Assessment of phytosanitary practices on the environment: case study potato of Loukkos (northwest Morocco)

Loukkos perimeter is among the most important irrigated agricultural areas in Morocco. It covers horticulture and market garden production, including potato. This crop is characterized by the intensive use of pesticides that could lead to health and ecological risks, via the food chain and contamination of natural resources, including groundwater. This study is aimed at assessing the use of pesticides in potato cultivation and their impacts on the environment and human health. Here, pesticide use was characterized by the number of treatments (NT), quantity of active substances indicator (QASI), and the treatment frequency indicator (TFI), through field surveys carried out on 50 Loukkos potato producers. The results showed that farmers use heavy pesticide treatments, mainly against late blight. We determined NT = 19 treatments, total TFI = 28.10, and QASI = 14.86 kg/ha. These values reflect a massive use of pesticides on this crop, which could therefore constitute a challenge and a major constraint for the development of sustainable agriculture in this zone, due to their negative environmental and health effects. It is, therefore, necessary to react quickly to make changes in phytosanitary practices with the aim to monitoring pesticide use via the agro-environmental indicators to reduce health and environmental impact of intensive pesticide use.


Introduction
Potato (Solanum tuberosum L.) is the fourth most important agronomic crop in the world after wheat, rice, and maize (Sampaio et al., 2020;Sookhtanlou et al., 2021). In Morocco, the potato is one of the most economically important crops. The area sown with potatoes varies from 50,000 to 60,000 ha per year. It represents l8 to l9% of the total surface area of cultivated vegetable crops (Alaoui et al., 2021). According to a section of the widely used FAOSTAT database, the cultivation of potatoes is widely practiced with an estimated area of 57,534 ha and a production of 1,707,068 T with an average national yield of 29.67 T/ha (FAO (Food and Agriculture Organization of the United Nations), 2022). Together with sugar crops and cereals, potatoes represent one of the leading agricultural products in Morocco, principally Vol:. (1234567890) for irrigated zones, including the Loukkos perimeter. In view of the fact that this crop requires inputs, especially pesticides, the problems of the irrational use of this production factor are posed with acuity in the face of biodiversity and public health. More concretely, upon completion of the Green Morocco Plan (GMP) period, the government launched in 2020, Green Generation 2020-2030, a new Moroccan agricultural strategy, being a strategic sector with the ambition of doubling its GDP by 2030. This strategy is aimed at promoting modern agriculture, with high added value crops adapted to export markets. A change toward more intensive agricultural practices in the foreseeable future, as foreseen by this new strategy, will further increase the risk of diffuse pollution of water, air, and soil from agricultural sources. This can undoubtedly pose different implications for both natural resources and humans because of the heavy use of pesticides. Besides, potato plants are susceptible to a wide variety of diseases that severely can reduce the yield, quality, and storability of tubers (Meno et al., 2021). Without pesticides use, there would be a 78% loss of fruit production, a 54% loss of vegetable production, and a 32% loss of cereal production (Tudi et al., 2021). In intensive agriculture, as is the case in the Loukkos area, potato cultivation faces major difficulties, mainly related to the control of late blight, caused by Phytophthora infestans, which remain the most expensive potato pathogen to manage worldwide (Goss et al., 2014). The potato is a crop that is very consumptive of pesticides in the Loukkos perimeter, since it is exposed to multiple attacks by pests and diseases that damage the product and cause significant economic losses. Concomitantly, aphids cause serious losses in potato plants and tubers, mostly because they vector viruses (Saguez et al., 2013). The absence of an environmentally friendly alternative for the management of potato pests and diseases has left farmers with no option other than pesticides used in potato crops. For this reason, the use of pesticides on potatoes is an integral part of agricultural practice at the Loukkos perimeter. However, the misuse of these products could hurt both human health (Berni et al., 2021b) and the environment (Berni et al., 2021a) including the contamination of surface and groundwater, soil, and the living environments of non-target organisms (Farahy et al., 2021;Rissouli et al., 2017), through the flow processes, leaching, and spraying. On the other hand, exposure to pesticides also affects biodiversity (Pelosi et al., 2021;Shefali et al., 2020;Wen et al., 2021). They could alter the functioning of the endocrine system (Girard et al., 2020) and the use of pesticides in mixtures can act additively, synergistically, or antagonistically in the environment (cocktail effect) (López et al., 2021). In Morocco, between 2008 and 2014, total pesticide imports increased from 17.135 tons/y to 19.180 tons/y (Berni et al., 2021a). In addition, due to the lack of education and the presence of a counterfeit market, pesticides constitute a major problem to be addressed by occupational and environmental health (Menouni et al., 2022). Based on the results of the intoxication analysis, pesticides are a serious public health problem in Morocco, as long as they have been incriminated; according to the Moroccan Anti-Poison and Pharmacovigilance Center, pesticides caused 4110 cases of poisoning between 2008 and 2014 (Berni et al., 2021b). On the other hand, the National Food Safety Office (ONSSA) destroyed last year 136 tons of potatoes due to exceeding MRLs or the use of unauthorized pesticides (Bahouq et al., 2021). However, the phytosanitary protection practices implemented by potato producers are poorly documented at the Loukkos perimeter and, therefore, remain poorly known. Given these findings, the evaluation of the pressure of plant protection practices on the environment is necessary to highlight the current state of the crop from an environmental point of view. In addition, the evaluation of pesticide use becomes a fundamental requirement to ensure sustainable development. The integration of indicators in tools to evaluate the sustainability of practices is an important issue (Lamichhane et al., 2019), including the treatment frequency indicator (IFT) and the quantity of active substances indicator (QASI) (Fouillet et al., 2022;Hossard et al., 2017), recently used in the Ecophyto plant in France to reduce pesticide use Vernier et al., 2013). In this light, agroenvironmental indicators can be used as a monitoring tool to minimize pesticide use in Loukkos perimeter (Abbou et al., 2022). The objective of this work is to assess the pressure of pesticide use in potato cultivation at Loukkos perimeter, northwest of Morocco, by determining agro-environmental indicators, and whose aim is to contribute to the more responsible use of plant protection products and the development of sustainable crop protection in this region.

Description of the study area
This study was conducted within the Loukkos perimeter of northwest Morocco. Its total area is 2650 km 2 . The region has a useful agricultural area of 147.500 ha, 45.000 ha of which are irrigated. The region has a Mediterranean climate with an annual average temperature ranging between 11 °C in winter and 25 °C in summer, and annual average rainfall is approximately of 700 mm between October and April (Sarti et al., 2021). This area is a major asset for the development of the region. It is characterized by intensive agriculture including horticulture and market gardening (Abbou et al., 2022). The sandy soil originated from the Loukkos region called "R'mel" is inorganic and poor in nitrogen, and its texture is sandy (Benicha et al., 2016;Elhani et al., 2019).

Conduct of surveys
To assess potato practices, field surveys were carried out using a questionnaire containing information on the farmer (age, sex, and education level), the agricultural planted area, varieties, and pesticide treatments (frequency, dose, target, period, time to harvest,…). A total of 50 farms were surveyed representing different areas of Loukkos (El Aouamra, Oulad El Ghoumari, Zlaoula, Laghdira, and Rehamna). All potato farmers themselves used chemical pesticides on their farms.

Agro-environmental indicators
In the present study, pesticide use in cultivation in Loukkos perimeter was characterized by three agro-environmental indicators: the number of treatments (NT), treatment frequency indicator (TFI), and quantity of active substances indicator (QASI). The NT is defined as the sum of the total number of products applied per pass on the agricultural plot during a marketing year. A mixture of two products applied during the same passage also counts for two treatments. The TFI reflects the intensity of pesticide use on a farm (Pierlot et al., 2017). It is commonly used in Europe to assess the reliance of cropping systems on pesticides (Yvoz et al., 2020). The TFI is 0 if no chemical pesticide is applied. High TFI values demonstrate both high application frequencies and the application of doses exceeding formally approved rates. (Zemmouri et al., 2022). The QASI is a simple indicator of the quantity of active substances used per ha (Möhring et al., 2019). It is also among the important indicators used to monitor the Ecophyto 2018 plan in France (Hossard et al., 2017).

Characteristics of the farmers surveyed
Data distribution of some features available in the data set includes the variety, age, educational attainment, and farm size were used to describe the population and the farms to measure the variables studies. The results are presented in (Table 1).

The main pests and diseases of crops in the plain of Loukkos associated with potatoes
Phytophthora infestans, the pathogen of potato late blight which is a devastating disease of potatoes among all farmers surveyed, causes stem and leaf rot, leading to significant economic losses. It is more and more frequently encountered in prospected farms. This disease can only be treated as a preventive measure, mainly in the function of the risk level and pluviometry during the cycle of crop growth. Late blight is recognized thanks to oily and brown, rounded spots on the upper surface of the leaves. The presence of late blight is still signaled, but the incidence is much more important with the increase in humidity. On the other hand, the sunniest months are the most favorable for the apparition of aphids belonging to the order Hemiptera and the family Aphididae. The latter develops in priority on the leaves of the lower part of the plant and especially in the lower face of the leaves, leading to severe yield reduction and loss of tuber quality. The present research findings indicated that the disease severity was significantly noticed during surveys, which makes agriculture depend on the pesticides used, pushing the farmers to use, heavily the pesticides to fight against these diseases. Nevertheless, pesticides pose a particular danger to farmers, not only through their massive use, but through the absence of personal protective equipment, adequate storage, no respect for good practices. Nevertheless, pesticides pose a particular danger to farmers, not only through their massive use but through the absence of personal protective equipment, adequate storage, and no respect for good practices, due to the low level of education of the producers and lack of training qualifying who remain a strong obstacle with the good knowledge of the ecotoxicity of the pesticides and their dangers chronic. This situation may lead to a risk of contamination and thereby health risks.
Categories of active substances identified during potato crop production cycle From the 31 commercial products used for the cultivation of potatoes, 25 different active substances, belonging to 19 chemical families, have been identified. In terms of quantity, fungicides remain the most used with 84%, followed by insecticides with 9% and herbicides with 7%. Among these substances, 56.7% are not registered on the potato crop in Morocco. The pesticides used are classified, in terms of toxicity according to the WHO, as moderately hazardous (67%) and slightly hazardous (12%), while (21%) are listed as unlikely to be acutely hazardous in normal use. Irrational use of the latter can have chronic and acute health effects, depending on the level and route of exposure. Moreover, on the ecological side, 66% of these substances are difficult biodegradable, while 24% are rapidly biodegradable. This can lead to significant health and ecological consequences due to their persistence and accumulation in soils, surfaces, and groundwater, and their adverse effects on biodiversity. Pesticide preparations based on organophosphates (chlorpyrifos-ethyl and dimethoate), carbamates (mancozeb, propamocarb, and maneb), phenylamides (metalaxyl), pyrethroids (deltamethrin), neonicotinoids (thiacloprid, sulfoxaflor, and imidacloprid), bipyridiles (diquat and paraquat), and substituted ureas (linuron) ( Table 2) were the most used pesticide substances against the pests of Loukkos potato. These pesticides all have, with different degrees, potential for toxicity and can, unfortunately, be harmful, both to humans and to non-target organisms. Mancozeb is the active ingredient most used in all the surveyed sites, to control mildew. Its availability in several commercial specialties (Turbo ZM, Uthane, Buster, Systemil 72 WP, Ridomil gold MZ 68 WG, Agrizibe, and Dithane M45) and the existence of several pesticide shops further facilitates its use. The application rates vary from 2 to 6 kg/ha per treatment, which is two to three times higher than the approved dose/the registered rate. Regarding the specifications of the commercial specialties used, we noticed that these pesticides are presented in the form of concentrated emulsions EC (51.28%), soluble concentrates SL (16.80%), wettable powders WP (13.44%), concentrated suspensions SC (9.24%), water-dispersible granules WG (5.88%), powder for powdering DP (2.52%), and oily substances OD (0.84%). All these formulations are mainly used against mildew and aphids. Problems related to formulations use can extend beyond the farming area when residential areas are nearby. In addition, many drinking water wells exist in or near these farming areas. The results of the study showed health and environmental risks related to the use of plant protection products in the Loukkos region.

Number of treatments (NT)
Regarding phytosanitary problems, potato production is threatened by adverse pests and diseases, severely affecting potato yield and tuber quality, including late blight and aphids, which requires the implementation of fairly heavy curative and preventive protection programs depending on the level of infestation risk and pluviometry level. The average number of pesticide treatments applied on potato crops is NT = 19 treatments per cycle. The results showed that NT was strongly linked with the total number of fungicides sprayed NT = 14 all along the vegetal cycle, mainly targeting late blight, followed by insecticide treatments NT = 4 for aphids during the sunny months, and at the end, herbicide treatments NT = 1 to control all the weed flora present in plots using pre-emergence herbicidal treatment (Table 3). In terms of the efficacy of insecticide treatments against aphids, one should intervene as the first aphids arrive and then re-intervene as soon as new aphids are present. The application rates used often do not correspond to approved ones, while the treatments carried out via backpack sprayers or pull-type sprayer are done without any wearing protective suits or masks.

Quantity of active substances indicator (QASI)
In terms of pesticide consumption by category of active substances used in potato farms surveyed, we obtained an average value for the indicator of the total quantity of active substances used, QASI = 14.90 kg/ ha. According to our results, fungicides, mainly used to fight against mildew, are the most used with an average of QSAI = 14.14 kg/ha, that is to say, a contribution of 95% of total QASI, followed by herbicides against adventitious weeds, applied before the planting of seeds with QASI = 0.45 kg/ha and insecticides against aphids with QASI = 0.31 kg/ha, that is to say, respectively, 3% and 2% of total QASI (Table 4). This QASI value reflects a strong trend in pesticide use. On a time scale, these practices can be involved in ecotoxicity thresholds of active substances being exceeded in different compartments of the environment, through accumulation, dispersion, persistence, derivation, and degradation giving out even more toxic metabolites.

Treatment frequency indicator (TFI)
To further characterize plant protection practices, particularly the intensity of pesticide use, we used the treatment frequency indicator (TFI). The average total TFI for all surveyed farms is 28.10, i.e., 28 treatments at the registered dose per crop cycle. Fungicide treatments contribute with 74.54% of total TFI, while the use of insecticides, targeting mainly downy aphids, represents 21.46% of the total TFI. In contrast, the herbicides come last with contributed 4% of the part of the TFI total (Table 5). It should be noted that this total TFI value still very high, reflecting a heavy use of pesticides in potato crop, strongly related to the total number of fungicides sprayed. These practices remain alarming because of the degradation and the accumulation of pesticides in the natural environment. In the long run, this can lead to significant sanitary and ecological risks.

Discussion
In Africa, potato production is threatened by adverse pests and diseases, a major potato production limiting factors, severely affecting potato yield and tuber quality (Munyaneza & Bizimungu, 2022). The results of our surveys have shown that late blight and aphids are diseases and pests causing important economic damages at the production level of the potato in the Loukkos perimeter, which pushes the farmers toward the massive use of pesticides. Aggravating the situation, application of pesticides in mixtures without any agronomic justification combined with the absence of personal protective equipment contributes to the farmers' pesticide exposure and the deterioration of the environment. In the territory of the Loukkos in Morocco, our surveys showed that pesticide use proved the only protective method practiced to control late blight and aphids in potatoes. In Europe, aphids gave a mean annual loss of 850,000 tons of potato production (Namgung et al., 2022). Annually, late blight causes global losses of nearly 10 billion euros (Sanabria et al., 2020). On the other hand, the low education level of potato producers (67% do not have any level of education) can lead to pesticide misuse. As the result, this situation, in combination with the absence of use of protective equipment, could considerably increase the risk of exposure of farmers to chronic and acute pesticide effects, as well as the exposure of public health to pesticide residues. In fact, in terms of quantifying and measuring the intensity of pesticide use in potato crops, this study highlighted the high pesticide pressure, marked by high values for both the TFI = 28.10 as well as the QASI = 14.90 kg/ha and the NT = 19. Our results showed that the three indicators were strongly linked with the total number of fungicides sprayed, reflecting the high use of fungicides against potato late blight, caused by the fungus Phytophthora infestans. These practices are not without consequences for non-target organisms. This could be due, on the one hand, to the curative and preventive treatments with the same active ingredient (mancozeb) against downy mildew throughout the vegetative cycle, the disease most feared by all the farmers, which could probably increase the resistance of late blight later on to this active ingredient used at a wide range. On the other hand, the neglect of factors interacting during treatments, such as meteorology and pulverization schedule, applied doses and water quality of treatment (pH, conductivity, …). Also, pest resistance to pesticides is leading growers to further increase the number of treatments and doses applied (Le Bellec et al., 2017). This was frequently observed during the course of our surveys. These bad practices could increase the risk of environmental contamination via dispersal, derivation, persistence, degradation, and/ or bioaccumulation in the long term. In addition, the application of pesticides in mixtures is a very common practice. It is used by farmers in order to save believing it the pesticides use in mixtures, in the aim to increase the efficiency and reduce the spraying charges, without agronomic justification, can worsen the environmental Table 4 Values of QASI calculated on basis of the total herbicide, fungicide, and insecticide use in Loukkos region

QASI (kg/ha) Overall
Herbicides Insecticides Fungicides QASI 0.45 0.31 14.14 14.90 Table 5 Values of TFI calculated on basis of the total herbicide, fungicide, insecticide use in Loukkos region

TFI Overall
Herbicides Insecticides Fungicides TFI 1.13 6.03 20.94 28.1 and the sanitary situation since it could have/present more dangerous effects than when the substances are applied individually (Hernández et al., 2013). Certainly, more attention should be directed to specific residue mixtures that could also generate cryptic, synergistic toxicity effects in bees as well (Xiao et al., 2022). It is to be noted that in Morocco, these indicators have not been previously reported for potato crop, which led us to compare our results with those obtained for other crops in Morocco or elsewhere with the same crop or other crops (MAAARO, 2022;Florence et al., 2011;De Baan et al., 2015;Bettiche, 2017;Kanj, 2018;El Bouzaidi et al., 2020;Berni et al., 2021a) (Tables 6 and  7). The comparison of the results with the literature shows that these values remain very high and reflect an intensive use of pesticides, which may present risks, both for human health (Basu et al., 2021), as well as for the environment (Liess et al., 2020). Moreover, the survey results showed that a mixture of different active ingredients (linuron, diquat + paraquat) is the basis of the chemical weed control strategies in potato cultivation. Unfortunately, these products have harmful and toxic effects on health (carcinogenic, toxic for reproduction …). In addition, previous studies have shown the presence of pesticide mixtures in air, in the soil at agricultural in Europe and Africa (Degrendele el al., 2022). This will further increase the risk of diffuse pollution of water, air, and soil from agricultural sources. The seriousness of this situation is amplified by the use of pesticides in the mixture throughout the plant cycle (mixtures of a systematic fungicide with a contact fungicide, mixtures of an insecticide, with a fungicide). While the impacts of individual pesticide compounds on non-target organisms are usually studied, we still lack information about the toxicity of environmentally relevant mixtures as also emphasized in the European Green Deal (Kuchovska´ et al., 2021). Hence, the presence of mixtures of pesticides and biocides in different environmental matrices is a concern because of their potential synergistic, additive, and/or antagonistic effects on non-target organisms (Pérez et al., 2021). Indeed, previous studies have shown the presence of pesticide mixtures in the air in agricultural, urban, or remote locations in Europe (Degrendele et al., 2022). Especially, the amount of field or experiment data remains largely limited for use of pesticides mixture of potatoes in Morocco. Therefore, the assessment of pesticide use will have a positive impact on environmental monitoring and human health. In addition, other factors can be in question to the exposure toxicity, such as formulation, due to fact that it's one of the principal variables of modulation of their toxicities (Samuel et al., 2007). According to the survey results, the pesticide formulations identified included the following: EC (51.28%), SL (16.80%), WP (13.44%), SC (9.24%), WG (5.88%), DP (2.52%), and OD (0.84%). It gets worse, as most of the used formulation poses a high exposure risk. Additionally, 56.7% of used pesticides are not approved for potatoes or are destined for other crops. However, empty pesticide packaging and containers are abandoned in nature, reused, or burned in the fields. These bad practices, in association with high values of agro-environmental indicators found, in the absence of rapid intervention, could cause great concern for the environment and health. Beyond the assessment of the use of pesticides, this study should be completed by a risk assessment for human health and the environment, and by study of agro-environmental impact indicators, which will be the subject of continuous work.

Conclusions
Loukkos irrigated perimeter is a very important zone in the economy of northwest region of Morocco. However, the overuse of pesticides due to non-compliance with good phytosanitary practices noted and observed during field surveys and the very high values of pesticide pressure indicators, determined for potato crop, can lead to an increase in the risk factors both for the environment and for human health. It should therefore be noted that these irresponsible practices can be a major obstacle to sustainable agriculture. From a methodological point of view, this study showed the interest of using agro-environmental pressure indicators as a new way to minimize pesticide use. A better control of the latter by all the partners will allow production to increase, to preserve its sanitary quality, and to be at the heart of the challenges of sustainable development.
Therefore, future efforts should be directed toward the use of indicators as a decision support tool for crop monitoring. Monitoring is also essential to reduce pesticide use (e.g., bans and restrictions on delete more toxic substances, use easily biodegradable substances, use of bio-pesticides, and adapting integrated pest management). The use of the risk assessment tool for pesticide toxicity for humans and the environment will be the objective of our next work.
Author contribution All authors contributed to the study's conception and design. Data processing and analysis and data collection and analysis were performed by Mohamed Abbou. The first draft of the manuscript was written by Mohamed Abbou, Mohamed Benicha, and Mohamed Chabbi. All authors provided input into various aspects of the study, provided ongoing critique, and approved the final version of the manuscript. All the authors declare that they have seen the revised manuscript and approved the version to be published. All the authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Availability of data and materials All data generated or analyzed during this study are included in this published article [and its supplementary information files].

Declarations
Ethics approval The methodology for this study was conducted by the guidelines of the National Institute for Agricultural Research, Tangier (Morocco), and by the ethics committee of the Faculty of Sciences and Technics Tangier (Morocco). All authors have read, understood, and we have complied with the statement on "Ethical responsibilities of Authors" as found in the Instructions for Authors.

Consent to participate
Informed consent was obtained from all individual participants included in the study.

Consent for publication
The authors affirm that provided informed consent for the publication of the paper to be published by Environmental Monitoring and Assessment.

Competing interests
The authors declare no competing interests.