|on our magical Lady's Mantle|
Armyworm fact sheet from
Manitoba Agriculture, Food and Rural Initiatives
True Armyworm infestations are more common in years with cool wet spring weather, which follow years of drought. The cool wet spring weather is thought to slow down the development of parasites which usually keep armyworm populations under control.
After hiding under debris during the day, movement and feeding occur at night - or on cloudy days.
Armyworm larvae are pale green in the early growth stage and dark green in later stages. Full grown larvae are smooth, striped and almost hairless, up to one to two inches in length. A series of stripes on the body are arranged by a thin, white, broken line down the middle of the black followed by a wide, dark, mottled stripe halfway down the side, then a pale orange stripe with white border, a brownish mottled stripe, and slightly above the legs, there is another pale orange stripe with white borders.
The adult armyworm is a light brownish gray moth or "miller" with a white spot about the size of a pinhead on each front wing. When expanded, the wings are about one inch across. Moths lay eggs at night in folded leaves or under leaf sheaths of small grain plants and other grasses. They prefer to lay eggs in moist, shady areas of vegetation.
For control, I'm using Btk
"Bacteria are present everywhere in our natural environment, including in soil, in food and even on our skin. Bacillus thuringiensis (Bt) is a bacterium that is found naturally in the soil and is known to cause illness in various insect larvae, including caterpillars of pest species such as gypsy moth, spruce budworm and cabbage looper.more on Btk from the Ministry of Forests, Lands, and Natural Resource Operations, British Columbia
There are more than 20 varieties of Bt. The "kurstaki" variety (Btk) is used for caterpillar control and other varieties are used for blackfly and mosquito control. It is not harmful to humans, birds, pets, fish, honey bees, beetles, spiders, etc. Within each variety are numerous strains. The Btk used for caterpillar control is the HD-1 strain."
I'm also introducing some beneficial insects - Trichograms Trichogramma brassicae
H was not impressed this morning when she discovered what I had left in the fridge overnight. Grin. I'm going to release them into the vegetable garden later this morning and will update later... :o)
and some really nerdy further reading:
Demography and life history of the egg parasitoid,
Trichogramma brassicae, on two moths Anagasta kuehniella and
Plodia interpunctella in the laboratory
S Iranipour, A Farazmand, M Saber, and Jafarloo M Mashhadi
Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
Department of Plant Protection, Faculty of Agriculture, University of Maragheh, Maragheh, Iran
Agriculture and Natural Resource Research Center of East Azarbaidjan, Tabriz, Iran
Journal of Insect Science: Vol. 9 | Article 51
10 July 2009