Tuesday, May 31, 2011
With where the wheat growth stages are in the southern part of the state, this means we should be paying critical attention to the weather and risk of Fusarium head blight infection. A check of the Fusarium Head Blight Prediction Center today for the southern third of Wisconsin indicated that the risk of FHB infection was low, except for a few pockets along the Illinois border that were in the moderate range. However, looking at the one to three day forecast, the risk of FHB infection is predicted to be low. A foliar fungicide would not be recommended at the current moment. We will continue to monitor conditions during this week as well as over the next couple of weeks to provide updates for the risk of FHB as well as management recommendations. For information regarding products that can be effective at suppressing FHB (with well-timed applications), please check here. Pay close attention to individual fungicide labels especially in regards to the latest growth stage that a product can be applied as well as any pre-harvest intervals for applications.
What about other diseases? As I scouted at both locations today, there were three main diseases noted including BYDV, Septoria lead blotch, and powdery mildew. Across the four locations assessed the past two days, the BYDV at Lancaster had the highest incidence and the incidence of this disease at Janesville was similar to what we observed at Arlington yesterday. Powdery mildew also appeared to be slightly more severe at Lancaster than at the other locations, although symptoms were still mostly in the lower canopy to the flag-3 or flag-2 leaf, depending on variety. The two videos below provide some pictorial evidence of what was being seen for both diseases at Lancaster.
Monday, May 30, 2011
On my drive up to Chilton this morning, I couldn't help but notice lots of wheel tracks in the majority of winter wheat fields! At Chilton, the Winter Wheat Performance Tests looks very good. The growth stage is Feekes 8 (flag leaf emerging) to Feekes 9 (flag leaf ligule and collar visible). The wheat head is right around the nodal area for the flag-2 leaf. From a disease perspective, things look really clean. There is a a little bit of BYDV, some Septoria leaf blotch and also powdery mildew. The key observation for Septoria and powdery mildew is that the symptoms are really only around the base of the plants. Right now, a foliar fungicide would not be warranted here at the Chilton performance tests.
At Arlington, the wheat is looking great. Similar to Chilton, the main diseases noted included BYDV, Septoria leaf blotch, and powdery mildew. Outside of BYDV in the upper canopy, the symptoms and/or signs of Septoria and powdery mildew are in the lower canopy near the base. Wheat ranges from Feekes 8-9 (flag leaf emergence) to the boot stage (Feekes 10) to some early heading depending on the wheat variety. In addition to monitoring for foliar diseases, this also means we need to turn our attention to monitoring the risk of Fusarium head blight. While we are probably a few days off from early flowering for some of the varieties, a current check of the Fusarium Head Blight Prediction Center indicates that the risk of FHB is low throughout the state. The one to three day prediction's are also indicating a low risk of FHB around the state.
Monday, May 16, 2011
Looking ahead, there exist some thresholds as you scout at Feekes 7 and 8 to determine if a foliar fungicide may be warranted.
At Feekes 7, the thresholds are:
Powdery mildew: check the uppermost leaf - the threshold is an average of five pustules per leaf.
Wheat leaf rust: check any leaf - the threshold is an average of one pustule per leaf.
Septoria leaf blotch: check the uppermost leaf - the threshold is 25% of the leaves having expanding blotches
At Feekes 8, the thresholds are:
Powdery mildew: check from the flag-2 leaf (2nd leaf below the flag leaf) and upward - the threshold is an average of five pustules per leaf on the flag-2 leaf.
Wheat leaf rust: check from the flag-3 (3rd leaf below the flag leaf) and upward - the threshold is an average of one pustule per leaf on the flag-3 leaf.
Septoria leaf blotch: check from the flag-2 and upward - the threshold is 25% of the leaves having blotches
If you note disease in the lower canopy but not on any of the leaves discussed above, consider increasing the frequency of your scouting to determine if there is evidence of new pustules or blotches moving into the upper canopy.
For further information regarding factors to consider for determining the need for a foliar fungicide recommendation, please check here.
For information regarding the efficacy of several foliar fungicides against different wheat diseases, please check here.
Results across our different studies the past few years have indicated that the best response to a foliar fungicide application has occurred when powdery mildew was the target and the wheat variety was susceptible. When the wheat variety was resistant to powdery mildew, we have not seen a consistent response, if at all.
The Wisconsin Soybean Program has announced the 2011 WI Soybean Yield Contest. This contest encourages growers to challenge themselves to produce higher yields and to be rewarded for their efforts. Top growers will be recognized for achieving high yields while using sound, environmentally friendly production practices that are profitable as well.
Trophies and cash prizes will be awarded to first, second, and third place winners in each of two contest classes: non-irrigated and irrigated. The winner is the entry that has the highest soybean yield based on bushels per acre at 13 percent moisture.Contest brochures, rules and entry forms can be found at www.coolbean.info.
For more information feel free to contact Shawn Conley at 608-262-7975
Friday, May 13, 2011
For more detailed information regarding soybean emergence please see Predicting When Soybeans Will Emerge.
Table 1. Soil temperature monitored at 2 inch depth at the Arlington Agricultural Research Station in 2011.
Image 1. Developmental images of soybean planted on May 4th at Arlington, WI in the long term-rotation study.