in-crop-weather State Indiana Crop Weather Week Ending Date August 8, 2004 Issue IN-CW3204 Agricultural Summary Many farmers were concentrating on preparing grains bins along with harvesting equipment for the upcoming fall harvesting season, according to Indiana Agricultural Statistics. Showers and strong thunderstorms moved through isolated areas earlier in the week. Cool nights and below daytime temperatures have slowed soybean progress. Harvesting of corn for silage was underway. Blue mold is evident in some tobacco fields. Field Crops Report There were 5.6 days suitable for fieldwork. Ninety-nine percent of the corn acreage has silked compared with 88 percent last year and 96 percent for the average. Sixty-three percent of the corn acreage has reached the dough stage compared with 26 percent last year and 48 percent for the average. Seventeen percent of the corn acreage has reached the dent stage compared with 2 percent last year and 12 percent for the average. Corn condition improved and is rated 80 percent good to excellent compared with 61 percent last year at this time. Ninety-five percent of the soybean acreage is blooming compared with 78 percent last year and 91 percent for the 5-year average. Seventy-two percent of the soybean acreage is setting pods compared with 39 percent last year and 62 percent for the average. Soybean condition improved and is rated 75 percent good to excellent compared with 59 percent last year at this time. Third cutting of alfalfa hay is 24 percent complete compared with 10 percent last year and 36 percent for the average. Other activities during the week were repairing equipment, spraying, scouting fields, mowing roads and waterways, moving grain to market, hauling manure and taking care of livestock. Livestock, Pasture and Range Report Pasture condition is rated 14 percent excellent, 61 percent good, 19 percent fair and 6 percent poor. Livestock are in mostly good condition. Cooler temperatures have helped. ----------------------------------------------------- Crop Progress Table Crop Progress Table ----------------------------------------------------- : This : Last : Last : 5-Year Crop : Week : Week : Year : Avg ----------------------------------------------------- Percent Corn Silked 99 98 88 96 Corn in Dough 63 38 26 48 Corn in Dent 17 5 2 12 Soybeans Blooming 95 90 78 91 Soybeans Podding 72 56 39 62 Alfalfa Third Cutting 24 NA 10 36 Crop Condition Table ----------------------------------------------------- : Very : : : : Excel- Crop : Poor : Poor : Fair : Good : lent ----------------------------------------------------- Percent Corn 2 4 14 54 26 Soybean 3 5 17 54 21 Pasture 0 6 19 61 14 Soil Moisture & Days Suitable for Fieldwork Table -------------------------------------- : This : Last : Last : : Week : Week : Year : -------------------------------------- Percent Topsoil Very Short 1 2 1 Short 13 14 4 Adequate 81 79 75 Surplus 5 5 20 Subsoil Very Short 1 1 1 Short 14 14 7 Adequate 82 82 78 Surplus 3 3 14 Days Suitable 5.6 5.2 5.0 Contact information --Greg Preston, Director --Bud Bever, Agricultural Statistician E-Mail Address: nass-in@nass.usda.gov http://www.nass.usda.gov/in/index.htm ----------------------------------------------------------- WEEDS Winter Annual Weeds Emerging in Mid-Summer? As recently as July 26,we have observed marestail and cressleaf groundsel emerging in our soybean research plots at the Southeast Purdue Ag Center near North Vernon, IN. These emergence events are occurring well after postemergence treatments of glyphosate have been applied. So the question becomes, would it be worthwhile to treat production fields having the same problems? Many of the phone calls I receive during this time of the year center on late-season weed control, especially in full- season soybean . Weeds such as giant ragweed, giant foxtail, fall panicum, and common cocklebur emerging through the soybean canopy in late July and early August cause growers to question the overall effectiveness of their weed management practices. More recently, late-season escapes of marestail have generated a lot of attention, particularly in southeast Indiana. Many of the marestail escapes in this area are due to poor control with glyphosate (populations with enhanced tolerance or resistance to glyphosate have been identified in 19 counties in greenhouse screening trials) . However, field observations alone may overestimate the number of cases of glyphosate resistant populations. If you suspect you have a true case of glyphosate resistance in your field, please see an article we wrote last year on this topic and if you are still convinced, you can use the following link to get directions to send samples to us for screening . Screening efforts this year are supported in part by a grant from the Indiana Soybean Board. Now, back to the question of what to do now about the two winter annuals mentioned earlier. Soybeans can tolerate some weed competition during the first 4 to 6 weeks after emergence and not suffer any yield loss. Yield losses typically occur in soybean when weeds are not controlled for 6 weeks or more after emergence. To manage weeds in soybean, most growers use a combination of soil-applied herbicides and/or glyphosate postemergence weed management practices during the first 3 to 6 weeks after planting. We then rely on the crop canopy to suppress weeds for the remainder of the growing season. So a question to be addressed is, "How much yield loss do I suffer from late emerging weeds if I don't control them?" There are several factors to consider when addressing this question. First, when one can see weeds above the soybean canopy, they are usually in excess of 3 feet tall. Most herbicides are labeled for use on weeds that are less than 1 foot tall, and applications to large weeds are mostly ineffective. Second, high temperatures and limited soil moisture reduce the ability of the plant to absorb the herbicide, which will reduce herbicide effectiveness. Third, weeds that have emerged above the soybean canopy have already exerted their competitive effect on the soybean. My previous research indicates that light infestations of late emerging weeds do not impact yield if there was at least a 6 week weed-free period earlier in the season starting no later than 3 weeks after planting. So, it is unlikely that the late emerging marestail and cressleaf groundsel will have any impact on soybean yield. However, the marestail in this case is behaving as a summer annual and will produce seed by the time soybean is harvested. Postemergence treatments of herbicides (glyphosate, FirstRate/Amplify, or Classic) might be warranted to minimize seed production if you are certain that the field does not contain glyphosate or ALS (FirstRate/Amplify or Classic) resistant populations and soil moisture conditions are optimal for plant growth and herbicide activity. However, you will have to weigh the benefits of reducing weed seed production against some stand loss due to driving a sprayer through tall soybeans. At this point we don 't know if the cressleaf groundsel will produce seed this year or next spring. Stay tuned --each week we seem to learn more about winter annual weeds in southeast Indiana! --Bill Johnson, Department of Botany and Plant Pathology, Purdue University ------------------------------------------------------------------------ Weather Information Table Week ending Sunday August 8, 2004 ----------------------------------------------------- | Past Week Weather Summary Data |--------------------------------- Station | Air | | Avg | Temperature | Precip. |4 in. |---------------|------------|Soil |Hi |Lo |Avg|DFN|Total |Days |Temp ----------------------------------------------------- Northwest (1) Chalmers_5W 91 49 69 -4 1.64 2 72 Valparaiso_AP_I 88 47 69 -4 1.12 2 Wanatah 88 45 67 -5 1.27 2 75 Wheatfield 88 47 67 -5 1.23 1 Winamac 87 48 69 -3 2.23 2 74 North Central (2) Plymouth 87 50 69 -5 1.16 2 South_Bend 88 50 70 -3 0.83 3 Young_America 86 48 69 -5 0.92 2 Northeast (3) Columbia_City 86 47 68 -4 1.50 2 76 Fort_Wayne 87 50 70 -4 1.51 2 West Central (4) Greencastle 89 46 69 -7 0.80 2 Perrysville 91 47 69 -4 0.56 1 79 Spencer_Ag 89 49 70 -5 0.77 2 Terre_Haute_AFB 90 48 71 -4 0.02 2 W_Lafayette_6NW 89 45 68 -4 1.27 2 81 Central (5) Eagle_Creek_AP 87 53 71 -4 0.75 3 Greenfield 88 51 70 -4 1.03 2 Indianapolis_AP 88 51 71 -4 0.86 1 Indianapolis_SE 88 48 69 -6 0.91 2 Tipton_Ag 87 47 68 -5 0.84 2 76 East Central (6) Farmland 87 47 68 -4 0.65 1 68 New_Castle 86 46 66 -6 0.54 1 Southwest (7) Evansville 90 50 73 -5 0.02 1 Freelandville 88 54 72 -4 0.00 0 Shoals 89 51 72 -4 0.01 1 Stendal 91 54 73 -4 0.00 0 Vincennes_5NE 90 51 72 -4 0.00 0 South Central (8) Leavenworth 88 52 72 -4 0.71 1 Oolitic 90 50 71 -4 0.75 1 77 Tell_City 91 55 75 -3 0.01 1 Southeast (9) Brookville 91 50 72 -2 0.91 1 Milan_5NE 88 51 70 -4 0.91 2 Scottsburg 87 49 71 -5 0.93 1 -------------------------------------------------- Weather Information Table (Continued) Week ending Sunday August 8, 2004 ----------------|-------------------------------- | Accumulation |-------------------------------- | April 1, 2004 thru Station | August 8, 2004 |-------------------------------- | Precipitation |GDD Base 50oF |-------------------------------- | | | | | |Total | DFN |Days|Total| DFN ------------------------------------------------- Northwest (1) Chalmers_5W 22.30 +6.04 44 2009 -79 Valparaiso_AP_I 14.75 -2.25 50 1893 +1 Wanatah 14.74 -1.82 52 1777 -32 Wheatfield 27.55 +11.39 56 1859 +0 Winamac 19.43 +3.19 55 1929 +6 North Central (2) Plymouth 17.73 +0.89 56 1867 -141 South_Bend 16.60 +0.72 56 1973 +95 Young_America 19.75 +4.08 51 2029 +60 Northeast (3) Columbia_City 18.63 +2.76 60 1851 +59 Fort_Wayne 20.23 +5.49 55 2007 +41 West Central (4) Greencastle 19.35 +0.74 53 2020 -199 Perrysville 16.76 -0.93 43 2212 +133 Spencer_Ag 23.02 +4.00 59 2169 +80 Terre_Haute_AFB 14.83 -3.04 50 2351 +137 W_Lafayette_6NW 20.69 +4.37 40 2038 +72 Central (5) Eagle_Creek_AP 16.93 +0.23 54 2244 +50 Greenfield 18.35 -0.08 55 2130 +31 Indianapolis_AP 22.50 +5.80 49 2333 +139 Indianapolis_SE 18.45 +1.03 49 2142 -34 Tipton_Ag 16.95 +0.40 52 1954 +45 East Central (6) Farmland 17.75 +1.53 53 1994 +135 New_Castle 20.24 +2.42 43 1769 -132 Southwest (7) Evansville 19.55 +2.39 46 2651 +91 Freelandville 19.17 +1.33 47 2371 +83 Shoals 22.69 +3.35 52 2367 +162 Stendal 19.71 +0.67 48 2524 +120 Vincennes_5NE 19.42 +1.58 56 2464 +176 South Central (8) Leavenworth 27.27 +7.63 55 2394 +196 Oolitic 22.63 +4.19 56 2235 +130 Tell_City 24.29 +4.90 48 2698 +262 Southeast (9) Brookville 16.08 -1.76 45 2250 +257 Milan_5NE 23.15 +5.31 73 2216 +223 Scottsburg 30.67 +12.46 52 2329 +58 ------------------------------------------------------------------- DFN = Departure From Normal (Using 1961-90 Normals Period). GDD = Growing Degree Days. Precipitation (Rainfall or melted snow/ice) in inches. Precipitation Days = Days with precip of .01 inch or more. Air Temperatures in Degrees Fahrenheit. Copyright 2004: AWIS, Inc. All rights reserved. The above weather information is provided by AWIS, Inc. For detailed ag weather forecasts and data visit the AWIS home page at www.awis.com or call toll free at 1-888-798-9955.