Products used in agriculture and forestry within the group of pesticides used to kill, repel or inhibit insects and their development stages for plant protection. The name is derived from the Latin terms "insecta" (insect) and "caedere" (kill). Insecticides act as contact, feeding or breathing poisons on the insects or their developmental stages (eggs, worms). Insects as pests in viticulture were already controlled in ancient times because, unlike microorganisms, they were visible as enemies of the vine. In many biblical texts and wall paintings there are reports of locust plagues in Egypt in particular. Greeks and Romans fought insects with sulphur mixed with oil and Pliny the Elder (23-79) writes about the use of arsenic. Marco Polo (1254-1324) of China reports the same. From the middle of the 18th century, salts of lead, iron and mercury were increasingly used.
The first synthetic agents on a chemical basis were already developed at the end of the 19th century. Initially, they were broad-spectrum insecticides that were toxic to almost all insects. The first was antinonnine (a methylphenol) from Bayer in 1892, which was used both as an insecticide and as a herbicide. In 1938 the first phosphoric acid ester was developed and in 1939 DDT was used for the first time. DDT was used extensively for several decades in the fight against insects. It was only at a late stage that the adverse effects such as poor biodegradability and accumulation in the fatty tissue of mammals became apparent. From the early 1970s onwards, many organochlorine compounds were then banned, including DDT.
There is a wealth of specific insecticides. The approved conventional preparations are mostly pyrethroids, phosphoric acid ester derivatives or chlorinated hydrocarbons. A distinction is made between products with immediate effect (when the worms have already hatched) and those with immediate and permanent effect (when further hatching is expected). The so-called moult inhibitors (block the moulting) or moult accelerators intervene in the larval development with hormone-like effects and lead to the death of the larvae. A subform are the ovicides (lat. ovum = egg), which kill the sexual products (= eggs) of insects or inhibit their development. In the 2010s, neonicotinoids, which act on the nerve cells of insects, came into disrepute and are blamed for the worldwide bee mortality. Even the smallest amounts cause lasting damage to bumblebees and honeybees. They are also contained in insect sprays.
In viticulture, insecticides are used to control, among other things, Dickmaulrüsslerweevils, grasshoppers, grasshoppers, mites, grapevine stingers, rhomboid moths, grape moths and cicadas. Within the framework of biological plant protection, insecticides are completely avoided, whereas integrated plant protection avoids them wherever possible. Instead, the control is carried out on a biological basis in the form of fungi, bacteria and viruses. One example is the soil bacterium Bacillus thuringiensis. Furthermore, natural enemies such as predatory mites are used or the confusing method(pheromones) is applied. See under organic viticulture.