Final diagnosis


Marginal necrosis (tipburn)

Marginal necrosis can affect lower leaves as is the case on this lettuce.  <b> Marginal necrosis </b>
Many leaves of this lettuce show a dryness limited to the edge of the blade.  <b> Dry marginal necrosis ("Tip burn") </b>
Dark brown to brown spots of dry consistency dot the edges of the lower leaf blades;  it is found that the leaf blade is also chlorotic in this area.  <b> Marginal necrosis </b>
The lamina may sometimes be completely bordered by a slightly chlorotic brown necrotic change.  <b> Marginal necrosis </b>
Tipburn1
Tipburn2
<b> Marginal necrosis </b> (tip burn) on this salad plant
<b> Marginal necrosis </b> (tip burn) clearly visible on the edges of the leaves of this salad
<b> Marginal necrosis </b> can result in the formation of large fringes of necrotic tissue along the edge of the limbus;  these will dry out if weather conditions allow.
There are differences in sensitivity between types of salad.  Varieties with thin and very cut leaves are particularly susceptible.  <b> Marginal necrosis </b>
The altered tissues constitute nutritive bases very favorable to the establishment of <i> Botrytis cinerea </i> and to a lesser degree of <i> Sclerotinia sclerotiorum </i>.  <b> Marginal necrosis and <i> Botrytis cinerea </i> </b>
Tipburn4
Tipburn5
Tipburn6