Distinguishing between these two types of lodging is important to making future crop decisions. Late season stalk rot features breakage of the stalk, usually in the lower internodes. Such plants have brown rind color and hollowed pith areas. Root lodging, on the other hand features intact stalk tissue with green rind colors. Root lodging can occur nearly any time during the season but when occurring near or before flowering the plants tend to recover somewhat with the stalk bending upwards. Root lodging requires strong winds and generally occurs when secondary root did not develop enough horizontal roots to avoid the lodging. Hybrids do vary in this tendency, having differences in root growth direction tendencies. Those with more vertical roots could be better for drought, being able to absorb water at greater soil depths, but have trouble in a highly organic soils especially those that hold the moisture towards the surface. Pest factors such as rootworms and nematodes also influence root lodging.
Stalk lodging due to stalk rot is affected by a different set of factors, as discussed in recent blogs. Leaf damage from disease or hail, cloudy weather, early season rain affecting kernel numbers are predisposing factors to stalk rot. Certainly, hybrids vary in reaction to these factors as well.
Excess moisture before flowering can be associated with both types of lodging in that root development could be underdeveloped and kernel numbers could be increased. Likewise, high plant density can cause reduced root development and less than optimum photosynthesis. Late season storms, with soaked soils favor more root lodging in hybrids with less developed brace roots whereas the moisture reduces the stresses associated with stalk rot.
Distinguishing between the two types of lodging can allow analysis of probable causes and planning for corrections for the next season.
About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.