The idea of a mass capture method in order to suppress a population of harmful insects is based on the assumption that males are caught before mating with females, thereby achieving the effect of “male vacuum”. As a result, a significant number of females remain unfertilized, and plant damage is reduced. To obtain a high effect, at least 80% of the males must be removed from the population, which is usually possible in climatic zones where only one generation of the pest develops, and the population is relatively low (for example, in the conditions of the North-West and Central regions of Russia).
This technique, in the presence of a highly attractive pheromone preparation, can be used to protect against species with insignificant migratory abilities, monogamy, or limited polygamy. Positive results were obtained using the mass capture method to protect plants from a number of pests of the lepidopteran (leafworm and moths) and beetlewing (bark beetles and nutcracker) detachments. Significant successful experience in the widespread use of the method of mass capture was obtained in Sweden and Norway in 1980-1983, when it was used to protect coniferous forests from the bark beetle beetle – a printing press.(Ips typographies L.)., Which then had an outbreak of numbers. About 1 million pheromone traps were placed in the forests of these two countries, in which about 10 billion beetles were captured.
In Russia over the past few years, the method of mass capture has also been effectively used to protect spruce forests in Moscow, Smolensk, Bryansk and Kaluga and several other areas from this species of bark beetle.
To protect plants by mass trapping, pheromone traps of the same design are used as for monitoring (both glue and glueless), but with dispensers with a higher dose of synthetic pheromone (Fig. 29). In fruit orchards they are placed evenly, on average 25-50 traps per 1 ha. To combat the bark beetle-typographer, barrier traps are placed at the rate of 2–4 traps / ha, placing them on hardwood or shrubs in order to avoid the population of healthy spruce trees. The method of mass capture pest control of agricultural plants is most promising in homesteads and summer cottages.
Fig. 29. Catching butterflies in pheromone traps (original):
A – willow crooked leaflet; B – eastern codling moth
For example, the uniform placement of pheromone traps on the entire summer cottage (one trap on every second tree) completely eliminates damage to the fruit of the apple tree by the moth.
In large areas, the application of the method of mass capture is technically more difficult, since it is necessary to maintain a significant number of traps, and therefore it is not always widely used to protect crops from pests. This problem can be solved by creating traps and pheromone preparations that operate throughout the growing season and do not require maintenance. Another limiting factor is the initial density of the pest population – it should be relatively small, so, with a high number of the natural population, mating can occur earlier than the males reach the trap.