[CANUFNET] Aphid thresholds

[Ian Wilson]

Ken,

If you want to go with something that's more scientific, you could try monitoring honeydew droplets using the methodology of Steve Dreistadt, see this reference:
http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2237&Type=2

I've used this technique before and it works well, but it's more time consuming because you have to hang out monitoring cards and then go collect them again.  In practice, I think many cities just rely mostly on complaints - in part because it's less time consuming than having a systematic monitoring program, but also because tolerance thresholds vary widely.  Even within the same city, some neighborhoods may tolerate a lot more honeydew than other neighbourhoods.

Ian Wilson
City of Kelowna

From: CANUFNET [mailto:canufnet-bounces at list.web.net] On Behalf Of Ken Snowden
Sent: Thursday, October 03, 2013 9:32 AM
To: canufnet at list.web.net
Subject: [CANUFNET] Aphid thresholds

Good morning all,

After a trying year with a prolonged drought, we saw a dramatic increase in calls regarding aphids and issues with the accompanying honeydew.  We are seeking input on thresholds for aphid damage on street trees to develop a baseline for  our IPM program.  I have received information from a few neighboring cities, and have found varying responses that range from budget availability to number of phone calls.  Most online information I find tends to lean towards agricultural crops rather than urban forestry.  We want to help educate our residents and spray only as a last resort but need a well-founded number to use as a baseline.  City of Surrey responded that they use number of aphids per leaf...what are other municipalities using?

Your help would be appreciated,

Ken Snowden
Arbourist II
City of Abbotsford Parks, Recreation and Culture
Phone: (604) 853 5485 ext. 5886
Cell: (604) 626 3945
Email: ksnowden at abbotsford.ca<mailto:ksnowden at abbotsford.ca>

'To exist as a nation, to prosper as a state, to live as a people, we  must have trees'
Theodore Roosevelt


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