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Landry The sex pheromone was identified by Regine Gries, Grigori Khaskin and Gerhard Gries at Simon Fraser University. “Populations of the gall midge.

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Presentation on theme: "Landry The sex pheromone was identified by Regine Gries, Grigori Khaskin and Gerhard Gries at Simon Fraser University. “Populations of the gall midge."— Presentation transcript:

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3 The sex pheromone was identified by Regine Gries, Grigori Khaskin and Gerhard Gries at Simon Fraser University. “Populations of the gall midge Dasineura oxycoccana on cranberry and blueberry produce and respond to different pheromones” by S. Fitzpatrick, R. Gries, G. Khaskin, D. Peach, J. Iwanski, G. Gries in Journal of Chemical Ecology 39(1): 37-49; The sex pheromone is a potential monitoring tool for cranberry tipworm. Here I report the outcome of field tests of the sex pheromone on cranberry farms in British Columbia, Canada. Funded by AAFC (DIAP partnership with LMHIA), BCCMC, BCCGA and Investment Agriculture Foundation.

4 CC CC CC CC CC CC CC CCCC CC CC CC CC CC CC CC CC OAc Chemistry of Cranberry Tipworm Pheromone The parent molecule is a straight-chain 17-carbon alkene with two functional groups. The molecule is named 2, 14-diacetoxy-8-heptadecene. This racemic molecule is a mixture of 4 optical isomers.

5 CC CC CC CC CC CC CC CCCC CC CC CC CC CC CC CC CC OAc (R) CC CC CC CC CC CC CC CCCC CC CC CC CC CC CC CC CC OAc CC CC CC CC CC CC CC CCCC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CCCC CC CC CC CC CC CC CC CC (S) (R) (S) Only one optical isomer is Cranberry Tipworm Pheromone

6 CTW pheromone was tested on two farms in Traps were baited with the isomer (S,S)-2,14-diacetoxy-8-heptadecene, or racemic pheromone or a blank lure. Male cranberry tipworm J.-F. Landry photo

7 Tipworm males in traps baited with single isomer CTW pheromone Average number Dotted lines show Delegate sprays

8 On this farm, the number of CTW males caught in traps baited with CTW pheromone … … was a good predictor of the percent of shoot tips infested with CTW eggs, larvae or pupae. Tipworm males caught in traps baited with CTW pheromone Average number Tipworm males caught in traps baited with CTW pheromone Average number Shoot tips infested with eggs, larvae or pupae Average Percent

9 Increased trap catch on July 11 corresponded to … … the first major increase in immatures (week 8). Shoot tips infested with eggs, larvae or pupae Number per 10 shoot tips Eggs First Instars Second Instars Third Instars Pupae J.-F. Landry photos

10 The preceding graphs show that single isomer pheromone has potential to be an excellent monitoring tool. Unfortunately, synthesis of this single isomer (S,S)-2,14-diacetoxy-8-heptadecene is very expensive. Therefore, the single isomer pheromone will not be available commercially. The following graph shows the attractiveness of racemic 2,14-diacetoxy-8-heptadecane, which is less expensive to synthesize. Also shown is the attractiveness of traps to females.

11 Tipworm males caught in traps baited with single isomer or racemic pheromone Single isomer Racemic Average number

12 Tipworm females were caught in all traps, regardless of bait. Average number

13 Racemic 2,14-diacetoxy-8-heptadecane is much less attractive than is the single isomer (S,S)-2,14-diacetoxy-8- heptadecene. Monitoring with racemic will not provide precise information about activity of cranberry tipworm adults. Female cranberry tipworms entered all traps without discriminating among baits. Therefore, in 2013 we tested the relationship between number of females caught in unbaited traps and percentage of shoots containing immatures (eggs, larvae, pupae).

14 Tipworm females caught in unbaited white sticky traps Average number % of shoots infested with eggs, larvae or pupae On this farm (and all others), the number of females caught in unbaited traps … … was a poor indicator of the percent of shoot tips infested with CTW eggs, larvae or pupae.

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16 × live immatures dead live & dead empty cocoons D DDeM M

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