Observations of the mating disruption process led to further development in 1978. Researchers found that when male moths search for pheromone emitting sources they actually land on the microtubes containing synthetic pheromone and attempt to mate. It was suggested that if insecticides were mixed with the sticker used to adhere the microtubes to the plant foliage, males would receive a lethal dose upon contact. (Staten and Haworth, 1981). This process, termed Attract and Kill technique, would quickly remove males from the population. Male removal through the attracticide technique is more efficient than a mass trapping program because many more of the discrete toxic sites can be distributed in the field compared to the more expensive trap. Labor requirements would be reduced as well. In comparison to the traditional strategy of crop chemotherapy where the pest's entire environment becomes lethal through broad application of an insecticide, the attracticide strategy lures the pest to distinct sites of the toxicant and permits large reduc- tions in the amount of insecticide needed. A synergistic effect is seen by combination of the pheromone and insecticide and nor- mal rates of both materials can be reduced. Pyrethroid insec- ticides used in the attracticide system are applied at only 2-5 % of the rate used in conventional applications. The rate of pheromone in the attracticide system may be reduced to one half that used in the mating disruption technique. Tests of the attrac- ticide system demonstrated its effectiveness (Butler and Hen- neberry, 1982; Butler et al., 1983). Other investigation showed little or no adverse effect on major predaceous taxa (Butler and Las, 1983). Beneficial insects are not drawn to the toxic sites. Because the attracticide strategy is more robust than the mating disruption technique, it can be applied against more in- tense pest pressure. However, it is not uncommon for pink TABLE 2. Comparison of survi- val rate of Heliothis virescens moths released in field cages with cotton foliage treated with pher- omone plus fenvalerate versus fenvalerate only. % live after 13 hours % live after 37 hours 50 moths released per ca bollworm infestations to increase to levels that are not effectively controlled by either the attracticide system or conventional insec- ticide treatments alone. For higher pest pressures typically en- countered later in the season, the simultaneous application of the attracticide system with regular insecticide application has given effective control when either treatment alone would have failed. The combined use of sex pheromone applications with conven- tional insecticide applications has been studied for a number of insects. In this technique pheromones are applied alone or as the attracticide system: with a small amount of insecticide in the sticker. Simultaneously, a conventional insecticide application is applied at the normal rate. This process has been termed Attract and KillTm Dual Application or the bio-irritant technique. It is suspected that the pheromone released by females may increase their activity in addition to initiating searching behavior by males (Palaniswamy and Seabrook, 1978; Saad and Scott, 1981). The increased movement of both sexes may enhance exposure of both sexes to the insecticide resulting in higher mortality of the adults. Early tests of the bio-irritant technique in field cages were con- ducted in Arizona in 1983. Fenvalerate at the standard rate of 84 gms ai/ha, was applied alone and in combination with the sex pheromone for Heliothis virescens Fabricius in microtube for- mulation. Male and female moths were released into cages and counted at 13 and 37 hours later. Data showed differences in adult survival between pheromone plus insecticide and insec- ticide alone (Table 2). After 37 hours only 4% of the moths in the pheromone plus insecticide treatment were alive compared to 24% alive in the insecticide only treatment. Data collected in 1984 from commercial fields demonstrated that pyrethroid sprays alone were unable to suppress pink bollworm moth flights for more than two days (Fig. 2). During Pheromone + Fenvalerate Fenvalerate 22,0 54,0 4.0 24.0 ge; 2 cages per treatment FIG. 2. Mean number of pink bollworm males captured in pheromone traps. Arizona, 1984. PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX 30 25 21 PYRETHROID 0.84 kg/ha 20 19 18 PYRETHROID 0.84 kg/ha 17 ATTRACTICIDE 12.3 gm/ha 16 S 15 0 14 - 13 PYRETHROID 0.84 kg/ha 0- 12 - 1 1 0 10 9 j 8 a- 7 m 6 0 5 3 2 0.75 0.50 TRAP THRESHOLD 0.25 0 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 MAY JUNE 156