Jean, Thank you very much for providing the very detailed info and pertinent links. It will definitely help with id. Regards, Mike On Fri, Mar 25, 2016 at 10:35 PM, <gardenpt@aol.com> wrote: > Jane, > > Most likely the troublesome cutworms at your place are Noctua pronuba > which go by various common names, among them greater yellow underwing,large > yellow underwing, and the winter cutworm. > > This page shows the adult and displays the seasonality in the northwest. > The bright orange of the hind wings is easily recognized when the moth > suddenly flies out its daytime hiding place, commonly a clumping perennial > or small shrub. Noctua comes is quite similar as an adult but the > caterpillar is quite different than that of N. pronuba.) > > http://pnwmoths.biol.wwu.edu/browse/… > > The winter cutworm arrived in the northwest approx the year 2000. They > overwinter as caterpillars. They typically feed at night during the fall, > winter, and spring when temperatures are in the 40s or above. Thus, their > damage is often attributed to slugs. You can differentiate the damage of > these two pests by closely examining the edges of the holes in the leaves. > Here, they specialized on my Pacific Coast iris hybrids, but they will also > damage numerous other perennials, among them rhubarb leaves. > > This pub has excellent images which will help you ID the larvae. > http://pestid.msu.edu/insects-and-arthropods/… > > As does this: > > https://ag.ndsu.edu/archive/entomology/… > > > Also see bugguide: > http://bugguide.net/node/view/9821/ > > Least-toxic management includes various techniques and, as you've > commented, some make sense for individual pots/small plantings, others > don't: > - row covers > - handpicking (at night, about 10:30 or so) then snip in half or put into > soapy water > > - Btk (Bacillus thuringiensis kurstaki), which is specific to > caterpillars, but is effective only when they are half-grown or younger. > Mature specimens may be 2..5 inches long. > Btk is available under several product names, among them Dipel, Thuricide, > Caterpillar Killer, and more. (I suspect the cats are too old for this to > be effective at this time; they will soon pupate and the moths will emerge > in May.) > > > Hope this helps, > Jean > from Portland,Oregon > > > -----Original Message----- > From: Jane McGary <janemcgary@earthlink.net> > To: Pacific Bulb Society <pbs@lists.ibiblio.org> > Sent: Sun, Mar 20, 2016 4:37 pm > Subject: Re: [pbs] Cutworms and bulbs > > > > On 3/20/2016 3:37 PM, Diane Whitehead wrote: > > When do these moths lay their eggs? Maybe some nets or screens could > keep them out of your greenhouse. > > > > > > I should have mentioned that the "greenhouse" is 20 by 40 feet and the > sides are hardware cloth (wire mesh), not solid. I don't know if the > moths can get through the mesh but they might get in under the roof or > some other unprotected place. Juncos (small birds) sometimes get in; I > suspect they walk between the bottom of the door and the gravel path. > The protected situation also attracts many spiders, which may help > control the moths. > > Most advice on controlling cutworms in the home garden involves making > little cardboard collars and putting them around the young plants. That > is probably fine for somebody who is growing a dozen little plants -- > not a thousand. > > Jane McGary > Portland, Oregon, USA > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >
