Corn Diagnostic Guide - Tasseling to Maturity
|
Appearance |
Symptoms |
Possible Cause(s) |
|---|---|---|
| Silking impaired | Delayed silking or failure to silk |
|
| Silks clipped off |
| |
| Tassels malformed | Tassels fail to emerge |
|
| Tassels and upper stalk and foliage bleached, premature drying | ||
| Tassels develop as a mass of leaves |
| |
| Leafy condition in the tassels |
| |
| Plants discolored | Yellowing of leaf margins, beginning at tips; affected tissue later turns brown and dies | |
| Irregular, purple-brown spots or blotches on sheaths |
| |
| Stalks malformed and/or broken | Lower stalk internodes easily compressed; stalks may lodge (break over) - (see Stalk Rot) |
|
| Lower internodes easily compressed; black linear streaks on stalk surface | ||
| Plants lodge, stalk may break |
| |
| Premature death of all or some parts of plants | Sudden death of entire plant |
|
| Extensive areas of leaf tissue die prematurely resulting in leaf drying |
| |
| Top kill - premature death of all or portion of plants above ears. | ||
| Leaf tissue removed | Ragged holes in the leaves |
|
| Shredding, tearing of leaves |
| |
| Small, irregular holes in leaves |
| |
| Large irregular holes in leaves |
| |
| Plants discolored or stunted | Slight to severe stunting; yellowing and sometimes reddening of foliage |
|
| Lesions on plants | Irregularly- or wavy-margined, pale green to yellow or pale brown streaks | |
| Tan leaf lesions with parallel sides or spindle shaped and with buff to brown borders |
| |
| Long, elliptical, gray-green or tan lesions | ||
| Small (1/16 to 3/8 inch) circular to oval lesions | ||
| Elongated irregular brown water-soaked leaf stripes or spots on lower leaves |
| |
| Oval, circular or rectangular lesions on leaves |
| |
| Circular to oval lesions, brown centers with yellow to orange borders |
| |
| Numerous brown to black pustules on any above ground part, especially the leaves; leaves dry out | ||
| Damage to ears | Dark 'bruises' on husks |
|
| Large chunks removed from husks and ears; kernels eaten off |
| |
| Tunneling or chewing feeding damage on kernels |
| |
| Ears break over and/or drop to ground |
| |
| Ears or kernels malformed | Ears not filled, partially filled, or smaller than normal ('nubbins') |
|
| Excessive ear shoots which are leafy and barren |
| |
| Soft, glistening galls on the ear, later black and powdery | ||
| Ears twisted with irregular kernel rows and imperfectly developed ear tips |
| |
| Red streaking of seed coats; most common at ear tip |
| |
| Ears rot or are moldy | Individual kernels or scattered groups of kernels with pinkish mold | |
| Pink to red mold growing through kernels from the silk end |
| |
| Powdery, green or blue-green mold on and between kernels, usually at ear tips |
| |
| Husks bleached; white mold between kernels |
Planting to Emergence || Emergence to 8-10 Leaves || 8-10 Leaves to Tasseling || Tasseling to Maturity || Corn Diagnostic Guide
Adapted by James H. Hill, Iowa State University - Hancock County Extension Education Director, from information prepared by Dale M. Studt, retired ISU Extension Crop Production Specialist.
