Trials offer hope of "benign" long-term control of leaf miner

Trials of leaf-sprayed biological stimulants suggest they could have a role in managing the damaging horse chestnut leaf miner (Cameraria ohridella).

Image: James Bowe (CC BY 2.0)
Image: James Bowe (CC BY 2.0)

Dr Glynn Percival, manager of the Bartlett Tree Research Laboratory at the University of Reading, and Berkshire arboricultural consultant Simon Holmes, assessed the efficacy of three "systemic inducing agents" (SIRs) and a conventional insecticide, deltamethrin, against the pest, which established itself in the UK's horse chestnut trees in 2008.

Percival had earlier assessed the three foliar treatments - Messenger (active substance harpin protein), Phoenix (potassium phosphite) and Rigel (salicylic acid derivative) - to control apple scab.

"The synthetic insecticide deltamethrin provided the greatest degree of HCLM control with two foliar sprays providing 100 per cent HCLM control," they found.

"Efficacy of SIR inducing agents based on reduction of HCLM mines per leaf after three sprays averaged across both the 2010 and 2011 growing seasons was in the order potassium phosphite > salicylic acid derivative > harpin protein > water control."

They concluded: "Commercially available SIR inducing agents exist that provide potentially acceptable degrees of HCLM control provided at least two sprays are applied during a growing season."

Percival told HW: "I think the SIRs offer a more environmentally benign means of pest control, and the other advantage is that they can be applied as a root drench."

The laboratory has also funded a PhD student to look at SIR in combination with for example bio-control agents, he added.

"I believe with time a non-chemical control package can be developed that will offer long-lasting insect control. After all when we go abroad a single injection against diphtheria etc., lasts 10 years, [whereas] use of antibiotics lasts only as long as the course of the tablets - that's how I compare SIRs against conventional spray. Once the insecticide wears off the tree becomes re-infested."

The results are published in Urban Forestry & Urban Greening.


Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

Pest & Disease Factsheet - Moles

Pest & Disease Factsheet - Moles

Protect against root damage caused by tunnelling.

Pest & Disease Factsheet - Plane anthracnose

Pest & Disease Factsheet - Plane anthracnose

Take action to avoid this disease causing dieback and rendering plants unsaleable

Pest and disease management - Phytophthora root rots

Pest and disease management - Phytophthora root rots

Treatments to defend against these pathogens should be used alongside good hygiene practice.


Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Latest Plant Health Alerts