2016 Row Crops Inservice. Insect Updates SCOTT STEWART THE UNIVERSITY OF TENNESSEE

Transcription

1 2016 Row Crops Inservice Training: Insect Updates SCOTT STEWART THE UNIVERSITY OF TENNESSEE

2 CORN

3 Non-Bt corn refuge requirements have not changed for 2016 The amount of non-bt corn required as a refuge for Bt corn varies depending on whether you live in a designated cotton county. Designated cotton areas in Tennessee: The counties of Carroll, Chester, Crockett, Dyer, Fayette, Franklin, Gibson, Hardeman, Hardin, Haywood, Lake, Lauderdale, Lincoln, Madison, Obion, Rutherford, Shelby and Tipton A HIGHER NON-BT CORN REFUGE IS REQUIRED IN COTTON COUNTIES

4 Cotton

5 Commercially Available Bt Cottons 2015, Unsprayed Plots, Cumulative Season Totals Percent Reduction in Boll Damage vs. Non-Bt b a ab a WideStrike WideStrike 3 TwinLink Bollgard 2

6 Bollgard II vs. Bollgard III 2015, Unsprayed Plots, Cumulative Season Totals Percent Reduction vs. Non-Bt a a a b a b a a BG2 BG3 0 Sq./Blm Damage Boll Damage CEW Larvae FAW Larvae Bollgard 3 and TwinLink Plus will not be sold in 2016

7 Regional Cotton IST Trial 2015, Thrips Injury Injury (0-5) at 35 Days After Planting a cd cd d b c e e Untrt Acephate 6.4 Acephate 15 Acephate 24 Cruiser C. Avicta Gaucho Aeris Tobacco thrips resistance to Cruiser Next Year?

8 Cotton thrips control At planting options are recommended but limited Imidacloprid: Gaucho or preferably Aeris seed treatment Acephate: in-furrow spray or hopper box Imidacloprid: in-furrow spray (e.g., Admire Pro) Foliar sprays with Acephate, Bidrin, etc. Not recommended as a stand alone treatment May be needed in addition to at planting treatments In fact, I am encouraging a pretty aggressive approach of a timed application at the 1-2 true leaf stage

9 Kudzu Bug? A. True B. False Hatching green stink bugs 0% 0% True False

10 SOYBEAN

11 Kudzu Bug

12 Kudzu Bug Distribution Courtesy of Wayne Gardner, UGA

13 Memphis Agricenter 2015

14 Brown Marmorated Stink Bug Distribution Confirmed 2009 Confirmed 2010 Confirmed Corn Soybean Tree fruits, etc. Homes/structures 2011 Confirmed 2012 Confirmed 2013 Confirmed 2014 Confirmed 2015 Confirmed

15

16 Other Concerns Resistance of soybean loopers to Diamide insecticides??? Belt, Besiege, Prevathon

17 Insect Management in Grain Sorghum SCOTT STEWART

18 Corn Earworm

19 Sorghum Webworm

20 Headworm Thresholds Corn Earworms and Fall Armyworm: treat when corn earworms or fall armyworms average 1 per head, either alone or in combination Sorghum Webworm: treat when you find an average of 3-4 larvae per head Count each as ¼ of a corn earworm Moth of sorghum webworm Headworms are a common problem (especially in late planted milo)

21 Headworm Test (Bad Timing) Small and Large Corn Earworm at 15 DAT

22 Sorghum Webworms (Lorenz, Marianna, 2014) 12 Larvae/10 Heads a ab ab Pyrethroid insecticides are inconsistent on corn earworm and simply unreliable on webworms Karate Z 1.6 oz/acre Transform 1 oz/acre UTC Dimethoate 16 oz/acre Mustang Max 4 oz/acre Lorsban 16 oz/acre 4 abc bcd Stallion oz/acre Besiege 1.25 ZC 7 oz/acre 2 0 cde de e e 11 Days After Treatment e Blackhawk 0.75oz/acre Blackhawk 1.5 oz/acre Only labeled treatments shown

23 Sugarcane Aphids A new pest of sorghum

24 Can be devastating

25 Aphids Commonly Found in Sorghum I don t remember where I stole these pictures

26 SCA Only light, yellowish colored aphid likely to occur in large colonies Does not appear to survive hard freezes

27 Harvest Issues Lorenz

28 Thresholds for Sugarcane Aphids Threshold: Treat when 30% of plants are infested plants with localized areas of honeydew and high populations Defense against the sugarcane aphid (Sorghum Checkoff)

29 SCA Trial (Case Study, Milan, 2015) Mid-Canopy Leaves Average Numbers on LOWER LEAF Untreated Transform 1 Sivanto 4 Centric 2 Lorsban 32 Sivanto 7 Transform 1.5 Dimethoate DAT One application made during early flowering Lorsb 16 + Dimeth 16

30 SCA Trial (Case Study, Milan, 2015) Flag Leaves Average Numbers on FLAG LEAF DAT Untreated Transform 1 Sivanto 4 Centric 2 Lorsban 32 Sivanto 7 Transform 1.5 Dimethoate 16 Lorsb 16 + Dimeth 16 One application made during early flowering

31 SCA at Milan (2015)

32 SCA Trial at Milan, Yield Single Application (2015) Threshold was reached at about the time of head emergence All treatments sprayed with Besiege

33 Management tips for sugarcane aphids Resistant hybrids? Use an insecticide seed treatment and plant as early as agronomically acceptable Scout and treat using the best insecticides My first spray in 2016 will be Sivanto at 4 oz/acre Use good IPM principles for managing other pests (avoid unnecessary/disruptive sprays) Consider a pre-harvest application to prevent harvest problems if aphid numbers justify an application Transform, if available, fits well here at oz/acre but still have 14 day pre-harvest interval

34 Wheat & BYDV

35 Yield Response of Wheat to Late Winter Foliar Insecticide TN, Planting Dates (untreated seed unless indicated) Application between Jan. 31 and Feb Cruiser, P = NipsIt P = Gaucho P < 0.05 NipsIt Cruiser, P < 0.05 P < 0.05 Gaucho, P = 0.07 P < 0.05 P = P < 0.05 Average for IST + Foliar: 4.1 B/A Average for Untrt Seed: 6.2 B/A Bushels per Acre

36 Questions? PB 1768 Utcrops - Utcrops News Blog - New Agent Training - Sorghum Scouting Video coming soon to a theater near you