Erfaringer med bekæmpelse af bladsygdomme i majs i Danmark

Transcription

1 Erfaringer med bekæmpelse af bladsygdomme i majs i Danmark Erfaringer med bekæmpelse af bladsygdomme i majs i Danmark Lise Nistrup Jørgensen Aarhus Universitet Flakkebjerg Lise Nistrup Jørgensen, Aarhus Universitet, Flakkebjerg, Slagelse Agenda Importance of maize Relevant maize diseases Disease biology Results from field trials in Denmark Impact on yield and yield parameters Can Fusarium also be a problem? Lack in thresholds etc. 1

2 Maize in Denmark Maize area in DK ha Mainly silage maize But also more grain maize Maize after maize is common practise Increase in problems with diseases have been observed Maize diseases Sygdomme engelsk anamorph Majs øjeplet Eyespot Kabatiella zeae Majs bladplet Northern corn leaf blight Exserohilum turcicum Helminthosporium turcicum Drechslera turcica Southern corn leaf blight Northern corn leaf spot Helminthosporium maydis Drechslera maydis Helminthosporium carborum Drechslera zeicola 2

3 Majs bladplet Exserohilum turcicum eller Helmintosporium turcicum Nothern Corn leaf blight Cigar shaped spots Fast development after flowering Severe attack looks like frost damage Spread from plant debris Spores spread with wind over long distances Diferences in cultivar susceptibility. Both specific and none specific resistance Humid conditions stimulates attack Optimum temp C Losses can be as big as 50% 5 Life cycle of H.turcicom 3

4 Eyespot (Kabatiella zeae) Small circular spots Might develop fast following flowering Latent time: 4 10 days Spread from debris Some differences in susceptibility Wet conditions stimulates Spores spread by rain Optimal temp C Losses from early attack around 50% 4

5 Development of attack of Kabatiella in the crop 2011 Axelrubrik Kabatiella above cup above ESKE above FLAK gs 51 gs 63 gs 69 gs73 gs 75 gs79 gs 83 Days of spraying Locality First appl gs. % attack 2nd appl GS % Attack Eskebjerg 5/ (0%) 20/7 51 (5%) Flakkebjerg 19/7 39 (0%) 16/8 69 (10%) 5

6 Control of eyespot in maize Flakkebjerg august Untreated Opera 1,5 l/ha (early) Control of Kabatiella in maize 23 sept Flakkebjerg 1,2 BAY F111 1,5 Opera 4/7 4/7 Untreated 6

7 Control of Kabatiella in maize Flakkebjerg 2 x 0,5 Comet 1,5 Opera 19/7 + 16/8 19/7 Untreated Control of disease Eskebjerg; assessed 27 Sept. 67 days from last application untreated 2 x 0,5 Comet 5/7 + 20/7 2 x 0,75 Opera 5/7 + 20/7 7

8 Eskebjerg 27 sept Untreated 1,2 BAY F111 1,2 BAY F111 Early late Control from strobilurins Eskebjerg assessed 27 Sept. 3 month from spraying 1,0 Comet 200 (5/7) 1,0 Aproach (5/7) 8

9 %Control of eyespot gs 75 average of 2 trials gs 39 gs 51 split Opera, 1,5 Opera, 0,75 Comet, 1,0 Comet, 0,5 Aproach, 1,0 Maize trials Høst oktober 2011 Høst december

10 Debris from harvest of maize grain Yield increases from fungicides 2 trials Aproach, 2 x 0,5 Comet, 2 x 0,5 Opera, 2 x 0,75 Aproach, 1,0 gs 51 Comet, 0,5 gs 51 Comet, 1,0 gs 51 Opera, 0,75 gs 51 Opera, 1,5 gs51 Aproach, 1,0 gs 39 Comet, 0,5 gs 39 Comet, 1,0 gs 39 Opera, 0,75 gs 39 Opera, 1,5 gs 39 untreated flak eske

11 Ranking of yields at Eskebjerg LSD95 = 9.9 hkg/ha untreated Aproach, 1,0 gs 51 Aproach, 1,0 gs 39 Comet, 0,5 gs 51 Aproach, 2 x 0,5 Opera, 0,75 gs 39 Comet, 0,5 gs 39 Opera, 0,75 gs 51 Opera, 1,5 gs 39 Comet, 1,0 gs 39 Opera, 1,5 gs51 Comet, 1,0 gs 51 Comet, 2 x 0,5 Opera, 2 x 0, untreated Aproach 1,0 gs 51 Aproach 2 x 0,5 Opera 0,75 gs 51 Aproach 1,0 gs 39 Comet 1,0 gs 51 Comet 0,5 gs 51 Comet 0,5 gs 39 Opera 1,5 gs51 Comet 1,0 gs 39 Comet 2 x 0,5 Opera 0,75 gs 39 Opera 1,5 gs 39 Opera 2 x 0,75 Ranking of yields at Flakkebjerg LSD95=6.9 hkg/ha flak

12 Yield increase following different timing of fungicides, lsd95 = 8, gs 39 gs51 split Opera, 1,5 gs 39 Opera, 0,75 gs 39 Comet, 1,0 gs 39 Comet, 0,5 gs 39 Aproach, 1,0 gs 39 Net yield increases (hkg/ha) gs 39 gs 53 split 5 0 Opera 1,5 Opera 0,75 Comet 1,0 Comet 0,5 Aproach 1,0l 135 kr /hkg grain

13 Correlation between attack of eyespot and yield increases merudbytte hkg/ha R² = 0, % angreb på vs 75 Impact on grain and cob size average of 15 cobs Grain size TGW g Cob weight g Cob length cm Cob filling % Cob diameter, cm Untreated 274 A 135 A 15,0 A 94,0 A 4,1 A Opera vs B 182 BC 15,8 B 96,3 BC 4,4 B Opera 319 B 177 B 15,2 A 95,1 AB 4,5 BC vs x Opera 339 B 194 C 16,0 B 97,3 C 4,6 C Exampl e: 75 % 90 % 95 % 95 % 13

14 Målinger på kolber Cob size Untreated Opera early Cob size Untreated 2 x Opera 2 landsforsøg 2009, svampesprøjtning i kernemajs Udbytte og merudbytte, hkg/ha 1) ubehandlet 54,4 Nettomerudbytte, hkg/ha 2) st. 37 1,0 l Prosaro 16,3 11,3 3) st. 37 1,5 l Opera 19,4 12,1 4) st. 51 1,0 l Prosaro 25,4 15,5 + st. 63 1,0 l Prosaro 5) st. 51 1,5 l Opera 26,3 11,7 + st. 63 1,5 l Opera 6) st. 63 1,0 l Prosaro 9,5 4,6 7) st.63 1,5 l Opera 21,9 14,6 LSD 2 7= 8,4 Kernemajs = 95 kr/hkg 14

15 Fusarium in maize GER (Gibberelin ear rot) Mainly F. graminearum also F. culmorum Often seen as pink mould on kernels Fungal spores land on silk and mycelium moves down the silk and infect kernels and cob Also wounds created by insects or hail offers point of entry Pink growth also on outside husk Optimal temp C Long time with humidity stimulates process Produce DON, NIV, ZEN 15

16 Fusarium attack in maize Fusarium verticilium Produce fumesin Under warmer conditions Fusarium graminearum Fusarium culmorum Produce DON, NIV, ZEA Toxin in maize Mycotoxins in grainmaize ÅR DON max ZEA max Facts on toxins DON = 900 ug for pigs (Guidance limits) ZEA= 100 ug for pigs (guidance limits) More toxins in grain maize the whole kernel maize Late harvest increase risk of toxins 16

17 How to spray the crop? Common sprayers canbeusedonto gs Yield responses and authorisation of fungicide in maize Authorisation of fungicides Rumanien (Opera) France (?) Denmark (Opera ) USA ( Comet, Amistar and Tilt is authorized) Brasilien (several) Litaun/Letland (Opera) Which season has been payed for treatments? 2008: positive but not significant increases (7 8 hkg/ha 2009: Positive and significant yield increases (10 25 hkg/ha) 2010: Positive but not significant yield increases (5 6 hkg/ha) 2011: Positive and significantly increases (20 30 hkg/ha) 17

18 Conclusion on maize Fantastic trial season with eyespot in Good efficacy of Opera and Comet Opera authorized for the 2011 season Good yield increases when attacks are significant Fungicides respond to control of diseases Double treatments may be profitable Impact on several yield parameters Timing important for control Not all strobes are effective Yield increases has generally been positive but only significant in 2 out of 4 seasons Treatments is not relevant every year Need to improve knowledge on which diseases dominate and predict the risk for significant levels developing. 18