A new species of Eurytoma (Hymenoptera, Chalcidoidea, Eurytomidae) from South Korea, feeding on seeds of Prunus tomentosa Thunb. (Rosaceae)

Eurytoma tomentosaesp. nov., included in the Eurytoma amygdali species-group, is described from South Korea. This species could potentially be an economically important pest, as it interferes with reproduction by attacking the seeds of the garden plant P. tomentosa. A key to the two Eurytoma species feeding on Prunus in South Korea is provided.

Male attraction tο virgin females in the almond seed wasp, Eurytomα amygdali Enderlein (Hymenoptera, Eurytomidae)

Laboratory observations showed that adults of the almond seed wasp, Eurytoma amygdali Enderlein (Hymenoptera: Eurytomidae) were sexually mature on the first day of emergence. Experiments with an olfactometer showed that 1 to 12 day-old virgin females attracted the males. This attraction was found to be due to an odor, apparently a pheromone, released by the virgin females. The responsiveness of the males was higher the first part of the photophase. Under field conditions too, virgin females were attractive to males. “Delta” traps, containing 5-20 virgin females, suspended on almond trees, attracted and captured males released among the same trees. On the contrary, traps containing mated females or empty cages were not attractive to males.

Almond seed wasp (Hymenoptera: Eurytomidae) sex pheromone: effect of trap type, trap position, blend ratio and time of the day on male attraction

Field trials were carried out in order to evaluate some of the factors affecting male response of the almond seed wasp, Eurytoma amygdali Enderlein, to traps baited with the alkadienes (Z,Z)-6,9-tricosadiene and (Z,Z)-6,9-pentacosadiene, the male attractant of this species. The trials were conducted in Latomia, Microthivae, Kanalia and Sykourion (Thessaly, Central Greece) during the 2004 growing season. In all regions, captures in traps baited with a 7:3 ratio of the above blend significantly and positively correlated with male emergence from infested almonds that had been placed in cages in the experimental fields. Traps baited with the 7:3 pheromone ratio were significantly more effective in capturing males than traps baited with the 1:1 ratio, supporting the hypothesis that (Z,Z)-6,9-tricosadiene is the main component of this attractant. Of four trap types tested, Rebel and Lasiotraps attracted significantly more males than Delta and Funnel traps. Height had no effect on trap efficiency; however, males were captured earlier in the day in traps placed 2.3 m above grown than in traps placed 1.3 m above grown. Most male activity was recorded between 10 and 12 h, but captures were continuously recorded during the entire monitoring interval from 6 to 17 h.