them more susceptible to diseases. African land snails exert continuous and high-intensity pressure on modern intensive farming systems (Jayashankar et al.,2013; Jing et al., 2015). 5.3 Estimation of economic losses and control costs To assess the economic impact of the invasion of land snails in Africa, both direct losses and indirect costs need to be taken into account simultaneously. The direct losses mainly consist of the economic value loss caused by the reduction in crop yields and the decline in their quality. According to case data from various countries: In the tropical regions of Brazil, the yield of vegetables and fruits affected by snails is generally between 20% and 30%, and some small farms even have no harvest at all. The Indian state of Kerala has reported a significant increase in vegetable prices during years of snail outbreaks, due to intensified field losses and supply shortages. For economically underdeveloped invaded areas, these prevention and control costs are often unaffordable. In addition to the losses to agriculture itself, the invasion of snails has also brought about social and economic impacts: for instance, residents' courtyards being disturbed by snails require extra effort to clean up, and scenic spots and municipal greening increase management costs to maintain their image. In terms of public health, the medical burden has increased due to the transmission of diseases by snails, etc. Although these hidden costs are difficult to calculate precisely, they do increase the overall economic cost of invasive species (Jayashankar et al.,2013; Jing et al., 2015). 6 Prevention and Control Strategies and Management Challenges 6.1 Current control methods and effect evaluation At present, the prevention and control of A. fulica mainly include three major methods: physical, chemical and biological, which are usually combined into comprehensive management. In terms of physical methods, manual capture is the most direct approach. In many areas, community residents are mobilized to pick up snails by hand in the early morning or evening and destroy them in a centralized manner. This method is simple and easy to implement and can immediately reduce the number of snails, but it is labor-intensive and time-consuming in densely populated areas and large areas of farmland, and is often difficult to completely eradicate. In terms of chemical control, commonly used chemical agents include metal aldehydes, formaldehyde mixtures, and more environmentally friendly iron phosphate baits, etc. When these agents are scattered in the areas where snails are active, they can lure the snails to eat them and cause poisoning and death. At present, A more feasible biological approach is to utilize local natural enemies or pathogens: in some areas, local birds and rodents have been found to prey on A. fulica, but this is not sufficient to control its population. Another approach is to utilize the technique of luring enemies, that is, to attract natural enemies of snails to inhabit and hunt. For instance, India deliberately created a microenvironment for toads and lizards, hoping that they would feed on snail larvae, but the effect was limited (Abog et al., 2012; Patil andJagtap, 2022; Magar et al., 2023).
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