Although there are several races of the fungus that cause disease, Race 3 most likely causes the greatest impact in New York State. Lesions from Northern corn leaf blight in no-till corn in corn-soybean rotations in east central Nebraska. This pathogen was not seen as an economic threat until the mid 1970’s when no-till and other conservation tillage practices were becoming more prevalent. The market is segmented into seed corn, field corn and specialty corns (e.g., high oil, high amylose and white corn). Applications made too early may mean their protection has worn off before diseases reach critical levels. 0000008410 00000 n 0000066476 00000 n Gray leaf spot is also active in the lower to mid canopy at multiple sites across the state. ��w��|(_��S��b~pFFTmzA]*A#����g}՗R"ѷ�"�7&H�7�����B����s��q� L�I�㾶j���(g|���4]���'% ;J�0(Ry?���K1,GХ;A_������I.+r�X��5�Z��߻F��b����A~q�����~Q�g��lF��G�����8��y�]g�����vz���Y��|��H-�E~���j�����g��Ux�s��a6 Gray leaf spot (GLS) is a foliar disease of corn caused by the fungus Cercospora zeae-maydis. 0000009257 00000 n Albert E. Rossi, Plant Disease Research Laboratory, USDA-ARS, Frederick, MD. Gray Leaf Spot – Corn. 0000212072 00000 n 0000195934 00000 n 0000005945 00000 n Each disease has an economic threshold. 0000199891 00000 n 0000213179 00000 n 0000004619 00000 n High residue farming allows the gray leaf spot pathogen to build up in corn residue over time. Disease Facts Gray leaf spot is caused by the fungus Cercospora zeae-maydis.. Epidemics of gray leaf spot have been observed in New York State in the Southern Tier and the Hudson River Valley. It is going to be extremely important to be out scouting, especially if you are trying to make a decision on a fungicide application. Typical lesions are rectangular with straight edges. 0000197137 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. 478 0 obj <> endobj Is there a threshold for Northern corn leaf blight (or other diseases for that matter)? 0000000016 00000 n 0000003303 00000 n %PDF-1.6 %���� Gray Leaf Spot Now that harvest is completed, it is time to start thinking about next year and making seed corn selection decisions. One of the most common foliar corn diseases in Tennessee is gray leaf spot (caused by a fungus – Cercospora zea-maydis), especially in continuous corn fields (see Images 1 and 2). �r�O��$�.�#��w���3�OX�{{!�;I�O(Yda��\���i��a꫕S_0h�����ݛ�� 2��u�%�I�y���:j�z�ܡ������,+����W�r>����z���X�L8?�O��)O���1��w�keSr!��~��dCo �yq��h���� .��>����sh�t:�&�&ƠaUCJ$F���A/�G�_7����˫�Y���%�p�^V��ò������ 0000213580 00000 n %PDF-1.6 %���� 0000214633 00000 n much impact gray leaf spot will have on corn production. 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. Warmer weather favors gray leaf spot, while cooler weather favors northern corn leaf blight. Purdue University experts are seeing gray leaf spot lesions on some susceptible corn hybrids in Indiana, and they are encouraging farmers to scout fields to assess the level of disease. Northern corn leaf blight prefers cooler temperatures through grain fill. 0000213877 00000 n 0000159528 00000 n Smith said gray leaf spot and tar spot were major 2020 soybean diseases, with both of them starting early in the season and moving slowly due to hot temperatures. 0000215053 00000 n 0000213308 00000 n Plant Dis. 587 0 obj <>stream 0000194833 00000 n 0000004741 00000 n Yield-impacting diseases you can see at V10 to V12 include physoderma, northern corn leaf blight and gray leaf spot. 0000212390 00000 n Weather. All corn hybrids and inbreds are susceptible to gray leaf spot in varying degrees. While doing this, it is important to look back at this past year’s performance and evaluate how each product responded to the environmental conditions such as disease. Click image to enlarge. 0000212163 00000 n 0000212832 00000 n Make sure to properly identify the disease. This article is in the public domain and not copyrightable. Rainy and/or humid weather generally is most favorable to gray leaf spot. 0000216345 00000 n Figure 3. 0000214910 00000 n 0000213365 00000 n Two later-season diseases that can highly affect corn are tar spot and southern rust. 0000212446 00000 n Gray leaf spot (GLS) can be one of the most significant diseases on corn in the Midwest. 0000196607 00000 n Symptoms are gray, elongated lesions 1 to 6 inches long (Figure 6). 0000066745 00000 n Disease Facts Gray leaf spot is caused by the fungus Cercospora zeae-maydis.. Epidemics of gray leaf spot have been observed in New York State in the Southern Tier and the Hudson River Valley. x�bbRa`b``Ń3� ���ţ�1�a� -�� There are five known races of this fungus. Author Summary Gray leaf spot (GLS), a necrotrophic, foliar fungal disease of maize, contributes to maize yield losses worldwide. 2:26. 0000006579 00000 n 0000211370 00000 n The fungal disease causes lesions that lead to yellowing leaf tissue and reduced photosynthetic activity, causing shortened yield potential through smaller ears with fewer kernels. 0000197164 00000 n The disease is first detectable as small grayish lesions on the lower leaves, which run parallel to the veins. It is the most serious foliar disease of corn, not only in Kansas, but in the entire north central production region.

gray leaf spot corn threshold

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