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Published August 27, 2010, 12:00 AM

Dab of cooking oil will suffocate insects

Q: My ficus tree has small drops of white wax on the bottom of the leaves. If left alone, the leaves turn yellow and fall off. Any suggestions on how to handle the problem are appreciated.

By: Don Kinzler, INFORUM

Q: My ficus tree has small drops of white wax on the bottom of the leaves. If left alone, the leaves turn yellow and fall off. Any suggestions on how to handle the problem are appreciated.

(e-mail reference)

A: That is a scale insect invasion that is working on your tree. Depending on the size of your plant, scale can be eliminated by taking a cotton Q-tip and dipping it in light cooking oil and dabbing it on each of the insects. It will cause them to suffocate. If the plant is too large, then you need to invest in a systemic insecticide. Be sure to follow the directions on the label.

Q: I am puzzled as to why my morning glories are not blooming. They have climbed right up the trellis we made for them but have not bloomed. Thanks for your thoughts on this problem. (West Fargo)

A: The problem could be too much shade or too much nitrogen fertilizer. Other than that, I can’t think of a reason why they wouldn’t bloom.


Q: We are having squirrel problems. The squirrels at the lake are collecting acorns. One large squirrel began collecting stones from next to an oak tree a few days ago. He comes to the tree, selects a stone, rolls it around while smelling or licking it and then puts it in his mouth and takes off. I’ve tried to follow him into the woods to see what he is doing with them, but couldn’t find him. I don’t think he is taking all of them to the same place. The strangest thing is that he runs over thousands of rocks on our stairway to the lake in order to get to the stones by the tree. What do you think he is doing with the stones? Do they help keep acorns fresh? (Minnesota)

A: To know the workings of a squirrel’s mind! My guess is that the oak tree is exuding some sap that gets on the stones. Thinking he has found some form of tasty food that only needs to soften up through the winter, the squirrel picks them up for burial somewhere. My wife and I have observed squirrel activity for 25 years in our backyard and are continually amazed by their antics. They somehow reach squirrel-proof bird feeders, run across the yard with a pine cone that has no seed in it, somehow pry the lid off our garbage can that holds bird food, run off with a slab of suet that the squirrel barely can carry and much more.


Q: We have a honeysuckle vine that is being attacked by aphids so the leaves are drying up. What is a good treatment? Thanks for your service. (Portland, N.D.)

A: For now, try to get some Malathion to knock the population down. Next spring, just before the vine leafs out, get a systemic insecticide that contains Imidacloprid, such as Bayer, and apply the product according to the directions on the label. That will take care of any plant-munching insects for the entire growing season.


Q: I read your article on the website about planting a new lawn. Should I plant some oats or winter wheat with the bluegrass and rye mixture? I have sandy soil and watering times would be limited due to work. Any information would be helpful. (e-mail reference)

A: Yes, mixing oats in with the grass seed is an old practice to encourage a more stable and faster establishment. The oat seeds germinate faster than Kentucky bluegrass. This helps stabilize the turf grass ecosystem surface. You mow the oats when they get 3 to 4 inches in height through the fall. This also acts as protective mulch for the germinating Kentucky bluegrass seedlings.


Q: Do you know the best way to store a glut of potatoes? I store them in a cool, dark place, but they don’t last as long as I’d like. (e-mail reference)

A: Here is a website, http://oregonstate.edu/potatoes/storproc.htm, that is pretty descriptive. The website is intended for commercial growers, but I’m sure it also will be helpful to you.


Q: I found problems with almost every plant after looking at someone’s garden.

Horticulture is a foreign area to me, so I’m asking for your advice. The garden was established six to eight years ago in a spot where an old barn stood. The ground is very fertile. The spot has trees around it, so there is little air movement. The biggest problems are with the rhubarb and tomato plants. (e-mail reference)

A: The tomato foliage is being devoured by a sartorial leaf spot fungus. The rhubarb also could have a fungal disease. My guess is that everything just stays too wet. As you stated, the area has little air circulation. With the high dew points, temperatures and humidity, anything the least bit vulnerable will get some disease. Go to www.ag.ndsu.edu/pubs/

plantsci/hortcrop/pp659w.htm or www.ag.ndsu.edu/news/newsreleases/2010/

july-5-2010/expect-disease-problems-on-potatoes-and-tomatoes for information that may be useful. If it is any comfort to you or your client, you’re not alone.


Q: I inherited two apple trees. One produced a significant amount of small red apples. The other tree produced very few green apples. Since the fruit dropped off the one tree, the leaves are turning yellow and dying. There are branches with scaly or blistered bark. What’s happening to this tree? Any help would be greatly appreciated. (White Plains, N.Y.)

A: This could be apple scab affecting the leaf drop. It is a common malady on older trees of this species. I’d suggest contacting someone in your county Extension Service office. Go to http://cce.cornell.edu/learnAbout/

Pages/Local_Offices.aspx to find someone who can help you. You might be asked to send a sample and photos to the plant diagnostic lab at Cornell University to get my guess confirmed.


Q: I have a question about a cherry tree that belongs to one of my clients. I don’t know if it is dead or will make a comeback. The leaves are gone, the limbs are dried up and it doesn’t give out shoots like it used to. (e-mail reference)

A: There is no way I or anyone else could tell you why the tree died based on the information provided. There are ton of probabilities, such as stem canker, borers, bark beetles, bacterial wilt, fungal diseases and root rot. There also are a host of human intervention probabilities. I’m not trying to be difficult, but in order for any rational determination to be made, a sample with a history of the tree must be in hand. In all likelihood, a lab culture also would need to be made.

I’m telling you this so that you can respond to your client. The client gave you little information but expects an airtight answer. Here is some information on the bare minimum that is needed to get to the bottom of why a tree dies.

A horticulturist needs to know the planting date and form of plant when planted. Was it balled and burlaped, containerized or bare root? It would be good to know the genus, species and cultivar if possible. What is the exposure of the plant on the property? Is the plant out in the open, protected by buildings, a fence or something else? Does the tree get full sun, western or eastern sun or just partial sun? What cultural practices, such as watering, were used and what is the water quality? Were any fertilization or pesticide applications recently made?

It would be good to send photos of the affected plant parts and the entire plant. Send a plant sample showing the impacted plant parts transitioning to healthy tissue. I don’t know how this word can get out to everyone, but it has to start somewhere. It isn’t meant as a criticism, just guidelines to assist us in serving our clientele more efficiently and effectively.


To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu.

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