With some species. The control techniques, however, is a fundamental understanding of the biology, especially the behavior and population dynamics of the target insect. As a minim: . such information must include data on emergence patterns of adult insects; and development of the immature stages; migration of adults from hedgero cover crops, woodlands or distant hosts to the crop in question; frequency mating and ﬂight capabilities of the gravid female. Environmental and physiolo _ effects on production, release, reception and response to pheromone need to determined (see Shorey ch. 4) together with the behavior of both sexes as in, enced by the pheromone and the possible input of visual or auditory cues. . dators and parasites of the pest may also be attracted to the pheromone (Vite “ also Borden Ch. 8.5) and be unwittingly removed from the population along the pest insect. Learn more at
All this biological information is incomplete unless based on ', laboratory and field studies. , At the present time efforts to control insect populations by manipulating 2 pheromone systems are based on one of two strategies: 1) disruption of th sect’s communication system so that mating is not accomplished, and 2) re of a large proportion of the adult population by mass trapping.
21.3.1. Disruption of Pheromone chemical signals
This concept is based on continuous disruption of the pheromone communication system used in reproduction. Usually a high concentration of the sex or aggregate pheromone is broadcast into the environment with the aim of habituatal male’s central nervous system through continuous exposure to a pheromone ml above the threshold level (Bartell and Lawrence 1973, and references therein), adaptation of the male’s receptors so that he cannot physiologically respond to a female, or of producing such a high background concentration of pheromone ‘ the male is behaviorally incapable of locating the smaller amount released receptive female. Similarly, other chemicals which effectively block the pheromonal response could be used to the same effect. Whatever strategy is the same, to prevent successful mating. One of the problems of this approx that to have a significant impact on the next generation it may be necessary achieve at least 99% disruption of mating (Shorey 1970; Beroza and K ‘- l972); otherwise the reproductive potential of the insect can overcome the ,_ of the treatment. It has so far proved very difficult to prevent all but one or percent of the males from finding a female and mating successfully.
Any program of this type requires extensive information on the biologically behavior, of the insect. A sufficient quantity of pheromone must be to cover the required area for as long as adults are flying. Slow release sub I have been developed to ensure a continuous steady release of pheromone when the insects are present. Direct broadcast of pheromone onto vegetation ‘ usually effective since foliage absorbs the compounds and often accelerates; breakdown: resulting higher dosage levels increase application costs according to http://thongchaimedical.org/?p=179.
Unless the test area is an isolated population, migration of gravid females into the area may cause damage even though disruption of mating was completely successful (McLaughlin et al. 1972). in spite of the difficulties, however, a number of pheromone disruption experiments have been attempted with, for example, Douglas fir beetle (Furniss et al. 1972); pink bollworm (McLaughlin et al. 1972); cabbage looper (Shorey et al. 1972); gypsy moth (Stevens and Beroza 1972; Came- ron 1973).