Webworms Aren't Fatal To Trees
Neil Sperry
---DEAR NEIL: You mentioned recently that bagworms don't come out of trees and crawl around on other surfaces, but my place is loaded with them. They're covering the garage and my other plants. They are even in the house. I cut a few webs out of the trees and the worms are identical to those I see all over the place. This is an invasion. What can I use to kill these bagworms?
The larvae that you are seeing are called webworms. They attack trees such as pecans, mulberries, persimmons, box elders and catalpas among many others. They form large and unsightly webs and strip the foliage bare.
They are not going to kill your trees, however. They just make them look bad, plus, as you mention, they're all over everything. Sprays are ineffective on these while they're in the trees. The best means of controlling them is with a long-handled pole pruner extended to 16 or 24 feet and used just as they become visible. On lower surfaces you can use biological worm spray (B.t.) The bagworms I was referring to are in cases, or bags, about the size of your little finger. They attack cone-bearing plants such as junipers and arborvitae and can actually kill them if they strip off all the needles.
They are never seen without their bags. Their prime time is late spring into early summer. Almost any general-purpose insecticide will control them if it's applied while they are still actively feeding.
DEAR NEIL: What can I use to eliminate white flies in my privet hedge? They just about choke me when I trim it.
Use a systemic insecticide such as acephate (formerly sold as Orthene). They are tenacious pests. You'll probably have to treat several times on 10- to 15-day intervals during the balance of the summer and early fall.
DEAR NEIL: I have several Italian cypress trees around my swimming pool. They are infested with spider mites but the spray given to me by a nurseryman is making no progress. One of them also was hit by lightning. It's almost all brown. Is there any hope?
That doesn't sound good. By the time spider mites have browned the bottom portions of columnar evergreens, they usually will not produce new green growth to fill in. They do a lot of damage to many plants and it's not terribly obvious until it's too late. As to lightning damage, it varies from individual to individual. However, if the plant is that brown it's probably lost. It's probably time to consider replacements.
DEAR NEIL: Large, ugly mushrooms have taken over our back yard for the past several years. What can we do to eliminate them?
Apply dusting sulfur to them. They are funguses and it should stop the problem. You can also break them off with a hoe. For what it's worth, they are not particularly harmful to your plants unless they overtake and shade low plantings.
DEAR NEIL: Is a tree dead when its leaves are all brown and the trunk wood is still green?
Probably so, especially at this time of the growing season. The green chlorophyll that is within the wood of the trunk is the last tissue to turn brown. You can also tell by bending the small twigs. If they're green and supple there still is hope. If they're brown and crisp, it's time to replant. Try a different species on the chance that it was a soil-borne disease.
DEAR NEIL: What time of year should I plant a gift gardenia into my garden? What side of the house would be best?
Fall plantings can work if the plant can be protected from extreme winter cold. Gardenias need morning sun and afternoon shade, so eastern exposures are often best. They also require acidic soil. If they're grown in alkaline areas they will require a planting mix consisting of half brown peat moss and half pine bark mulch. It should be 12 inches into the ground and 10 to 12 inches above the soil line.
DEAR NEIL: I have several rose of Sharon plants at a house I own in the Metroplex area. Lately two have died suddenly. What causes that?
Cotton root rot fungus. It's a nasty disease that remains in the soil for many years. The symptoms you describe are typical for it. It attacks a wide range of plants in alkaline soils, most notably cotton and its relatives. Rose of Sharon is in the cotton (Malvaceae) family. There is no chemical control. Crape myrtles are a good substitute as they are very resistant.
DEAR NEIL: I have two sago palms that are old and large. How can I remove the side "pups" without hurting the mother plant? I'm not physically able to get them out.
Cutting and digging would be the only options. Find a friend who could use a sharpshooter spade and who would exercise great care not to damage the main part of the mother plant. Sagos are naturally clump-forming so you might be better off not to attempt it.
DEAR NEIL: Our beautiful 3-year-old buffalograss lawn looked great during the last two dry summers, but it looks terrible now. At the advice of the landscaper we have not fertilized it. I know buffalograss grows on little or no water. Is the rain the reason for our problems?
It's hard to know without seeing the grass. Buffalograss is definitely native to dry parts of North America. The main reason people recommend against watering and fertilizing it too much is that bermudagrass invades and overtakes it when you do. Some people also mow it very high, perhaps at 4 inches and higher. As a guess, your problem sounds like grass that might have become too luxuriant and perhaps just got too thick and dense for its own good due to this year's rainfall.
DEAR NEIL: You recently mentioned a pecan disease called pecan scab and you said to spray in the late spring and summer. What should we use?
That always depends on what is available. Companies traditionally change their product mixes over the winter so I'm reluctant to give long-term answers for applications that will be made in future years. Too many times my recommendations have been changed by the time people got into the stores to ask for them. You'll simply need to buy a fungicide that is labeled for use on pecan trees. Nurseries geneerally have them. Farm supply stores that sell to people with pecan orchards certainly should.
The larvae that you are seeing are called webworms. They attack trees such as pecans, mulberries, persimmons, box elders and catalpas among many others. They form large and unsightly webs and strip the foliage bare.
They are not going to kill your trees, however. They just make them look bad, plus, as you mention, they're all over everything. Sprays are ineffective on these while they're in the trees. The best means of controlling them is with a long-handled pole pruner extended to 16 or 24 feet and used just as they become visible. On lower surfaces you can use biological worm spray (B.t.) The bagworms I was referring to are in cases, or bags, about the size of your little finger. They attack cone-bearing plants such as junipers and arborvitae and can actually kill them if they strip off all the needles.
They are never seen without their bags. Their prime time is late spring into early summer. Almost any general-purpose insecticide will control them if it's applied while they are still actively feeding.
DEAR NEIL: What can I use to eliminate white flies in my privet hedge? They just about choke me when I trim it.
Use a systemic insecticide such as acephate (formerly sold as Orthene). They are tenacious pests. You'll probably have to treat several times on 10- to 15-day intervals during the balance of the summer and early fall.
DEAR NEIL: I have several Italian cypress trees around my swimming pool. They are infested with spider mites but the spray given to me by a nurseryman is making no progress. One of them also was hit by lightning. It's almost all brown. Is there any hope?
That doesn't sound good. By the time spider mites have browned the bottom portions of columnar evergreens, they usually will not produce new green growth to fill in. They do a lot of damage to many plants and it's not terribly obvious until it's too late. As to lightning damage, it varies from individual to individual. However, if the plant is that brown it's probably lost. It's probably time to consider replacements.
DEAR NEIL: Large, ugly mushrooms have taken over our back yard for the past several years. What can we do to eliminate them?
Apply dusting sulfur to them. They are funguses and it should stop the problem. You can also break them off with a hoe. For what it's worth, they are not particularly harmful to your plants unless they overtake and shade low plantings.
DEAR NEIL: Is a tree dead when its leaves are all brown and the trunk wood is still green?
Probably so, especially at this time of the growing season. The green chlorophyll that is within the wood of the trunk is the last tissue to turn brown. You can also tell by bending the small twigs. If they're green and supple there still is hope. If they're brown and crisp, it's time to replant. Try a different species on the chance that it was a soil-borne disease.
DEAR NEIL: What time of year should I plant a gift gardenia into my garden? What side of the house would be best?
Fall plantings can work if the plant can be protected from extreme winter cold. Gardenias need morning sun and afternoon shade, so eastern exposures are often best. They also require acidic soil. If they're grown in alkaline areas they will require a planting mix consisting of half brown peat moss and half pine bark mulch. It should be 12 inches into the ground and 10 to 12 inches above the soil line.
DEAR NEIL: I have several rose of Sharon plants at a house I own in the Metroplex area. Lately two have died suddenly. What causes that?
Cotton root rot fungus. It's a nasty disease that remains in the soil for many years. The symptoms you describe are typical for it. It attacks a wide range of plants in alkaline soils, most notably cotton and its relatives. Rose of Sharon is in the cotton (Malvaceae) family. There is no chemical control. Crape myrtles are a good substitute as they are very resistant.
DEAR NEIL: I have two sago palms that are old and large. How can I remove the side "pups" without hurting the mother plant? I'm not physically able to get them out.
Cutting and digging would be the only options. Find a friend who could use a sharpshooter spade and who would exercise great care not to damage the main part of the mother plant. Sagos are naturally clump-forming so you might be better off not to attempt it.
DEAR NEIL: Our beautiful 3-year-old buffalograss lawn looked great during the last two dry summers, but it looks terrible now. At the advice of the landscaper we have not fertilized it. I know buffalograss grows on little or no water. Is the rain the reason for our problems?
It's hard to know without seeing the grass. Buffalograss is definitely native to dry parts of North America. The main reason people recommend against watering and fertilizing it too much is that bermudagrass invades and overtakes it when you do. Some people also mow it very high, perhaps at 4 inches and higher. As a guess, your problem sounds like grass that might have become too luxuriant and perhaps just got too thick and dense for its own good due to this year's rainfall.
DEAR NEIL: You recently mentioned a pecan disease called pecan scab and you said to spray in the late spring and summer. What should we use?
That always depends on what is available. Companies traditionally change their product mixes over the winter so I'm reluctant to give long-term answers for applications that will be made in future years. Too many times my recommendations have been changed by the time people got into the stores to ask for them. You'll simply need to buy a fungicide that is labeled for use on pecan trees. Nurseries geneerally have them. Farm supply stores that sell to people with pecan orchards certainly should.
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