What are pesticides?
The word "pesticide" can be derived from Latin, pestis → plague, and caedere → kill. Pesticides are chemicals that reduce the persistence of unwanted and or harmful animals. They are used in crop protection, for the cultivation of u.a. Fruit, vegetables and cereals, as well as for the hygienic protection used in the production, processing, packaging and distribution of food and the like. 
What are pesticides chemically?
Pesticides refers to the super-grouping of all agents that protect plants and humans from pests and micro-organisms. They have many subgroups, of which the relevant ones are:
Pesticides; They protect plants from predators and pathogens
biocides; They have many target organisms, including microorganisms such as bacteria, viruses and fungi, as well as larger organisms such as e.g. Insects or rodents.
herbicides; Weed killers, which target or radical against plant life proceed.
Zu den Pflanzenschutzmitteln zählen Biozide, Herbizide, sowie Wachstumsregulatoren. Solche sind z.B. Insektizide, welche hauptsächlich aus Phosphorsäureestern, Carbamaten, Neonicotinoiden und Pyrethroiden zählen. Natürliche Insektizide sind z.B. Nikotin, Anabasin oder Piperin. Zu den angewandten Herbiziden gehören Aminosäurederivate wie das Glyphosat (eingestuft nach WHO als Karzinogen 2A, „steht im starkem Verdacht Krebs im Menschen auszulösen“). Diese machen ca. 18% der weltweit eingesetzten Herbizide aus. Die Sulfonylharnstoffe, wie z.B. das Amidosulforon (Nach GESTIS-Stoffdatenbank stark Gewässergefährdend). Diese machen rund 10,8% der weltweit eingesetzten Herbizide aus. 
The biocides are used outside the cultivation of plants, in the processing, production and distribution of food and other consumer goods. For example, Disinfectants with the subcategories of bactericides (kill off bacteria), virucides (kill off viruses), algicides (kill off algae) and fungicides (kill fungus). Such substances are among aldehydes, alcohols and chlorine-containing substances. In addition, the biocides include the rodenticides, the rodent control agents, mostly coumarin derivatives, which prevent blood clotting. There are also avicides (against birds), molluscicides (against snails), piscicides (against fish), acaricides (against arthropods) and nematicides (against roundworms).  All have their respective permitted and prohibited substances. 
How harmful are pesticides?
Pesticides can potentially cause damage to ecosystems, humans, and organisms for which they are not made. They are a constantly occurring and difficult to treat topic. Many studies on pesticides have no precise statements regarding their toxicology, KRM effect, or ecotoxicology. So there is no clear picture to the currently used pesticides. They move in gray areas, which represent clear applications in contrast to inaccurate, possible damage, that is to say the benefit of security due to ignorance. In recent decades, some pesticides have been banned.  And a few even worldwide, as part of the so-called Dirty Twelve (English "Dirty Dozen"). Although in Germany the "as low as reasonably achivable" principle for the limits of pesticide-restricted fruit, vegetables and cereals must be strictly adhered to, the amounts found are still considered harmful. 
Pesticides in cosmetics
Especially in natural cosmetics, in which herbal ingredients make up a large part of the composition, the question arises "Are there pesticide residues?". Depending on the initial conviction, this answer is different. If the plants were cultivated without pesticides, none are present in the plant raw material. If they were cultivated with pesticides, these traces are in the plant raw material. And yet, biocides can be included in the final product. Substances that protect the product itself. Of course, no such, as they are used in large-scale cultivation, but still. 
Are there alternatives ?
There are natural sources of plants own pesticides, nicotine, anabasine, piperine and the currently interesting pelagronic acid. Or natural predators of pests. But they are not effective enough for human needs, or cause other harvesting or processing problems. Germany alone has an annual consumption of more than 48 thousand tons of pesticides of all kinds (as of 2017) . However, biological pesticides are on the rise, but are not least held back by the economic aspect. Global sales of crop protection products increased by 5.6% in 2017 to around € 47.62 billion.  Nevertheless, the research is progressing steadily, and maybe the "dirty dozen" will soon get a dozen more.
What does all this mean now?
Pesticides are not such a big topic for nothing. Without them, it would be healthier, more environmentally friendly, hyperbolic, even utopian. At the moment, though, that's exactly what utopia is. With around 7.6 billion people, many with virtually nothing and even more who are already struggling to survive, one must think of the need for care. A similarly difficult topic would be nuclear power plants. They are far from being environmentally friendly and, moreover, represent a huge hazard. Although nuclear power only supplies about 11.7% (as of 2017)  of the electricity, it would now become 11,7% from one day to the next % are missing, so the cost would rise to the priceless. Like pesticides, it would be better without them, but we could not meet the needs, not those who are already starving, not those who are worried about hunger, or those who are not hungry at the moment are.
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