0000199581 00000 n <<18C2D1B427EF2E4F8DC800A03A6A6554>]>> �u�{�tlq��(T����fVI� �1�-s��;;J�,N(?a�P,B�Ģ��X$:�ʑ@� Warmer weather favors gray leaf spot, while cooler weather favors northern corn leaf blight. Corn grey leaf spot can be an extremely devastating disease as potential yield losses range from 5 to 40 bushels/acre. 0000004863 00000 n Both gray leaf spot and northern corn leaf blight are also active in the lower canopy of corn across the state. 0000214022 00000 n Statewide, yield losses can average 20 to 30 percent on susceptible hybrids. Early lesions are small, necrotic spots with yellow halos that gradually expand to full-sized lesions. Today, the disease has expanded to Delaware, Illinois, Indiana, Iowa, Maryland, Missouri, Ohio, Pennsylvania and west Tennessee. Each disease has an economic threshold. 0000211370 00000 n 0000215053 00000 n Northern corn leaf blight prefers cooler temperatures through grain fill. The spores can be wind-blown or water-splashed onto the lower leaves. 0000199918 00000 n 0000215618 00000 n 0000213965 00000 n Although there are several races of the fungus that cause disease, Race 3 most likely causes the greatest impact in New York State. Issue 98-23. It was initially detected in the southeastern coastal corn growing states of Virginia, Georgia and the Carolinas in the 1920s. 0000214169 00000 n Department of Plant Pathology MF2341 Corn Diseases Gray Leaf Spot of Corn Gray leaf spot of corn is caused by the fungus Cercospora zeae-maydis. Deciding whether to apply fungicide seems straightforward, but not every corn field may need fungicide to manage gray leaf spot, she says. High relative humidity (>90%) can lead to increased disease. 0000015356 00000 n 2:26. 0000216084 00000 n 0000003806 00000 n ea�������?����@����@&�M��fb����\x��ڲN�� tJ@��e�ު3|C� �Wttt000�Ch�r � P1:6 �$�ڴ������gd�h�nPU��7�������1>P\�����-�aCw�,у�/�mP(�ff�ePmId=�~BB���W�u � 6+X�01�b]��`�`�G�i%�)�Op��/>(� ��K9�X �D� WJ� endstream endobj 63 0 obj <>>> endobj 64 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text/ImageC]/Shading<>/XObject<>>>/Rotate 0/TrimBox[0.0 0.0 612.0 792.0]/Type/Page>> endobj 65 0 obj <>stream 0000014508 00000 n Generalized calendar of events for : common diseases in WI corn: Timings shown when the disease is typically visible and are approximate, varying according to location within the state. Crop Observation and Recommendation network. Gray Leaf Spot and Northern Corn Leaf Blight share some similarities, but it's important to accurately diagnose which disease is affecting your corn crop. Producers can also use foliar fungicides when the economic threshold is exceeded. Gray leaf spot (GLS) has reached threshold levels in some corn fields in southwestern Iowa and a fungicide application should be considered for these fields. 0000215347 00000 n �Q�8f>Ng���5�w������w?�|Vմ>�ԇ�ԁ���E ,|[���z�� m�WU߁ S&�x�N�2��.D ��:�/��#&�E "@����7PO�r8�>�3 Hm�����p0^�+=ؑD,?�]� Gray leaf spot is also active in the lower to mid canopy at multiple sites across the state. Gray leaf spot and yield losses in corn. Those black spots are more than unsightly -- they're stealing corn from you. The spores can be wind-blown or water-splashed onto the lower leaves. 0000199891 00000 n The fungus that causes gray leaf spot infects the corn plant during prolonged periods of warm weather between 75-80 degrees and at more than 90 percent relative humidity. 478 0 obj <> endobj 0000212000 00000 n We provide evidence for structural and detoxification-related mechanisms … �E�WBCВɈƤDt�ך)ᤗTE� Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight. 3. Gray leaf spot of corn. Symptoms are gray, elongated lesions 1 to 6 inches long (Figure 6). 0000213179 00000 n Mature lesions are tan to gray and expand linearly between leaf veins giving a rectangular shape. 0000067308 00000 n Numerous fields with significant levels of this disease have been reported in the past week. Is there a threshold for Northern corn leaf blight (or other diseases for that matter)? 0000216345 00000 n 0000214785 00000 n It is going to be extremely important to be out scouting, especially if you are trying to make a decision on a fungicide application. h�b```c``v��>� �� Gray leaf spot overwinters in and on corn debris left above and on the soil surface.