Every spring, alfalfa growth and development is different due to variations in climatic, variety, stand age and other crop production factors. With the 2019 growing season being off to a cooler than normal start, this has slowed alfalfa growth this spring. This is a good reminder that while calendar date may be one method used to determine when to harvest first crop alfalfa, this method is not the best method to use. Instead, the PEAQ method (Predictive Equations for Alfalfa Quality) developed by the University of Wisconsin does a better job.
Integrated Crop Management News
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Bean leaf beetle adults (Photo 1) are susceptible to cold weather and most will die when air temperatures fall below 14°F (-10°C). However, they have adapted to winter by protecting themselves under plant debris and loose soil. Each spring, adult beetles emerge from overwintering habitat and migrate to available hosts, such as alfalfa, tick trefoil, and various clovers. As the season progresses, bean leaf beetles move to preferred hosts, like soybean. While initial adult activity can begin before soybean emergence, peak abundance often coincides with early-vegetative soybean.
Corn planting began a couple of weeks ago and according to the May 5 USDA-NASS Crop Progress and Condition report only 36 percent of the corn crop is planted; 15 percent behind the 5-year average. The greatest progress has been in central and west central Iowa at 56 percent and 57 percent, respectively. Since May 5 there has been limited opportunity for planting to occur. Current weather forecasts for May 8 to 14 indicate two inches of rain and 20 to 30 lower than normal GDD accumulation across Iowa, which may cause additional planting delays.
As of May 6 2019, 36 percent of Iowa’s corn is planted according to the USDA-NASS. Under cool conditions (50 to 55oF soils), it may take more than three weeks for corn to emerge whereas corn in 70oF soils can emerge in less than a week (Licht et al., 2001).
As flood waters recede, the renovation of flooded pastures is just beginning. Now is a good time to check pasture plants for survival. Forage production is a function of the plant species, and their density and growth. Evaluate live plants (plant vigor), plant density, and desirable species versus weeds.
Iowa’s most significant soybean insect pest, soybean aphid, has host-alternating biology. This species has multiple, overlapping generations on soybean in the summer and moves to buckthorn in the winter. Fall migration to buckthorn is based on senescing soybean, and decreasing temperatures and photoperiod. For the majority of the year, soybean aphids are cold-hardy eggs near buckthorn buds (Photo 1). As spring temperatures warm up, soybean aphid eggs hatch and produce a few generations on buckthorn before moving to soybean (Photo 2). Tilmon et al.
Over the last five years, the North Central region of the U.S. has been responsible for 82 percent of the nation’s soybean harvest. Due to the region’s importance to soybean production for its various uses in feed, biodiesel and other widely used products, the North Central Soybean Research Program (NCSRP), through funding from the Soybean Checkoff Program, has sponsored on-farm surveys to farmers in the region to evaluate trends in farming practices and management systems.
Flood waters are receding, but the challenges in recovery for farmers and livestock producers are just beginning. We recommend producers get out in their fields as soon as possible to assess the damage to pastures and hay ground, then check out possible disaster assistance. Look for three things in the assessment: debris, silt on the forage, and thinned or dead forage plants. Debris includes wire, metal and trash that may be injurious to animal health and is usually found along fence lines and in the corners of fields.
Reports of winter injury in alfalfa fields are coming in across the state. Old man winter along with other management factors can take a toll on alfalfa stands. Older stands, stands that were harvested between mid-September and late October, and stands with minimal stubble appear to have suffered the worst winter injury. Additionally, in many fields it is obvious where the snow drifted and provided insulation and protection as those parts of the field are the greenest.
Private pesticide applicators whose certification expired in 2018 have until April 15, 2019, to renew their certification if they plan to renew by attending a Continuing Instruction Course (CIC) training program. In order to renew by training an applicator must attend a CIC in each of the three years of their renewal cycle.