1. Overview of insect pheromones
1.1 The discovery of insect pheromones
The word pheromones was originally written by Carlson (1959). In 1959, Putnamite and E. Heck first identified the chemical structure ((E,Z)-10,12-hexadecadienol) of the sex pheromone of silkworm, thus creating a precedent for the study of the chemical structure of insect pheromones. According to statistics, over 2,000 species of insect pheromones and their analogues have been identified and synthesized worldwide. More than 1,000 kinds of insect pheromones have been successfully synthesized and over 400 have been commercialized.
1.2 Classification of insect pheromones
Insect Pheromones mainly include sex pheromones, aggregation pheromones, trail pheromones, alarm pheromones, and epideictic pheromones. Among them, the sex pheromones, aggregation pheromones and botanical attractants(such as essential oils, flavonoids, alkaloids, glycosides, esters and fatty acids) are most researched and applied.
1.3 Characteristics of insect pheromones
Insect pheromones only react on insects of the same species, and are generally non-toxic to humans, animals and insects. It is trusted by people because of its high degree of specificity, low dosage, good effect at low population density, and long-term use without drug resistance. At present, insect pheromone is mainly used for monitoring, controlling and killing insect pests.
2 Applications of insect pheromones
2.1 Monitoring and investigation
The monitoring method using insect pheromone has the advantages of high sensitivity, simple operation, and low cost. By using insect pheromone and matching traps, the generation of pests can be investigated and the occurrence rule can be grasped so that the pest occurrence area can timely and accurately monitored. It can provide a reliable basis for pest control.
2.2 Inhibiting pests
Inhibiting pests by insect pheromone are mainly include trapping and mating disruption methods. Trapping methods use sex pheromone to induce insects to mate, then trap and kill them together, so that to reduce the density of the next generation of insect population. Or using aggregation pheromones and botanical attractants to attract large numbers of male and female adults and reduce the population of harmful insects. The mating disruption method is to release pheromones to interfere with insect’s mating and communication, so that to reduce the number of pests of next generation.
2.3 Pests quarantine
Customs and entry/exit port are the direct thresholds for the invasion of alien organisms. They also shoulder the important task of intercepting invasive alien species. Insect pheromones can give full play to its advantages in pest quarantine due to its specificity and sensitivity. There are already dozens of quarantine insect pheromones applied in ports across the country that can effectively help intercept the epidemic. This means is playing an increasingly important role in the quarantine process.
3 The development status of insect pheromones
The development of insect pheromone is divided into two phases. Before the 1950s, it was the discovery and laboratory research phase. In the 1960s, it began to enter the field application research phase. In addition to the application of sex pheromones, Beroza proposed a mating-interference method, and in 1969, he proved the possibility of controlling pest by this method. While other insect pheromones such as clusters, alarms, and tracers were found later. The development of micro-synthetic technologies, and the appearance of advanced analytical instruments have greatly facilitated the study of the chemical structure of insect pheromones. It has now been possible to analyze the composition, content and composition of an pheromone of an adult worm by capillary chromatography.
At present, there are already many mature insect pheromone products and dozens of trap products available. The development of all pheromone products is mainly in several directions: sex pheromone attractants, botanical attractants, and repellents and so on. The United States, Japan, Germany, France, and Brazil have applied pheromones in the protection of plant and forest, which has reduced the usage of pesticides. Europe and the United States have attached great importance to the monitoring of small roundworms. After more than 30 years of research, the monitoring and control technologies have become quite mature.
The insect pheromone has the advantages of strong specificity, low toxicity to humans and animals, no pollution to the environment and it can be widely used in agricultural and forestry production, customs quarantine, prevention and control of pests. For parks, outdoor playgrounds, hotels, and restaurants that are not suitable to use pesticides, insect pheromone can exert its advantages and help people to create a truly green and healthy living environment.