Attract-and-kill as a new strategy for the management of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) in potato: evaluation of its efficacy under potato field and storage conditions.

BACKGROUND: Attract-and-kill composed of pure sex pheromones of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) and the insecticide cyfluthrin resulted in 100% mortality of males under controlled laboratory conditions. The aim of the present study was to investigate the efficacy of this strategy in different potato agroecologies as well as under simulated potato storage conditions. RESULTS: Attract-and-kill was highly effective at reducing male flight activity and significantly reduced daily moth catches in pheromone-baited water traps (by 51.8-99.9%) in comparison with untreated plots. This largely depended on the field size, the attract-and-kill droplet size and the density applied per hectare. Highest efficacy, which was independent of pest density, was achieved when attract-and-kill was applied on larger potato fields using a droplet density of 2500 source points ha(-1) at a droplet size of 100 µL. Consequently, pest infestation on vegetative plant parts as well as on tubers was significantly reduced (by up to 90%) in comparison with untreated controls. Under simulated storage conditions with a high number of females and males released periodically, an efficacy of 84.1 and 87.2% was achieved in reducing tuber infestation by P. operculella and S. tangolias respectively. CONCLUSIONS: Attract-and-kill is very effective in controlling the two potato tuber moth species under both field and storage conditions; it is a new, attractive and (for storage conditions) low-cost method that can be easily integrated in potato pest management programmes, especially in small-scale agricultural systems of the tropics and subtropics.

Attract-and-kill: a new strategy for the management of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) in potato: laboratory experiments towards optimising pheromone and insecticide concentration.

BACKGROUND: Sex pheromones of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) are ideal tools to monitor pest flight activity but are not used as means of control. The aim of the present study was to test the suitability of an attract-and-kill strategy consisting of pure pheromones and the contact insecticide cyfluthrin as the active ingredient, formulated with plant oils and ultraviolet absorbers, and applied in droplet sizes of 100 microL. RESULTS: Cyfluthrin at a concentration of 5 g L(-1) resulted in the highest and fastest killing of males after 48 h, with a 100% mortality after 3-4 days. In contrast, control males survived for 13 days. In olfactometer experiments, the pheromone concentration of 0.5 g L(-1) was significantly most attractive against eight virgin females. At controlled conditions (20 degrees C), no reduction in efficacy of the attract-and-kill formulation was observed for a minimum period of 36 days, whereas under natural environmental conditions the efficacy reduced gradually after day 6 of exposure. The longer the droplet was exposed, the longer was the time to reach 100% mortality of males. CONCLUSIONS: Compared with attract-and-kill studies for other pest species, the results are promising as a means of achieving highly effective control of potato tuber moths under field conditions.