Can planting flowers improve pest control in organic tobacco?

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1 Can planting flowers improve pest control in organic tobacco? Aurora Toennisson, Joana Klein, and Hannah Burrack

2 Background: Biological Control Limited pesticide options in organic and PRC tobacco production systems more reliance on biological control Augmentative Biocontrol releasing beneficial organisms not recommended in tobacco Conservation Biocontrol modifying habitat to promote naturally occurring beneficial insects can provide them with extra resources can modify insecticide use

3 Background: Insectary plant selection Sunflower (Helianthus annuus) Buckwheat (Fagopyrum esculentum) Both used by growers and promoted by certifiers Work in organic vegetables shows potential of conservation biocontrol efforts (Jones and Gillett 2005, Brennan 2013) In Brazil, buckwheat + brassicas increased beneficial insects and decreased aphids in small plots

4 Questions How is pest insect abundance impacted by the presence of insectary plant strips? How is beneficial insect abundance impacted by the presence of insectary plant strips? A.Wild How do these impacts, if any, vary at field-scale relevant distances into the field?

5 Field Relevant Distances 8 rows Lee Hinshaw Photography Truck Row

6 Methods: Treatments Sunflower Buckwheat Natural border 2015 & sites 2016 & site Sunflower + Sunflower Row 8 Buckwheat + Buckwheat Row 8 Buckwheat + Sunflower Bare ground

7 Tobacco Biocontrol : Plot layout 16 th row of tobacco 12 th row of tobacco 8 th row of tobacco 4 th row of tobacco 1 st row of tobacco Beneficial insect planting (or unplanted control) ~61m (200 ft) Sticky card

8 Results from 2015/2016 Treatments Insect Effect of edge sunflowers Effect of edge buckwheat Effect of distance into the field Flea Beetles Pre-topping Post-topping + (2015) Hornworms - (2 wk) - (1 wk) - at 4 rows Aphids at 1 and 8 rows Budworms Parasitoids at 1 row All predators at 1 row Stilt bugs 0 - (2016) 0

9 Methods: Treatments Sunflower Buckwheat Natural border 2015 & sites & sites Sunflower + Sunflower Row 8 Buckwheat + Buckwheat Row 8 Buckwheat + Sunflower Bare ground

10 Tobacco Biocontrol : Plot layout 16 th row of tobacco 12 th row of tobacco 8 th row of tobacco 4 th row of tobacco 1 st row of tobacco Beneficial insect planting (or unplanted control) ~61m (200 ft) Sticky card

11 Tobacco Biocontrol : Plot layout 16 th row of tobacco 12 th row of tobacco Beneficial insect planting (or unplanted control) 8 th row of tobacco 4 th row of tobacco 1 st row of tobacco Beneficial insect planting (or unplanted control) ~61m (200 ft) Sticky card

12 Flea Beetles on Plants: Early Season Week 22 ab b b ab a 2xbuck 2xsun Bare Control Sun+Buck Mean flea beetles per plant

13 Flea Beetles on Plants: Early Season b b b b a Row Mean flea beetles per plant

14 Flea Beetles on Plants: Late Season b a a a a 2xBuck 2xSun Bare Control Sun+Buck Mean flea beetles per top 5 leaves

15 Budworms on Plants b b ab ab a 2xBuck 2xSun Bare Control Sun+Buck Mean budworm infested plants/stop

16 Other Insects on Plants Treatment had no effect on hornworms or aphids on plants Treatment had no effect on predators on plants Sticky cards from 2017 still need to be counted to determine effects on parasitoids

17 Results 2016/2017 Treatments Insect Effect of 2 rows sunflowers Flea Beetles Pre-topping 0 Post-topping + Effect of 2 rows buckwheat Effect of edge sunflowers + buckwheat 0 0 Hornworms Budworms Aphids on plants All predators on plants Stilt bugs 0 0 0

18 Conclusions Edge plantings can have beneficial effects along field edge, but only for a short distance (1-8 rows) Planting flowers in interior of field does not extend these benefits and may dilute them Sunflowers may increase flea beetle incidence Effects of flower strips are small and inconsistent Planting sunflowers or buckwheat flowering strips is unlikely to be a cost-effective insect management strategy

19 Future directions Very low aphid parasitism was observed Investigate what is limiting parasitoid abundance Perhaps investigate other plants that may be more attractive to beneficial insects Looking at landscape level patterns that effect aphid outbreaks

20 Acknowledgements Collaborators: Hannah Burrack and Joana Klein Tobacco Growers: J. Finch, W. Carter, C. Gaster, M. Faucette, M. McKinney, D. Watkins Technical assistance: Stephen Lambert, Frankie Fann, Madi Hendrick, Tiffany Moore, Bo Zhao, Jeremy Slone, Linda Della Rosa, Grant Palmer, Nelson Dominguez, Judith King Stats advice: Lauren Diepenbrock and Alejandro Merchan Funding: RJR Fund for Excellence, Tobacco Research Commission Photo credit: Jeremy Slone, Demetri Tsiolkas, David Orr, Debbie Roos, Lee Hinshaw, Alex Wild, Gail Starr

21 Questions? Read entomology.ces.ncsu.edu Like facebook.com/ncsmallfruitipm Follow Continue the conversation: tatoenni@ncsu.edu