Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Show Questions - April 26, 2012
1. With the season being four to six weeks ahead of usual in 2012, should we apply insecticides for flying insects to the lawn in June rather than in July.
a. Insect development is tied to the temperature, because they are cold-blooded. So when the warm weather comes early they are born early. When it comes to white grubs, generally we apply the Merit types of products in mid-June. So rather than the third week of June, this year they should be applied the second week. You wouldn't want to apply it in July, in any case, because that would be too late. We normally apply those products just before egg hatch in mid June.
For billbugs, product should be applied right now if you are going to use imidacloprid. And maybe a week from now, if you're going to use something like bifenthrin to control billbugs. Watch for the presence of lawn moths. We're seeing a lot of moths, and also adult sod webworms. Those moths are out laying eggs. Normally that would happen in late May-early June, we might expect it even as early as mid-May this year. You might need to treat earlier.
2. This viewer does a good turf program, crabgrass, pre-emergent, weed and feed, and grub control. They want to know the what the numbers mean on the fertilizer bag: N-P-K.
a. Unfortunately, the fertilizer numbers across the bag they're important, but we need to know the amount of product you apply and the concentration of each. What we're shooting for is somewhere between two and four pounds of nitrogen (N) per thousand square feet per year. You have to do the calculations. We have a lot of calculations on our website.
3. This is from Gothenberg. 20-year-old pear tree, the leaves are turning yellow, and it still has fruit at the end of the year, but are there diseases that would potentially cause that, and if so, what should they do about that?
a. With an older tree like that, there could be several things that could be turning the leaves yellow. If just a portion of the tree is turning yellow, you could have some sort of canker. That will turn a tree off-color. If the whole tree is turning a light color, it could be in the soil conditions. Best would be to take a sample in to your local extension office or to a diagnostic clinic. Bring a picture along and a sample of the leaves. The big thing is whether the whole tree is affected or just a portion of it is that light green color.
4. What to do about moles?
a. Moles are very active as soon as the ground warms up. You can try trapping them, which is labor intensive. Male moles will go roam three acres; they're very active this time of year looking for the females, so you get a lot of runs and a lot of problems. So, trapping: there several types of traps out there; that's labor intensive, and you have to be at it. There are products that are toxicants; the fumigant toxicants don’t work very well and are very dangerous. Toxicants that are in bait (Talparid is commercial bait) they have the exact same thing as Tomcat for moles. This looks like a gummy worm. When used precisely as directed on the label, most people have very good luck with that product.
5. From deepest, darkest West Yorkshire in the north of the United Kingdom: He has a question about growing monster pumpkins.
a. Our reach has gotten broad, for those of you who think we're sort of parochial in Nebraska.
6. In Kearney, cabbage planted and within two days, the leaves were all clipped off at the base. They put BT on it for insects. Will the cabbage plants come back?
a. Probably not. Could be cutworms. There are a zillion army cutworms out there. Protect those stems with a collar of some kind, or work something (like Sevin) into the soil around the base of those plants. The caterpillars will be there for a while, so protect the next crop. Those aren't going to recover.
7. Is there a turf variety that is resistant to grubs?
a. No. There are species that are more tolerant of grub feeding; tall fescue tends to be resistant to grub feeding and warm season grasses such as buffalograss are more resistant, but there are no grasses that are truly resistant.
8. In Bennington, this viewer has a tree peony with one strange flower, the leaves are curly, they thought it was from the graft, but it doesn't appear as though it was coming from the main plant. They wonder what's going on here, and the flowers have always been a really deep, dark maroon rather than that pink.
a. If you look at the distorted growth--there is a picture of foliage that was really mottled and off-color. From the symptoms in the pictures, this appears to be a virus of some sort. If they have other peonies, I would be concerned about it spreading. If that's the only one, it's always going to be there, but you could leave it in your landscape, as long as your neighbor doesn't have a tree peony, because this virus will move. Insects can move viruses to other tree peonies. The safest thing would be to remove it, but that can be expensive, and it may be something they want to keep. It will probably not live as long as a healthy one, given these symptoms.
9. Do grackles eat grubs? They are running all over the lawn and pulling up something.
a. They could be eating grubs, or earthworms, or moths. They like all those things. When they're going after the grubs or even the larvae, the armyworms, they're going to be putting a small hole into the turf. Grackles are a protected species, so you can't eradicate them. The best thing is to keep the lawn fairly short, they'll be less likely to be there, and they'll have a harder time getting down to it and finding those moths.
10. In Chester, they have night crawlers and they are so thick in the yard he has trouble pushing his lawn mower. What can be done?
a. Earthworms are obviously very beneficial: they're a source of food for wildlife, they aerate the lawn, they're important for breaking things down, so in 99.9% of the situations, we want to preserve earthworms for the beneficial value. But they can, like anything else, become a problem. There is no product that's labeled for earthworm control, but on a warm spring night when they're out and active, an application of Sevin (Carbaryl), that would probably reduce the material. It's a contact material. You have to do it in the early evening when the earthworms are first out and spray at that point, but they're the biggest problem. There will still be lots of earthworms in the surrounding area, in the garden, which is good. But that should help reduce them. You can power rake a bit and break down those castings. That won’t control earthworms. Rolling won't help, unless it's a very heavy roller.
11. Nutsedge in the garden is out of hand. Could it have come in with the compost? How can it be controlled it in the garden?
a. Yellow nutsedge can come in with compost, but odds of that are pretty rare. Yellow nutsedge is literally everywhere in this world, so it's hard to point a finger at compost. How to control it in a garden? Pull it, good exercise, or use the “glove of death,” the plastic glove with the terrycloth glove soaked in Roundup. The problem with that, in relatively recent data, if you don't use enough Roundup, you can stimulate tuber growth. You can pull them up until the longest day of the year, and then you should not pull them because that's when they start forming tubers. Pulling leaves the tubers in the ground and they become rhyzomes in the ground.
12. Raspberries: A 20 year old patch, last year the lighter colored in the vein, they trimmed them back to the ground, smaller plants have light veins, they're kind of curling, there is a lot of dead canes. Is this a disease issue, an age issue? Can new plants be planted if old ones are removed?
a. That’s plenty of time for viruses to accumulate in the plant material and when they're perennial plants, that is likely the case. You may decide to completely renovate the planting, take them out, and start over. You can rogue out any of the plants that will look like that, but you're going to have plants dying and that's going to continue because of the age. You're going to have accumulated diseases and have more problems. If you want raspberries back in the bed, take everything out, turn the soil, and let it rest a year, maybe even try solarization, because you're going to have a lot of fungal growth in there that is going to be a disease problem, but the plants will be stronger if they get new ones.
13. There are two-inch holes in the yard, they never see an animal, every night there are more holes. Any ideas?
a. If the holes are two inches with no soil around them, very clean, and in an area that is well groomed, it could be thirteen line ground squirrels, out of hibernation and moving around right now. If they're two inch and more of an angle and it's more in a wild area, it could be voles who build up a population very fast. With voles, sometimes you see a trail in between. It's probably one of those two if there is no dirt around the hole.
14. An Omaha viewer wants to know how and when to use floating row cover. She has a zucchini variety that claims it doesn't need bees for pollination.
a. If that's not an issue for her zucchini, you just drape it over; you can build a frame, but just drape it over, and then secure it firmly to the soil with soil bricks. That keeps the insects from going in. One of the places it works the best is for something like beans, snap beans, to keep the beetles away. But any time that you require insect pollination, you have to take that off; if they have a variety that doesn't require insect pollination, go ahead and use it. The big issue is keeping it secured to the ground, with the kind of wind conditions we have in Nebraska. You have to stake it down and then pull it up if you need bees to get in there.
15. In Valley: They built a new house, put down the new sod last fall, the grass is very thin, doesn't seem to be growing in some places, they haven't had to mow it yet, there are areas that seem to be thick, and they're in the shade. Any ideas on either management or what needs to be done to fix this issue?
a. There could be lots of issues. Number one, I would guess the quality of sod was pretty good that you put down, but what kind of soil did you put it on? Most of the soil on new houses ends up being clays; they've hauled all the topsoil away, that would be a concern. Also, when you sod a lawn, make sure you use a starter fertilizer that's high in phosphorus, and then that sod will need to be fertilized just like a mature lawn. We have information on how to start and maintain a sodded lawn on our website.
16. This is from Curtis: these peonies are 30 years old, they come up and bloom very well, then in June and July, the leaves turn brown. She wants to get them through the summer without this foliar disease.
a. This is probably botrytis blight. Anything you can do to avoid overhead irrigation helps and use really good sanitation. Remove dead leaves and in the spring, clean it up good to reduce inoculum. You can use a fungicide, but I would not recommend it.
17. This is a Lincoln viewer wanting to know how to get wild turkeys out of their yard?
a. A nice dog does it. They will chase them out all the time, even some cats will. We're talking about game species, so there are regulations within the three-mile rim of the city limits where you can't use a firearm or bow and arrow, or even a slingshot. Scaring them away, which we use sometimes, we call them scare repellants, work sometimes. Lasers, sometimes shining lasers at them will work. What are they feeding on? Eliminate what they are feeding on. That will help tremendously, but dogs and cats help a lot in the city limits.
18. This viewer has a small backyard with a plastic pond that is thick and green with algae. He had dumped and cleaned and filled and it's thick again and I know you have a pond that you manage compeletely differently.
a. If you have a natural bottom, unlike the rocks in the video or plastic, you never get algae. It's half shaded, but it's its own ecosystem. If you do have rocks and plastic, you can use snails. Snails are great algae eaters, you can buy them at pond shops and fish stores and there are also fish that will eat a lot of the algae. The biggest thing: keep it flowing and keep it shaded at least half the day. That will keep down the growth. There are fish-safe algaecides that can be used as well.
19. This is a viewer who took these images in Basset at a friend's house. They are backyard spots that are 6 to 16 inches across. They want to know what's causing them and I know you had an interesting conversation about the cause and then the secondary cause, potentially.
a. Just because it's in grass doesn't mean it's -- you know. First, I thought, with this picture in particular, it looks like a necrotic ring spot. It looks too severe for that. It looks like there might be animals would be involved. Insects might be involved. It could be grackles or other birds and even rabbits. They will pick up the dead grass and nest with it. Robins, most any bird, loves that pile of dead grass, and get some moisture from it, that helps make a nice nest. So it could be that it died from a disease or insect, or anything else, and animals grab the dead grass and nest with it, but it doesn't look like anything was eating it when it was alive.
20. We have a Norfolk viewer who has a maple tree shredded by hail a few weeks ago with no sign of new foliage yet and they were wondering if it will recover?
a. They will break secondary buds if you give them time. You don't want to fertileize, just be patient and hope we don't get another hailstorm right on top of it.
21. We had a viewer that brought in this little thing here, which is a linden, and it has some little gall things, and then we found a worm, wondering what that is.
a. Because there is no feeding damage on it and it's a linden, these are called pocket galls, and they're caused by a mite and they won't harm the tree in any way. It's just been such a warm spring that they're just extra abundant this year. But then we flip it over, and there's this little critter--an inchworm--on the back. It might be one of the fall inchworms. There is no feeding damage, so it's just a curiosity.
22. We're going to go to more spots and turf. This is a viewer in Sioux City whose dog is making spots in the yard. How can they make turf grow again?
a. Re-seed it. If it's Kentucky bluegrass or, in some cases, tall fescue, it will come back. The best thing to prevent those spots is just water it as best you can after the dog is finished. Tall fescue is a little more tolerant of dog urine than Kentucky bluegrass.
23. We have viewers that have tea roses that have black on the ends of the buds and it looks like a leaf growing right next to the bud.
a. There's a couple of things. If you see a lot of leafing around the bud, you might look at the leaves closely for mottling or mosaic or shoestringing. If that's the case, I would rogue the plant out. That's what I think of when I hear of that symptom. Look for virus symptoms.
24. This is a Wilbur viewer who has snakes in the garden, many of them coming from what appears to be a crack in the ground, and she wants to get rid of them.
a. Okay, there might be a stump or an old cistern in that area and that's where they hibernated. Pack it with gravel or lava rock and put the turf back over it. If you can prevent them from entering the cistern or stump area, that would be very helpful. Keep it well-mowed, make sure there are no cracks around the house, and they'll go someplace else if there is no place to hide.
25. We have a couple of viewers who have asked us questions about hibiscus this year, and again everything is early.
a. If your hardy hibiscus are not out of the ground, chances are the one you bought last year was not a hardy one. There are hibiscus that are annual and some that are perennial. so I would be concerned if you don't see that coming out of the ground yet.
26. Fred, we have an Omaha viewer with roses with spots and holes on the lower leaves, but no insects on top or below.
a. I would guess rose slugs, almost certainly. They feed quickly and then they're gone, so they may have already done the damage. Examine the leaves for the green slug-like things. If you find them, they're easy to control with insecticidal soap or neem oil or Sevin.
27. Zach, we have a little bit of a question about soft water so here's another one. This viewer has it in the outside tap. They're wondering whether if soft water will hurt the plants, and is the potassium salt better than sodium salt in terms of salt buildup.
a. In terms of the turf, the salt water is probably not going to do much damage, since it's probably a spigot. If it was an irrigation system, I would be more concerned, but through the spigot, it probably wouldn't make much difference. I'm not sure about this, but I would guess that the potassium salt would be better for the soil over the long run than the sodium salt. But again, since they're not applying it regularly through an irrigation system, I'd be shocked, with as much rain as we've been getting that it will leach that salt through.
28. We have a Lincoln viewer with flowering dogwood and the leaves are turning brown after flowering. Any diseases there?
a. Is this a newer or well-established tree? When you see leaves browning, you may have trouble with establishment and the roots may not be establishing well. It may be stressed and on its way out. I would simply watch it for a while and see how it progresses and make sure you're not over-watering it, but maintain adequate moisture, and don't do anything else.
29. Dennis, we have a Crete viewer who wants to know if he can transplant tree frogs three blocks. Will they stay in their new location or return to home?
a. Legally, you can only translocate them 100 yards. If everything is there, they may stay, but the best thing would be to move the tadpoles into the new location in water and they'll stay.
1. Do mosquitoes dunks kill your tadpoles?
a. No, they do not.
2. Do squirrels chew on downspout ends?
a. They chew on some things for territorial markings, but usually it's a wood product, and they rub their chins there.
3. Can you buy turtles to put in ponds anyplace?
a. Yes, you can. Pet stores will sell you sliders as long as your yard is fenced in.
4. What are the best fish for a small pond that is in the city?
a. I would go with the native minnows you can get at at a bait shop or even sun fish.
5. Does soft water kill creatures in the pond?
a. Soft water can kill amphibians, yes, because of the sodium and the salts.
6. Do snakes dig their own holes?
a. Only bull snakes.
1. A viewer has little apples that are pitted, and it looks like they have rust on them. Is it too late to do anything about them at present?
2. There is a spruce that has only new growth on the tips, no growth behind whatever.
a. If it's on a portion of the lower portion of the tree, it could be a needle cast disease that would affect second-year needles. In that case, a fungicide application would help.
3. Which virus in tomato is prevalent early and is there a control for that?
a. There is no control, except to rogue it out.
4. How do you prevent moldy strawberries in that strawberry patch?
a. Most of that is due to Botrytis fungus, which you need to make sure you have good ground cover and straw them before they get the full canopy, and there are fungicides you can use before flowering.
1. This viewer in Cresent, Iowa who wants to know how to kill crownvetch forever.
a. Probably applications of broad-leaf herbicides in the fall, repeatedly in the fall.
2. How often do you have to sharpen the blades of a regular old cutter mower instead of a gas-powered one?
a. A reel type mower? Sharpening the blades is difficult, but I would probably sharpen or adjust them at least once a month.
3. is there a nontoxic, pet-safe organic weed killer available for garden use?
4. Is perennial rye a grass that we recommend for shade in Nebraska?
a. We don't recommend perennial rye very much in Nebraska at all, or grass in the shade, for that matter.
5. Is it better to catch grass clippings or mulch them?
a. Always return them if you can.
6. And you smooth out the lumpy lawn from the night crawlers with what?
a. You can try a roller, heavier roller, or a power rake.
1. This is a Brainerd viewer that has millers in the lawn, in the house, and sitting inside the screen door. What can they do about that?
a. Very little. Turn off the porch light to keep them from coming to the porch. Other than that, they'll be gone in a couple of weeks.
2. We have a viewer who thinks they squished a junebug already. Is that possible?
3. A viewer has, what they described as little grains of white rice on a broad-leaf evergreen Euonymus. little tiny grains of white rice.
a. Probably Euonymus scale, and the treatment would be Permetherin in mid-May, or any of the contact insecticides.
4. Will vaseline keep bees and ants out of hummingbird feeders, a ring of it so they can't climb?
a. I don't think so.
5. Are ants required to make peony buds open?
a. No, they're feeding on the necture, but what they do do, is prevent herbivores from bothering the peony.