Waterhemp is a tall summer annual and a common Midwest weed, thriving in wet areas but is adaptable to various conditions. It is an invasive weed in both corn and soybean fields. Yield losses may range from 11% to 75%. It has separate male and female plants, producing over 1 million seeds per plant. Waterhemp seedlings have light green to red-pink stems. Cotyledons (first leaves) are oval to lance-shaped, hairless, red-green above, and dark red below. The first true leaves are oblong, dark green, shiny on top, reddish-pink underneath, and shallowly notched at the tip. Mature plants can be 2.5–12 feet tall, upright and branching. Waterhemp has a deep taproot with secondary fibrous roots, competing with corn and soybean crops for water and nutrients (Cornell University). The pigweed family includes waterhemp, Palmer amaranth, and redroot pigweed species. Palmer amaranth has longer leaf stalks than the leaf blade, broader leaves, sometimes with white chevron markings while waterhemp...

  New research from Virginia Tech University shows that small insects called springtails (Collembola species) help farmers fight herbicide resistant weed species in the soil. These tiny wingless insects are about the size of small rice kernel. They live in soil residue and feed on weed seed. There are more than 6,500 species of springtail (Collembola species) world-wide. Results vary by weed seed species depending upon the thickness of the seed coat.  Two Virginia Tech researchers (Jernigan & Sonoskie) found that in a 4-week greenhouse study, springtails reduced weed biomass by 23%. Unfortunately, at first the springtail affected weed seed seemed to increase weed germination for the first two weeks followed by a dramatic reduction in the last two weeks. The researchers think the springtails increased weed seed germination initially by breaking open the seed coat so that the weed seed could germinate faster. In the last two weeks, the germination was drastically reduced, pr...

Farmers first used cultivation to mechanically kill weeds. Hand hoeing, pulling weeds, then horse and tractor driven cultivators. Then they started using chemicals starting with 2-4D to chemically kill broad leaf weeds. New chemicals were developed and then came along glyphosate (Roundup) which became the most popular herbicide, especially when the glyphosate resistant gene was introduced into many crops. But like all new innovations, sooner or later they are replaced due to limitations.   Cultivation disturbed the soil and took a lot of fuel and time. Every time you disturb soil, you replant weed seed and you lose carbon in the form of soil organic matter. There can be as many as several hundred thousand weed seeds per square yard in soil. This weed seed can remain viable for a few years, a decade, or even longer. Weed seed with thicker coats and buried deep with tillage survive longer than those left on the soil surface with no-till. On the chemical herbicides, herbicide resistan...

Research suggests a link between the popular glyphosate weed killer Roundup and cancer. The World Health Organization's International Agency for Research on Cancer concluded glyphosate is “probably carcinogenic,” but the U.S. Environmental Protection Agency maintains more evidence is needed. Roundup and Glyphosate Roundup is the brand name for an herbicide containing the active ingredient glyphosate. Glyphosate is a nonselective weed killer, meaning it can kill most plants on contact within days or weeks. Agricultural workers often apply glyphosate by spray to large areas of crops. Article: https://www.consumernotice.org/environmental/pesticides/roundup/

  Farmer have a new type of weed resistance to worry about. Farmers have been using herbicide or chemical weed control for many years. Weeds have learned several ways to get around herbicides in order to survive. While it is recommended that farmers rotate different groups of herbicides and use full rates, sometimes that does not happen and weeds become herbicide resistant. That has been the main way weeds like pigweed, water hemp, and mares tail have become weed resistant. Some weeds have become resistant to one or several groups of herbicides and now some weeds have even learned to become resistant to almost any herbicide. That is a scary proposition! Often farmers use several passes of herbicides with different modes of action (MOA’s) to control weeds. The goal is to reduce the weed population down to zero so that no survivors pass on any genes that are resistant. The problem is that there are millions of weed seeds in an acre of land, stored over many years. So weed seed is alw...

  Every farmer spends a lot of time, energy, resources trying to find ways to reduce or eliminate troublesome weeds in their fields. Weeds compete with crops for water, nutrients, and even sunlight; reducing crop yields by as much as 30% nationwide. Chemical weed control has been the most commonly used weapon of choice. Now farmers may have a completely different tool called blue wave light. A company located in Xenia, Ohio, called Global Neighbor, is run by Jon Jackson. They have developed a weed inhibitor using mid-infrared blue light wavelengths to treat weed seed. The weeds seed remains viable, but the weed seed can not germinate. The blue wavelength damages the seed cells where germination occurs. A weed seed’s first root, called a radicle, does not grow so the seed eventually dies. Global Destroyer calls their new invention a weed destroyer and it is mounted on the back of a combine. As the weed seed and chaff passes through the combine, the weed seed is terminated by short b...

  As the planting season progresses, many cover crops and weeds continue to grow. Letting cover crops grow may reduce soil moisture, improve soil structure, reduce dust storms, and add soil carbon. Crop rollers naturally kill cover crops by mechanically terminating (crimping) them. Crimpers are used to kill grass cover crops (cereal rye, oats, barley, whet, millets, sorghum species), vetches (hairy, common), annual clovers (crimson and balansa), brassicas (kale, rape), buckwheat, sunflowers, and multi-species cover crops. Crimpers do not work well with perennial cover crops like red clover, alfalfa, or annual ryegrass. Best results when the heads or flowers are in the “boot” or head stage, when mechanically crushing cover crop stems kills them. Crimping advantages include suppression of weeds by forming a natural mulch, reduced summer soil temperatures, it conserves soil moisture, decreases soil erosion, adds organic matter, and reduces blowing soil. Crimping cover crops works well...

  A new study by Purdue University, Dr. Bill Johnson shows the benefits of cover crops for weed control. Cover crops are known to control grasses and marestail, but Dr. Johnson wanted to document other weed control benefits. For example, can you control weeds with out residual herbicides? What other weeds do cover crops control? Dr. Johnson found residual herbicides may not be needed if crop residue is high enough to suppress marestail and annual grasses weeds. For other broadleaf weeds, the cover crop residue was not enough to suppress broadleaf weeds. The cover crops plus residual herbicides were 100% effective at controlling weeds in his trials. Cocklebur was a problem weed which required the full rate of herbicide plus the cover crop residue to control it. Dr. Johnson discovered several other important weed facts about cover crops. Planting green or planting soybeans into cereal rye later had a much higher success rate than terminating the cover crop early. The Purdue research ...

Weeds often tell a story about how a farm is managed. Most weeds grow really well in soils low in calcium with low humus. Often potassium and/or magnesium levels are high, but not always. Many weeds act as collectors of minerals that are deficient in the soil. When weeds die, they often improve the mineral nutrition of the soil. If farmers can understand what the weeds are telling them, they can change their management to reduce weed populations. Two problem weeds are giant foxtail and Canada thistle. Both these weeds thrive in soils that are highly saturated, poorly drained, have low porosity, and have low humus. These soils have low oxygen levels and contain anaerobic bacteria which are generally harmful to crop health. Low calcium and phosphorus are common problems in these soils. For Canada thistle, copper is also often low. Thistle roots can grow 20 feet deep and are a perennial plant, so they are trying to add humus and get oxygen deep into the soil. Foxtail roots have shallow fi...

Some weeds are worse than others, especially poisonous weeds that are dangerous to humans, livestock, and pets! While attending several summer parties in Northwest Ohio (graduation, July 4 th, picnics), several poisonous noxious weeds were observed this year. Poison hemlock (Conium maculatum L.) and wild parsnip (Pastinaca sativa L.) are invasive non-native weeds often found growing together in Ohio. Both plants are in the carrot family and are similar to Queen Anne’s Lace or wild carrot (Daucus carota), the difference being that both these plants are poisonous and bloom earlier in the growing season. Both weeds are prolific seed producers with seeds remaining viable for 4 – 6 years for poison hemlock and around 4 years for wild parsnip, making these poisonous weeds hard to control. Poison hemlock can grow up to 6-10 feet tall and looks very similar to Queen Anne’s Lace or wild carrot except that poison hemlock is hairless, with no hairs on the stems or leaves. Poison hemlock has a bie...

A weed is any plant out of place, but what is the real purpose of weeds? Weeds, ecologically, are the first plants to inhabit nutrient deficient or disturbed soils. Most weeds grow in soils that are high in nitrates and are bacteria dominated. By studying the type of weeds that grow on your farm, you can start to figure out what conditions are limiting. The real purpose of weeds (believe it or not) is to improve the soil. Many weeds act as collectors of deficient soil minerals. Mother Nature does not like bare soils, so she finds something to grow (weeds) that improve soil so that other plants can grow. Each plant is an indicator of the conditions that exist in that field and indicates why some agronomic crops (corn, soybeans, wheat, hay) growth may suffer. Weeds give us a clue to what factors are either limiting or in excess. For example, the common dandelion seems to thrive in bringing calcium (Ca) back to the soil surface. It has a deep taproot, 3-4 feet deep and when the crop decay...