Efficacy of Acaricides and Lethal Concentration (LC 50 ) in Spider Mites (Tetranychus urticae) from Three Red Raspberry Fields in Western Washington

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1 Efficacy of Acaricides and Lethal Concentration (LC 50 ) in Spider Mites (Tetranychus urticae) from Three Red Raspberry Fields in Western Washington Beverly Gerdeman, Sharmila Sunwar, Hollis Spitler and Charles Coslor WSU NWREC Mount Vernon, WA

2 Or How the Beast Was Made a tale of Pacific Northwest red raspberry fields

3 % Mortality at 24 Hours 2017 Reports of Failure to Control Spider Mites 1. Acramite - 50WS (bifenazate) 2. Brigade WSB (bifenthrin) 2017 TSSM Lynden WA 100 Site 1 Site Acramite rate full Acramite 1/2 rate Acramite 1/4 rate Brigade 2 EC full rate Brigade 1/2 rate Brigade 1/4 rate Control

4 Twospotted Spider Mite Resistance Arthropod Pesticide Resistance Database 11/30/18 (MSU) Why are spider mites so prone to resistance? short life cycle abundant progeny arrhenotokous reproduction (parthenogenesis) Twospotted Spider Mites 512 cases of resistance reported including: Agri-Mek (abamectin) - 53 Acramite (bifenazate) - 14 Savey (hexythiazox) 11 Vendex (fenbutatin-oxide) and Malathion - 7 Brigade (bifenthrin) - 5 Kanemite (acequinocyl) - 4 Zeal (etoxazole) and Danitol (fenpropathrin) - 3

5 2018 Funding From WRRC and WSCPR to Continue Testing

6 Treatments Commercial formulations 1. Acramite - 50WS (bifenazate) 2. Banter WDG (bifenazate) 3. Agri-Mek SC (abamectin) 4. Brigade WSB (bifenthrin) Locations Two growers Three fields (2 Meeker and 1 Wakefield ) Spider Mites Field-collected mixed-age females

7 # Mites tested/miticide Rates ppm Miticide a.i. Control Field Rate ½ Field Rate ¼ Field Rate # Mites Acramite bifenazate Banter bifenazate Agri-Mek abamectin Brigade bifenthrin Efficacy of Acaricide = Total dead spider mites in a Petri dish Total spider mites tested in a Petri dish 100 Potter Spray Tower

8 Results Treatment Rates (ppm),% Mortality Spider Mites and LC 50 Miticide Field Rate % Dead mites ¼ Field Rate % Dead mites LC 50 (ppm) % Dead mites Acramite ( ) ( ) ( ) Banter ( ) ( ) ( ) Agri-Mek ( ) ( ) NA NA Brigade ( ) ( ) NA NA Field rate highest rate registered for caneberries LC 50 = Lethal concentration 50 - amount of active ingredients required to kill 50% of the population calculated using probit analysis. % dead spider mites resulting from the acaricide application. Values in the parenthesis represent ranges.

9 Percent Efficacy A P< B C D 0

10 Percent Efficacy Acramite Banter Agri-Mek Brigade a a a P< b b 60 cd cd c d ef efg fg efg fg e g 0 Full dose 1/2 dose 1/4 dose Control

11 Probit dead mites Probit dead mites Probit dead mites Probit dead mites A) B) A) Acramite (Bifenazate) B) Banter (Bifenazate) C) Log 10 Acramite dose (ppm) D) Log 10 Banter dose (ppm) C) Brigade (Bifenthrin) D) Agri-Mek (Abamectin) Log 10 Brigade dose (ppm) Log 10 Agri-Mek dose (ppm)

12 Consider Seasonality David James WSU Postharvest High numbers of predatory mites & other beneficials. Knockdown is all that s needed!

13 Conclusions Lower field rate for 3 miticides as good as full rate. Bifenazate products soft on predators versus abamectin. No interactions between cultivar and mites. Interactions between location and mites. Performance is related to grower management.

14 You make the beast

15 Thank You Washington Red Raspberry Commission Washington State Commission on Pesticide Registration Randy Honcoop This work is/was supported by the USDA National Institute of Food and Agriculture Project WNP00543 Application of a pesticide to a crop or site that is not on the label is a violation of pesticide law and may subject the applicator to civil penalties up to $7,500. In addition, such an application may also result in illegal residues that could subject the crop to seizure or embargo action by WSDA and/or the U.S. Food and Drug Administration. It is your responsibility to check the label before using the product to ensure lawful use and obtain all necessary permits in advance.

16 Statistical Analysis Procedures Data evaluated in JMP Pro (SAS Institute Inc. 2015). The mortality, survival, and efficacy of acaricide (%) values were normalized by angular transformation. The two-way ANOVA and mean separation (Fischer protected LSD) were performed in transformed data. The homogeneity of variances of mortality, survival, and efficacy of acaricide (%) were tested using Bartlett s test. All three experiments were combined after homogeneity of variance was satisfied by Bartlett s test. All data presented are nontransformed data. Probit analysis was performed in JMP Pro and different lethal concentrations (LC) were determined by using profiler function in JMP.