Evaluate the effect of Harpin protein (Messenger®) on fruit size in Forelle pear

The effectiveness of Harpin protein (Messenger) to enhance fruit size in ‘Forelle’ pear was evaluated over two seasons after non-statistical industry trials suggested a possible beneficial effect.

Messenger application, with or without Maxcell, had no effect on fruit size in the first season in a semi-commercial trial with 20 trees per plot randomised in 10 blocks.  Mist blower application of Messenger, with or without Maxcell, on one tree plots in the second season again had no effect on fruit size.

We conclude that Messenger has no effect on fruit size in ‘Forelle’ and would not recommend its use for this purpose.