DOI: 10.5061/dryad.pvmcvdnwt
title: Data from: Bait sprays combined with insecticides targeted at Drosophila suzukii have negligible impacts on non-target insects compared to full foliar spray applications

description: Current control of the invasive pest Drosophila suzukii relies primarily
 on insecticides, including the incorporation of phagostimulant baits. The
 impact of insecticidal bait sprays on beneficial insects in crops is
 largely unknown. Using a laboratory and field trial, we exposed non-target
 insects to insecticides with or without bait and compared these to
 non-insecticide controls. In laboratory arena tests, we assessed the
 impact on mortality. In the subsequent commercial raspberry field trial, 1
 m width spray bands of bait were applied weekly, using alternating 25% or
 50% field rates of spinosad and cyantraniliprole respectively. Results
 from the laboratory assays separated the insects into three categories: 1)
 adult Eupeodes corollae, Forficula auricularia, and Orius laevigatus, 2)
 adult Drosophila melanogaster, and 3) larval Chrysopa sp. and Adalia
 bipunctata. In the first group, bait + spinosad or spinosad alone were
 equally detrimental to the life expectancy of insects. For D.
 melanogaster, bait + spinosad was faster acting than spinosad without
 bait. No detrimental impact of the treatments was observed on the third
 group of larval predators. Baits alone did not increase insect mortality.
 In the raspberry crop there were no observed impacts of baits with
 insecticides on the abundance of insect pollinators or natural enemies
 compared to the full foliar applications of insecticides. This study is
 the first to test a range of non-target insects for toxicity to low dose
 insecticides combined with baits. Further field testing in commercial
 crops should explore the placement of bait droplets for optimal D. suzukii
 control, whilst minimising further impacts on non-target insecticides.
description: Two main experiments were done, the first on six non-target
 insects in a laboratory bioassay evaluating the toxicity of baits alone or
 in combination with an insecticide (spinosad) in comparison to the
 insecticide alone, or controls without insecticides. The second was a
 field trial in a commercial raspberry crop comprising a programme of
 alternating insecticides (spinosad and cyantraniliprole) as either a full
 foliar spray or as a reduced rate in combination with a bait spray.
 Impacts on non-target insects were assessed. Laboratory
 Bioassays Six non-target insects commonly encountered
 in fruit crops were tested (Table 1): 1) <em>Orius laevigatus
 </em>(Fieber)<em> </em>adults, a commonly used predatory
 biocontrol agent for the control of thrips; 2) <em>Forficula
 auricularia</em> L. adults, a common generalist predator of orchard
 pests; 3) <em>Eupeodes corollae</em> Fabricius adults,
 pollinators with larvae that predate aphids; 4) <em>Drosophila
 melanogaster</em> Meigen adults, common fruit fly from a wide range
 of habitats that contributes to organic matter degradation and is closely
 related to <em>D. suzukii</em>; 5) <em>Adalia
 bipunctata</em> (L.) larvae, and 6) <em>Chrysoperla
 </em>sp. complex (Stephens) larvae common natural predatory insects
 in fruit crops, feeding primarily on aphids. Two baits
 were used in the laboratory experiment: 1) Combi-protec®, a proprietary
 mixture of plant extracts, proteins, and sugars (Dedetec, Freiburg,
 Germany), and 2) ProBandz®, a natural product containing 54-58% sugars
 (Russell IPM, Deeside, Flintshire, UK). The bait solutions were prepared
 according to the product labels. Perspex boxes (22.5 x
 12 x 8 cm) with ventilated lids (Plain Leaded Net Curtain Fabric Dunelm, 1
 mm mesh size) contained two 90 mm discs of filter paper (Whatman®, 25 × 20
 mm), dampened with 1 ml of distilled water. On each filter paper disc,
 there was a 50 mm Petri dish containing two freshly picked bramble
 (<em>Rubus fruticosus </em>agg.) leaves (approximately 30 mm
 width x 40 mm length). One dish had a sugar feeder (2.1 mL Graduated
 Transfer Pipette bulb, Samco™) containing 5% sucrose solution and a sponge
 cloth wick. The second dish had an alternative food source, provided
 <em>ad libitum</em>, to optimise insect life expectancy (Table
 1). There were six replicate arenas for each species
 with five treatments for each, except for <em>O.
 laevigatus,</em> which had an additional treatment (ProBandz +
 spinosad; Table 2). The insecticide, ‘Tracer’ (a.i. spinosad 480 g
 L<sup>-1</sup>, Dow,) was compared either with or without
 baits to water only and bait only controls (Table 2). Each bramble leaf
 had six 10 μl droplets, three on each side of the central leaf vein (12
 droplets per box total). Baits (Combi-protec or ProBandz) were used at
 5%v/v. Spinosad was used at a concentration of 0.02% w/w, equivalent to
 the concentration if applied at the label rate of 96 g
 ha<sup>-1</sup> in a spray volume of 500 L. For <em>O.
 laevigatus</em>, ProBandz was also used with spinosad at 0.0016%
 w/w, equivalent to the concentration if applied at 8% of the label
 rate. Finally, the non-target insects being tested were
 introduced into the centre of each box. The ventilated lids were sealed
 with tape on to the boxes and then incubated in a growth chamber at 23 °C,
 60% RH, 16:8 L:D. <strong>Table 1.</strong>
 Non-target insects and their quantity, life stage, and alternative food
 source. All insects had a 5% sucrose solution feeder. There were six
 replicate arenas for each insect species. The Nutrimac™ product
 contained <em>Ephestia</em> eggs. Dried cat food was from
 www.iams.com/cat/cat-food. 
 <strong>Order:
 Family</strong> 
 <strong>Species</strong> 
 <strong>Insect source</strong>
 
 <strong>Stage</strong> 
 <strong>Number of
 individuals</strong> 
 <strong>Alternative food source, <em>ad
 libitum</em></strong> 
 <strong>Mortality assessment intervals
 (h)</strong> 
 Diptera: Syrphidae 
 <em>Eupeodes corollae</em> 
 Biobest 
 adult 6
 - 
 1, 24, 48 
 Dermaptera 
 <em>Forficula auricularia</em> 
 Unsprayed orchard 
 adult 3 male, 3
 female dried cat food
 1, 24, 48, 168, 336 
 Heteroptera:
 Anthocoridae <em>Orius
 laevigatus</em> 
 Biobest adult
 10 
 Nutrimac™ 1, 24, 48,
 72, 96 
 Diptera: Drosophilidae 
 <em>Drosophila melanogaster</em>
 Blades Biological 
 adult 6
 male, 6 female -
 1, 24, 48 
 Neuroptera:
 Chrysopidae <em>Chrysopa
 </em>sp. complex 
 Biobest 
 larvae 10
 Nutrimac™ 
 16, 24, 96, 144 
 Coleoptera: Coccinellidae 
 <em>Adalia bipunctata</em>
 Biobest 
 larvae 6
 Nutrimac™ 
 1, 24, 48, 120 
 <strong>Table 2.</strong> Laboratory
 bioassay treatments, active ingredients, and product concentrations. The
 percentage approved field rate of spinosad was 50% for treatments 1 and 4,
 and 8% for treatment 5. *This treatment was only tested for
 <em>Orius laevigatus.</em> 
 
 <strong> </strong> 
 <strong>Treatment</strong> 
 <strong>Manufacturer</strong>
 <strong>Percentage product
 conc.</strong> 
 1 
 Spinosad    
 Dow 0.02
 2
 Combi-protec 
 Dedetec 
 5 
 3 ProBandz
 Russell IPM 
 5 
 4 
 Combi-protec + Spinosad 
 Dedetec   Dow 
 5 0.02 
 *5 
 ProBandz + Spinosad
 Russell IPM
 Dow 5
 0.0016 
 6 Water (negative
 control) - 
 - 
 Numbers of individual insects, alive or dead, were
 recorded at regular intervals depending on the life expectancy of each
 species (Table 1). Insects were gently prodded with a small artists
 paintbrush and deemed alive if there was any movement. Missing insects,
 presumed consumed by surviving predatory larvae, reached up to 50% by 120
 h and 144 h for <em>A. bipunctata</em> and
 <em>Crysoperla </em>sp<em>.</em> larvae
 respectively and were considered as dead for analyses.
 Commercial Field Trial A replicated field
 trial was set up at a soft-fruit farm in Kent in two tunnels of a
 commercial Primocane raspberry (<em>Rubus idaeus</em> L.; cv.
 Majestic) crop. Plots were divided by a barrier of insect exclusion mesh
 (Gromax industries ltd, Gro-Net AA/6, hole size: 0.8 x 0.8 mm) clipped to
 the steel tunnel hoops. Mesh was used to limit the movement of
 <em>D. suzukii</em> and beneficial insects between treatment
 plots and to reduce spray drift between compartments. There were three
 sections of insect exclusion mesh falling on either side and in between
 the posts and wire systems that supported the raspberry canes. Mesh was
 also deployed along the leg rows in-between the tunnels. The mesh was
 secured with sandbags on the ground to allow easy movement of field staff
 and researchers for spray applications and assessments. The compartments
 were erected two weeks before the first treatment application when the
 first pink fruit was visible on the crop. Once the fruit harvest
 commenced, the treatment applications began. There were
 4 replicate plots of 5 treatments (Table 3) distributed along the length
 of two 119 m polytunnels. Each 6.9 x 8.9 m (w x l) plot consisted of two
 rows of potted raspberries spaced at 3 m apart (15 pots in each row, 3
 canes per pot). There was no untreated control as this was a commercial
 site and we wanted to avoid the risk of <em>D. suzukii</em>
 building up in the crop. <strong>Table
 3.</strong> Commercial raspberry field trial with alternating
 treatments of Tracer (a.i. spinosad) and Exirel (a.i. cyantraniliprole) at
 different field rates applied with and without Combi-protec (5% v/v)
 bait. 
 <strong>Treatment number</strong>
 <strong>Bait + % field rate
 insecticide</strong> 
 <strong>Rate of active ingredient (g
 ha<sup>-1</sup>)</strong> 
 <strong>Water volume</strong>
 <strong>(L
 ha<sup>-1</sup>)</strong> 
 <strong>Application
 method</strong> 
   
   spinosad
 cyantran. 
    
 1
 None + 100 
 96 
 90 500
 Full foliar 
 2 
 None + 50 
 48 45
 500 
 Full foliar 
 3 None +
 25 24 
 22.5 
 500 Full
 foliar 
 4 Combi-protec +
 50 48 
 45 
 40 1 m band
 5
 Combi-protec + 25 
 24 
 22.5 40
 1 m band 
 
 <strong> </strong>Alternating sprays, beginning with
 Tracer, were applied on 07/09/2022, 14/09/2022, 20/09/2022, and 26/09/2022
 at the crop fruiting stage, with a motorized knapsack with a handheld
 blower (Birchmeier REC 14 ABC, nozzle pressure 3 bar). For the first three
 treatments (Table 3) sprays were applied as a full foliar application at
 500 L ha<sup>-1</sup> (Albuz ATR 80 orange nozzle at 10.72 ml
 sec<sup>-1</sup>). The other two treatments combined with 5%
 Combi-protect bait were applied as a 1-meter band at 40 L
 ha<sup>-1</sup> (Lecher IDK-120-015 green at 13.68 ml
 sec<sup>-1</sup>) across the centre of the crop canopy, which
 was 2.1 m high. Treatments 1, 2, and 3 (full field rate foliar) and
 treatments 4 and 5 (low rate with bait sprays) applications took 223
 seconds and 22 seconds per plot, respectively. Spray applications measured
 from the start and end tank volumes were 87% to 105% of the target values,
 respectively. A preassessment for pollinators and a tap
 sampling survey for natural enemies was done before treatment application
 on 26/08/2022. Surveys consisted of a 1-minute (30 seconds along each side
 of the central-facing side of the row i.e., the middle of the tunnel) crop
 walk in each plot, recording beneficials contacting the crop (landing on
 fruit, flowers, and foliage). For tap sampling, a white tray (46 x 36 x 3
 cm) was held beneath the lateral stems of the crop, and then the
 corresponding canes were struck with a beating stick three times. The
 invertebrates that fell onto the white tray were counted. Six tap sample
 points were taken in each plot (three evenly spaced on each side of the
 central-facing side of the row). Both visual observations and tap samples
 were taken from a 1 m horizontal section on the canopy, relative to where
 the bait spray bands were applied in both full foliar and bait
 spray-treated plots. The post-treatment application
 insect surveys were done on 20/09/2022 (6 days after first 2 treatments),
 03/10/2022 (7 days after second 2 treatments), 05/10/2022 (9 days after
 second 2 treatments) and 18/10/2022 (22 days after second 2 treatments).
 These followed the same methods as the preassessment described above for
 pollinator counts and tap sampling. During the
 experiment, the average temperature was 16.3ºC (range = 36.5 ºC and 3.0
 ºC). The average relative humidity was 80.2% (range = 95% and
 35.5%).
description: # Bait sprays combined with insecticides targeted at Drosophila suzukii
 have negligible impacts on non-target insects compared to full foliar
 spray applications
 [https://doi.org/10.5061/dryad.pvmcvdnwt](https://doi.org/10.5061/dryad.pvmcvdnwt) ## Description of the data and file structure Dataset was written onto standard company datasheets and then transferred into Excel sheets. ### Files and variables #### File: Arthropod\_survey.xlsx **Description:** tap samples of invertebrates from raspberry plants ##### Variables * 27 arthropod taxa * 6 treatments which were colour coded * 4 assessments - including a preassessment #### File: Melanogaster\_Lab\_Assay.xlsx **Description:** Lab mortality data ##### Variables * alive - moving * l_moribund - moving but not normally * h_moribund - on back but legs twitching * dead - immobile * 3 assessment dates * 6 replicates * 5 treatments #### File: Orius\_Lab\_Assay\_-\_DATAv2.xlsx **Description:** Lab mortality data ##### Variables * alive - moving * l_moribund - moving but not normally * h_moribund - on back but legs twitching * dead - immobile * 3 assessment dates * 6 replicates * 5 treatments #### File: Ladybird\_Lab\_Assay.xlsx **Description:** Lab mortality data ##### Variables * alive - moving * l_moribund - moving but not normally * h_moribund - on back but legs twitching * dead - immobile * 3 assessment dates * 6 replicates * 5 treatments #### File: Earwig\_Lab\_Assay.xlsx **Description:** Lab mortality data ##### Variables * alive - moving * l_moribund - moving but not normally * h_moribund - on back but legs twitching * dead - immobile * 3 assessment dates * 6 replicates * 5 treatments #### File: Lacewing\_Lab\_Assay.xlsx **Description:** Lab mortality data ##### Variables * alive - moving * l_moribund - moving but not normally * h_moribund - on back but legs twitching * dead - immobile * 3 assessment dates * 6 replicates * 5 treatments #### File: Pollinator\_surveys.xlsx **Description:** counts of insects on raspberry plants ##### Variables * numbers of different pollinating insect taxa * 8 arthropod taxa * 6 treatments which were colour coded * 4 assessments ## Code/software Microsoft Excel can be used to view the files. ## Access information Other publicly accessible locations of the data: * NA Data was derived from the following sources: * NA