Garden Insects Good and Bad forum: Cutworms
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|Cutworms are another notorious pest of growers. They also have the common name "C worms " as when they are disturbed they curl up into the shape of the letter C. One day your plants are standing nice and tall and healthy and the next they are laying on the ground with their stems chewed off and in some cases the whole top of the plant chewed off has disappeared.
Curled up larvae of Naenia typica
Cut worms are the reproductive larvae and pupa from some types of moths. The moths, generally those small ones seen flying at night, themselves, are harmless to your plants. Like butterflies, the adult moths just gather nectar from the plants. It is their larvae, the young caterpillars, that are the mean munching machines causing the destruction to your plants.
Cutworms eat by using chewing mouth-parts. This means that they have jaws with teeth that can bite and tear into plant parts. Some cutworms may not necessarily even bite all the way through the plant. Instead they may just chew enough on it to cause damage that can be seen as wilting of your plant.
The same as with aphids and some other type of insects, some cutworms are specific pests of certain types of plants, grasses, and shrubs.
Basically there are four types and methods in how cutworms do damage to plants. They are the solitary surface cutworms, climbing cutworms, subterranean cutworms and the army cutworm.
The solitary surface cutworms are the ones that you see the most damage from. These are the cutworms that chew your plants at the soil line or right below it that you may find laying on the ground. That is, unless the cutworm has taken it back into it's burrow and then you won't see your plant parts at all unless you do some digging.
As I mentioned up above, some plants you see in your garden maybe experiencing the "wilting" look. Most people will try and give the plant more water or fertilizers to perk it back up. Before you try and doctor the plant, check around the base of the stem above and just a little ways below the surface line. If a cutworm has chewed part of the plant and then moved on to another plant, all the doctoring will not save that wilted plant and you might as well pull it out or try and take cuttings from it to root.
Now the climbing cutworms do exactly that. They will climb up your favorite shrubs and vines and even rose bushes and eat not only the leaves, but also the buds and fruits of the plants. Scouting everyday can be a big help in controlling the climbing cutworms. If you happen to notice your buds are missing or gaps in the foliage that wasn't there the day before you may have a cutworm busy at work.
Orthosia gothica on a Geranium.
The subterranean is the ones that confuse people to with their damage. They live and feed below the soil. All of the chewing damage they do is to areas of the roots, crowns and other under ground structures of the plants. If you see weak, stressed wilting and dying plants, again you would need to dig down into the root system of the plant to see it is maybe a disease or environmental problem or a busy cutworm.
With armyworms you will see a lot of destruction very fast and very easily. Armyworms are laid in a mass quantity and hatch generally all at once. They love to eat the tender top shoots especially. They will try and stay together in a mass group chewing as they go along. Once they strip one plant or tree they will move on together to the next spot. I have seen army worms hatch and immediately start chewing and over a course of a couple of days totally defoliate a large tree leaving it no leaves to photosynthesize and produce food, ultimately killing it.
The moths generally lay one batch of eggs a year, but that batch of eggs can be a few to as many as a hundred. Due to environmental conditions, not all will survive to hatch into larvae. The females like to look for weedy areas or areas where the grasses are taller than several inches high to lay their eggs. Occasionally they will lay them on the the stems of plants if that is all that is available. The eggs may be laid singly or in small groups. They are very hard to discover in the grass.
Some varieties of cutworms mate in the Spring and others in the Summer. Whichever time they do, it takes about five to ten days for the eggs to hatch. Once hatched the larvae will begin to immediately feed. It can take them about a month to a month and a half to go from hatching larvae to an adult moth.
Cutworms, while being very destructive are one of the pests that are a little bit easier to get rid of. They just take a bit of work. The best way to get rid of them is by cultural practices instead of trying to use chemicals that are expensive and do not work as effectively.
Try using some of these cultural practices.
1. Plow, fallow, turn soil and fields in mid to late summer to destroy eggs by keeping them from hatching.
2. Cultivate your fields in the spring again, this exposes any cutworms that may have survived through the winter.
3. Encourage toads to your area. They enjoy cutworms in their diet. Don’t forget to create a home for them. Sometimes, they may even make holes for their home a long side of rows and fallows. Check before you cover any holes up that you don’t have a beneficial living there.
4. Use composted manure instead of green manure. Eggs, unseen by you could be attached to the green manure and have enough time to develop and start a path of destruction. A good mulch to use is a combination of chicken manure and oak leaves mixed together.
5. Using strips of cardboard, make collars around the base of your plants. Place these collars at least 2” deep and 2” away on all side s from the base of your plant and 3” high. Check your collars and replace with a wider width if necessary as your plants develop.
6. Save your eggs shells, then crush them up. Gently scratch around the base of your plant, then place the egg shells on the soil and lightly cover.
7. Fill baby jars with molasses, bury them near the plants to the rim of the jar as a trap. The molasses coats their bodies and they can’t move and die.
The best practice always is to scout and keep areas free of weeds and debri that could become potential breeding grounds.
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