1. This southeast Wyoming viewer thinks they have corn rootworm beetle, which are black and yellow. Their cornstalks look beautiful, then they become weak and fall over. Then these worms appear, followed by these black and yellow beetles. They're wondering what it is, and how do they treat it.
a. There may be a few issues here. Perhaps it's true that western corn rootworm is distributed well into the panhandle of Wyoming. At one time it wasn't. The larva would be responsible for the weakness of the stems falling over, but there could be other reasons as well. It would be important to really look at the roots themselves. They should be creamy-white, small, wormlike larvae that feed on the roots and undermine the strength of the plant so that it doesn't withstand the strong Wyoming winds. So check that out first before you make a conclusion that it is corn rootworm. If it is, you might check with your local co-op for control recommendations. Most products require that someone be certified to apply it, but there may be some exceptions.
This viewer may also be talking about the corn ears and the beetles that get in the ears. Or pertaining to the silk feeding, the western corn rootworm will feed on silks, interfering with pollination and with kernel filling. When the silks are green, that's the time to apply something both for corn earworm and corn rootworm. I think permethrin is appropriate for sweet corn to keep the rootworms or insects from feeding off the silk.
Any damage that occurs to the ear attracts other kinds of beetles, called picnic beetles.
2. This is a viewer that apparently has done some pruning on large silver maple trees last winter. Their question is whether they should add iron.
a. If it's been severely pruned the last thing you want to do is inject iron. You can blow leaves off a plant if you over inject it with iron, especially if they're young with new growth. I'm going to say no, hold off. If it was as severely pruned as they describe they want to delay that possibility for at least a year.
3. This viewer planted five dwarf burning bushes. They were doing fine, and now one is losing its leaves from top to bottom. They did not say where they're from or what part of the state they're in. This might be pathological, might be environmental.
a. If the bush is losing from the top to the bottom, you want to look at the base of the bushes to see if you're dealing with root rot, or even rodent damage. Dying from the top down, it gives us the indication that water isn't able to get to the bottom of the plant. That's the first place we start seeing wilting and loss of leaves. You have to get down there, take a look at the base, if it's turning colors, brown or black in coloration, it may be if there's a sunken canker in there, or a rodent may be feeding in there.
4. This York, NE viewer has two wisteria that are in the sun until noon, then in the shade. They're 18 years old and have never bloomed.
a. Eighteen years is a long time, but Japanese and Chinese wisteria can be frustrating that way. For some reason they can take a long, long time to bloom.
One recommendation to induce blooming is root pruning. In late fall, make 18" deep cuts in the soil with a spade, about four feet from the trunk, in a circle around the plant. The theory is that you stress the plant to the point that it stops vegetative production and goes into flowering and seed production mode. Wisteria are so vigorous that they usually recover from root pruning just fine, but that would be one of the extreme techniques that you could try.
In the end it's a matter of time. You just have to be patient until it reaches that point where it finally decides to bloom. Or try planting one of the American wisteria, such as 'Amethyst Falls', which bloom much sooner than the Asian types.
5. This Omaha, NE viewer has large planters outside with Begonias and Coleus that attract hundreds of bees. They're wondering if the bees are in the soil.
a. There are bees called Ground Nesting Bees that like soft soils. So if the pots are large enough it may be that you have these Ground Nesting Bees choosing those pots as a site to create a nest. If you water regularly that may be a deterrent. They might be hovering around, thinking "hey, this is a good place to set up house," but they will no longer be interested in it because if it is too wet there's nothing they can do. The color as well may be attracting bees.
6. This Lincoln, NE viewer wants to know how long Treflan (Preen, trifluralin) lasts.
a. Higher application rates will last longer than lower rates. If you leave it on the soil surface without incorporation or without watering it in, it photodegrades in about 48 to 72 hours. If they just throw it on the surface and hope for good weed control, they're not going to get it. So it's really hard to say how long it lasts. It depends on what rate they put it down, what product they use, whether they incorporate it or water it in. It can be short-term if they don't get it watered in or anywhere from three to six weeks depending upon rate.
7. This Lexington, NE viewer has spinach and beets. The leaves are turning splotchy with whitish-brown spots. They had the same thing happen last year.
a. Whitish-brown splotches on spinach and beets could be a leaf spot. Leaf spot in western Nebraska on sugar beets probably will go to spinach and regular beets. It's a little early for that pathogen to be showing up this time of year. It likes it a little bit warmer and more moisture. A picture would be great so that I could have a better view of what we're looking at.
It could also be an insect such as a Beet Leafminer or Spinach Leafminer. The larvae feed between the layers of leaf tissue. They will not make a nice sinuous path, but they'll make a blotch. Check the leaves to see if there's a sinuous trail on that leaf. Recent growth may not have it, because they time their infestation fairly early in the season.
8. This Iowa viewer has nine different fruit trees. They had good crops in previous years, but not a single bloom this year and they haven't had any freezes. A second Brainard, NE viewer has an 8 years old peach tree that didn't blossom. They say it may have gotten dry last summer. What causes the lack of flowering?
a. I've had this question about fruit trees a lot this year. If you think back a couple of years we had a very damaging freeze in 2007, and almost all of the fruit trees lost their flower blossoms that year. So we had no fruit production that year, which allowed trees to store a great deal of energy for blooming and fruit production the next year.
Last year in 2008, we did not have any late frosts and most fruit trees set a good crop. We had very heavy production on fruit trees. When a fruit tree puts on a very heavy fruit load in a given year, then often the next year it kind of takes a vacation. The tree needs to regenerate energy resources, so it does not produce for a year, then will bloom and set fruit again the following year. So fruit trees can get into an every-other-year cycle of production.
Obviously you want to have a few fruits on trees every year. So, next year when the tree blooms and sets fruits, you'll want to thin them. For apples, thin to about one fruit per spur or one per 6 inches of branch, and for peaches one fruit per 8 inches of branch. This will get them back to an every year blooming cycle.
9. This Sioux City, IA viewer has 15-year-old African Violet's, indoors, and they're seeing small crawling bugs that turn into what they're calling "fruit flies". They're wondering what to use to control them.
a. Could be whiteflies. The adult stage will feed on the terminal growth, but are completely white.
Also I think what might be happening is the plants are overwatered, and the soil develops fungi that is attractive to dark wing fungus gnats. They deposit their eggs in the soil. The worm-like larvae have shiny black heads and move through the soil eating fungus. The dark colored adult gnats fly around houseplants and lay their eggs in soil.
I recommend changing the watering schedule and allowing the soil to dry out more between waterings. It might interrupt the life cycle of the fungus gnats.
10. This Omaha, NE viewer has a fescue/bluegrass lawn mix. Their first question is when do they apply the second step of the lawn program for weeds and fertilizers. They put down a pre-emergent on April 1st and now they're wondering about putting down insect control.
a. April 1st is about two to four weeks too early for their pre-emergent application. By delaying putting that first application down you get more season-long weed control.
The second application of a four-step program has fertilizer and broadleaf herbicide in it. That can be put down anytime. But once that seed head has extended on weeds you're not going to get great control.
If they don't have insects there is no reason to put down a third step. Grubs are the only insect that we want to go after with a preventative. Don't worry about a preventative insecticide for any insect other than white grubs.
11. This Lincoln, NE viewer was digging dandelions and found grubs. Is it time to do grub control?
a. If a lawn has a history of grubs, the preventative control of white grubs is the practice that we currently utilize. Mid-to late May though mid-July would be the best time for application. I'd skew it more toward the first part of June. The grubs that you see now are full grown. They feed last year and will transform into beetles that will show up the first few weeks of June at the porch lights. Don't do anything about them. If you see them, pick them up and throw them out for the birds as little snacks.
12. This viewer says that last week we showed three stages of spray damage on dandelions. Their question is whether the seeds are still viable after we've killed the plant with glyphosate (RoundUp) or another herbicide.
a. That's why we talking about timing being critical. Perennial weeds are better controlled in the fall. Spring applications, because the timing is off, usually result in really bad control. Or they actually accelerate seed production because the plant's natural defense mechanism, when it's under stress, is to produce seed. Dandelion plants have the capacity to set anywhere from 50 to 500 seeds per head. You may be putting out 500 seeds if you spray it with improper timing. That's why we urge you to consider a fall application.
So if you time it right, before the yellow is visible on dandelion flowers, it hasn't started to set seed.
13. This is a viewer who sent us a little sample. It's an old rose, probably 'Harrison's Yellow' from the description. They say the original plant came from Kimball County about 15 years ago. Their concern is that it's got orange-colored growths, a few dead branches, and things like that going on. They wonder what is going on and what they can do about it.
a. The orange growth we're seeing is rust. Roses, specialty older roses, are very susceptible to rose rust. It can cause the defoliation of the plant and weaken it. If we get rain like they're predicting, you'll want to treat with a fungicide. Choose a product that will control rust on roses and make that application.
You might want to look closely and see if you have canker development on some of those stems, too. You'll need to prune these out eventually and just monitor the rose overall. Unfortunately one of the downsides of those old historic roses is they're not resistant to most of the common rose diseases.
14. We have a Mullen, NE viewer that wants to know whether blackberries can be grown out west and what varieties you would recommend. Then a second question is from a viewer in York County and they want to know how to prune thornless blackberries.
a. Blackberries prefer soil pH in the range of 5.8-6.5. Do a soil test and amend the soil if necessary to bring the pH within an acceptable range. Blackberries tend to be slightly less winterhardy than raspberries, so be sure to choose a cultivar well-adapted for your location.
Other cultural practices for blackberry are similar to those for raspberry. Keep them well watered so they have good fruit production.
Think about choosing a thornless blackberry, because they're easier to manage without getting scratched up trying to harvest or prune them. Thornless, erect cultivars include 'Navajo', 'Arapahoe' and 'Apache'. 'Chester' is a thornless, trailing blackberry. Thorned cultivars with good production include 'Triple Crown' and 'Illinois Hardy'.
Raspberries and blackberries have two types of canes- primocanes and floricanes. Primocanes, are the first year's growth, and then floricanes are second year, fruiting canes. In the year that they first come up, blackberry primocanes can get very long- very, very long- and weep over so that wherever they touch the ground they'll root down and you'll have a new plant. That's why blackberry plantings can be almost like a thicket. In that first year when the primocanes come up, toward the end of May-beginning of June, you're going to top the canes at about 48 inches. That's forces development of secondary branches. In about February/March you'll prune the secondary laterals back to about 18 inches.
You'll harvest the floricanes in summer, then in fall prune them all out down to the ground. If you haven't already topped this year's primocanes, then do that, although that ideally would have been done in May and June. Keep following this process each year, of topping those prima canes, and then the laterals in the late winter, February/March.
15. Jim, this is a Benkelman, NE viewer who has a redbud, 5 years old, and some of the larger branches are dead with holes in the branches.
a. Most likely it's bark beetles. There may be some borers, but those are probably the secondary manifestations of some stress that's far greater and preceded the insects. I'm wondering if the redbud is in a hostile area of the landscape, planted in a less than ideal location. Usually people plant redbuds in full sun, but they are an understory tree that prefers growing in the shade of other trees. In full sun, they're usually stressed, usually too dry. You know, there's lots of things that go wrong with them. If you're going to plant one, put it in the shade of other trees. It will be more healthy and vigorous, and not be attacked by secondary insects like bark beetles.
16. A Lincoln, NE viewer wants to know how to get rid of the lily of the valley in flowerbeds. They've tried glyphosate (RoundUp).
a. Lily-of-the-valley is difficult to control, even if it's growing in a area by itself and not scattered amongst other plants. Digging it out won’t work if they have other plants nearby.
Interestingly enough, glyphosate seems to be everyone's choice, "Let's use RoundUp". It often doesn't work. Often combining glyphosate with 2, 4-D will give better control. Cut plants back and immediately spray or paint them with that product is the way to get it into the system and getting it moving through. It's not a lost cause, but you're not going to squirt something at its base and hope it dies. It is not going to be as simple as that.
For example, trumpet vine, one application is not going to kill it. Cut the stems back and immediately paint the mixture on the cut stem. We're not talking about cut it, then do a few garden chores, and come back. Paint the cut surface immediately. The plant's natural defense is to seal up that exposed surface as quickly as possible. People have dipped pruning shears in herbicide and snipped the plants with them. If they are really convinced they need to go with a herbicide, cut and spray, cut and spray, and hope for the best.
17. Amy, this is a viewer in Bellwood by Columbus. Plum and nectarine trees have brown on the fruit when they're ripe. They want to know what they can do this year to prevent that from happening.
a. That's a fungus called brown rot. Ironically I'm working on a new publication that will be out in the next month and a half. You need to treat with a fungicide. You are going to do that right as the fruit is being set-on to really protect it. You may have to do a second application. Sanitation is the other big thing. Remove the rotting fruit from the area so it doesn't infect other fruits. Just take a look at the UNL Extension Publications web site, http://ianrpubs.unl.edu, and hopefully you can find information there shortly.
18. This Friend, NE viewer has a Concolor Fir that has bright purple growths at the tips of the top branches. They moved it last year, because it was getting too much water. So it's been a little sickly, but now it's got the purple on the top. Wonder what that is.
a. That is the new little cones that are just developing this year. In a lot of our evergreen trees, when the new cones come out, they're very small. They're about the size of a jellybean and they sit right on the top of the new growth, or the new candle as it comes out. They can be brightly colored, reddish or purplish.
I had a call similar to this a few weeks ago, Kim, and the question was, "Why didn't it open? If it's a cone, why isn't it open?" This is just the development stage for them right now. If you look farther back on the branches, you might see green cones, which are still closed, and those are the cones from last year. You might eventually have the third-year cones, which are probably brown and open. This is a natural life cycle of the tree.
Lighting Round
Sarah
1. This is a viewer who wants to know whether mimosa trees will live north of Wahoo?
Generally not. It's not very winter hardy for this part of Nebraska.
2. This viewer has crabapple trees that are half dead and wonders whether they should fertilize them?
No. Fertilize won't hurt, but can make it worse. Keep the trees well watered and well mulched through the summer.
3. This viewer wonders whether cutting the roots to build a retaining wall around huge silver maples are going to hurt those maples.
Yes, it will seriously damage the tree. I wouldn't do it.
4. How about the latest date to plant the early vegetables like spinach without having them bolt?
We're approaching that now. I wouldn't go any later than May 15th. We're really right at that point.
5. Is there any way to straighten a 10-inch caliper pear that blew over in one of the windstorms last spring?
No, not easily or to achieve long-term good health for the tree.
6. How about eating the stalks of the rhubarb if they cut the flowers off?
No. Don't eat the flower stem stalks. Eat the leaf stalks.
Amy
1. This is a viewer who removed a big maple and has big mushrooms in the turf. Anything to do?
No. The mushrooms are breaking down the roots of the old maple tree. There is no control.
2. This is a viewer who has fruiting apples, didn't get them sprayed for anything, including cedar apple rust. Is it too late for a spray program?
Wait to see if you get spots to form. You may want to do an application right after full bloom to protect the fruit. It's been dry so diseases haven't been too bad yet.
3. This viewer has serviceberries, but has noticed that the serviceberry fruits look like they won't fill out or be full. They look rotty.
Could be a fungal thing. I can't remember if serviceberry gets fruit rot or not. Continue watering and maintain good plant health.
4. This viewer has grass clippings that molded. Can they still use them on the garden or the mold spread?
I wouldn't use it just to make sure it doesn't go to the vegetable crops depending on what type of mold it is.
Roch
1. This viewer wants to know if the patch kits that you can buy for turf, do those work in the lawn for spot seeding?
No, because they're predominantly annual ryegrass or perennial ryegrass. You will want to plant back what was originally in the lawn. Or else you are going to have a little bit of weed patch. I am not a fan of patch products.
2. How about using tomato juice to get rid of dog urine spots?
It will get rid of the basic nature of the urine, but bottom line it won't take care of it.
3. How can they kill the weed seeds under a bird feeder without hurting the birds? Anything that will work?
They could solarize the soil. A pre-emergent herbicide will work, but the birds might pick up the granules. Probably want to avoid that.
4. How do you kill trumpet vine?
Cut it off at the stem and hit it with a glyphosate (RoundUp) and 2,4-D application.
5. How about a climbing rose? They have already tried 1/4 cup glyphosate and 1/4 cup 2,4-D on the stump and it didn’t work.
This is probably a timing issue; try again in fall. You want to cut the stem and immediately put that on.
Jim
1. This viewer has wild columbine and all the flowers are being deformed by aphids. Anything they can do?
Just trying to spray it all off with a soapy solution, a little bit of velocity in the water will knock them off. That will take care of them.
2. This viewer has little bugs on the hollyhock that looks like baby lightning bugs and holes in the leaves.
Most common is hollyhock weevil, but the description doesn’t seem consistent with that. Carbaryl (Sevin) is a good product to control hollyhock weevils. It's best to control it as soon as you can.
3. How about controlling thrips on roses?
It’s almost an impossibility. Imidacloprid can surpress thrips in rose and that’s an option next year, not so much right now.
4. This viewer has snails in their garden under their hostas, not slugs.
Pick them where possible. Put down moist burlap, so they'll collect underneath there, and then dispose of them. That's a good plan.
5. This one says says they have flea beetles in the flowers.
Flea beetles come and go so there's probably only one generation. Again, carbaryl (Sevin) is a good product for controlling flea beetle larvae and the adults as well.