It has to do with winter weather. AS part of their life cycle they need specific weather. A cold period follower by humid spring. They hatch under a change from cold weather to time with initiation of growth of new foliage in iris in spring.
Without these specific climate conditions they don't survive. They evolved with iris. Much the same way there is a southern limit for survival of iris.
Chuck
-----Original Message-----
From: D Perry-Seandel Iris Gardens seandelirises@yahoo.com [iris-species] <iris-species@yahoogroups.com>
To: Sean Zera zera@umich.edu [iris-species] <iris-species@yahoogroups.com>
Sent: Tue, Mar 10, 2020 9:11 pm
Subject: Re: [iris-species] iris borer, Iris tectorum
Thank you for the map, Sean. Could it be the borers are not happy with the hot summers and lack of long cold periods that are typical with the deep South? Maybe lack of humidity for the western states?
Dell PerrySeandel Iris Gardens
800 Purcell Dr
Plano, TX 75025
972-816-3418
seandelirises@yahoo.com
On Tuesday, March 10, 2020, 07:45:32 PM CDT, Sean Zera zera@umich.edu [iris-species] <iris-species@yahoogroups.com> wrote:
Here's a (very) rough map of the range of iris borer (Macronoctua onusta): https://bugguide.net/node/view/11123/data. It's based on user-submitted photos so not complete (obviously they occur in Michigan), but gives the general idea. The borer is a native species, with Iris versicolor and I. virginica (and I. hookeri?) as its natural hosts. Since it doesn't occur in the Deep South even though suitable native iris hosts do, there must be some other reason that it's a northern species.
Sean Z
On Tue, Mar 10, 2020 at 4:52 PM Shaub Dunkley sdunkley1@bellsouth.net [iris-species] <iris-species@yahoogroups.com> wrote:
I've heard that too and also interested about the line. TBS grow with less enthusiasm as you go deeper in the hot & humid Southeast. At some point people stop growing them at all, such as Florida and coastal areas along the gulf. Less TBS might explain a failure of borers to establish range?
Shaub Dunkley, Z7a NC mountains
On 3/10/2020 11:45 AM, D Perry-Seandel Iris Gardens seandelirises@yahoo.com [iris-species] wrote:
Is there a North/South line also? It seems the people who have them are not in the deep South or Southwest.
Dell Perry Seandel Iris Gardens
800 Purcell Dr
Plano, TX 75025
972-816-3418
seandelirises@yahoo.com
On Tuesday, March 10, 2020, 10:04:45 AM CDT, gary white in2iris@yahoo.com [iris-species] <iris-species@yahoogroups.com> wrote:
The iris borer does indeed exist west of the Mississippi River. It is also found west of the Missouri River. I am in Lincoln, Nebraska (southeast Nebraska) and the borer is very much alive and thriving here. It does disappear west of us in central Nebraska. It does not exist in western Nebraska, and does not get to the Rockies. The Mississippi forms the border between Illinois and Iowa, and Nebraska is a few hundred miles west of the Mississippi.
Gary White
On Monday, March 9, 2020, 05:56:09 PM CDT, Betty G bettyg@cybermesa.com [iris-species] <iris-species@yahoogroups.com> wrote:
Can tbose of you who responded to this post, please indicate where in the US you are growing irises? I have heard that iris borers do not exist west of the Mississippi. Can any of you let me know if it has crossed the Mississippi? Betty
On 3/7/2020 5:33 PM, dkramb dkramb@badbear.com [iris-species] wrote:
Does anyone know if Iris tectorum is susceptible to iris borer? And if
so, like to what degree compared to beardeds?
Thanks,
Dennis in Cincinnati
