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

Photograph	Description	Possible Causes and Management
Nitrogen (N) (top)
	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
	Older, mature leaves show a light yellow-green appearance compared to control leaves.
	Plants exhibit a downward curving of the leaves. Weak stems and an overall yellow-green color are characteristic of nitrogen deficiency.
	Both root and shoot growth of nitrogen-deficient plants are significantly less than the control.
	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)
	Phosphorus-deficient plants develop darker-green leaves.	Low Substrate Phosphorus
	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.
	Phosphorus-deficient leaves and a healthy leaf.
Potassium (K) (top)
	Potassium-deficient plants are more compact in appearance.	Low Substrate Potassium
	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.
	Leaf necrosis begins with grayish-green irregular spots that turn into papery light brown to brown patches.
Calcium (Ca) (top)
	Calcium-deficient plants are severely stunted compared to the control.	Low Substrate Calcium
	As symptoms progress, leaves of the axillary shoot develop tip necrosis while the flower bud dies.
	Necrotic spots appear at the bases of mature leaves. As deficiency symptoms become more severe, the necrotic spots turn dark brown to black.
	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)
	Magnesium-deficient plants develop tan-gray necrosis from the leaf tips moving toward the leaf base.	Low Substrate Magnesium
	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)
	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
	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.
	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.

Photograph	Description	Possible Causes and Management
Boron (B) (top)
	Growth of boron-deficient plants is stunted and compact. The terminal shoot has stopped growing.	Low Substrate Boron
	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.
	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)
	Initial symptoms of copper deficiency include smaller plant growth and the upper two-thirds of the plant lack axillary shoot development.	Low Substrate Copper
	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.
	Advanced symptoms lead to the collapse of the stem supporting the flower followed by flower necrosis and abortion.
Iron (Fe) (top)
	Initial symptoms develop as yellow-green chlorosis on the younger leaves.	Low Substrate Iron
	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.
	A close-up of advanced iron deficiency.
Manganese (Mn) (top)
	Manganese-deficient plants develop a uniform light green color on the youngest leaves.	Low Substrate Manganese
	As symptoms advance, the recently mature leaves develop random necrotic spots within the leaf blade interior.
	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)
	On the recently mature leaves, the central region of the leaf has brownish-green coloration.	Low Substrate Zinc
	Chlorotic regions on young leaves turn light green. Flowers have fallen off and there is an absence of new flower growth.
	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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