Cutworm Prevention and Management

I wrote a post last weekend entitled Vine Weevil Larvae? featuring a rather unpleasant discovery on my plot. I had concerns that it was a vine weevil larvae, however I wasn't entirely convinced as I thought it was too big, not quite the right colour, and that it appeared to have legs as you can see below (vine weevil larvae apparently don't have legs).

However, thanks to Trevor over at UK Veg Gardeners, who has identified my rather unattractive and unwanted visitor as a cutworm, a rather confusing name since they are not worms but are actually larvae of night-flying moths. It appears that they hide under soil (I found them just under the surface of the soil) and venture out in the dark to eat. They tend to attack the first part of the plant they encounter, i.e. the tender stem of your precious seedlings, subsequently cutting it down. So, quite a clever name really :) The larvae have a fondness for asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato, and tomato plants.  However, the adult moths do not cause plant damage.

This picture below (courtesy of Neil Phillips) is of a cutworm larva of the Large Yellow Underwing (Noctua pronuba). The ones I found did not have the same colouring, however they curled up in exactly the same way and look to be of a very similar size.

As I have discovered, cutworms over-winter under the soil. So, what can you do to prevent cutworm? Furthermore, what can you do to get rid of them? There are a number of strategies to try and stop them from eating your carefully-nurtured seedlings:

1. Dig over your plot in the autumn. This helps destroy or expose overwintering larvae or pupae;
2. Keep your plot weed-free in autumn and winter. This removes potential egg-laying sites and a food source for young cutworms.
3. Regular dig-over soil in winter to expose the larvae to predators;
4. Lightly dig-over soil a couple of weeks before planting, again to expose larvae to predators;
5. If you know that an area is infected, dig it over to a depth of about 2 inches and manually remove and destroy the cutworm - the removing bit I coped with, the destroying bit I did not;
6. Encourage insectivorous birds by hanging feeders;
7. Avoid using green manure as it will encourage egg-laying;
8. Avoid planting in areas that you know are infested with cutworm;
9. Place aluminium foil or cardboard collars around seedlings. Make sure one end is pushed a few inches into the soil, and the other end extends several inches above ground.  This should prevent most species of cutworms from getting to your plants.  The collar can be removed when the stem of the seedling grows to about the thickness of a pencil;
10. Push 3 toothpicks into the soil around and close to each stem. The cutworm has to curl its body around the base of the plant at soil level to eat, the toothpicks prevent it from doing so. 

Tomorrow, I will be having fun doing more of number 5 :(