Garden Answers

Pests

Will mice eat my plants and kill them during the winter?
How do I get rid of these annoying black flies buzzing around my house?
What do you use and when to control web worms?
How can I protect my plants from wildlife?
What are the most current insecticidal treatments for peach trees?
How do I protect my trees from mites?
What can I do to keep the from Deer eating my roses and trees?
How do I get rid of earwigs?
We have an aspen covered in ladybugs. Is this symbiotic?
How do I get rid of these small black flies in my houseplants?
How do I get rid of birds that are making a mess of our deck and home?

Question: My neighbor told me that mice will eat my plants and kill them during the winter. Is that true?

Answer: That's a good question. Folks don't often think about it, but it's surprising how common a problem this actually is! Shrubs, bulbs and even perennials provide a good food source for these guys throughout the winter months. They'll dig up bulbs, eat the fleshy roots of perennials, but most often like the bark off of shrubs, especially junipers. I don't know why, but something in the junipers really appeals to them!

What happens is in the spring, you'll start to notice yellow or brown dried patches scattered throughout your plant that haven't been there before. Diagnosing this problem is simple. Go to the base of the plant near the ground and look carefully at the stems. If the mice have been at them, it'll be obvious: the stems will be light tan or yellowish showing the exposed inner wood.

Unfortunately, the dried areas indicate that the mice have managed to kill that particular branch. Once the damage is done, the only thing to do is to cut out that branch. Over time, it will fill in again. Spreading Decon under your shrubs during the winter should eliminate the problem.

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Question: Help! I have these really annoying black flies buzzing around my house. How do I get rid of them?

Answer: You're not alone. Those are fungus gnats, and they're fairly common indoors during the winter months. The larvae live in the soil feeding on dead organic matter, mature, and then start flying around. They're more noticeable now simply because we keep our homes closed up against the cold. They also thrive in wetter soils, and I've found that many of us will keep our houseplants much damper through the winter than at other times of the year. Though fungus gnats are certainly a nuisance, they rarely hurt the plant.

One of the easiest ways to help control fungus gnats is to monitor the watering. Shorter days and slower plant growth enable them to do just fine with less water. You can also use an insecticide to kill the larvae in the soil. A granular systemic will work okay. The most effective solution is to use a drench of Malathion (diluted according to the label and applied to moist soil), but it smells pretty bad, so most folks don't like to use it indoors. Another product is Knock Out Gnats, which is a strain of BT specific for these guys. It's safe to use, but pricey. Killing the adult form of the fungus gnat is difficult. Probably your best bet would be to get some of those yellow sticky cards. They won't wipe them out, but will help reduce the number of them. Hope this helps.

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Question: What do you use and when do you spray trees to keep the web worms in control?

Answer: There are two types of "webworms" we run into here in the valley. "Webworms" are caterpillars that congregate together, spinning nest of silken webbing. The most common is the Tent Caterpillar. This guy shows up in late April into the middle of May, depending on the year. They are primarily a problem with trees in the genus Populus (such as Aspens and Cottonwoods). There are three approaches to controlling this guy. The first is to do nothing. They rarely hurt the plant, they are more of an aesthetic problem. Birds in the area eat these guys up pretty effectively also. The second approach is to physically remove the nests and destroy them. Obviously, this only works if the nests are low down and not too numerous. The last approach involves spraying. There are several insecticides that you can use. Hi-Yield 38 Plus is probably the best broad spectrum insecticide. Another new product that works great is Fertilome Borer, Bagworm, Leafminer & Tent Caterpillar Spray. What's nice about this product is that it is safe to use, there's not toxicity to us or the birds, but it sure does a number on those little monster caterpillars! Either of these products are most effective when the caterpillars are small, so keep your eyes open on trees that you've had these guys on before, and spray as soon as you see them.

The second "Webworm" is the Fall Webworm. The guy shows up in late summer into early fall and feed off a number of different trees including Cottonwood, Ash, Birch, Crabapple, Sycamore, and many others. Control of this guy is the same as for the Tent Caterpillar.

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Question: I went out to water my Mammoth Sunflowers (which were about 5" tall) and all 15 or 20 of them were gone. They are in an unfenced area bordering an irrigation ditch. One or two plants were left that looked like they had been nipped off, all the rest were completely gone, including the roots. I discovered what may have been a partial deer hoof print. Was it deer? Raccoon? Skunk? About 15' away is another group of Sunflowers planted by the seed in our bird feeder. These plants are about 18" and were not touched. Is this a common problem? I'm replanting them this weekend, do you have any hints on how to protect the plants this time?

Answer: First, let me say that you're not alone in your frustration. Lots of folks are coming in complaining of similar situations. There are actually a number of critters that can be doing this. Deer are certainly a possibility. I would expect to see a number of prints in the vicinity if it's them. You can discourage them either with a Rottweiler (or similar large-sized dog) or with Deer Repellent. Use a repellent that has "putrescent egg solids" (or something to that effect) in the ingredient list. Though no repellent works 100% of the time, these types of products have proven to be the most effective in deterring deer.

Another possibility would be smaller animals such as rabbits, prairie dogs, ground squirrels, and mice. These guys are a little tougher to deter. Animal repellents work even less well on these guys. You can put out some D-Con for the mice and try trapping with a live trap for the others.

A less obvious possibility is cutworms, though I don't think that's what's getting your sunflowers.. These little caterpillars hide underground during the day and come out to feed during the night. They cut the plant off at ground level, leaving the roots, and they usually don't attack plants as large as yours. They tend to specialize in small, tender, new seedlings. There are a number of insecticides that you can apply to the soil to control them.

It could also be birds. Again, I think your plants are too big for them to bother. Like the cutworms, they tend to pull out small seedlings. I guess I'd try to keep an eye on the area over the next week or so to see if you can gain any clues as to what's going on. Good luck.

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Question: I have some peach trees on my property and have treated them with different insecticides in the past, but it seems that each year I hear something different. What am I supposed to be doing now?

Answer: It's a little late to be starting treatment, but it's much better than doing nothing. The peach tree borer attacks members of the genus Prunus that set a "stone type" fruit. This would include peaches, plums, cherries, and apricots. It can also affect their ornamental relatives such as Cistena plum, pink flowering almond, purple leaf plums, European bird cherries, Schubert chokecherry, flowering cherries, double flowering plum, Nanking cherries, and more. Basically that means that each of these plants has the potential for getting peach tree borer, and to be sure they don't, each should be treated to prevent it.

What this borer does is tunnel around under the bark like other shade tree borers, but it does it low down on the tree near ground level. The best treatment is actually a drench around the tree (use a watering can or a bucket) of Permethrin. Timing is important, but with this guy, the tree should be drenched June 20, July 10, and again on July 30. Wet the bottom 6"-8" of the trunk and soak the ground immediately around the trunk. You can use the 2.5% concentrate of Permethrin according to label directions. The 38% concentrate is NOT labeled for use on edibles. You can use it on ornamentals at 4 tsp./gallon and apply it June 20 and again July 20.

If you notice a gummy, jelly-like ooze around the base of the tree which indicates the presence of peach tree borer, you've missed the window of opportunity to drench for them. However, you can get some mothballs made of paradichlorobenzene (PDB) to fumigate these guys out. Crush the balls into a coarse powder. Dig a shallow trench an inch or two deep, and a couple of inches away from the trunk of the tree (never put the crystals up against the tree - it can hurt the tree). Sprinkle the crystals lightly (it doesn't take much) into the trench, and cover them with soil, mounding up around the trunk 5"-6", and water the soil to seal in the fumes. This isn't as effective as the drench, but it's better than doing nothing. If this is too confusing, we do have a hand-out with instructions we give folks who come in looking for insecticides to treat their peach tree borer. Hope this helps.

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Question: Help! It looks like I have mites in all of my trees! Is that going around right now?? I have some Kelthane that I used last year on my Ash tree. Now it looks like the mites are in my Aspen trees. My question is how much and how often do I use the Kelthane? How do I know for sure that I got it covered adequately?

Answer: We have had a lot of problems with spider mites this summer. Actually, I'm hoping that we're on the downward side of the problem. Spider mites tend to thrive in hot, dry weather, and should start decreasing with the cooler fall weather we're having.

The first thing I want to be sure of is that you really have spider mites. They are very tiny, usually JUST BARELY visible to the naked eye. Their feeding damage produces a yellowish brown stippling of the leaf. It can make the leaf look bronzy or silvery. In very bad infestations, you can sometimes see a gossamer fine webbing that the mites produce. Sometimes there are other things going on that people blame on spider mites. The best would be for you to bring out a sample for us to look at if possible and we can tell you for sure.

Control of spider mites isn't difficult, but it does involve a few tricks and some persistence to be successful. There are a number of insecticides that will work on them, but not all insecticides will do a good job. Kelthane is an old material that used to work great, but has not worked nearly as well the past couple of years. I think that our mites are developing a resistance to the product. If you want to try it, the spray that we sell is mixed at 1 teaspoon per gallon of water. The two best products I can offer you now are Insecticidal Soap or Hexakis. Hexakis does a better job I think. You can get it in Ortho Systemic Insect Killer. Spraying this time of the year shouldn't be a problem, but it can burn plants sometimes when it's hot during the summer. Be sure to read the label completely before using it.

Insecticidal Soap does a good job, but you have to do a perfect job spraying the tree. It has to physically get on the mite to kill it. It has no residual at all. Once it's dry, it's basically gone. Insecticidal Soaps are very safe, essentially non-toxic. Another thing; Insecticidal Soaps are not the same as your dishwashing soap. They are specially formulated to kill the bug you want, but not burn the foliage as kitchen soaps can often do.

Two common insecticides NOT to use for mites are Sevin and Permethrin. They work very poorly killing mites and often kill off the natural predators and parasites that feed on the mites, so the mite population explodes, making your problem worse.

One spraying will usually not give good control of spider mites. You should plan on spraying your plants three times at one week intervals. Another thing that can help, at least on smaller plants, is to give the plant a hard shower with cold water, concentrating on spraying the undersides of the leaves. What you're trying to do is to knock the mites off of your plant. Any that are knocked off will die. Doing this two or three times a week for two or three weeks will often solve the problem. Hope this all helps.

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Question: I’m hoping that you have an answer to my problem. Deer keep eating my roses and young trees! What can I do to save them?

Answer: There are a number of repellents available that work with varying degrees of success. The one that has worked best in most trials contains "putrefied egg solids.” Sounds pretty gross, but it really doesn't smell up the yard and it usually does keep the deer away. The only disadvantage to it is that you have to apply it regularly, at least once a week, or each time after you water. I have several deer repellent products that contain this material.

Other things that have been tried include bundles of human hair and pieces of deodorant soap hung out on your plants. I've never seen either one of these work very well. One last possibility is dried blood or blood meal. We sell blood meal as an organic nitrogen fertilizer. You sprinkle it around to feed your plants but the smell of the blood tends to deter deer. I've had spotty results with this--sometimes it works, sometimes not.

People lose lots of newly planted, smaller trees to the deer. You really have to plan ahead because deer can absolutely strip a tree overnight to the point where it’s not recoverable. Deer can be pretty persistent. Most people build a 6’ tall fence around the tree. You can use metal “T” posts that are used for agricultural fencing or even 2” diameter rounded poles. Sink them in the ground till they’re solid and stable. You’ll need three or four posts around each tree and put them far enough away from the tree so the deer can’t reach over the top to munch on your trees. The wire fencing you hang on the posts needs to be strong enough that they can’t push it aside or through it. I’d use “Hog Wire” or even chain link fencing fabric.

Now, having said all that, we do carry a light plastic “Deer Netting.” It says to attach it to stakes around your trees and shrubs to keep the deer away. Frankly, I’m skeptical, but it is an option for you. If you want to try it, let us know how it does.

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Question: I’m finding earwigs all over my plants. Do they eat plant leaves? How can I get rid of them?

Answer: Earwigs generally don't eat plant leaves. They have very weak mouth parts and the foliage of plants is too tough for them to chew on. They mostly eat decomposing organic matter, and from that standpoint, they really are beneficial. People often find them in cracks and crevices or under loose bark on plants. They're not hurting anything, they just like to hide during the day in dark, cool nooks and crannies.

About the only problem I see Earwigs causing is that they will eat the fruit of your Strawberries. As the fruit ripens and gets soft, they can sometimes start munching on them, but other than that, I tell folks to try to ignore them. If they are causing problems or are just unbearable, we get good control with Sevin Bait. It's a treated grain product that attracts them and when they eat it, the insecticide kills them.

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Question: We've got an older aspen that seems to be totally covered in ladybugs. is this symbiotic or just coincidence?

Answer: The presence of the Ladybugs usually indicates that there are Aphids in your Aspen tree. Aphids are small pear-shaped insects that suck the sap from your tree. There are a lot of different Aphids that feed on a lot of different plants. They can come in a variety of colors though the one you see on Aspen trees is usually green. I usually don't get that shook up about them. There are a lot of different insects (like those Ladybugs) that feed on them. You can kind of think of Aphids as the Wildebeests of the insect kingdom. Just hang in there, the Ladybugs will soon do a good job of cutting down the numbers of Aphids and your Aspen tree should be just fine. If you want to get rid of them right now, there are a number of insecticide sprays that will do a good job on them. Some choices are Permethrin, Malathion, Insecticidal Soap, Ultra Fine Oil among others.

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Question: I was watering my houseplants the other day and noticed a lot of small black flies in them. What are they and how can I kill them?

Answer: Those little guys are fungus gnats. They’re fairly common indoors during the winter months. The larvae live in the soil feeding on dead organic matter and the harmless fungi that grow on it. After they mature, they emerge as those little charcoal gray gnats that are so annoying. They’re more noticeable now simply because we keep our homes closed up against the cold. They also thrive in wetter soils, and I’ve found that many of us will keep our houseplants much damper through the winter than at other times of the year. Though fungus gnats are certainly a nuisance, they rarely hurt the plant. 

One of the easiest ways to help control fungus gnats is to monitor the watering more closely. Shorter days and slower plant growth enable them to do just fine with less water. You can also use an insecticide to kill the larvae in the soil. A granular systemic will work okay. The most effective solution is to use a drench of Malathion (diluted according to the label and applied to moist soil), but it smells pretty bad, so most folks don’t like to use it indoors.  Another product is Knock-Out Gnats, which is a biological control for these guys. It’s extremely safe to use, but a little pricey.  Killing the adult form of the fungus gnat is difficult. Probably your best bet would be to get some of those yellow sticky cards. They won’t wipe them out, but will help reduce the number of them.

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Question: We have a wonderful oak tree that towers over our deck.  The problem is that the tree seems to have many birds that are resting in them, not that we see so many, but our deck and the side of our home is loaded with bird droppings. We do not want to get rid of our shady tree but we are wondering  how do we get these birds to rest in another tree, we have many that are behind our home, but it seems they are drawn to this one for some reason.

Answer: Getting birds to change their habits can be a challenge, as anyone who has tried to discourage birds from eating all the cherries from their trees can testify! There are only a couple of possible options I can offer you.

The first is to scare the birds away with a “scarecrow” type object. There are inflatable owls, snakes and hawks you can put up in the tree to scare them away. You’ll have to move these guys around occasionally as the birds will eventually get used to them and it won’t repel them. There are also decoys that really don’t look like anything except for two big black eyes with streamers attached to it. The movement of the streamers often startles the birds away. There is also “flash tape” which is a shiny, reflective plastic ribbon that you hang from the tree. As the ribbon moves in the breeze, the sun reflects from the metalized surface which can startle the birds away. Several years ago I saw mile after mile of vineyard in the Central Valley of California with clusters of these ribbons to keep birds from eating the ripening grapes. I guess if it helps farmers whose livelihoods depend on keeping the birds away; it has definite possibilities in our backyards.

The second option is to startle the birds away with noise. I don’t think that this really is a good option for you, but it is used in commercial orchards. They use a propane cannon that occasionally sets off a big boom that startles the birds away. Either way, I think if you can keep them away from your tree for several weeks, you can expect them to change their habits and hopefully, you won’t have to contend with the problem. Good luck!

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