Fisher, Glenn C.

Kaufman, Diane

Kowalski, Judy

Qiang Yang, Wei

Undetermined

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Section V.Soil ArthropodsEVALUATION OF SURROUND KAOLIN CLAY FILM AS AMANAGEMENT TOOL FOR ROOT WEEVIILS IN STRAWBERRIESDiane Kaufman, Wei Qiang Yang, Glenn Fisher, and Judy KowalskiOregon State University, North Willamette Research and Extension Center15201 NE Miley Rd., Aurora, OR 97002503/678-1264diane.kaufman@oregonstate.edu, wei.yang@oregonstate.edufisherg@bcc.orst.edu and judy.kowalski@oregonstate.eduThe experiment was conducted in a third year planting of 'Totem' strawberries at the NorthWillamette Research and Extension Center that was naturally infested with strawberry rootweevils. The objective was to evaluate the effect of Surround on feeding and behavior ofadultroot weevils during spring through summer, 2003. A preliminary trial previously conducted withcontainerized nursery plants had suggested that a coating of Surround on plant leaves tended torepel adult root weevils. This experiment was designed to see ifSurround would have arepellent effect in field-grown strawberries. Pitfalltraps (12 per plot) were monitoredeveryweek during the summer in an attempt to track the movements ofadult root weevils and see ifthey were feeding preferentially among the different treatments.The following treatments were applied regularly from first bloom(4/15/03) to the first weekofSeptember: Surround product #1 applied every7 days(S#l - 7); Surround product #2 appliedevery 7 days (S#2- 7); Surround product #1 applied every 14 days (S#l - 14);untreated control.The only difference between Surround products #1 and #2 was the surfactant used in theformulation. Both Surround products coated theplants inwhite. Treatments were arranged inarandomized complete block design with five replications. Individual plots were four rows wide(13.3 feet) by 25 feet long. Allother strawberry plants weredisked under in early spring, 2003,thereby leavingour plots surrounded on all sides by bare ground to facilitate containment ofadult weevils within the experimental area.Because weevils were primarily concentrated inone area of theexperimental area, each plot was"enriched" with 12 to 14 larvae onApril 22, 2003 (following procedures used by Tanagoshi etal.), inan attempt to have weevils more uniformly distributed over allplots. Weevil larvae usedto enrich plots were primarily late instar black vine and rough strawberry removed fromprimroses growing inpots. Larvae were added toplots by making a 3 to 6 inch deep hole with apencil near a strawberry crown, dropping ina larvae, and re-filling thehole with soil.12Each pitfall trapconsisted of a 16 oz plastic cup lined witha short plastic cup, and topped with atapered 7 oz plastic cup withthebottom removed to act as a funnel. Twelve pitfall trapsper plotwere installed on June 2, 2003. Insect numbers were recorded from pitfall traps examined two tothree times per week fromJune 9 to August 14,2003. The objective ofmonitoring adult rootweevilpopulations during summer was to determine if the Surround had a repellent effect,thereby causing increasingly more weevilsto gravitate toward untreatedcontrolplots over time.Because previous researchhas shown that 4 to 5% ofa knownadult root weevilpopulation tendto fall into pitfall traps, they provide a means for tracking populations and movements over time.Populations of potential root weevil predators (carabid groundbeetles and spiders) caught inpitfall traps were also recorded. All insects caught in traps were released on-site.Table 1. Total number ofadult root weevils recovered from pitfall traps, 6/9 - 8/14/03.Treatment Strawberry RoughstrawberryBlack vine TotalS#l-7 78 3 1 82S#2-7 77 2 2 81S#l - 14 63 5 3 71Control 76 2 3 81Significance ns ns ns nsMean 73.5 3 2.25 78.75There were no differences among treatments in number of root weevil adults recovered frompitfall traps from early June to mid-August, 2003. The small number ofrough strawberryandblack vine weevil adults recovered from pitfall traps may suggest poor survival andestablishment of transplanted larvae in the field.Because another indicator ofadult root weevil activity is leaf-notching, the number of notchedleaves counted in two minutes per plot were also recorded during week 4 (6/30/03) and week 8(7/28/03) of the trial.Table 2. Number ofnotched leaves.Treatment Notched leaves 6/30/03 Notched leaves 7/28/03S#l-7 17.8 28.4S#2-7 24.0 23.8S#l - 14 11.8 22.8Control 13.6 19.0Significance ns nsMean 16.8 23.5Therewere no differences among treatments in the number ofnotched leaves counted on eitherdate.Because number of eggs laid and number of larvae produced per treatment is the most criticalfactor, root weevil larvae will be dug and counted during winter 2003/2004.There were also no differences among treatments in number ofcarabid ground beetles or spidersrecovered from pitfall traps duringany week ofthe trial. Mean weekly carabid ground beetlepitfall trap counts remained fairly consistent and ranged from a low of60 during the week ofJuly 7, to a high of97 during the week of August 11, 2003. Spider counts were highest duringthe first week ofJune (mean of88) and fell steadily during each week to a low of6.5 during theweek ofAugust 11, 2003. There was also a change from a predominance of hunting spidersearly in the summer to web weavers later in the summer.

Evaluation of surround kaolin clay film as a management tool for root weevils in strawberries

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Evaluation of surround kaolin clay film as a management tool for root weevils in strawberries

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