Tipburn in lettuce has been a problem since the first farmer planted lettuce. Any grower will at some stage have the problem occur to some extent on his farm during warmer periods. The classic tipburn symptom is necrosis of the tips of rapidly growing young leaves. Tipburn is visible externally on butterhead and cos types, [...]
It is often quite difficult to identify a deficiency or toxicity symptom in the field because they never really occur as a single element deficiency or toxicity. Each of the elements are inter dependent and they influence each other within certain ratio’s. One would find for instance that phosphorus toxicity, is expressed as either a [...]
Physiological disorders caused by low temperatures Low temperatures injury only occurs with fruit that are in storage (either in transit or in storage rooms). Small circular pits each 3-9mm in diameter and up to 1 mm deep appear. They can coalesce to form large irregular sunken areas. The minimum temperature that cucumber fruits should be [...]
Growth cracks symptoms There are two types of cracking found on tomato fruit. Concentric cracking are cracks that vary in depth and size found in circles around the stem and radial cracking which are cracks running from the stem to the blossom end of the fruit. Concentric growth cracks on tomatoes Cause of [...]
Cat-face tomato fruit Symptoms Fruits have a long scar at the blossom end that extends inwards and renders the fruit unmarketable and disfigured (abnormal). There are bands of scar tissue between swellings and cavities that extend deep into the fruit body. Most of these cat-face fruit ripen unevenly. Due to the scar tissue, cat-face fruit cannot [...]
Hollow fruit description Hollow fruit, also called puffy fruit or boxy fruit are angular in shape instead of round, however one should be careful since some tomato fruit are genetically more hollow or angular than other. The first signs inside the fruit are the lack of “gel” surrounding the seed, leaving a gap between the placental [...]
Severe zippering with secondary scarring of the tomato skin. Zippering symptoms Zippering are thin scars running from the top of the shoulder of the fruit down the length to the blossom end. These longitudinal scars have small transverse scars along it, which resemble a “zip” (thus the name). More than one of these [...]
Blossom drop Symptoms Blossom drop (flower buds abscise) occurs prior to anthesis under stress conditions. The early indications of blossom drop are the yellowing of the swollen area which joins the flower to its stem. After the flower has fallen or abscised, a small dried out stub is left over. Which is quite disheartening since there [...]
Blossom-end-rot (BER) Symptoms This physiological disorder looks like a typical fruit disease. The symptoms generally occur at the blossom-end of the fruit and begins with a light tan, water soaked lesions, which when enlarged, turn black and leathery. As in tomatoes and watermelons, blossom-end-rot usually appears when the fruit is about half-grown The affected areas first [...]
