Identifying Iris Borer Damage And Killing Iris Borers

by johnah on November 12, 2020

Identification of Iris Borer Damage And Killing Iris Borers

The first thing you need to do is identify the type of damage you have. There are two types of damage: (1) white or light brown spots, which appear on leaves; and (2) dark brown or black rings, which form around the base of leaves. You may notice that some areas look like they have been burned.

These areas are not dead, but rather have been damaged by fire ants.

If your plants have both types of damage, then it means that the insects were feeding on the plant when they attacked. If you see only one type of damage, then it means that the insect was attacking from above and did not feed at all on the plant before attacking.

When looking at the damage, you will see that there are three stages: (1) the initial attack stage, where the ant bites into the leaf; (2) the second stage of attack, where small holes develop in leaves; and (3) finally, a final stage of death after which no new holes appear.

You can tell if an area has had multiple attacks because there will be many different kinds of holes. It is also possible that you will see different stages of damage on the same leaf.

Identifying Iris Borer: The Best Way to Kill Iris Borers

If you want to kill these insects, then the best way to do so is to cut out the areas that are infected. Be careful not to cut into healthy tissue or else you may end up spreading the problem further into your plant.

If you are able to remove all of the infected areas, then you should be able to save your plant. However, given that the insects can fly into your yard from a neighbor’s yard or from a field nearby, your plant may become reinfested. You can prevent this by using an insecticide.

If you want to use an insecticide when treating the borer, then it is best to use something that is highly concentrated, like an insecticidal soap. This will kill the adult borer and prevent future infestations.

Identifying Iris Borer Damage And Killing Iris Borers at

How to Prevent Iris Borer

The best way to prevent these insects from attacking your plant is to make sure that you have good air circulation around your yard. This means that you should keep the grass short and avoid other plants that create a lot of shade. It’s also a good idea to use mulch in your yard.

You should also be sure to dispose of any clippings, moldy leaves, or other organic matter that may be lying around. These types of things provide food for slugs and other insects, some of which may be iris borers. Finally, you should make sure that your yard is free of other types of pests, like aphids and whiteflies, since these insects may attract iris borers into your yard.

As long as you take the steps to ensure that your yard has good air flow and is free of other types of insects, you shouldn’t have a problem with iris borers. If you do find any of the signs of infestation listed above, you should take steps immediately to get rid of the insects before they cause further damage.

If You Suspect an Infestation

It is best to take action immediately if you think that you have an infestation. The longer that you wait to take action, the more likely it will be that the insects will do severe damage to your plants. If you think that there is a problem, then call an exterminator or remove the infected parts immediately.

It is also a good idea to keep an eye on your yard in the future. If you think that there is a problem with the air flow in your yard or you start to notice other types of insects, then you should take immediate action. The longer that you wait to take action, the more likely it will be that one of your plants will become severely damaged.

The Clean Cut Way to Get Rid of Iris Borer

To prevent the problem in the future, keep your yard clean. This means cutting the grass and removing any sort of clutter, such as leaves. You should also make sure that you don’t allow any overgrown weeds or wildflowers to grow within twenty feet of your irises.

Iris borers are not picky about what type of iris they will eat. If you have bearded irises, they will eat those. If you have freestanding types of irises, they will eat those too.

This is why it is very important to make sure that you get rid of any other plants and weeds within twenty feet of your plants.

As long as you take the proper steps to eliminate these pests, you should be able to grow beautiful irises for several years.

How to Identify and Get Rid of Iris Borers.

This is how you identify iris borers and some steps on how you can eliminate them.

Iris borer adult – The adult stage of this insect is a metallic blue-colored, slender, long legged fly. They resemble a wasp and they are about ½-inch long. They lay their eggs on or very near the rhizome of your plant.

Iris borer egg – The eggs are small and white and round and less than ¼-inch in diameter. They are placed near the rhizome of your plant. The reason that they are placed so close to the rhizome is that when the egg hatches, the larvae can feed on the inside of the plant without having to crawl very far.

Iris borer larva – The larvae are white C-shaped creatures that have a black head. They have small hooks on their underside which they use to feed on the inside of the stalk. This feeding prevents the plant from transporting nutrients and water, which eventually kills the plant or causes it to become weak and die.

They can grow up to 1½ inches long.

Iris borer damage – The adult flies are relatively harmless; however, the larvae cause extensive damage to your iris plants by feeding on the inside of the stalk. They are most likely to attack plants that are overcrowded or in poor condition. If you are growing your irises in the ground, they will probably not cause damage unless there is a problem with the soil.

Iris borer prevention – Keep your irises well-watered and mulched around the base of the plant to prevent weeds from growing. This will make it harder for weeds to steal water and nutrients from your iris plants. It will also make it harder for the flies to lay their eggs on or near the base of your plants.

The flies are attracted by the smell of the weeds and they rely on them to find your irises. By eliminating the weeds, you will eliminate one source of food for the flies.

Iris borer treatment – The eggs of this insect are very small and hard to see if you don’t know what you’re looking for. If you remove all of the weeds from around your irises, you will prevent a lot of the adult flies from showing up. You can also spray the plants with insecticide to kill the eggs, but because they are hidden inside the plant, you probably will not be able to get them all.

Another option is to divide and transplant your iris plants every year. The flies will find the iris plants in the spring when they first start to flower. If you move your plants every year, it will be more difficult for the flies to locate them every year.

Identifying Iris Borer Damage And Killing Iris Borers from our website

In fact, if you keep moving the plants long enough, the iris borer fly might become extinct because it won’t have any food.

Another thing you can do is to make a barrier. Spread a sheet around your irises to keep the flies from being able to get inside. Attach it to stakes and make sure that it hangs down low enough to block the space between the plants and the ground.

You can also spray the plants with insecticide.

A very organic method that some gardeners prefer is to introduce natural predators into your garden. You can purchase beneficial nematodes and release them in your garden to control the bad insects. You can also purchase ladybugs and release them in your garden.

(Note: Before you do this, you should read other articles on this website about these insects and their possible effect on your garden)

Organic insecticides – You can purchase several types of organic insecticides at your local garden center that are available specifically to kill flies. Most of the time, these are in the form of a spray. Follow the directions carefully.

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Weevils (Curculios)

Adult weevils are ¼-inch long, very distinctively shaped, with a neck and head that is obviously not joined to the rest of the body, and their wings are folded up over their backs. They are mostly brown or black in color.

Adult weevils feed on the leaves of your plants. They also lay eggs in the soil that turn into baby weevils, which then eat into your plants roots. Both the adults and the young can cause damage to your plants.

The adult weevils can be easily handpicked off your plants and thrown away. Dig up your plants and dispose of the root parts that have been damaged by these pests.

Chemical options – If you prefer to use chemicals, carbaryl (Sevin) is the most common insecticide used to kill weevils. It is recommended that you purchase and use a ready-to-use product, such as Bayer Tree and Shrub Insect Killer. This should be sprayed on your plants until they are wet.

Re-treat after 10-14 days.

Identifying Iris Borer Damage And Killing Iris Borers -

Natural enemies – The main natural enemy of the adult weevil is the parasitic fly, which lays its eggs inside the weevils. Normally this keeps their numbers down.

For whatever reason, in some years there are many more adult weevils than usual. One year, my neighbor had such a heavy infestation that he resorted to using a chemical pesticide. About a week later, I noticed a lot of dead weevils lying alongside the road in the morning.

When I asked him about it, he said that was because the chemical that he had used melted the weevils and they had run out of the soil and died on the surface.

Diseases – Unfortunately, there are no known diseases that attack adult weevils.

The life cycle of a curculio (weevil)

The adult weevil goes through a complete change of skin (molts) several times before emerging as an adult. Some types of weevils will pupate in the soil, while others will do so in trees. Females lay eggs inside plants.

The eggs hatch and the young feed inside the stems. They then drop to the soil where they mature and eventually emerge from the ground to become adults. This whole process takes about a month.

The eggs, larvae, and pupae of curculios are very sensitive to heat. They cannot survive temperatures much over 80 degrees F. Most of this type of weevils’ life cycle is spent underground (except the adult stage).

Because of this, most Curculios are seen in late summer and fall.

Weevils go through the following stages in their life cycle: egg, larva, pupa, and adult. The eggs are small and white and are usually laid on the roots or stem of a plant. The tiny grub-like larvae hatch from the eggs and feed on plant tissue.

After several moltings, the larvae form a protective shell called a pupa. This stage lasts about one week.

Sources & references used in this article:

Insects attracted to light traps placed at different heights by SW Frost – Journal of Economic Entomology, 1958 –

The iris borer, Macronoctua onusta Grote: its behavior and methods of control by CR Neiswander – 1961 –

Diseases of the iris in West Virginia and their control by JG Leach, ES Elliott – 1965 –

Growing Iris in the Home Garden by United States. Agricultural Research Service. Crops … – 1969 –

Growing iris in the home garden by HM Cathey – 1977 –

Method and composition for insect and animal control by EK Wade – 1964 – University of Wisconsin–Extension

Method and concentrated composition for insect and animal control by L Kensek – US Patent 6,676,955, 2004 – Google Patents



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