104 articles

Author: Darcy Telenko Physoderma brown spot is caused by Physoderma maydis, the only class of fungi that produce zoospores, spores that have a tail (flagellum), and swim free in water. P. maydis can survive in soil and crop debris for 2 to 7 years. The pathogen can be dispersed by the wind or splashed into the whorls of the developing corn. Corn is most susceptible to infection between growth stages V5 to V9. Therefore, even though we are seeing symptoms now as corn is into R-stages, infection occurred in standing water in the whorl. Dark purplish to black oval spots along the midrib of the leaf and on the stalk, leaf sheath and husks are distinguishing characteristic symptoms of Physoderma brown spot. In addition, infected leaves have numerous very small round or oval spots that are yellowish to brown and occur in bands across the leaf. Management options for Physoderma[Read More…]




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Author: Lyndon Kelley, Irrigation Educator – MSU Extension/Purdue Extension Deck:  Maximizing profit and returns on resources invested can be dependent on the last irrigation application. Late August and early September often bring the question, “When can I stop irrigating?”  The factors that enter into making this decision are fuel costs which have been sliding higher, and grain and forage values that have had recent lows. Turning off the irrigation water to soon could lower yields or reduce test weight. Irrigating beyond the crop’s need wastes resources: time, energy, and money. Late August and early September weather conditions usually alleviate the late season irrigation application questions. The typical crop water use drops just as the average rainfall increases.  Often, late season irrigation is not needed. However, many of the area’s late planted crops will have substantial water needs well into September, signaling the need for some type of irrigation scheduling or[Read More…]


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Authors: Joe Ikley and Bill Johnson Even with some recent rainfalls across the state, many areas across Indiana are still experiencing a drier than normal planting season (Figure 1). While the primary concern is receiving enough rain this month to have a good finish for our cash crops, many cover croppers have reason for concern about establishing cover crops. We are only a few weeks away from the primary establishment period for cover crops across the state, so we wanted to post a reminder about some herbicide/cover crop combinations that can be problematic. Here is a summary of research conducted at Purdue and other Midwest Universities about cover establishment following corn and soybean residual herbicides: Corn herbicides Pyroxasulfone (Zidua) and metolachlor (Dual, etc) can hinder annual ryegrass establishment. Atrazine or simazine at > 1 lb/A will be problematic for legumes and mustards unless lots of rainfall occurs after application. <[Read More…]


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Author: John Obermeyer Several caterpillars in the ear can be very similar in appearance and habits, so identification to species of some of the worms in ears can be tricky. Note that, in general, you cannot use overall body color or damage for identification. Some identification tips, though not foolproof, appear below for the corn earworm, western bean cutworm, fall armyworm and European corn borer. We suggest you inspect cornfields soon before the larvae leave the ear and pupate.          





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Author: Darcy Telenko Corn diseases have been on my radar these past few weeks as I am just getting my boots on the ground in Indiana. Many aerial fungicide applications are going out around the region, corresponding to crop maturity and the uptick of grey leaf spot. As a result the biggest question I have received this week is, “Should we spray our corn for grey leaf spot?” Fungicides can be effective at reducing disease and protecting yield, but there are a number of factors that should be considered: the field history/previous crop, the amount of disease present in the field, hybrid susceptibility, weather conditions, and the price of corn and cost of fungicide application. Grey leaf spot is probably the most prevalent disease issue this year to date. It is caused by the fungus Cercospora zea-maydis. Symptoms of grey leaf spot usually first appear in the lower canopy a[Read More…]


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