Responses to aggregation pheromones for five Carpophilus species (Coleoptera: Nitidulidae) in a California date garden

The nitidulid species, Carpophilus mutilatus Erichson, C. hemiptertus (L.), C. freemani Dobson, and C. obsoletus Erichson, responded to their aggregation pheromones during a 17-mo study in California date garden. The pheromones were dramatically synergized by volatiles from fermenting whole-wheat bread dough; pheromones alone attracted only 1.0-29% as many beetles as the combinations with dough, and dough alone attracted only 0-2.9% as many as the combinations. Unbaited controls caught no Carpophilus. C. mutilatus was the most abundant species and individual trap catches were as high as 63,500 per week. Cross attraction was significant in some cases, especially for C mutilatus responding to the pheromones C. hemipterus and C. obsoletus but was minimal compared with responses to the species' own pheromones. The pheromone of C. lugubris Murray was also tested, but no C. lugubris were detected in the date garden. Two additional nitidulid species were caught consistently: C. (Urophorus) humeralis (F.) and Haptoncus luteolus (Erichson). C. humeralis responded significantly to all of the pheromones but especially to those for C. hemipterus, C. lugubris, and C. obsoletus in combination with dough. H. luteolus was attracted only to the dough. Adult beetles were present in the dates on the ground throughout the year, but flight activity, as measured by trap catch, occurred erratically. All species had an intense period of flight activity in April and May, following a winter with favorable rains and an abundant food supply. This flight terminated abruptly when dates spilled to the ground during harvest and were hydrated by a rain storm. Flights of C. freemani, C. obsoletus, C. humeralis, and H. luteolus were more frequent in summer than for C. mutilatus or C. hemipterus. Flight activity during December and January was low for all species, but there was great variability in patterns of flight activity. The use of these pheromones is discussed in relation to pest management.