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Considerations for later planted soy beans; rose tipsBy David G. Hallauer Meadowlark District Extension Agent, crops, soils, horticulture Mother Nature's changeup--an extended period of planting preventing moisture. Her curve--adding in some wind, hail, and some flooding. How should this affect soybean planting decisions? First--maturity: Avoid the temptation to switch to a substantially shorter-season variety. While planting a variety that is too late in maturity will increase the likelihood of frost damage, switching to a substantially earlier maturing variety should be resisted. First, early-maturing varieties planted late in the season will usually have limited vegetative development, short stature, and low yield potential. Second, any given variety will have fewer days to flowering, pod development, and maturity when planted late compared to earlier planting dates. Plant development speeds up as day length shortens and nights lengthen. As a general rule, for every three days delay in planting, maturity is delayed by only one day. With hastened development, the highest yields in a late-planted or double-cropped system are often achieved by using the same variety or one only slightly shorter in maturity as what is used in full-season production. Second--seeding rate: Because late planting shortens the period for vegetative growth and reduces canopy development, increasing the seeding rate alone or in combination with narrow row spacing can help the crop compensate by providing the opportunity to produce more pods in the canopy. Seeding rates can be increased by 30 percent to 50 percent in high-rainfall environments if planting is delayed until late June or July. Although past research has demonstrated no consistent benefit for narrow row spacing (less than 30 inches) in Kansas, narrow rows may have an advantage in late plantings in the eastern half of the state. Let's hope Mother Nature's fastball isn't an early freeze. Blackspot of Roses If you've got a rose susceptible to blackspot, this has been a difficult summer. Blackspot usually starts on the lowest leaves and works its way up. On leaves, it shows up as dark, circular lesions with feathery edges. On young canes, it causes raised purple spots. New leaves are the most vulnerable to infection. Blackspot tends to be most severe when the relative humidity is high, the plant's leaves stay wet for six or more hours, and the temperature is warm--between 75 and 85 degrees. The infected leaves often yellow between spots and eventually drop with severe cases defoliating the entire plant. What can you do to defend against blackspot? Plant roses in areas with good air movement and lots of sunlight. Keep irrigation water off of the leaves. Drip irrigation is a good option. If possible, prune out infected rose canes, to keep the disease from spreading through the plant. Remove all of an infected plant's fallen leaves and canes--they still harbor the fungus. And if you're not willing to use a fungicide, avoid planting susceptible roses. Chemically controlling the disease can require a season-long, 10- to 14-day spray schedule. Fungicide control options are available from your Extension Office. A list of resistant rose varieties is available at http://www.ppdl.purdue.edu/ppdl/weeklypics/3-22- 04.html/ .
Date: 7/24/08
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