Red Septa Research Articles

Mating Disruption of Paralobesia viteana in Vineyards Using Pheromone Deployed in SPLAT-GBM™ Wax Droplets

A paraffin wax formulation releasing pheromone for mating disruption of insects was tested during 2005 and 2006 in Vitis labrusca vineyards infested by grape berry moth, Paralobesia viteana (Lepidoptera: Tortricidae). In early May of each year, 1-ml droplets of SPLAT-GBM wax containing 3% sex pheromone of P. viteana were applied to every wooden post at a rate of 400/ha in replicated 1.3-ha plots. Moth captures in sex pheromone baited traps placed at the vineyard borders and interiors revealed significant disruption of male moth captures in treated plots, with activity of one application lasting over 10 weeks during both years. Treatment with SPLAT-GBM did not affect the proportion of clusters infested until the end of the second growing season, when infestation was 27% lower in the treated plots than in the control plots. Comparisons of moth captures in traps placed inside 15.2 x 16.5 m vine plots that were untreated or received varying densities of 0.2-ml wax drops or Isomate-GBM hand-tied dispensers at the recommended rate of 450/ha indicated that orientational disruption increased with droplet density. Similar numbers of moths were captured in plots that received 10 or 30 drops per vine as were trapped in plots with twist ties spaced at 0.4 per vine. Moth captures in monitoring traps baited with increasing sizes of wax droplets (0.2, 0.5, or 1-ml drops) or red septa containing P. viteana sex pheromone suggest decreasing ability of male moths to reach traps with increasing pheromone loading. This study indicates that wax-deployed pheromone can reduce crop infestation by P. viteana after 2 years of deployment, and that the increasing of pheromone release by using application of greater droplet densities or by using larger droplets will improve the level of disruption achieved.

Differences between attractive diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), sex pheromone lures are not determinable through analysis of emissions

Abstract1 Conjoint comparisons were made between trap captures of male diamondback moths, Plutella xylostella (L.), and gas chromatographic measures of sex pheromone emissions from grey and red rubber septa. The objective was to correlate trap captures with emissions.2 Irrespective of their composition, all mixtures that were released from grey septa effected the capture of more males than the same mixtures released from red septa. There was no difference between captures by any of the mixtures when emitted from grey septa. However, when emitted from red septa, a nominal 50 : 50 ratio of (Z)‐11‐hexadecenal (Z11–16:Al) and (Z)‐11‐hexadecenyl acetate (Z11–16:Ac) effected the capture of more males than either nominal 70 : 30 or 67 : 23 ratios. Generally, the emitted ratios of Z11–16:Al and Z11–16:Ac from both types of septa were variable, ranging between 6 : 10 to about 40 : 10.3 No statistical correlation was found between the emissions and trap captures by any single component, group or ratio of components. These results suggest that the environment substantially affects the emission of sex pheromone components from rubber septa. As a result, the demonstration of geographical biotypes of diamondback moths and other insects may be difficult.

Insect Sex Pheromones: Formulations to Increase the Stability of Conjugated Dienes1

Formulation substrates were tested for their ability to suppress isomerization of pheromone components containing the conjugated diene structure. Formulation substrates compared were red natural rubber septa (sleeve-type stopper); gray halo-butyl isoprene blend elastomer septa (sleeve-type stopper); black halo-butyl elastomer septa, containing carbon filler (flange-type stopper, designated 55C); and black halo-butyl elastomer septa (flange-type stopper, designated 50C). All substrates except for 55C contained mineral filler. Red septa were cured with sulfur and the others were cured with phenolic resin. During the first 2 weeks of field exposure, isomerization of ( E, Z )-7,9-dodecadien-1-ol acetate was fastest in red septa followed by 55C black (5-fold slower), and the gray (7-fold slower). Isomerization of ( Z, E )-9,11-tetradecadien-1-ol acetate was fastest in red septa and slower in 55C black (8-fold during the first 2 weeks). Isomerization of ( E, E )-8,10-dodecadien-1-ol was fastest in red septa, followed by 55C black (3.7-fold slower during the first 2 weeks) and gray (4.7-fold slower). After 43 days in direct sunlight, the ( E, E )-8,10-dodecadien-1-ol acetate isomer content decreased from ca. 96% of total isomers by 16.7, 16.8, and 13.0% in the gray, 50C black, and 55C black, respectively. Type of filler, carbon or mineral, had no effect on stability, and differences in stability of the conjugated dienes in the nonsulfur-cured formulations substrates were minimal. Because of its convenient shape, gray is the preferred substrate for minimizing isomerization of conjugated dienes. Based on these data, conjugated dienes with field lives of 2–3 days in red rubber septa are predicted to last 2–3 weeks in gray septa. The most important factors for minimizing isomerization were avoiding isomerization catalysts such as sulfur and minimizing exposure to sunlight.