Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Show Questions - June 28, 2012
1. Hostas: Something is eating the leaves. Some have holes in in the center, some have chunks from the edge, some have not leaves left, just stems.. Don't see insects. Is this gnat damage? Or rabbits?
a. Probably slugs; they are night feeders and they hide down in the moist mulch. They come out at night to feed and do the kind of damage you described: large holes, small holes, middle of the leaf, edge of the leaf. Two things to do: first off, let's document that it is slugs: look for the slime trails that are on the leaves. Slugs need a moist environment. Sometimes we are our own worse enemy; reduce the watering and you can dry the hostas out a little bit to get rid of the slugs. If it is still a problem, baits are available at a nursery or garden center. The bait is sprinkled around the base of the plants.
2. How to dispose of old weed killers and containers and how do you get rid of the “glove of death”?
a. If the weed killer still has a readable label, follow label instructions for use or disposal. These can be taken to a household hazardous waste collection. (Possibly through the county extension office.) The "glove of death" is a cotton glove put on top of a rubber glove and dipped in Roundup. The best way to deal with the used glove is to put it on the window sill in the garage or somewhere and let it dry out, store it in a zip lock bag, and use it again. Or, if you really want to get rid of it, rinse it out thoroughly, dry it out, and throw it away. Empty pesticide containers, after they are triple rinsed and punctured, throw them in the trash.
3. A viewer has Knock Out® shrub roses. On many, all of the new foliage is bright red. What they are not saying is whether or not it is bright red and filled with bristly, soft thorns.
a. It sounds like a viral thing, especially if it is attacking newer leaves. Possibly rose rosette. This is a difficult question. A picture would be helpful. Look at the entire plant to see if the thorn to leaf ratio and leaf spacing is consistent throughout the plant. If so, this may simply be normal new growth. That new tender growth on Knock Outs will sometimes be a brighter color. Keep an eye on it. If you see rapid or distorted growth, this may be disease. You can send a sample and/or pictures in to the Plant and Pest Diagnostic Clinic, 448 Plant Science Hall, Lincoln, NE 68583-0722, (402) 472-2559.
4. A viewer has 4-year-old Knock Out® roses. When can they be moved?
a. Either early in the spring, before they are leafing out much; also late August is a good time to consider moving plants. If you are considering moving a plant, prepare it for moving now. Make sure it has all of its energy and is ready to be moved. Keep an eye on the weather, what kind of summer we have. This may not be the ideal year to make a move. You may want to wait until next spring.
5. A picture showing iris that have been dug up. They have lots of brown on the leaves and holes in the rhizomes, some sawdust looking material and rot. Is this a disease and will it spread? What should be done?
a. That looks like classic iris borer damage. Sawdusty material. There's some rot going on in there. A pinkish white caterpillar is often found in the rhizomes. The adult is a moth and it easily flies from one iris bed to another and lays its eggs. The older the bed, the more suseptible it is to borers. Clean up the bed and deal with the disease issues. It would be best to renovate the bed, digging up all the iris and cleaning them out. Usually this is done in August, but in 2012 it could be done in late July. Make sure you clean up all the pieces before you replant them. There's a NebGuide on iris, including dealing with borers (find it at http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=821). Be careful not to put them back into the bed until it is cleaned up; till it well and make sure the insects are removed.
6. How do you get rid of poison ivy; how common is it to find it in urban areas?
a. Poison ivy is fairly common on in urban areas, back fences, rights of way. There are a number of different controls. The best one is called an ivy control, the product in it is triclopyr. Fabulous control. And normally you can spray it. It's a selective product, make sure you spray it on the growing leaves. There are other products, but triclopyr is the best. Take the proper precautions and don't burn it and don't get it all over yourself.
7. A viewer has Harrelson apples. The picture shows marks on the leaves and the apples, mostly small and round. Is this environmental or disease?
a. A lot of organisms attack apples because of some kind of injury. It is possible that something has hit the fruit, caused a dent; sometimes when they are too dry, a fungi or bacteria can get in. If there's a big hole in the fruit, you might think insect. If it is sunken, you may think fungus or bacteria. This could be hail damage. Brown spots could be insect damage as well.
8. A viewer that has 'Black Beauty' eggplant. How big does it need to be to pick it? It is about the size of a pear.
a. In our experience, they are usually pretty big size. As they mature and are getting ready to pick, I will give them a tug, if they release easily they are ready. Our vegetables this year may not get to their full advertised size. Even if you are doing everything right, we are just having extreme weather.
9. A viewer has ticks all over, in the house, on the chair. She has them crawling on her while watching television. What can you use to control them in their yard and home?
a. It is common to find one crawling on us and the animals. I guess they have animals. Animals can bring them in, or humans work in the landscape and bring them in. And the ticks look for someone to eat or something to eat. They are looking for small animals to feed on. Keeping the landscape well manicured, the habitat pushed back as far away from the house, is the best approach. Inside, it is important to exam the kids, the animals, and yourself. They love to eat around the hairline in the scalp area. Especially the children. Look in the dog's and cat's ears and remove any ticks that you find. You can buy things to get rid of them. They are expensive. In the house, vacuum them up. I am reluctant to recommend a treatment in the house, but if you have a lot of them, call a professional pest control operator. Have them come in and take care of it. They will have products that you cannot get and they can do a good job and get rid of them. You have to have a lot of them before you spend that kind of money. The ticks will not reproduce inside the home. They feed and drop off and look for a place to estivate. They eventually die in the house.
10. Can we identify this? It is growing along the highways.
a. It’s bird’sfoot trefoil. Many people would consider it a weed, but it's quite beautiful. It's a good low maintenance plant. We are considering mixing it with fescue or buffalograss and it is beautiful this year.
11. This is a viewer that has a Washington Hawthorn. It has "stuff" on the branches and on the fruit. How should it be treated?
a. This is a Cedar Hawthorn rust. Usually does this on the fruit. Every once in a while you will see it on the leaves. It produces these long tendrils that release spores. Then those spores infect your juniper. You will see this on hawthorn and cherry. Prune it out to get rid of it. I believe there may be some fungicides out there.
12. The viewer who has grown garlic and done harvesting and it got wet. Some are soft and starting to dry off again. And they are wondering about botulism.
a. With garlic, botulism is a concern. It's a low acid plant. You could bring it to the lab and have it tested.
13. This is a viewer who wants to identify weeds in their turf. Is there a good book?
a. Yeah, from the University of Nebraska. It’s called Weeds of the Great Plains.
14. People are starting to see a foliar disease from the base up on tomatoes. Are we talking blight?
a. It can be a bacteria or a fungus. That bottom to top movement indicates that. One thing you can do is try to water your plants from the soil, not overhead. Try not to get your leaves wet. If it is fungus or bacteria causing it, they favor a moist environment. If you are seeing the bottom leafs that are affected, remove them in order to prevent movement up the plant.
15. This viewer wonders when to cut the canes back on red raspberries after they’re done bearing.
a. I don’t know if I would get too anxious to do it. They are probably everbearing and will continue to bear for some time. Once those have flowered and bore they will not do it again, but they are feeding the whole colony of raspberries. Leave them up. As we get into next spring or later this fall you can remove the canes that bore and leave the others for next year.
16. This is a viewer in the Holdrege/Orleans area who wants to know if it is too late to apply grub control.
a. No. Now would be fine with probably a Merit-type product. One key is to water it in. It is more important than ever to get water on it, maybe a quarter of an inch to move the product down. The eggs are just beginning to hatch. Not a bad time at all.
17. This is Kentucky bluegrass question: They have Kentucky Bluegrass all over; some in shade, but lots in sun. How much moisture is needed in central and western Nebraska to keep the crowns alive? They don't seem able to apply enough water to keep it green. That's a great question.
a. You can water it all season long to keep it green or let it go dormant. But you you don't want to go back and forth. If it goes brown, depending on the weather, apply about a quarter inch of water every 3-4 weeks just to keep the crowns alive. Keep traffic off it. About three weeks or four weeks, about a quarter inch of water.
18. This is a Kansas viewer who has the blackberry called Triple Crown in a sunny spot in the garden. But some of the berries are getting hard and brown. Is this fungal?
a. I’m not an expert with that particular fruit. It sounds like could be a fungal infection that causes the fruit to swell and harden. Could be a nutrient issue. Get it diagnosed. You don't want to treat for fungus if that's not the problem. If you have an odd berry, don't worry about it. If you have a bunch of them, get it to a lab.
19. Jeff, I'm going to ask this, because I've seen it on campus. They have sumac. It is turning yellow and orange and canes appear to be dying. Anything going on?
a. I haven't seen anything that's starting to go into fall color or dormancy. That one of those things for all of us to keep in mind: has it received any water? I know sumac is tough. And you don't think about watering. But if it is in a really dry location, it may be in survival mode.
20. Fred, best control for Zimmerman pine moth in Ponderosa and Austrian pines? This viewer is from Mitchell.
a. There are two windows for treatment. Like any borer, control the borer after it hatches from the egg but before it can tunnel in. Most years, the third week of April would have been a good time; we missed that. Late July, early August, when the adults are flying and laying their eggs is the other window. That would be the time. Sevin would work; permethrin or bifenthirin would work. Almost any product. But the timing is critical.
21. This is a question about zoysia. This year it didn’t green up. What caused it to die? Will new turf planted in that area survive?
a. That's an usual question; it’s hard to kill zoysia. It is unusual that it died. You might want to can that and sell it to people. If you seed fescue or Kentucky bluegrass back into that spot, I would be surprised that it would be affected. However the zoysia will come back. The rhizomes are still there.
1. A viewer has a ten-year-old pawpaw that has fruit. Do they self-pollinate?
a. They do self-pollinate. I think it helps if you have more than one tree. I encourage them to get another one. This spring was good for this tree
2. A sugar maple with half the bark eaten by deer.
a. Get a new tree.
3. This viewer put plastic with rock under crabapple trees to kill the suckers. Will it work or will it kill the tree?
a. It will not kill the suckers and it may kill the tree. Get the rock off and plastic off and prune the suckers.
4. Is it time to prune crabapples?
a. Not a bad time.
5. Do watermelon and cucumbers cross pollinate? Or is it squash and pumpkins?
a. Squash and pumpkins.
1. This viewer has arborvitae that’s tending to turn black along the stems.
a. It sounds like the whole thing is dying out. It sounds like a canker. Prune out the areas.
2. We are still getting calls about astor yellows. What do people do?
a. You have to rogue it out.
3. After a rain this viewer has mushrooms that grow in rings.
a. It is called fairy ring. It gets bigger and produces stalks. You don't have to kill it. Just mow it off.
4. Potato plants are shriveling.
a. If they’ve been over-watered it could be root rot. If they’ve been under-watered it’s probably drought stress.
5. Dead spot of turf with green in the middle. What is it?
a. Summer patch.
1. It is so hot, is it time to do weed control?
a. I would avoid it. Wait until it cools off. It is not going to be effective. Plus it is dangerous for the grass. >
2. Is it time to fertilize?
a. No lawns are slowing down. For the professionals they can do things with low rates of nitrogen.
3. We had a viewer who heard on a radio program that you should spray/spritz your lawn for five minutes at noon.
a. No. Only if you have a compromised root system (summer patch) or white grubs. The spritzing was supposed to cool off the lawn. It might work for just nano seconds. If you have a well-watered lawn, it won’t work. It is not recommended.
4. Will sod root and continue growing in ththis heat?
a. Cool season roots have a tough time when soil temperatures are over 70 degrees. They will root down but not very much. Their death will outpace their growth. You have to modify your irrigation practices because grass will have shorter roots in the summertime.
1. This viewer has a burning bush that's turning pink.
a. Spider mites. You need to treat it with bifenthrin. Be sure to get the undersides of leaves
2. On corkscrew willows, the leaves are curling. It has black bugs and webbing.
a. I think lace bugs. Maybe the webbing you are seeing are the adult bugs.
3. Anything that will deter flies in a hunting cabin?
a. Caulk them out. Keep them from coming in.
4. Are there any worms or borers that attack pin oaks?
a. Everything attacks pin oaks. Sure.
5. Is there such a thing as a trap crop for controlling Japanese beetles?
a. Not for the average homeowner. Just professionals.