Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: November 9, 2009
Publication Date: November 9, 2009
Citation: Burks, C.S. 2009. Mating disruption for control of navel orangeworm in Central California. International Conference on Methyl Bromide Alternatives and Emissions Reductions, November 10-13, 2009, San Diego, California. 79:1-4. Interpretive Summary: The navel orangeworm is the key insect pest of almonds, and mating disruption has recently been developed as a strategy for its control. We examined, over two years, three blocks of almonds totaling ca. 850 acres. In 2008 we monitored weekly with egg traps and pheromone traps (using unmated females as a pheromone source), and took harvest samples from one tree per variety per ten acres. In 2009 mating disruption and treatment plots totaling ca. 550 acres were selected to obtain even representation of varieties, and mating disruption was applied. The mating disruption treatments significantly suppressed males in pheromone traps and eggs in egg traps, and navel orangeworm damage was significantly lower in treatment than in comparison plots in 2009 but not in 2008. These data provide evidence that mating disruption significantly affected navel orangeworm biology and damage at this site, which had very different characteristics of varieties, soil, and growers compared to sites where mating disruption had previously been demonstrated to reduce navel orangeworm damage. These results will facilitate adoption of mating disruption in almonds and reduce use of insecticide while controlling damage to this crop, worth >$2.5 billion (unprocessed) annually.
Technical Abstract: Previous research showed that mating disruption can significantly reduce navel orangeworm damage to almonds at harvest. However, that research was conducted in Kern County and primarily in the variety Nonpareil and a few varieties, such as Monterey and Caramel, commonly used as pollenizers for Nonpareil. Here we present data examining the impact of mating disruption as a part of integrated management of navel orangeworm in a different geographical location and under different conditions of production, including substantial representation of the varieties Butte and Padre. Mating disruption completely eliminated the capture of males in sticky traps baited with unmated females as a pheromone source. Males captured in traps in adjacent untreated comparison blocks were also greatly reduced. Fewer eggs were found on egg traps in treated v. comparison blocks. Analysis of partial harvest data showed significant reduction of navel orangeworm damage in one of three blocks of Nonpareil, and numerical reduction in damage in Padre in two of the three blocks. These preliminary data suggest that mating disruption had a measureable impact on navel orangeworm behavior, fertility, and damage under the conditions at this site.