PHEROMONE TRAP MONITORING-SYSTEM FOR SWEET-POTATO WEEVIL (COLEOPTERA,APIONIDAE) IN THE SOUTHERN UNITED-STATES - EFFECTS OF LURE TYPE, AGE,AND DURATION IN STORAGE

Studies were conducted to develop a pheromone trap monitoring system f or the sweetpotato weevil, Cylas formicarius (F.), in sweet potato, Ip omoea batatas (L.) Lam., in the southern United States. The current st udies examined the effects of lure type, age, and their duration in co ld storage on weevil collections in traps. We also characterized relea se rates of pheromone off soxhlet-extracted and nonextracted ruber sep ta. Most commercially prepared (matrix sheet system) lures and methyle ne chloride-extracted rubber septa did not differ in their attractiven ess to C. formicarius when loaded with 10 mug of pheromone, but they d id not differ when loaded with 100 mug of pheromone. Traps baited with extracted rubber septa caught more weevils than those baited with mat rix sheet lures. In another experiment, weevil counts did not differ a mong traps baited with rubber septa that were soxhlet-extracted with m ethylene chloride and those not extracted for septa obtained from two commercial suppliers. Regression parameter estimates from log10 releas e rate (ng/h) on log10 dosage did not differ among soxhlet-extracted a nd nonextracted rubber septa obtained from one of the suppliers and ex tracted septa obtained form the other supplier. Lure age, however, did affect attractiveness to C. formicarius. The percentage of weevils ca ught per night decreased with an increase in lure age for ages between 0 and 80 d. However, nonextracted lures from one of the suppliers can probably be used for their attractiveness more rapidly; hence, a shor ter replacement time of between 1 and 2 mo is probably sufficient. Tim e in cold storage did not affect the attractiveness of soxhlet-extract ed rubber septa. Septa loaded with 10 mug of synthetic sex pheromone, sealed in air tight vials and stored in a refrigerator at 5 +/- 1-degr ees-C for .2.2 yr, were as attractive as those stored for only 90 d. T he importance of these data in a pheromone trap monitoring program for this weevil is discussed.