Insect sex pheromones: Evaporation rates of alcohols and acetates from natural rubber septa

Abstract

The half-lives (t 1/2) of alcohol sex pheromones, 1-alkanols, acetate sex pheromones, and an epoxide (disparlure) were determined on natural rubber septa. Thet 1/2 values for the homologous alcohols from decanol to heptadecanol increased regularly from 2.2 to 1117 days, but thet 1/2 of octadecanol was 609 days. Thet 1/2 values of (Z)7-, (E)7-, and (Z)9-tetradecen-1-ol acetates were 154, 168, and 199 days, respectively, whereas those of five other tested 14-carbon acetates ranged from 310 to 350 days. The dependence oft 1/2 values on chain length and double-bond position is consistent with the hypothesis that molecular size is an important variable affectingt 1/2 values. Also, in accordance with the hypothesis, when aZ-alkenyl compound has a much shortert 1/2 than the corresponding saturated compound, thet 1/2 values of theZ compound and itsE isomer may be quite different. Thus, (E)-9-tetradecen-l-ol acetate had at 1/2 of 331 days. Thet 1/2 of disparlure was 180 days. The effect of thecis-7,8 epoxide group is apparently similar to that of the olefin group in lowering thet 1/2 below the value that would be expected solely on the basis of chain length.

Quantitative comparison of behavioral and neurophysiological responses of insects to odorants

“…The (initial) rate of emission of pheromone from the glass tube is higher than from most slow-release formulations. For example, the half-life of Z-7 : 12Ac on robber septa is 34.8-35.9 days (Butler and McDonough, 1979). Based on this half-life, the initial emission rate from a septum dosed with 1 mg is 6.1 • 10 .5/xmol/min.…”

Effects of pheromone loading, dispenser age, and trap height on pheromone trap catches of the oriental fruit moth in apple orchards

“…Controlled-release pheromone lures have included cotton dental wicks, rubber septa, polyethylene vials, laminates, hollow fibers, membranes, and polymeric systems (13). Rubber septa have been the most widely used substrate for the controlled release of many insect sex pheromones (5,40). Flint et al (10) showed that rubber septa were an excellent substrate for the controlled release of gossyplure for pink bollworm Pectinophora gossypiella (Saunders), and rubber septa baited with codlemone have been the most common substrate for the codling moth (27).…”

Synthesis and field evaluation of synthetic blends of the sex pheromone of Crocidosema aporema (Lepidoptera: Tortricidae) in soybean

“…It is therefore likely that changes in the pheromone blend in time and space explain the difference between wind tunnel and field experiments. In our experiment, it is proposed that the blend becomes slowly enriched in the alcohol, given that it is less volatile than the acetate 33,34 (Vp = 4.37E-4 torr and Vp = 6.35E-4 torr, respectively), 35 and it may therefore be concluded that soon after the experiment begun, the 15:1 (OH:Ac) initial mixture approximated to the 1:0, decreasing hence its attractivity, and that the 1:1 was enriched in the alcohol, becoming more similar to the blend that was most active in the wind tunnel. In fact, the 15:1 and 1:0 initial mixtures performed similarly throughout the experiment, and so did the 1:1 initial mixture towards the end (Figure 2), possibly due to a complete evaporation of the acetate.…”