Two decades of berry moth research: what have we learned?

Transcription

1 Two decades of berry moth research: what have we learned? Rufus Isaacs Department of Entomology Michigan State University

2 Paul Jenkins Luis Teixeira

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5 Yield per hectare (metric tons) Tons per acre Does berry moth reduce yield? Weighed and counted Concord berries at harvest Estimated yields per acre % cluster infestation causes 1/2 ton per acre yield loss Percent damaged clusters

6 Percent clusters infested Risk is greatest near wild grape More moth activity near woods border interior More clusters infested near woods and treelines Moths can fly 2-3 ft. 5 Absent Present Absent Present

7 The challenge of timing sprays for GBM Risk Assessment Protocol (Cornell, 1991) At low risk sites: no woods, no GBM history, no snow Treat if infestation over 6% clusters in late July Treat in early August if needed At high risk sites (near woods, history of GBM, snow) Treat 1 days post-bloom Treat early August Treat if infestation over 15% clusters in late August

8 3/1 3/16 3/31 4/15 4/3 5/15 5/3 6/14 6/29 7/14 7/29 8/13 8/28 9/12 9/27 1/12 1/27 critical day length Wild grape bloom as the biofix egglaying starts Gen egglaying starts Gen 2 biofix wild grape bloom For 218 May 6 in Lawton June 7 in Suttons Bay

9 Eggs laid on clusters Better timing of sprays for economical GBM control Mid-season: 81 GDD from wild grape bloom (or 91 for broad-spectrum insecticides) Late-season: 162 GDD from wild grape bloom (or 172) If a fourth generation: 243 GDD from wild grape bloom (or 253) Wild grape bloom GDD after wild grape bloom GDD after wild grape bloom Accumulated degree-days from March 1, base 47 F Generation 1 Generation 2 Generation 3

10 Putting berry moth degree days online

11 Using the MSU berry moth degree day model Online: wild grape bloom Date GDD June / / / / / /

12 Putting it all together: programs with focus on GBM bud swell Degree day model GBM moths prebloom bloom wild grape bloom post bloom berry sizing berry touch veraison ripening harvest GBM eggs Gen. 1 Gen. 2 Gen. 3 Main insect pests Cutworm Flea beetle Rosechafer Leafhopper GBM Jap. Beetle GBM MALB Control windows Lorsban Pyrethroids Neonics Pyrethroids Intrepid Altacor Altacor Venom

13 Eggs laid per female Effect of temperature on egglaying 6 a 4 2 b b C 18 C 28 C Degrees F

14 Threshold for flight is 59 C

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16 Many new insecticides for GBM Targeted insecticides Pre-mix insecticides Biological insecticides

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18 GBM damaged berries / 1 clusters Accurate timing + effective sprays = improved GBM control 4 35 Standard IPM Border 4 35 Standard IPM interior

19 % clusters with GBM Multi-year demonstration vineyard Reduced-Risk IPM Conventional Standard Pre-harvest sample at vineyard border

20 Reduced levels of infestation at borders Standard program Damaged Clusters out of 5 IPM program Damaged Clusters out of Distance from Border (ft)

21 Testing targeted applications Targeted IPM Modified AgTec sprayer used to apply reduced risk insecticides (Intrepid, Belt, Altacor) to high pressure areas. Standard Applied grower s standard program to the entire vineyard as a comparison. Sampled for GBM damage every two weeks. Recorded # of GBM infested berries on border and interior.

22 Trials at Cronenwett Farms with Mark Ledebuhr of Application Insight Slave tank for targeted insecticide delivery

23 % GBM damaged clusters % GBM damaged clusters Similar control with targeted IPM or standard programs Targeted IPM Precision Spray Standard Standard Border Jun 1-9 Jul Jul 29 Jul - 5 Aug 13-2 Aug 27 Aug - 1 Sep 1-19 Sep Targeted IPM Precision Spray Standard Standard Interior Jun 1-9 Jul Jul 29 Jul - 5 Aug 13-2 Aug 27 Aug - 1 Sep 1-19 Sep

24 Beneficial insects in Michigan vineyards

25 Bare ground Buckwheat Grass Wildflowers % berry moth Ground cover Average natural enemies/plot 12 Bare ground Grass Buckwheat Wildflowers 6.5 b 23.3 a 34.3 a 31.8 a

26 Average % GBM survival 1 Reduced-Risk Lower survival of GBM larvae in reduced-risk programs Conventional 2 8/14 9/2 9/13 Mean % GBM survival /29 8/12 8/ /14 7/28 8/1

27 Average % parasitism Higher parasitism of GBM larvae in reduced-risk programs Parasitism of E. viteana Larvae 4 3 Year 1 Reduced-Risk Conventional 2 1 8/14 9/2 9/13 4 Year 2 Mean % parasitism /29 8/12 8/26

28 What have we learned? GBM reduces yields (and increases disease). Hot spots near woods need extra attention. Degree day model improves control. 81 or 91, just before berry touch (Gen 2) 162 or 172, near veraison (Gen 3). Some new insecticides are highly effective. Selective insecticides enhance biocontrol. IPM programs integrating these components can minimize GBM infestation.