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.
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Article Written by Stefan Vogrincic, Consultant, Grower2Grower
Article Edited by Marie Vogrincic, Editor, Grower2Grower