Category: Pesticides

PESTICIDES RESIDUES IN FOOD

Pesticide residues in food

Recommendations for pesticide use The use of pesticides is so widespread in intensive agriculture that the presence of chemical residues in food is considered inevitable. The agricultural and industrial practices that enable mass food production are based on the widespread use of chemicals. But every insecticide treatment on crops leaves chemical residues in the food we eat. Agrochemical producers, aware of the possible danger of the toxic products they produce, refer to the safe, recommended and authorized use of pesticides, determining that instructions for use and safety periods between pesticide application and harvesting should be respected. But are these recommendations safe? This information can be questioned, to the extent that growers pay the independent laboratories that establish these recommendations. Recommendations for pesticide intake Most studies on the effects of pesticides on human health have been conducted on agricultural workers and agrochemical handlers. But the reality is that we are all exposed to a cocktail of pesticides through food intake. It is difficult to conduct studies of other kinds, because determining the consequences of pesticides in food is difficult to assess, as most people are exposed, by other routes, to many other chemicals. Since the use of pesticides is considered to be already widespread in the current food production system, once the damage that each pesticide can cause is known, regulatory agencies try to delimit their risks by determining the safe level of intake of each pesticide. Maximum Residue Limit (MRL) in Food The Codex Alimentarius Commission (a body under FAO and WHO) sets maximum residue limits (MRLs) for pesticides in food. But there are several problems with this regulation of risk through MRLs. Problems in the determination of the MRL calculation Logically, the criteria for determining MRLs are the result of the effects of pesticides in tests carried out on laboratory rats. The procedure consists of estimating the maximum daily amount that laboratory rats could consume without being harmful during their lifetime. The results are extrapolated considering that humans have a longer half-life and higher weight than laboratory rats. And, to be on the safe side, they formulate a safety factor, which sets the maximum permissible value at 100 times less than the no-effect level. But the lab rats do not eat salads, which contain vegetables with different (approved) levels of pesticide residues. In other words, the overall limit of the set of insecticide residues ingested in different foods is not considered, but the individual limit of each food. And in these cases, the whole may be more than the sum of its parts. There are more problems in the calculation of MRLs. In that extrapolation from the rat to the human adult, the MRLs are determined with respect to the body weight of an adult. But, since children do not weigh 80 kg, which is the average calculation weight, children consume much higher relative levels of the pesticide. The current European Union Directives for baby food determine strict MRLs. The problem is that this population group is not protected to the same level when consuming fresh fruit and vegetables. Combined exposure to pesticides from food Adults are also not really risk-free with the setting of maximum residue limits for toxic substances in food. Our combined exposure to pesticides in fresh foods, in processed foods, in the environment or in water, is not being considered when setting MRLs. Pesticides accumulate in the body, so small but continuous exposures can eventually result in a noticeable buildup. Because a lot of little ones make a lot. And, in reality, no one has really taken into account the health effect of exposure to small doses of pesticides on a prolonged basis. The problem of the period of the insecticide effect on the organism There is another disturbing fact in this matter. In the 1960s Western society began to become aware of the harmful and in many cases carcinogenic potential of DDT. It was banned in many countries at the end of the decade, in the USA in 1972 and in Spain in 1977. In other words, it can take a long time from the time the harmful effect of a substance is confirmed until its use is banned or limited. DDT continues to be legal in India. And no one can deny that thanks to DDT malaria was eradicated in Europe and other parts of the world. Compliance control Finally, regarding the presence of pesticide residues in food, it is true that the European Food Safety Authority (EFSA), and other public bodies, periodically analyze food samples to determine whether pesticide residues are within maximum residue limits (MRLs). In recent years, a very low percentage of foodstuffs have contained pesticide residues. Thus, the European agency, and other public bodies, conclude that chemical residues do not pose a health risk to consumers. But what if the MRL is not calculated according to real criteria for the elderly and children, and what if possible future long-term effects of residues on the body have not been taken into account? Then this limit and the certification of compliance is giving a false idea of safety to consumers. More information Codex Alimentarius EFSA: Pesticide residues in food: what´s the picture in EU?

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phytosanitary

Efficiency of pesticides

How is the timing of pest control treatment determined? Many of the applications of pesticides for pest and disease control are done preventively and, according to the Food and Agriculture Organization of the United Nations, 40% of pest and disease control treatments are done late. In pest control, it is not only the type of pesticide used that matters, but also the timing of the treatment. In Integrated Pest Management, it is not so much the what that matters, but the how, and above all, the when. Case study: timing of fall armyworm (Spodoptera frugiperda) treatment Spodoptera frugiperda (corn leaf worm, fall armyworm, grass worm, southern grass worm, common names) is an agricultural pest that causes great damage worldwide, mainly because treatments are carried out late.. In this case, treatments should be carried out at the latest when the larvae of the pest are in the third instar stage or molt, when the insect larvae are approximately 1.2 cm long. The cause of failure in its control is mainly due to late treatments, when the larvae are already protected inside the corn head. How to know when? Fighting a pest is not simply repeating treatment with the chemical product you know well, or trying new ones that you do not know, but it is necessary to act knowing the pest’s habits and its biological development, which are decisive to know when the treatment will be more efficient to control the pest. FuturCrop is the software that predicts the opportune moment to carry out monitoring, the initial moment of the pest and the generational cycles of its populations. This information will allow us to determine in advance whether economic treatment thresholds could be reached (by the number of generations, population density peaks and the result of sampling or trapping) as well as when the pest is most vulnerable. El software también crea las gráficas térmicas del cálculo de los eventos fenologicos de las plagas y facilita información relevante para la identificación y monitoreo. FuturCrop controls the development of 179 pests that affect more than 250 crops. You can see pests and crops here.

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TOXICITY OF PESTICIDES

The pesticide industry Global pesticide consumption was estimated at around $59 billion in 2016, 50% of which was in the developed countries of Europe and North America. This race towards the chemical protection of food began with what is the oldest organic pesticide, DDT (dichlorodiphenyltrichloroethane) which was synthesized by Müller in 1939, for which he received the Nobel Prize in 1948. Its use made it possible to combat major epidemics (typhus transmitted by lice and malaria transmitted by mosquitoes). However, its use is currently restricted in most countries because of its high toxicity and persistence, which causes serious ecological and human health damage. Characteristics of the agricultural pesticide industry Classification of pesticides Pesticides is an umbrella term for fungicides (to control fungi), herbicides (weeds), insecticides (insects), etc. There are also other classification criteria: by their mode of action, they are named according to the pests they control: fungicides control fungi, herbicides control weeds, insecticides control insects, etc. Pesticides can also be classified according to the following criteria: Toxic pesticides Short-term toxicity Toxicity a If we analyze pesticides for their toxicity, they are all toxic to humans and animals, but to varying degrees, depending on the dose and time of exposure. There are pesticides whose action affects not only pests, but also human biological processes. Such is the case of neurotoxic insecticides that act on nerve impulse transmission, common to insects and humans. This category includes organochlorine, organophosphate, carbamate, pyrethroid and nicotinoid insecticides. Endocrine disruptors are chemicals that alter the human and animal hormonal system. Studies on pesticide residues in food, based on data from the Spanish Agency for Consumer Affairs, Food Safety and Nutrition (AECOSAN), show that 28% of the foods analyzed contain pesticide residues (mostly within authorized limits). This percentage increases to 45% for fruits and vegetables. For example, 49 pesticide residues were found in pears, 16 of which were endocrine disruptors. Long-term toxicity In addition to short-term toxicity, there is another toxicity, the symptoms of which occur after exposure to small doses over a long period of time. But these damages are more difficult to assess and there are no conclusive studies. Environmental toxicity Pesticides also have an environmental effect. Most carbamates have low to moderate toxicity to mammals. However, bees are very sensitive to the presence of carbamates. But it is not only carbamates that influence bees. Two recent studies published in the journal Science show that the widespread use of neonicotinoid insecticides has negatively affected bee colonies. Bees are involved in seed and fruit production through pollination. Bees play a key role in biodiversity. But they also play an important role in food production. According to the Food and Agriculture Organization of the United Nations (FAO), one third of food depends on bees. Future of pesticides The European Commission presented in June 2022 a proposal to oblige a 50% reduction in the use of chemical pesticides in the European Union by 2030. Each Member State will propose different national targets, depending on the starting situation of each State. This proposal is part of the objective of creating a sustainable food system, according to the European Green Pact and the strategy “From Farm to Fork. Links De la From farm to fork. Strategy within the framework of the European Green Pact. European Green Deal Hazard classifications, FAO

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Effects of Climate Change on pests

Effects of Climate Change on pests

Effects of Climate Change on Pests The increase in temperatures due to Global Warming alters the biological cycle of pest development, extends the period of time during which they are present in crops, and expands the territories in which they are present. But these are not the only effects of climate change on pests. As the temperature rises, so does the metabolism of insects, increasing the number of generations per season, shorter reproductive cycles and, logically, increasing their population density. More reproductive cycles because pest metabolism is accelerated. Climate change not only means an increase in temperatures, but also in humidity and CO2. And these three increases largely determine the increased incidence of crop pests and diseases. Rising temperatures accelerate the metabolic rate of insects, and thus their reproductive rate. Some studies estimate that an increase of 2 degrees Celsius in the temperate zones of the planet could mean up to 5 additional biological cycles of certain pests. Insects belonging to the order Hemiptera and Thysanoptera (such as bugs and thrips), are the most benefited under these climatic conditions, since the increase in temperature favors their reproductive rate. In addition, the pests appear earlier in the crops (between 5 and 9 days for Carposina sasakii, Grapholita molesta and Phyllonorycter ringoniella in apple crops), and their presence in the crops lasts longer. Soil becomes more uniform in temperatures, therefore pests can live in other habitats. Climate change will increase the risk of pest spread in agricultural and forest ecosystems, especially in the colder Arctic, boreal, temperate and subtropical regions. The range of pests is expanding into new territories. New pests of tropical origin can survive in cold areas now considered temperate. A single unusually warm winter may be enough to favor the establishment of invasive pests in a geographical area. The tomato moth, Tuta absoluta, a tomato pest from South America, first appeared in Europe in 2006 and rapidly spread to almost all Mediterranean and Central European countries. It is a pest that rapidly accelerates its reproductive rate with increasing temperatures. Some pests, such as the budworm, which feeds on a large number of crops such as corn, sorghum and millet, and the Tephritid fruit fly, which damages other crops in addition to fruit, have already spread due to the warmer weather. The codling moth, Spodoptera frugiperda, has a life cycle that ranges from 35 to 61 days. Global warming of the planet causes this life cycle to shorten, increasing the number of generations and lengthening the period in which the pest can be active. New technologies for the new situation in the control of agricultural pests This requires that, in order to face these new challenges, the sector must adopt new ways of working that will allow it to foresee these changes and face integrated pest control and management with greater guarantees. Links Climate change fans spread of pests and threatens plants and crops, new FAO study Climate change impacts on twenty major crop pests in Central Asia, the Caucasus and Southeastern Europe, FAO

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Copyright © 2016. Todos los derechos reservados

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