Isolation of Sex Pheromones
In 1976, Conrel. an Albany International Company, of Norwood, Mass. was granted an Experimental Use Permit for Gossyplure H.F.® by the U.S. Environmen- tal Protection Agency in Arizona and 6 in southern California (about 1174 total hectares) were treated with Gossyplure H.F.® for pink bollworm control. A substantial reduction in the need for chemical insecticides was realized. Also, in 1977, about 9300 ha of cotton in Arizona and southern California were treated with Gossyplure H.F.®, again under the afore- mentioned Experimental Use Permit. Dosages applied ranged from 9.1 to 23.7 g of pheromone per hectare per season applied at the rate of 2.8 g/ha. Insecticide usage was reduced from 26 to 79.3% in all pheromone-treated cotton fields except one where more insecticide had to be applied.” Lack of isolation, poor timing, and/ or inadequate pheromone application were suggested as the reasons for the lack of effectiveness in some fields. In 1978, the Environmental Protection Agency granted full registration of Gossyplure H.F. ® for use on cotton for pink bollworm control. Check out http://tonganfishers.org/human-pheromones-factors/.
In 1978, the same authors” selected a test area near Gila Bend, Ariz. It consisted of a 142—ha cotton farm of 14 fields ranging in size from 4 to 16 ha. Six fields were treated with Gossyplure H.F.® , six were mass trapped with Gossyplure H.F.® bait, one field (mass trapped) was eliminated from evaluation because of late planting, and one field served as an untreated control. Only the results obtained in the fields treated with Gossyplure H.F.® and in the one untreated field were reported. Treatments with Gos- syplure H.F.® began May 19, and all fields had been treated once by June 1, i.e., the treatments occurred during the presquare stage of plant growth. Early in the season, all six fields were retreated at intervals of 12 to 20 days, but from early July to late August, retreatments were applied about every 7 days. On August 10, three of these six pheromone-treated fields were treated with insecticide and remained on an insecticide spray schedule for the remainder of the season. From 38 to 51 g/ ha of pheromone were applied from May 19 to August 31 (38 g to the three fields turned over to insecticides) according to http://thongchaimedical.org/?p=176
The number of male pink bollworm moths caught in gossyplure-baited traps was reduced 95% or more in pheromone-treated fields compared with the untreated check field. Also, fewer than 1% of 632 clipped-wing virgin females on mating tables” mod- ified for pink bollworm“° were mated in pheromone-treated plots compared with 26.5% of 215 virgin females on mating tables in the untreated control plot. From July 1 to August 30, percentages of infested bolls ranged from 0 to 40% in the pheromone- treated plots and from 2 to 88% in the untreated plots according to http://etinnova.it/pheromone-cologne-olfactory/.
III. TOBACCO BUDWORM
A. Isolation and Identification of the Tobacco Budworm Sex Pheromone
Gentry et al.‘“ and Berger et al." reported the presence of a sex attractant in tobacco budworm females. Subsequently, several investigators used virgin females as a pheromone source in bait traps for studies of seasonal activity, populations, comparison of trap types, and various other biological parameters
Later," a highly volatile material was obtained from ether washes of calling tobacco budworm females that was attractive to males of the species in the field. Subse- quently,‘'-“ Z-ll-hexadecenal (Z-11 I-IDAL) and Z—9—tetradecenal (Z-9 TDAL) were identified as sex pheromones of the tobacco budworm. However, a 16:1 (the ratio that occurs in females) mixture (called “virelure”) of the two chemicals did not always produce trap catches in the field equivalent to catches with crude solvent extracts of virgin females. Thus, the existence of other components of the pheromone was sug- gested." Subsequently trace amounts of Z-7-hexadecenal. Z-9-hexadecenal, were also identified from heptane pheromones