What a mess they can make and quickly

A very topical subject matter at present, and I know it may seem as though I’m repeating the theme of articles, is caterpillars. I have never seen as much damage, caused by caterpillars, to cucumber plants than what I have witnessed this season.  They are a major pain and unfortunately can be found on all of the main greenhouse crops. The rate at which they have caused damage is alarming.

On Friday I alerted a grower to the damage I found.  The damage was centred at the head of the plant.  If it wasn’t for the small holes I may not have noticed it.  When I looked hard, I saw tiny caterpillars hiding in the head.  My advice to the grower was to apply a BT spray that afternoon.  When I returned to the property, the following week, I noticed there was a noticeable decrease in the amount of damage and there were dead caterpillars, but there was also a small number still alive.  I advised to spray a further application this week to keep on top of the caterpillars.  I have read that the interval between applications for a BT is 3-14 days, but please check with your supplier first to confirm this.  

Please remember that a BT (Bacillus Thuringiensis) is a naturally occurring bacteria, so if you wish for this to work then ideally do not mix it with other combinations and give it a few days to work before applying anything that might reduce its effectiveness. 

Look closely

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Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower