Corn Tar Spot (Phyllachora maydis) is showing up in Southwest/Central Ohio in Preble and Madison counties. Corn that is tasseling or reaching silking stages with warm, humid, foggy, cloudy and wet weather create favorable conditions for corn tar spot to develop. Tar spot looks like small raised black spots on corn leaves when air temperatures are 64°F - 73°F, high humidity (>75%), and long periods of leaf wetness. Once the tar spot reaches the upper leaves during grain fill, photosynthesis is reduced and it decreases kernel development and grain yield. Tar spot is a corn disease originated in Central America and is spreading rapidly by wind into corn growing states. Corn will mature early with reduced ear weight, poor kernel fill, stalk rot, and possibly lodging with yield losses ranging from 0-60 bushel per acre, depending upon disease severity. There are several ways to combat tar spot. No corn hybrid is totally resistant but some varieties (especially early maturing) are mo...

As summer progresses, not only do the crops grow, but also the Ohio Field Days multiply. Here are some field days coming up. July 22: Maria Stein, Ohio, Manure Science Review, 9 AM–3:30 PM The event focused on the latest research, technologies, and best practices in manure management and water quality. Hosted at Homan, Inc., 6915 Olding Road, Maria Stein, Ohio. Topics: Comparisons between manure and commercial fertilizer, nutrient best management practices, updates on water quality and Lake Erie, H2Ohio initiatives from the Ohio Department of Agriculture. For more information, visit: ocamm.osu.edu or waterqualityextension.osu.edu August 5: Allen Dean Farm, Soil Health Field Day, ½ Mile North of RT 6 on CR 13, Bryan, Ohio 43506. 1 PM–8 PM with a Gourmet Meal. $25 per person. Call or text Shelley: 419-533-6844. Speakers are Dr. Elizabeth Rieke on Soil Microbiome and Brain Rath, Soil Health Institute. August 13: Planter & Technology Field Day, 9 AM–1 PM includes lunch. Precision Agri ...

  As wheat and barley harvest progresses, farmers often ask what should they do with wheat straw? Should I keep the straw on the field to build soil organic matter (SOM) or should I sell it? What is the value of the wheat straw and how many nutrients are being lost? Does straw residue hurt the next crop? Straw is a valuable resource in high demand for bedding or mulch and livestock farmers are even using straw to add fiber to their livestock rations. Fewer farmers are growing wheat today and a little barley is being grown. At a minimum, straw sellers should consider the value of nutrients leaving the farm plus the value of the lost organic material plus the harvesting cost. The nutrient value of straw varies but 9-12 pounds of nitrogen (N), 3-4 pounds of phosphorus (P2O5) and 25-45 pounds of potassium (K2O) per ton can be lost on fields that yield 1-2 tons straw per acre. Based on N-P-K values of $.60-$.90-$.40 per pound, the nutrient value per ton varies for N from $5.40-$7.20, fo...

New research show that microbes, especially bacteria and now fungi are the best at pulling moisture from the sky and making it rain. Dust and dirt particles can help it rain, but they are not as efficient as microbes. A recent article in Science Advances shows how the rain cycle works. Most rain starts as atmospheric water vapor and has to freeze into ice crystals before it comes down, turning into rain. Water in the atmosphere does not always freeze at 32OF. In fact, atmospheric water can stay liquid down to -40OF below zero. Temperatures are much lower at cloud level so clouds can stay full of moisture till it gets cold enough and attaches to something to freeze to cause ice crystals and then turn to rain. “Supercooled” water is a liquid cooler than normal freezing water because it has nothing to hold onto. For clouds to make snow, ice, or rain, it needs a “seed”, a tiny particle for the water molecules to grab onto to form an ice crystal before it falls from the sky as rain. Dust, s...

  Corn and soybeans require a steady supply of phosphorus (P) for early seedling vigor, root development, and stalk growth. P is used by plants in the lipid layer of the cell wall, as the backbone to genes (DNA and RNA) and for energy transfer (ATP). While P is an essential element (ranked 8th in the amount needed) it is one of the big 3 nutrients (N-P-K) because it yields more bushels per acre. Recommended corn and soybean soil test are between 20-40 ppm Mehlich. In corn, most rapid P uptake occurs after the V6 stage (six leaf collars). About 80% of absorbed P ends up in the grain. Post-tasseling P availability is critical to maximize yields. In early vegetative planting (Planting to V6), P is essential for root, shoot, and initial ear structure development. Severe P limitations early can permanently reduce yield potential. The most rapid uptake of corn P is V6 (vegetative stage) to R1 (reproductive stage). Demand spikes as biomass multiplies after V6 (4 to 6 weeks after planting)...

In the last few weeks, some areas have received a considerable amount of rain, some would say excess rain. While all microbes live on water films in the soil, too much water changes the microbial community. Excess water also displaces oxygen in the soil which is detrimental to both certain types of microbes and also to plant health. Roots need to be able to absorb oxygen for respiration to break down the root sugars for energy. Oxygen is the fuel to making both fires burn hotter and also for plants and animals to burn oxygen and sugars to produce energy. In flooded soils, the majority of obligate aerobic microbes die within 24-72 hours. As dissolved oxygen is depleted; biological activity drops by 50% within 48 hours. Then facultative and obligate anaerobic organisms take over. Obligate means that either oxygen is totally required (obligate aerobes) or not required (obligate anaerobe). Aerobe mean oxygen loving, anaerobe means absence of oxygen. Facultative microbes may live in either ...

After a week of relatively good weather, farmers have mostly finished planting. Crops are starting to grow with the warmer weather but crops are quite variable. Having spent some time out West in the states of eastern Nebraska, Iowa, Missouri, Wisconsin, Illinois, Indiana, and even Texas; overall the crops look good. That is until you get about an hour west of Fort Wayne and into Northwestern Ohio along US Route 30; then unfortunately, the ground is soggy and crops are still struggling to emerge. Eastern Indiana, and Northwest Ohio had some good crops but many fields just recently got planted. Now forecasted weather reports are coming out saying that the USA has a 60-100% chance of a “Super El Nino” developing between May and July and lasting until the end of the year. In El Nino years, surface water in the eastern Pacific Ocean warms up and this causes extreme weather across the USA. In extreme Super El Nino years, the sea surface temperatures rise 2.5-3.00C or causes about a 4.5-5.40...

  A week of good weather finally is letting farmers either replant or finish planting. May weather was more like March and April weather while March and early April were warmer than normal. Some crops look good but many are still struggling and stands are quite variable. Wheat looks the best and likes cool wetter weather. Hay is finally started to get made. Now farmers are turning to spray spraying tweeds and get nitrogen (N) put on corn. With warmer weather, corn should start growing and have a better color. Microbial populations double with every 8-90F in soil temperature. This is good for getting nutrients into the plant and also in helping the plant with its N needs. For corn, N fertilizer prices are really high and corn prices are low, so putting on what N is needed and no more is the most economical. When N was cheap, the common rate was 1.2# of N per bushel of corn produced. So, for 200-bushel corn, a total N rate of 240# N was advised and for 250 bushel 300# N. With new cor...

A week of good weather is welcomed news as farmers finish planting and replanting. The past several weeks have been cold and wet and crop growth has been slow. Warm weather increases plant growth and warms up the microbes to release abundant nutrients. A number of agricultural pests including insects, pathogens, and weeds are now slowing down crop growth. On insects, seed corn maggot and wireworms are two of the worst Midwest seed insects. Cold, wet, soggy fields allow these insects to thrive. Seed corn maggots ( ) are pale larvae that burrow into and hollow out germinating seeds and young seedlings. Infestations cause poor crop stands, stunted growth, and plant death and are a problem in cool, soggy, and manured fields. Wireworm ( Melanotus communis Gyllenhal ) is the most common wireworm attacking corn and soybeans and is the larval form of the click beetle. Wireworms have a slender elongated body and are dark brownish orange. They have a distinct head and projecting mouthparts with...

  Spring is always a fickle thing when it comes to weather. Late March and April weather was more like May and May was more like April even March at times. The difference this year is cold, wet, and windy are common themes. Some farmers have a lot planted, some a fair amount planted, some for the first time. Others are already replanting. Although a week old, USDA's crop progress report is probably fairly accurate but behind for the weekend plantings. Estimates at that time were 34% of corn acres are planted in Ohio (much higher by now), with 20% of corn emerged. For soybeans, 34% of soybean acre were planted and 16% of soybeans emerged. Planted and emerged acres are probably much higher by now and warmer weather is expected. After a drought last year which lasted most of last fall and winter, most areas have recharged but that is highly variable. Along US 30, rain has been steady since March 10th with over 26 inches reported. Some areas North are less than half that amount. On cor...

  Several dairy farmers have been asking the question: Does improving soil health improve dairy cow health and dairy cow performance? Either higher milk yields, higher components, or just overall herd health? It’s a tough and complicated question to prove definitely, but the answer appears to trend in the direction of YES to all of the above. Milk is about 87% water and 13% solids. As it comes from the cow, the solid portion is about 3.7% fat and 9% solids not fat. Milk has fat soluble Vitamins A, D, E, K. The solids not fat portion is protein, carbohydrates (primarily lactose) and minerals including calcium and phosphorus. Milk is a good rich, dense food source especially for young growing children but also for older adults to avoid calcium deficiency. Researchers at Cornell University compared three fields, one unmanured and two that were manured at three different locations. The number of sites is low so our confidence in the data is rather limited. This was research conducted b...

  Seed imbibition is the process by which dry seeds absorb water, swell, and start germinating. A corn seed will absorb 30% of its weight in water while a soybean seed absorbs 50% water by weight to start germinating. Water moves into the seed coat, to the embryo, and the endosperm which greatly expands the seed and softens the seed coat. Soon radical roots start growing which are the first seed roots. For corn and soybeans, the soil temperature needs to be above 500F but 600F to 700F is much better. Seeds can take 18-20 days to germinate at 500F, but only 8-10 days at 600F and 1-5 days at 700F. This measurement is taken 2 inches deep in the soil. Generally, the soil temperature and moisture are a little more uniform when seeds are planted at least 2 inches deep or deeper. Corn can be planted 3 inches deep to get a more uniform emergence or at least down to moisture. Most areas have received adequate moisture this spring, but there are still areas with much less moisture due to thi...

Researchers at the USDA have identified a leading culprit for the massive honey bee die off.: Varroa mites harbor virulent virus that weaken and eventually kill honey bees. Varroa mites have become resistant to amitraz, the only remaining widely used miticide for hives. Amitraz was widely used, but no longer is considered effective at controlling Varroa mites in honey bee hives. The Varroa mite is an external parasitic mite that attacks and feeds on honey bees. The Varroa mite is one of the most damaging honey bee pests in the world. A significant mite infestation leads to the death of a honey bee colony or hive, starting in late autumn through early spring. Often hives become weak over the winter and the honey bee population in a hive is decimated by spring. Without management for Varroa mite, honey bee colonies typically collapse within 2 to 3 years in the USA. The Varroa mite can reproduce only in a honey bee colony. It attaches to the body of the bee and weakens the bee. The Varroa...