|Burks, Charles - Chuck|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/1/2004
Publication Date: 12/1/2004
Citation: Burks, C.S., Higbee, B., Daane, K., Bentley, W., Kuenen, L.P. 2004. Mating disruption for suppression of navel orangeworm damage in almonds. Proceedings of the 32nd Almond Industry Conference, December 1-2, 2004, Modesto, California. p. 1-10.
Interpretive Summary: The Navel orangeworm (NOW) attacks almonds, pistachios, walnuts, and figs, which had combined average yearly cash receipt value of $1.2 billion between 2000 and 2002, and it is estimated that the combined losses to and costs of management of NOW for the almond and pistachio industries for 2001 might have been $100 million. In 2003 we found that both mating disruption and hullsplit insecticide treatments significantly reduced damage to almonds compared to untreated controls, but that there was no significant difference between damage in the most effective of the mating disruption treatments and the hullsplit insecticide treatment. In the current study (2004 growing season), we used replicated plots within the almond site with the heaviest NOW pressure to further compare effects of the mating disruption and hullspilt treatments, and to examine whether the two treatments had an additive effect when applied simultaneously. There was significantly less NOW damage to Nonpareil almonds in the plots receiving the mating disruption treatment compared to the untreated controls, but damage in the plots receiving the hullsplit insecticide treatment was significantly less than that in the plots receiving the mating disruption treatment, and there was no significant difference between NOW damage in almond in the plots receiving both treatments compared to those receiving only the hullsplit insecticide treatment. These results provide growers with a quantitative assessment of the relative benefits on these treatments in a regulatory environment which is increasing less favorable to hullsplit treatments with organophosphate and pyrethroid insecticides, such as those used in this study.
Technical Abstract: In 2004 we compared Navel orangeworm (NOW) seasonal abundance in the absence of pheromone release to data from the same sites the previous year, and examined the hypothesis that mating disruption and hullsplit insecticide treatments together could offer greater protection from NOW damage than either treatment alone. Comparing flight trap data taken from June through August from 3 square miles of almonds and three square miles of pistachios, we found higher numbers of moths but the same trends as the previous year, when the traps at these sites were 200-300 yards from pheromone mating disruption blocks. NOW abundance in these almond sites was generally low through June and much of July, and increased in August. In pistachios, in contrast, NOW abundance was high in June and July. Within 1 square mile of almonds that had received heavy NOW pressure in 2003, we used 4 20-acre replicates each to compare the effects of mating disruption, azinphosmethyl and permethrin at hullsplit, or both the mating disruption and hullsplit insecticide treatments with an untreated control. Comparison of flight trap data within the treatment plots to traps between the treatment plots and in an adjacent section demonstrated that the mating disruption treatments reduced male capture in female-baited flight traps throughout the experimental section. We nonetheless captured significant numbers of males in the non-mating disruption treatment plots and showed complete trap shutdown in the mating disruption plots. NOW damage to Nonpareil almonds in this experimental section ranged from 2.5 to 6.5% in 2004, compared to 6 to 12% in 2003. There was significantly less NOW damage in the mating disruption treatment plots than in the untreated controls, and also significantly less damage in the plots receiving only hullsplit insecticide than in those receiving only mating disruption. There was, however, no significant difference in NOW damage between the insecticide-treated plots and those treated with both insecticide and mating disruption, indicating that there is no additive benefit from using both the mating disruption and hullsplit insecticide treatments.