The winter wheat crop is greening up and as such growers will need to pay attention to crop growth stage in order to make adequate management decisions. Wheat growth stage identification is critical for effective timing of fungicide, insecticide, herbicide, and fertilizer applications. Hence, crop growth staging is extremely important, since failure to correctly identify these stages may lead to inadequate timing of applications, which may result in violation of pesticide label restrictions (products being applied off label), inferior efficacy or product performance, and injury to the crop. In addition, effective and timely pesticide applications and pest and disease management are extremely important for profitable wheat production as they all affect the number of tillers/heads produced per acre, seeds produced per head, and seed size. These all add up to higher grain yields and excellent test weights.
If you have not done so already (and you probably haven’t due to the excessive rainfall…), now is the time to check fields in order to identify crop growth stage. Currently, most of the wheat in Ohio is between the green-up and erect stem stages (Feekes 2-5) of development and will likely begin jointing (Feekes 6) within the next 7-10 days as the weather continues to warm up.
Feekes Growth Stage 2-5 (tillering, green-up and erect growth). Tillering (the production of side shoots) usually occurs in the fall and early spring. For most of the early planted fields, particularly those in the southern half of the state, tillering is now complete (Feekes 3) and the wheat is either at or approaching the erect stem stage (Feekes 4) of development. This is the ideal stage for evaluating your wheat stand, begin scouting for insects and weeds, top-dressing nitrogen, and finishing-up herbicide application. For those late-planted or northern fields that are still greening-up (not yet at the Feekes 3 growth stage), a nitrogen application at this time will likely increase tillering, and consequently, the number of head produced per foot of row. However, for those fields at the Feekes 4-5 growth stage, nitrogen application will have very little effect on tiller development but will affect the number of seeds produced per head and seed size. To read more about evaluating wheat stands see this C.O.R.N. newsletter article from a couple of weeks ago: http://corn.osu.edu/newsletters/2015/2015-06/wheat-is-starting-to-green-up.
Feekes Growth Stage 6 (first node visible). This growth stage can be identified by examining the large tillers in the fields for the presence of the first node. Pull multiple large tillers, strip down the lower leaves and leaf sheaths on the stem, and check for the presence of the first node at the base of the stem. If this node is visible (or can be felt), your wheat is at jointing (growth stage 6). At growth stage 6, the node is above the soil line and appears as a slightly swollen area of a slightly different shade of green from the rest of the stem. If the node is not yet visible, the wheat is probably at Feekes growthstage 5. Feekes growth stage 6 usually occurs mid- to late April.
Growth stage 6 signals the beginning of stem elongation. Nitrogen should be applied by this time to maximize yield. This is also the growth stage when some herbicides can no longer be applied. For instance, herbicides such as 2,4-D, Banvel, or MCPA should not be applied after Feekes growth stage 6.0, as these materials can be translocated into the developing spike, causing sterility or distortion. Huskie and products containing tribenuron and thifensulfuron can be applied through Feekes stage 8, and bromoxynil can be applied until stage 9. Keep in mind that the tribenuron/thifensulfuron-containing products such as Harmony Xtra should generally be mixed with dicamba, 2,4-D or MCPA to broaden the spectrum of control, which affects how late they can be applied. The chart on page 143 of the 2015 Weed Control Guide provides a snapshot of growth stage information. For more on wheat growth stage identification visit:http://ohioline.osu.edu/agf-fact/pdf/0126.pdf
You should also begin scouting for early season diseases such as Septoria and powdery mildew. However, we do not recommend foliar fungicide application this early in the season. Although some producers may be interested in tank-mixing foliar fungicides with nitrogen or herbicides, our data shows that under conditions in Ohio fungicide applications at or before jointing do not provide adequate protection of the flag leaf and the heads.
Keep reading the C.O.R.N. newsletter for more updates on the progress of the wheat crop and management tips and guidelines.