Nutrient Deficiencies of Nemesia

By Dharmalingam S. Pitchay, Amy L. Williams, James L. Gibson, Brian E. Whipker, Paul V. Nelson, John M. Dole, Brenda R. Cleveland and F.R. Walls

Fertility monitoring and management for nemesia requires a balancing of the plant's needs. Growers must be aware and manage the root substrate pH, electrical conductivity (EC) and provide adequate, but not excessive, levels of all essential elements.
Nutrient deficiency descriptions are unavailable for most floriculture crops, yet growers must often make quick diagnoses. A research project initiated at North Carolina State University in Raleigh documented deficiency symptoms in Nemesia 'Blueberry Sachet' to assist growers. Using a plant diagnostic lab to identify the source of problems is still the best way to ensure accurate diagnoses, since many nutritional, physiological, insect and disease problems can mimic each other.

Disclainer: Growers should read and follow all label directions. Test the corrective procedure on a small number of plants prior to applying it to the entire crop.

Macronutrients · Micronutrients

Macronutrients
Photograph
Description
Possible Causes and Management
Nitrogen (N) (top)
Click for Larger Image Nitrogen-deficient plants are noticeably smaller compared to the control. The stem turns light green and lower leaves are begin to turn light green. There is less axillary shoot growth.
Low Substrate Nitrogen
Click for Larger Image Older, mature leaves show a light yellow-green appearance compared to control leaves.
Click for Larger Image Plants exhibit a downward curving of the leaves. Weak stems and an overall yellow-green color are characteristic of nitrogen deficiency.
Click for Larger Image Both root and shoot growth of nitrogen-deficient plants are significantly less than the control.
Click for Larger Image A comparison of nitrogen-deficient and control mature and young leaves. At the advanced stage, mature leaves are uniformly chlorotic and ultimately turn necrotic.
Phosphorus (P) (top)
Click for Larger Image
Phosphorus-deficient plants develop darker-green leaves.
Low Substrate Phosphorus
Click for Larger Image Necrosis is randomly occurring at the midvein, leaf tip and basal part of the leaf. Spotting quickly coalesces into complete leaf necrosis. Mature leaves shrivel rapidly.
Click for Larger Image Phosphorus-deficient leaves and a healthy leaf.
Potassium (K) (top)
Click for Larger Image
Potassium-deficient plants are more compact in appearance.
Low Substrate Potassium
Click for Larger Image Necrotic spots appear on recently mature leaves. As symptoms advance, the margins of the leaves begin to collapse as the necrotic spots fuse into larger necrotic patches.
Click for Larger Image Leaf necrosis begins with grayish-green irregular spots that turn into papery light brown to brown patches.
Calcium (Ca) (top)
Click for Larger Image Calcium-deficient plants are severely stunted compared to the control.
Low Substrate Calcium
Click for Larger Image As symptoms progress, leaves of the axillary shoot develop tip necrosis while the flower bud dies.
Click for Larger Image Necrotic spots appear at the bases of mature leaves. As deficiency symptoms become more severe, the necrotic spots turn dark brown to black.
Click for Larger Image A comparison of control flower stalks to calcium-deficient flower stalks. As the deficiency advances, flower stalks become necrotic, which affects flower bud development.
Magnesium (Mg) (top)
Click for Larger Image Magnesium-deficient plants develop tan-gray necrosis from the leaf tips moving toward the leaf base.
Low Substrate Magnesium
Click for Larger Image As symptoms progress, the majority of the mature leaves within the middle of the shoots have a light-tan, papery, necrotic burn.
Sulfur (S) (top)
Click for Larger Image Initial symptoms of sulfur deficiency include older, mature leaves remaining dark green, recently mature and young leaves turning light green and axillary shoots becoming greenish-yellow.
Low Substrate Sulfur
Click for Larger Image As symptoms progress, the overall size of the plant is severely stunted. The plant takes on a greenish-yellow color and the flowers fade from purple to light pink.
Click for Larger Image Advanced sulfur deficiency results in necrosis of the young and youngest leaves, which turn light brown and wither. Flower buds are light yellow-green. Flower size is reduced and bud abortion is apparent.
Micronutrients (top)
Photograph
Description
Possible Causes and Management
Boron (B) (top)
Click for Larger Image Growth of boron-deficient plants is stunted and compact. The terminal shoot has stopped growing.
Low Substrate Boron
Click for Larger Image Initial symptoms with boron deficiency show that the young leaves are yellow-green and are reduced in size. Bud abortion occurs on the newest shoots.
Click for Larger Image Around the growing point, a multitude of axillary shoots gives a deformed rosettelike appearance. Youngest leaves have yellow-green acropetal chlorosis with small, brown necrotic spots. Mature and recently mature leaves are thick, leathery and have a glossy, pale-green appearance.
Copper (Cu) (top)
Click for Larger Image Initial symptoms of copper deficiency include smaller plant growth and the upper two-thirds of the plant lack axillary shoot development.
Low Substrate Copper
Click for Larger Image Light-greenish-gray chlorosis of the basal and mid-regions of the leaf quickly turn to light-brown necrosis. Deformation of the leaf and dark-brown necrosis eventually affect the entire leaf.
Click for Larger Image Advanced symptoms lead to the collapse of the stem supporting the flower followed by flower necrosis and abortion.
Iron (Fe) (top)
Click for Larger Image Initial symptoms develop as yellow-green chlorosis on the younger leaves.
Low Substrate Iron
Click for Larger Image Progression of iron deficiency. Overall, the plant is light green. The young leaves develop a bright-yellow color. Eventually, the youngest leaves wither and develop light-tan necrosis.
Click for Larger Image A close-up of advanced iron deficiency.
Manganese (Mn) (top)
Click for Larger Image Manganese-deficient plants develop a uniform light green color on the youngest leaves.
Low Substrate Manganese
Click for Larger Image As symptoms advance, the recently mature leaves develop random necrotic spots within the leaf blade interior.
Click for Larger Image With advanced symptoms, the overall plant is paler green and the necrotic spots fuse together on the recently matured leaves to form light-tan papery patches.
Zinc (Zn) (top)
Click for Larger Image On the recently mature leaves, the central region of the leaf has brownish-green coloration.
Low Substrate Zinc
Click for Larger Image Chlorotic regions on young leaves turn light green. Flowers have fallen off and there is an absence of new flower growth.
Click for Larger Image Young leaves have a yellow-green tip chlorosis that turns necrotic. Sepal tips on some flowers are necrotic and brown.

Amy L. Williams, Dharmalingam S. Pitchay and James L. Gibson are graduate research assistants, Paul V. Nelson is professor in floriculture, John Dole is associate professor in floriculture and Brian E. Whipker is assistant professor in floriculture at at North Carolina State University, Department of Horticultural Science, Box 7609, Raleigh, NC 27695-7609. Bobby Walls and Brenda Cleveland are NCDA Agronomic Division Members NCDA&CS Agronomic Division, 4300 Reedy Creek Road Raleigh, NC 27607-6465. We would like to thank Paul Ecke Ranch, Encinitas, CA., Tom Abramowski, Rockwell Farms, Rockwell, N.C., and the North Carolina Commercial Flower Growers' for grant support, Paul Ecke Ranch for supplying the cuttings and Smithers-Oasis for supplying the propagation medium.

Disclainer: Growers should read and follow all label directions. Test the corrective procedure on a small number of plants prior to applying it to the entire crop.

© Copyright NC State University, 2002

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