HortFACT - Visual Symptoms Of Nutrient Disorders In Tamarillos
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Photo 1a (19K) | 
Photo 1b (25K) |
Potassium deficiency severely restricts the growth of tamarillos resulting in the development of small leaves. Visual symptoms first appear on the oldest leaves with the development of a distinctive brown discoloration of the main veins (Photo 1a). The tissue between the main veins is usually ridged giving a corrugated effect to the leaf (Photo 1b). The leaves are also darker green than normal.
The concentration of potassium in the leaves showing symptoms was 0.7% dry matter.
Photo 2a (19K) |
Phosphorus deficiency resulted in a severe reduction in the growth of tamarillos without the development of obvious visible leaf symptoms (Photo 2a). The size of the leaves were particularly affected.
The concentration of phosphorus in the leaves of the severely deficient plant was 0.13% dry matter.
Photo 3a (15K) | 
Photo 3b (21K) | 
Photo 3c (18K) |
Symptoms of zinc deficiency develop first on the oldest leaves with the appearance of a yellow-green interveinal and marginal chlorosis which is highlighted by bands of dark green tissue remaining on either side of the main veins (Photo 3a). As the deficiency becomes more intense, necrotic areas may develop where the chlorosis is most severe. The necrosis is usually more prominent at the tip rather than at the base of the leaf (Photo 3b). Recently matured leaves may also develop an interveinal chlorosis as well as being severely cupped downwards, while the youngest leaves on the plant remain healthy (Photo 3c).
The concentration of zinc in the leaves showing severe signs of the deficiency was 8 ppm.
Photo 4a (17K) |
Symptoms of copper deficiency include the development of a faint marginal yellow-green chlorosis towards the tip of the oldest leaves (Photo 4a). The youngest leaves remain green and healthy.
The concentration of copper in the leaves showing symptoms was 2 ppm.
Photo 5a (15K) | 
Photo 5b (21K) | 
Photo 5c (17K) |
The first sign of molybdenum deficiency is the development of small necrotic lesions on the petioles and stem of the lower half of the plant (Photo 5a). The lesions towards the base of the stem develop into corky zones (Photo 5b)). Symptoms on affected petioles, exhibit larger necrotic lesions but less corky tissue (Photos 5a and c). There were no obvious visual symptoms on the leaf blades.
The concentration of molybdenum in the leaves with affected petioles ranged from 0.01 to 0.05 ppm. The concentration in healthy plants usually range from 0.2 to 1.0 ppm (Table 3).
TOXICITIES
Photo 6a (16K) | 
Photo 6b (20K) |
The oldest leaves are affected first by excess nitrogen. Symptoms include the development of an irregular interveinal chlorosis, with the regions of paler tissue beside the main veins (Photo 6a). Generally there is a zone of green healthy tissue at the point of attachment of the petiole. Continued exposure to excess nitrogen results in premature defoliation of the plant. The youngest leaves are least affected although they may be cupped downwards (Photo 6b). Excess nitrogen can greatly reduce the growth of tamarillos.
The concentration of nitrogen in the leaves showing symptoms was in excess of 6% dry matter.
Photo 7a (20K) | 
Photo 7b (26K) | 
Photo 7c (21K) |
Symptoms of excess phosphorus include the development of a faint chlorosis over the older leaves. Shortly after the appearance of this chlorosis, pale brown necrotic spots develop mainly in the midrib region in the base of the leaf (Photos 7a and b). With time the symptoms spread progressively to the younger leaves, resulting in a faint interveinal chlorosis. It is usual to find all affected leaves to be cupped downwards (Photo 7c).
The concentration of phosphorus in the leaves showing symptoms was in excess of 3% dry matter.
Photo 8a (22K) | 
Photo 8b (19K) | 
Photo 8c (23K) |
Excess potassium results in the appearance of a distinctive pattern of marginal and interveinal chlorosis on the oldest leaves (Photo 8a). A wide zone of healthy green tissue usually surrounds the main veins on the affected leaves (Photo 8b). Tissue between the main veins may also be ridged upwards giving a corrugated effect to the leaf (Photo 8c). As the symptoms develop further, irregular necrotic spots appear on the chlorotic tissue (Photo 8a). Eventually the worst affected leaves wither and are shed from the plant.
The concentration of potassium in the leaves showing the symptoms was in excess of 8% of the dry matter.
Photo 9a (27K) | 
Photo 9b (34K) | 
Photo 9c (30K) |
Boron toxicity severely limits growth. Visual symptoms first appear on the oldest leaves with the development of a pale green interveinal chlorosis which eventually affects all leaves (Photo 9a). As the chlorosis becomes more extensive, small brown necrotic patches develop between the minor veins and along the leaf margins. These patches increase in size and eventually coalesce to form a continuous zone of dead tissue between the major veins (Photo 9b). All leaves show a pronounced downward cupping, including the youngest leaves which show no other symptoms except a faint chlorosis (Photo 9c).
The concentration of boron in the leaves showing symptoms was in excess of 1200 ppm dry matter.