Friday, 12 June 2015

This Week at the Farm (June 12, 2015)

June is cutworm month and cutworm scouting is crucial at this time of the year.

Cutworms include several species of noctuids that feed on a broad range of host plants but they are not worms!  Cutworms are the larval stage of several species of economically important noctuids that can cause damage in prairie-grown crops including canola, mustard, wheat barley, triticale, peas, alfalfa, clover, timothy and several fescue species.  Some cutworm species prefer broadleaf to grass- or cereal-type host plants but some will consume whatever plant is available.

Cutworms overwinter as eggs and larvae so damage will occur in field crops from April until August, depending on the species.

Larvae feed by shredding or clipping leaves or stems of growing plants so seedlings can be highly susceptible.  Cutworm damage is characterized by missing seed rows or bare batches where plants have been consumed beneath the soil surface.  Wilted, drying or brown vegetation can indicate larval feeding occurring below the soil surface or within the crown of a plant.

This cutworm larva was found curled  up in the soil near the crown of a timothy plant near Falher, AB
One of the four objectives of the CARP Cutworm project is to document the species diversity and distribution of cutworms causing damage in our commercial fields.  For our lab, this includes collecting live larvae and rearing them.

These cutworms were collected in canola in a field near Peoria, AB
Cutworm larvae are hand-collected by IPM staff or by producers.  Once they arrive at our laboratory, each specimen is assigned an ID number in order to track their development.

Rearing then involves measuring, feeding, and changing each larva every 2-3 days.  Each larva is housed inside a plastic container (1oz) prepared with filter paper to regulate moisture in the container.  Every 2-3 days, each larva is provided with a prepared media containing antibiotics and nutrients specific to their needs.

This GIF shows a cutworm collected from wheat near Falher, AB feeding on a piece of media.

Each larva is photographed and measured as they develop.  This generates an image library that we will use to develop a tech-transfer document intended to help identify species of cutworm at different growth stages.

More information on the CARP Cutworm Project can be found here
More information on cutworm monitoring can be found here

Albertans can use the 2015 cutworm reporting tool to help us identify cutworm infestations which updates a live map.