**4. Attract-and-kill (A&K) System**

Often the use of this technique reduces the male catch, causing mating disruption, however it does not imply reducing the damage caused by the pest. Probably, this should occur by the en‐ try of mated females originating from untreated areas, so specific applications of insecticides may be indicated to reduce this negative effect. Although, Pastori *et al.* (2008) reported that us‐ ing SPLAT® dispensers containing *B. salubricola* pheromone associated with *G. molesta* phero‐ mone, with or without cypermethrin in the formulation, found that the presence of the insecticide did not affect the results. Moreover, França et al. (2012) (unpublished data) ob‐ tained a greater reduction in both male catch of *N. elegantalis,* oviposition on fruits and damage reduction, when used SPLAT® dispensers containing pheromone associated with cypermeth‐ rin compared with SPLAT® containing only pheromone (Figure 2). The mating disruption tech‐ nique led to the same reduction of damage caused by *G. molesta* in peach orchards, compared with orchards submitted to insecticide spraying, demonstrating the great advantage of using this method (Härter *et al.* 2010). Therefore, using mating disruption, the number of insecticide applications can be reduced or even absence, making the production environmentally sustain‐ able and economically viable, since the money spent on insecticides can be used in obtaining the product to carry out the disruption. Thus, this tactic is quite appropriate for cultures where no residues of pesticides is required or desired, such as fruits for export; and with the consumer profile in transition, becoming increasingly discerning, the search for an alternative control

182 Insecticides - Development of Safer and More Effective Technologies

method is essential to the acceptance and retention of the farmer in the current scenario.

**Figure 2.** Mean number of *N. elegantalis* eggs throughout tomato crop cycle, variety TY, treated with Splat 1 (with cypermethrin), Splat 2 (without cypermethrin) and control (led by the producer) submitted to treatments 20 and 30 days after transplanting (Camocim de São Félix, Pernambuco, Brazil, 2011-2012). Columns with different letters are

significantly different (p>0.05) by Tukey test.

A novel approach using sex pheromones is the attract-and-kill system. This strategy is a new pest management technique, an extension of mating disruption, which is character‐ ized by the inclusion of an insecticide (killing agent) in addition to the pheromone active ingredient or a feeding attractant (attracting agent). By doing this, it is possible to ach‐ ieve the same control methods as mating disruption, with the potential for increased effi‐ cacy, resulting from the toxicity of the insecticide (Ebbinghaus *et al.* 2001). Unlike mating disruption, which functions by "confusing" the insect, attract-and-kill system attracts the insect to a pesticide laden gel matrix, distributed as small droplets in the crop, which, upon contact, kills the insect.

With this system, blanket coverage of the crop is not necessary, and so the amount of insecticide can be significantly reduced. Such an approach would permit reductions in the amounts of insecticides used and would minimize contact with the environment, the crop, and beneficial organisms. An additional benefit of an attract-and-kill formulation is that these formulations generally require less pheromone to be effective, since the target species does not need to be overwhelmed by the pheromone; it only needs to be attracted to it.

However, when pheromones are used as the attracting agent, only males are killed. Never‐ theless, removal of males from a population may not have a significant effect on reproduction unless a large percentage of the male population is killed, as a small percentage of the male population will serve to mate with most sexually receptive females. Thus, the development of an attract-and-kill system might be enhanced with chemical lures that are effective in bringing females into a target. Although the majority of chemical attractants are female-produced sex attractants that lure males, female may use chemical odorants to locate and select mates, host plants and food.

The use of attract-and-kill suffers from some of the same constraints as mating disruption, including the high degree of pest selectivity, a reduction in efficacy with increasing pest density and risk of immigration of mated females. Besides, the different longevity in the insecticide activity and the attractiveness of the droplets set a time-limit for the application. The attractand-kill drops often deteriorated quite rapidly under some weather conditions, such as powerful storms, pelting rain, intense heat, and solar radiation. These conditions may affect the stability and longevity of the system.

As with any management tool, the operational use of pheromones must be considered within the context of an integrated pest management system. Commercialization of the attract-andkill approach has been undertaken by IPM Technologies Inc., who has global rights to a proprietary and patented matrix, combining insecticide and attractant in a UV sensitive carrier material. Marketed as "Sirene ™" and "Last-Call™ " in Europe and the U.S., respectively, this technology was granted US EPA registration in 1998 and California registration in 1999. The robust matrix can accept, protect and release a wide variety of chemicals (acetates, alcohols, aldehydes) so it has the potential to be deployed against many pest species in diverse ecosys‐ tems.

Attract-and-kill systems are more powerful than other semiochemical mediated control strategies such as mating disruption in that male moths are incapacitated and removed from the ecosystem. Yet, this approach has the obvious advantage of limiting any potential nega‐ tive ecological effects of the insecticide, as only those insects coming to the lure will be af‐ fected. These systems has been successfully used against several pests, including the boll weevil*, Anthonomus grandis*; codling moth, *C. pomonella* (Charmillot *et al.* 2000) and apple maggot, *Rhagoletis pomonella* (Bostanian & Racette 2001), oriental fruit moth, *G. molesta* (Evenden & Mclaughlin 2004), among others.

**5. The push-pull strategy**

pesticides or biological control agents.

the insects onto the trap crop (Figure 3).

Insects control methods exploiting natural chemical messengers, collectively known as semiochemicals, are becoming increasingly familiar. Semiochemicals are substances that, in their natural context, carry information or chemical cues for a given interaction between organisms, triggering a behavior or a physiological response in the receiving individual. They are subdivided into allelochemicals, related to interspecific communications, and pheromones, in intraspecific communications (Vilela & Della Lucia 2001). One major developments now set to revolutionize the use of semiochemicals is the realization that semiochemicals should not be used alone, but be combined with population-reducing agents such as highly selective

The Use of Behavioral Manipulation Techniques on Synthetic Insecticides Optimization

http://dx.doi.org/10.5772/53354

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Thus, it is rare for a single semiochemical to be very effective when used alone. Instead, the usual approach is a 'push-pull' strategy, also called stimulo-deterrent diversion— which involves 'pushing' the insects away from the harvestable, economic crops, and 'pulling' them onto a trap crop where their population is reduced by a biological control agent or highly specific but slow-acting insecticide (Foster & Harris 1997). Therefore, antifeedants, non-host volatiles, compounds associated with plant defense, visual cues, synthetic repellents, alarm pheromones and oviposition deterrents can be used to achieve the 'push', while the sex pheromone, host volatiles, visual, gustatory and oviposition stimulants can be used to 'pull'

**Figure 3.** Push-Pull strategies, "pull" and "push" tools and the agents used to reduce pest population.

In fruit production, the fruit flies control is based on the use of insecticides in total cov‐ erage or in the form of toxic lure. The toxic lure is based on the use of food bait associ‐ ated with an insecticide. In this attract-and-kill system, the insects are killed when in contact or ingest the insecticide. Spinosad baits containing spinosad in different concen‐ trations, water, sugar and attractants were effective in controlling the fruit fly, *Ceratitis capitata* and *Anastrepha fraterculus* (Raga & Sato 2005). The formulation SPLAT ®, afore mentioned at mating disruption, is also used in attract-and-kill system, since its formula‐ tion consisting of waxes and oils and allows the inclusion of a wide range of insecti‐ cides and attractants with potential to control several species of fruit flies. SPLAT® system has been evaluated as a strategy to attract-and-kill for fruit flies *Bactrocera dorsa‐ lis* and *Bactrocera cucurbitae* in the United States with promising results (Vargas *et al.* 2008, Vargas *et al.* 2009). There are some reports in the literature of a SPLAT® formula‐ tion containing spinosad 0.10%, which provided control of *C. capitata* adult, even after submitted to simulated rainfall, and showed a smaller effect on the parasitoid *Diachasmi‐ morpha longicaudata* compared with other toxic baits (Zanardi 2011).

Although this method presents the advantage of causing less impact on non-target organ‐ isms, some restrictions are observed, for example, the low persistence of toxic lures after rainfall events, as can be seen in the example cited above. These barriers are being solved with the advancement of research on this technology.

Mating disruption and attract-and-kill are similar technologies that have been used to control a wide range of insect pests, typically species in Lepidoptera, Coleoptera, and Diptera (El-Sayed *et al.* 2006). These two technologies may be able to contribute to the eradication of new incursions of invasive species, because like other inversely densitydependent approaches, they have the greatest probability of success against pests at very low density, which is initially the case after an incursion. Making clear the differ‐ ence between these control systems, the mating disruption relies on the principle of pre‐ venting pheromone communication between sexes, but the insects remain alive in this area during the disruption, whereas in attract-and-kill systems they are removed from the population. Besides, attract-and-kill systems for field control typically use insecti‐ cides, while in disruption, insecticides may be used but they are not the primary ap‐ proach of the system.
