Abstract
Visual symptoms of N, P, K, Ca, Mg, Mn, Fe and B deficiencies were induced in Caladium × hortulanum Birdsey ‘Candidum’. Characteristic symptoms were photographed and described and a key summarizing these symptoms follows:
a. Chlorosis or necrosis not expressed;
b. Petioles brittle and/or leaves orbicular.........................................................................................................................B
bb. Plants grow slowly, but have no other symptoms......................................................................................................P
bbb. Rust colored spots on underside of leaf near petiole, spots may become “windows” (only the cuticle and epidermal layer remain)................................................................................................................................................. Ca
aa. Chlorosis and/or necrosis expressed;
b. Chlorosis primary symptom.
c. Interveinal and veinal chlorosis
d. Chlorosis evident as leaves unfurl............................................................................................................... Mn
dd. Chlorosis not evident as leaves unfurl, older leaf blades and veins may turn bright yellow as they abscise................................................................................................................................................................... N
cc. Interveinal chlorosis...................................................................................................................................................Fe
bb. Both chlorosis and necrosis expressed.
c. Interveinal chlorosis developing into necrotic spots, leaves turn bright yellow (except basal veins remain green) as they abscise............................................................................................................................................. Mg
cc. Necrotic specks (@ 1 mm) near veins, general chlorosis............................................................................... Mn
bbb. Necrosis primary symptom.
c. Necrotic lesions (2–5 cm) on leaf apex and distal m argin.................................................................................K
cc. Marginal necrosis.
d. Necrosis spreads toward the center of the leaf, margins dry but the leaf blade around petiole remains intact.......................................................................................................................................................................K
dd. Interveinal rust colored, blotchy areas.........................................................................................................Ca