LEAF CURL

Leaf curl is a general term for the curling of plant leaves, caused by pest, disease or chemical means.  Peach leaf curl is a very common example - with peach leaves becoming curled and distorted due to fungal disease or sometimes pest attacks. In this case, prevention is always better than 'trying to' cure! Spraying with a copper fungicide prior to leaf break helps.

  Potatoes are also prone to leaf roll due to virus attack.  Aphids (greenfly, blackfly), can also cause leaf curl, (e.g. plum leaf curling aphid).

Leaf scorch however - identified by a typical 'scorched' appearance - can indicate a plant mineral deficiency, or a reaction to chemical sprays or even excessive sunlight in an un-shaded greenhouse.