Mating disruption (MD), also known as sexual confusion, is a pest management technique designed to control certain insect pests by introducing artificial stimuli that confuse the individuals and disrupt mate localization and/or courtship, thus preventing mating and blocking the reproductive cycle. It usually involves the use of synthetic sex pheromones, although other approaches, such as interfering with vibrational communication, are also being developed.
History Confusion sexuelle, or mating disruption, was first discussed by the Institut national de la recherche agronomique in 1974 in Bordeaux, France. Winemakers in France, Switzerland, Spain, Germany, and Italy were the first to use the method to treat vines against the larvae of the moth genus Cochylis.
Mechanism
In many insect species of interest to agriculture, such as those in the order Lepidoptera, females emit an airborne trail of a specific chemical blend constituting that species' sex pheromone. This aerial trail is referred to as a pheromone plume. Males of that species use the information contained in the pheromone plume to locate the emitting female (known as a “calling” female). Mating disruption exploits the male insects' natural response to follow the plume by introducing a synthetic pheromone into the insects’ habitat. The synthetic pheromone is a volatile organic chemical designed to mimic the species-specific sex pheromone produced by the female insect. The general effect of mating disruption is to confuse the male insects by masking the natural pheromone plumes, causing the males to follow “false pheromone trails” at the expense of finding mates, and affecting the males’ ability to respond to “calling" females. Consequently, the male population experiences a reduced probability of successfully locating and mating with females, which leads to the eventual cessation of breeding and collapse of the insect infestation. Mechanisms of disruption Researchers distinguish two broad mechanisms by which mating disruption can act on moth populations: competitive disruption, in which synthetic pheromone sources compete with calling females for the attention of males (an effect that is density-dependent and tends to plateau as more dispensers are added), and non-competitive disruption, in which the male's sensory or behavioural response to pheromone is itself impaired, for example, through sensory desensitisation or camouflage of the natural plume, an effect that is not linked to pest density. A 2025 study by entomologist Dr Vernon Murray Steyn and colleagues on the false codling moth (Thaumatotibia leucotreta), a major agricultural pest in Africa, found that disruption of this species followed a "hybrid" profile: males were disrupted competitively at low pheromone dosages, but disruption shifted to a non-competitive mechanism at higher dosages (800 dispensers per hectare and above), which coincided with a jump to 96–99% mating disruption in stone fruit and table grape orchards. The same study found that clustering dispensers into as few as 36 release points per hectare achieved disruption levels statistically indistinguishable from 800 uniformly distributed dispensers, indicating the number of pheromone sources could be reduced substantially without loss of efficacy once non-competitive disruption was achieved. The mechanism underlying disruption also has practical implications for the cost of application. Because competitively disrupted species require pheromone sources to be numerous and well-distributed to compete effectively with calling females, reducing the number of release points in these species tends to reduce disruption efficacy, for example, clustering 200 dispensers per hectare into 18 release points reduced disruption of light brown apple moth (Epiphyas postvittana), a competitively disrupted species, by roughly 10% compared to uniform distribution. By contrast, Steyn et al. found that once false codling moth disruption shifted to a non-competitive mechanism at higher dosages, the number of pheromone release points could be reduced substantially (from 800 individually distributed dispensers to as few as 36 clustered release sites per hectare) without a significant loss of disruption, since non-competitive disruption does not depend on pheromone sources competing with females for male attention. The California Department of Pesticide Regulation, the California Department of Food and Agriculture, and the United States Environmental Protection Agency consider mating disruption to be among the most environmentally friendly treatments used to eradicate pest infestations. Mating disruption works best if large areas are treated with pheromones. Ten acres is a good minimum size for a successful MD program, but larger areas are preferable.[2]
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