National Corn Handbook. For example, an early-maturing product may produce fewer leaves or develop through growth stages faster then a slower paced late-maturing product. Iowa State University Extension Preview.

However, in South Dakota the most widely used system is the Iowa State classification approach (Ritchie et al., 1993). Corn ear abnormalities have been noted the past few years. Today managing your corn crop requires knowledge of the different growth stages of the corn plant. CORN GROWTH STAGES. orn growth stages are based on the leaf collar method, where fully emerged leaves (leaf collar visible) are used to stage vegetative development. Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications.Each week throughout the growing season I will discuss the various corn growth stages and management issue at each stage. Abstract. By understanding how corn grows and develops, producers can more confidently assess crop damage, estimate if it will recover and apply herbicides and other crop inputs at the best time. Kernel development proceeds through several distinct stages that were originally described by Hanway (1971) and most recently by Abendroth et al. A corn plant’s growth stage is either part of the vegetative (V) or reproductive (R) periods. Counting the number of leaves would seem to be a simple way to document corn development, but folks still tend to become confused over this simple strategy. Includes numerous photos … PDF How a corn plant develops001.pdf File Size:9MB. Key growth stages and brief descriptions are listed in Table 1. As with leaf staging protocols, the kernel growth stage for an entire field is defined when at least 50% of the plants in a field have reached that stage. Corn plants all have the same general development steps; however, the time between stages and the total number of leaves on a plant can vary. The (V) stages are designated numerically as V1, V2, V3, etc. Corn Field Guide Lori Abendroth Iowa State University, labend@iastate.edu Roger Elmore Iowa State University Robert G. Hartzler Iowa State University, hartzler@iastate.edu ... at this stage compared to other growth stages. R2–R3: Stress causes kernel abortion starting from the ear tip. Corn Growth Stages .
(2011).

Tracing back the information on various field calls often pointed to a misunderstanding of proper growth stages when making post-emergence herbicide applications in addition to pre-tassel fungicide and insecticide applications. It is important to accurately growth stage corn particularly if you are planning to apply a post-emergence herbicide because each herbicide has restriction based on corn growth stage or plant height (Table 1). Because it is difficult to transport corn plants from the field to that doorframe to measure their growth, agronomists developed other means to measure the phenology or development of corn. through V(n) where (n) represents the number of leaves with visible collars. (1986) How a corn plant develops, 1986. This system divides corn growth and development into vegetative (V) and reproductive (R) stages (Table 5.1). A number of classification approaches can be used to identify a corn plant’s growth stage. Herbicide applications made past the recommended application stages can result in significant crop injury. This publication is designed to aid those involved in corn production to more fully understand how the corn plant develops. Corn Growing Degree Days Corn Maturity (Days) GDD 85 to 100 2100 – 2400 101 to 130 2400 – 2800 131 to 145 2900 – 3200 Growth Stage GDD V2 200 V6 475 V12 870 VT 1135 R1 1400 R6 2700 GDD Requirements of a 2700 GDD Hybrid From NCH-40 Growing Season Characteristics and Requirements in the Corn Belt. Corn Growth Stages This identification system divides plant development into vegetative (V) and reproductive (R) stages.

Severity of stress will determine the extent of For more detail on staging corn, consult Corn Growth and Development from Iowa State University Extension.