Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
2012 Show Questions - August 2
1. Five year old walnuts have a lot of caterpillars, black with white hairs. They are skeletonizing the leaves. What can they do to control them on the upper branches? They have picked them off the lower branches.
a. These are walnut caterpillars in the last stage. The earlier stages are tan, kind of red, rusty colored. In the last stage they are black and hairy and look totally different than the earlier stages. They have interesting behavior: between each molt when they shed their skin, they all climb down to the trunk of the tree or the base of one of the lower branches. All you have to do is wait for them to come down and you can scrape them off or spray them. It is an interesting behavior that we can exploit as pest managers. Scrape them off or spray them with something like Sevin. You don't have to have a hose end to get up there. Be patient and get them when they come down.
2. Bluegrass in front yard, fescue in the back; they do have an irrigation system. With the severe drought, they know the fescue will die. They water three days a week about one hour per zone. Is that enough irrigation for turf? Too much?
a. We don't know how much water “an hour” is. Take a straight walled can (tuna, peanut, coffee can) and run the irrigation for 15 minutes. Stick a ruler in the can and see how much water collected. If there is a quarter of inch, then an hour is a full inch. Some soils can't take an inch an hour. The heavier type soils--silty clay loams--that tend to be east of Kearney can take maybe a quarter to half an inch per hour. They would need to run double sets, about 30 minutes each and wait 24 hours and run another 30. If they are putting on an inch an hour, that is too much. Fescue needs an inch to an inch and a half per week. Irrigating like they are may be wasting water. The key is to measure how much is being applied and adjust accordingly. And always deduct the local rainfall out of the requirements before irrigating.
3. When dealing with aster yellows, how do you sterilize the tools? Do the chlorine wipes work? Can the potting soil or the soil in the bed be reused?
a. Aster yellow is caused by a phytoplasm and is similar to a virus when we look at transition. It can move on tools as well as by insects. You can sterilize to tools in a 10% bleach solution or with alcohol. The soil can be reused, but be sure to remove the plant material.
4. A viewer in Stanton is raising beans, but is not getting any beans. Is it the heat?
a. It is the heat. We are getting the same question about several vegetables; the plants are not setting fruit. When the temperature is this high, pollen will desiccate. Hopefully when it cools down the plants will produce again.
5. A Crete viewer asks where are the insects?
a. Like plants, the insects are struggling with the heat. Less plant material; it's too hot. Sometimes the temperatures actually have exceeded what the insects survive well in. With certain types of insects, we're seeing fewer. Other types, like spider mites, the opposite can be true.
6. A viewer found this growing on plants by a small creek. [Image of a white coil with black speckles item wrapped around a stem].
a. We're guessing it is a parasitic plant living off the other plant. We will have Cheryl Dunn take a look at it and may be able to have a better identification on a later show. They are a unique part of the plant kingdom.
7. An Omaha viewer has a dwarf, freestone peach. There is black on the inside of the pit and a hole in the outside of the peach. What is this and how can it be combatted next year?
a. This is probably insects feeding. I recommend a good fruit tree spray, fungicide and insecticide, if they want to grow quality peaches. Any little hole in the skin, birds will get to it and bugs will eat at it. Once the wound was there it opened it up.
8. A viewer has one tomato plant and every tomato has a hook-like protrusion.
a. This has not been well researched. I can't tell you what causes. Most likely it is related to pollination and formation of the fruit after the initial pollination. It is odd. It is one of the more fun ones on tomatoes. No reason you can't use that tomato.
9. A Harlan County country home: they have 3/4 to inch-long feces under the eaves. They don't think it is an insect.
a. It could be bats. The feces will have silver flakes in it from all of the insects. Take some of the feces to the Extension office or send it off to Dennis Ferraro at UNL for identification.
10. A volunteer tree is growing through the center of a lilac. Possibly an ash, an inch to an inch and a half in caliper. Can they kill the ash without killing the lilac?
a. If they trim it back, it will promote lateral branching. Cut it way back (to 6 inches) and immediately paint it with ready to use Roundup. Make sure you don't get it on the lilac. It will probably translocate in the woody tissue and damage the ash tree. They will have to do that that several times. Once it is dead, it will snap off. It won't be a one time application. Paint the Roundup on with a brush, being very careful not to get it on the lilac.
11. This viewer has a group of six peonies.One of them in the group has dried up and turned brown. Stem is green, the leaves are not looking good. What could this be and will it spread?
a. If the leaves are browning from the bottom up and you are watering, you could have root and crown root. That's something that's going to be stress specific. I wouldn't worry about the other plants. Make sure you are not over watering. Drought stress will favor root rot. I wouldn't recommend any treatment and see how it continues here into the fall when we might get better growing conditions.
12. This viewer has a 22 year old Black Hills spruce. They watered for a long time several weeks ago. Now they are seeing needles on the south, southwest starting to purple. Environmental or spider mites?
a. It could be mites. With purpling, I think of needlecast, rhizosphaere needlecast. It will cause that purpling affect. It could be the needles dying from a disease that affected them earlier in the season. If it is, you will see the needles down the branch dying into the second year growth; new growth will be fine. Look closely to see the fruiting structure: dark dots on the needles. If that's the case, then you want to look at a management program next spring. Not now. Since the viewer mentioned the damage to the south and southwest side, this could be a canker coming in and affecting a certain part of the crown. Look for pitch on the branch associated with that part of the tree. If it was an environmental scorch situation, I would think that the new needles would be affected. They would feel the water deficit first.
13. This is a viewerwho has a Burr oak about twelve feet tall; its leaves come out in the spring and then they get skeletonized.
a. Two options; one is the sawfly, also known as the oak leaf skeletonizer. It strips the upper and lower surfaces of the leaves, leaving brown patches. The other possibility is the canker worm that can come out in the spring. They leave nothing but the veins behind. The important thing is to go out and see if there's insect activity now. And if there's nothing there, no point in treating. Making a note and next spring, go out starting in early May and into June, check on a regular basis and catch what's doing it and then treat for that.
14. Is Canada Green an appropriate grass for anywhere?
a. They sell it as adaptable to everywhere. It is essentially annual Candian Ryegrass and will grow almost anywhere for just a year. No, we wouldn't recommend it.
15. A viewer has a narrow leaf cottonwood and it has pod-like things.
a. Petio galls, these are caused by aphids. They are at the base of the leaf. They won't cause injury. Don't worry about it. They are all part of nature.
16. A viewer needs to attend to drastic broadleaf issues in their lawn and needs reseeding. When should they do a broadleaf application to get ready for seeding?
a. In a normal year, we would be saying mid to late August. If we had daytime highs in the low 80s and there's a possibility of that, albeit, slight. With these temperatures there's less potential for injury for non target plants like tomatoes and grapes. I will say broadleaf control will have to wait unless we have a span of highs of low 80s---highs not lows. And to be followed by temperatures not to exceed mid 80s. That's not the projection this year. Dryer than normal, hotter than normal until October. In that case, we'll miss seeding windows, not only turf, but fall vegetable plantings. Mid to late August is when you want to put broadleaf herbicides down, but chemicals do not work as well in the high heat. Most of the chemicals need a 2 to 3 week delay before seeding. And recommended fescue seeding is mid September. You can push it to the end of September. Bluegrass until mid October and still have successful establishment. In normal years. This is not a normal year. You might get lucky if you want to go for it.
17. This is a viewer that has some issues in their grapes. The grapes within the cluster themselves are not looking good at all. Are there diseases of grapes prevalent this year?
a. If there's moisture, black rot; you will have individual fruits that will shrivel up. If it's drier, powdery mildew is possible. If you want to manage this, you need a fruit tree spray program. If you want to control diseases, get on a program early in the year, not now, you need to be an a standard program.
18. This viewer thinks they see cardinals snipping away at the flowers of vine crops and taking chunks off their baby cucumbers. Have you seen that?
a. It can happen. Bluejays and starlings will do it, too.
19. An ongoing problem: big potatoes with what look like worm holes – grubs?
a. They could be three-year grubs, so at the end of the season fall tillage is important. With the potato pieces in the spring, you can treat those with Sevin. You can use a fungicide. It may be cutworms, it might be something else; and there is not much that can be done now.
20. A viewer planted Knock Out® roses and daylilies, mulched around them, and they seam to be dying. A dyed mulch question: Their question is does the dye in the mulch have a toxic affect?
a. No. Some are so fine, they tend to seal up the surface, they make water penetration be repelled. If was a fine mulch, we can see negatives, in terms of toxicity in the dye, all of the dyed mulches are vegetable based. This is more likely to be a water issue.
21. Ths viewer has aspens and every year they get spotting and dying leaves. They spray with fungicide, but it doesn't seem to be helping.
a. There could be afew different leaf spots. If you're not seeing results from the fungicide, you may be applying it at the wrong time. If you are not seeing results, bring in a sample to make sure. If you make a fungicide applicationand you don't see a response, it could be an error in timing.
22. An Iowa viewer has perennials that have turned brown and appear to have died. Will they come back later in the fall or next spring?
a. It depends on the perennial. Hostas? they probably won't grow back this fall, but are probably just dormant and will come back next year. You can cut them back and if this dry weather continues for another month, maybe give them a good soaking. Coneflowers or phlox? you want to dead head them or cut them down to the ground. Hopefully they'll be able to survive in a dormant state and they'll come back next spring.
23. A viewer has two pin oaks and they've seen what they think is carpenter ants. Should they do anything?
a. The only concern is that they can come into the home. You can use a bait around the tree. I would try to get rid of them. They are not hurting the tree. They may even be beneficial.
24. A viewer that had a yellow honeylocust that was cut down and is continually resprouting. What can they do about it?
a. If it’s in the lawn, use a chemical like 2-4,D---repeatedly. Continue to do that until all of reserve in the roots is gone.
25. Are there diseases of oaks that are show up as spotting on the foliage?
a. Yes, there are several diseases.
1. A Columbus viewer wants to know if their red potatoes can be harvested now because the plants are dying.
2. Will they store as well?
a. No, probably not.
3. What about hybrid eggplants; how do you know it is time to pick them?
a. The skin should be clear color, dark purple or white, smooth and shiny. If the skin is dull, they are over mature.
4. Should they have pruned the every-bearing raspberries canes after the first crop?
a. Yes if they wanted a fall harvest.
5. How about blackberries?
a. Yes. The fruiting canes should be pruned after they are done fruiting.
6. Can this viewer drastically cut back old yews right now and still get good growth next year?
a. No, I wouldn't do it now. Wait for dormancy, from November to March.
7. How can you tell when acorn squash is ripe?
a. Dark, shiny green skin, but hard enough that you cannot push your thumbnail in to it. Really firm.
1. Is there a wilt pathogen that would move between sunflowers and cucumbers?
2. The hand sanitizers that we talk about using on tools; is there anything to stay away from?
a. Just make sure the ingredients include alcohol.
3. The rust covered foliage that some pears have this year: can they go into the compost or would that spread?
a. It will not spread if it fully composts. Make sure it is broken down; if you have enough heat and stir it properly it will break it down.
4. Two viewers have morningglories with a grayish substance on the foliage. What is that?
a. Probably powdery mildew. Try watering from overhead.
5. A concolour fir with a grayish cast on second year needles, what is this?
a. Could be a canker, that's the thing I would look at first. There are needle casts on firs, but it's not common. May want to bring a sample to the local extension office.
1. How often should we water turf to keep it alive?
a. To keep it alive, once a week for fescue and once every two to three weeks for bluegrass; to keep it green, once a week for fescue and three times a week for bluegrass.
2. What about irrigating buffalograss?
a. Once every two to three weeks.
3. What time of day is best to water to save water.
a. Predown or early morning.
4. Is it possible to overseed with a blend of bluegrass and fescue so there's some turf next year after this dry year.
a. Yes, you want it to be dominated by fescue, just ten percent blue grass.
5. What is the timing for fall preemergent this year?
a. All bets are off. We have no idea.
6. What about violet control this year?
a. Normally, September, around Labor Day and again three weeks later. But with the warmth expected to go later in the fall, I will say this is not true. We will keep the viewers updated later this month.
1. A pollinator question: there's a lot of birds in this person's yard, but they are not seeing insects. Did the birds eat them?
a. The insects are just hot or dead, reduced numbers.
2. A viewer did everything right on the squash bugs, but the eggs dropped into the foliage. Do they need to get the eggs?
a. No, the empty eggs will remain on the leaves.
3. Are there borers in Burr oak? Single hole at the base?
a. Sure. Almost every tree has a borer. It is subject to borers.
4. Is there any way to control the bullet gulls on oaks?
a. Treat just as the tree is leafing out in the spring. That's when the wasps lay their eggs.