Products containing harpin (PreTect, ProAct, Messenger) have various effects on plants improving the quality of fruit.
- They also stimulate the defense system of the plant and increase resistance to disease.
- Such treatments need to be applied pre-bloom to stimulate resistance to primary blossom infection.
- The effects tend to be short lived so repeated applications are needed.
- PreTect is available in the UK and its effects on fireblight are currently under evaluation.
- Trial results in the USA have been promising.