In the agricultural production of today, there are many factors that may adversely affect crop yields. Among these factors, pests and diseases can be described as a category that can cause very serious losses. Therefore, in terms of agricultural production, scholars have done a lot of researches on how to minimize the impact of pests on crop yields. With the rapid advancement of science and technology, scholars have gradually found an effective way to reduce the number of harmful insects from the source: to reduce the survival rate of the insect population and increase its mortality rate. The specific method is to use the insect pheromone to interfere with the normal growth of insects or make them to lose the ability to reproduce offspring. Well, in this article, I will give a detailed explanation of insect pheromones.
In terms of its chemical nature, insect pheromone is a hormone substance secreted by the insect itself that regulates its behavior, and it can also be synthesized artificially. According to the difference of insect pheromone's mode of action, it can be divided into the following two types: releaser pheromone and primer pheromone. The former is mainly felt through the sense of smell. It is released by an individual, and the other individual that feels this pheromone will immediately change its behavior and make a reaction specific to this pheromone. The change of this behavior is reinstated with the disappearance of pheromones. the releaser pheromones including sexual pheromones, guidance pheromones, and assembly pheromones. While the hierarchical differentiation pheromone and “queen material”(such as Methyl oleate, coniferyl alcohol) in the colony belong to the latter category. The two kinds of pheromones are related to each other, and are controlled by the endocrine system.
When insects are disturbed, warning pheromones are released by insects. When a spotted purple worm attacked by an “enemy”, it will immediately release a small drop of liquid, which would cause nearby locusts to stop eating and to leave. The liquid substance proved to be a sesquiterpene, a highly unstable hydrocarbon. Oviposition pheromone is relatively rare, its role is also more special. For example, there is an apple fly that lays eggs on the fruit and uses its pheromone to mark the surface of the fruit. So if this pheromone is sprayed in an orchard, the purpose of pest control can be achieved.
In view of the unique ecological role of insect pheromone, they have been widely applied in agricultural production. We have already mentioned that the pheromones that can be directly used in pest control are sex pheromones and assembly pheromones. Sex pheromone can attract the same species of heterosexual insects to be mated together from far away. At present, there are more than 300 species of insects known to have sex pheromones, of which more than 100 species have been isolated and purified, and more than 30 species of sexual attractants can be artificially synthesized. Sex pheromones can only be released when adult insects reach sexual maturity. It has been estimated that each female moth can secrete approximately 0.05-1 micrograms of sex pheromones, which can induce male moths to mate together from hundreds of meters or even several kilometers away.
According to the attraction function of sexual pheromone, it can be used to predict the number of pests and the degree of damage, and most importantly, to control the reproduction of pests. The specific methods are the following: The first method is the trapping method. This method uses the synthetic preparation of sex pheromone to trap the male moths and then kill them with viscose or poison. It can effectively reduce the reproduction of female moths. The second is the mating disruption method, which uses artificial synthetic pheromone preparations to spread the odor that contains large amounts of sexual attractant substances in the large pest-producing plots, so that male moths cannot discriminate sexual attraction substances released by female moths and lost the direction of looking for female moths, so that to reduce the number of populations. The last is the method of Luring sterilisation, which use sex pheromone formulation in combination with a sterilizing agent. After the male moth is seized with a sex attractant, and then contacted with the sterilizer film to produce a sterilization effect. The sterilized male moths is then returned to the field and mated with the female moths. This method is applied to the male caterpillars, and the control effect is over 90%. These three methods have a very strong killing effect on insects, and also have a very beneficial effect on agricultural production.
In summary, insect pheromone is a compound used by insects to represent various information such as aggregation, foraging, mating, and alertness, and is a chemical language for communication between insects. Among them, insect sex pheromone is a compound that regulates the sexual attraction of males and females. It is sensitive and specific, and has a long-distance and strong temptation. These characteristics show the good prospects of insect pheromone in pest control. I believe that insect pheromones will make more contributions to our daily life.