Repellency, semiochemicals

Pureswaran, D. S. and J. H. Borden, New repellent semiochemicals for three species of Dendroctonus (Coleoptera Scolytidae). Chemoecology 14 67-75, 2004. 

Borden, J. H., D. S. Pureswaran, and L. M. Poirier, Evalnation of two repellent semiochemicals for disruption of attack by the monntain pine beetle, Deruhoctonus ponderosae Hopkins (Coleoptera Scolytidae). J. Entomol. Soc. Brit. Columbia. 101 117—123, 2004. 

The queen is usually reproductively dominant within the colony and uses chemical cues as both primer and releaser pheromones to suppress the production or fecundity of other sexuals, inhibit reproduction by worker castes, modulate reproductive behaviors (e.g., inhibit swarming and orient swarms), attract males, regulate worker tasks and worker ontogeny, and produce host repellents in slave-making species. Considering the importance of queen semiochemicals in social hymenoptera, few queen pheromones have been chemically identified. The queens of most social hymenopteran colonies are attractive to workers, allowing them to be properly tended as well as to facilitate the dissemination of other pheromone cues. However, the retinue pheromone has been chemically identified in very few species. In the 1980s, queen pheromone components were identified in the fire ant, Solenopsis invicta [91,92], and in the Pharaoh s ant, Monomoriumpharaonis [93]. 

Here we present the results of a preliminary study to investigate the chemical composition of secretions from carpal glands of feral pigs living in densely vegetated, humid tropical lowland rainforest habitats with a view to exploiting semiochemicals to improve trapping efficiency and to identify repellents. 

Biochemical pesticides include all naturally occurring substances (or their structurally similar synthetic analogs) that are intended for use as attractants, repellents, desiccants, semiochemicals, plant and insect regulators, and induced systemic response (ISR) and systemic acquired response (SAR) inducers. 

This work indicates that the guava-derived semiochemical, DMDS, is an effective repellent for Diaphorim citri at concentrations as low as 10% in SPLAT AGP Repel. When incorporated into SPLAT, the resulting matrix demonstrated the capacity to extend the release period of this extremely volatile compound, prolonging the repellent s efficacy in the field. Field trials have shown that SPLAT AGP Repel with DMDS alone significantly reduces Diaphorina citri captures in infested orchards, indicating the potential for this formulation to reduce HLB infection rates in areas treated with SPLAT AGP Repel. 

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