RESPONSES TO AGGREGATION PHEROMONES FOR 5 CARPOPHILUS SPECIES (COLEOPTERA, NITIDULIDAE) IN A CALIFORNIA DATE GARDEN

The nitidulid species, Carpophilus mutilatus Erichson, C. hemipterus ( L.), C. freemani Dobson, and C. obsoletus Erichson, responded to their aggregation pheromones during a 17-mo study in a California date gard en. The pheromones were dramatically synergized by volatiles from ferm enting whole-wheat bread dough; pheromones alone attracted only 1.0-29 % as many beetles as the combinations with dough, and dough alone attr acted only 0-2.9% as many as the combinations. Unbaited controls caugh t no Carpophilus. C. mutilatus was the most abundant species, and indi vidual 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 of C. hemipterus and C, obsoletus but was minimal co mpared with responses to the species' own pheromone. The pheromone of C. lugubris Murray was also tested, but no C. lugubris were detected i n the date garden. Two additional nitidulid species were caught consis tently: C. (Urophorus) humeralis (F.) and Haptoncus luteolus (Erichson ). C. humeralis responded significantly to all of the pheromones but e specially 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 y ear, but flight activity, as measured by trap catch, occurred erratica lly. All species had an intense period of flight activity in April and May, following a winter with favorable rains and an abundant food sup ply. This flight terminated abruptly when dates spilled to the ground during harvest and were hydrated by a rain storm. Flights of C. freema ni, 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 vari ability in patterns of flight activity. The use of these pheromones is discussed in relation to pest management.