Re: CULT: borer hatch
- Subject: Re: [iris-talk] CULT: borer hatch
- From: G*
- Date: Tue, 29 Feb 2000 09:48:55 -0500
From: Gullo <tgf@frontiernet.net>
Hi Carolyn,
This far north, I don't think 1 or 2 stray 70 + degree days are enough to prompt the hatching of borer eggs. The weather is just too variable for that to make sense from
a survival standpoint for the borers unless they hide out in the soil until more consistently warm weather comes along, which still could be a couple of months off for us.
Which is not to say that temperature is not somehow involved in the process. I've heard the degree days idea floated around or perhaps it has something to do with nighttime
minimums. Don't know for sure. It would be nice to have some sort of formula to be able to calculate the precise timing of the hatch, but I don't know if that will ever be
possible ( probably just too many variables ). I've made a habit of tracking the appearance of the little troublemakers in my garden so I have a general time frame as to when
to expect them. Depending on how early or late the spring is progressing alters when I begin spraying with Murphy's Oil Soap.
Here is a listing of the first borer sightings for the past 6 years.
5-9-94
5-7-95
5-16-96
5-10-97
4-23-98 ( spring warmth was very early )
4-28-99
Almost a full months swing. Need to start spraying before the borers hatch, though even late spraying is helpful to catch later hatching eggs. The World of Irises has
some interesting things to say about the borer. One idea is that not only do eggs overwinter, but also that pupae can as well. I think I've read elsewhere that it is even
possible for adults to overwinter as well. Another interesting ( alarming is probably a better word ) observation from the book is the fact that the young borer larvae can
climb to the tops of nearby leaves and then release a thin thread of silk and be blown to surrounding iris plants. The stuff nightmares are made of.
Anyway I think we are 1.5 to 2 months away from BHD this far north. And I hope none of the little critters show up for the party. Wishing everyone borer free irising.
Have a nice one.
Michael Gullo
West Walworth, NY
zone 6
Carolyn Schaffner wrote:
> From: Carolyn Schaffner <drsnooks@buffnet.net>
>
> >I've heard several theories about the little creatures that >share our love of irises ....... my favorite is the one
> >that says they hatch on the first day that the temperature >reaches 72 degrees Fahrenheit. It's not a favorite because >I'm convinced it is more right than the others, but
> >instead because it lends some certainty and definition to
> >the season; it creates sort of a holiday.
>
> ----> If the creatures referred to are iris borers, does anyone have
> more information on the temperature theory?
>
> Here in Buffalo, (New York State, Northeast USA, shore of Lake Erie
> (lake temp.32F) zone 5b/6a), we had a warming spell last week in which
> the temps climbed rather slowly from the 30'sF to at least 72F for two
> days. Nights were 50'sF. We are now at -32F, with snow flurries
> yesterday.
>
> The location is important because it seems the borer are not found in
> other areas of the USA.
>
> Did we get enuf warmth to bring the buggers out? And if so, will this
> cold weather knock them off?
>
> Several researchers at Rutgers University have studied these things and
> I'm expecting some printed material soon. Perhaps it will give info.
>
> Carolyn Schaffner in Buffalo, NY
>
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