Dan West Garden Center
December 2008 Newsletter©
Spray Programs
If you’ve ever tried to grow fruits, vegetables, flowers…well, just about anything in the Memphis area, then you’ve found out what a challenge it is, because we have such a wide variety of diseases and insects that attack everything we want to grow. Sometimes just a single spraying can clear up an isolated attack, but for many plants, it’s best to be on a spray program that prevents the problem before it starts. Fungicides especially, work best as preventatives. Borers are a good insect example for planning ahead. Too often, so much damage has been done to the conductive tissue of a tree before we notice a problem, that the tree can’t be saved. So plants that we know are likely to get borers are better off if we protect them from the start. So this month’s class is about protecting plants that are likely to be attacked and what products you need to keep them alive or to harvest their bounty. I like to address this subject every year because products and their labels change and we quickly forget what and when to do it, so this is your yearly reminder.
Fruit trees pose the biggest challenge. They get borers and a multitude of insects and fruit diseases.
Step one is to start clean. Spray the dormant trees with a combination spray containing dormant oil and lime sulfur. This can be done anytime the tree is dormant and the temperature is above freezing for a couple of days. Spray the tree thoroughly and the ground under the tree as well. The oil covers and kills any over-wintering insects or insect eggs and the lime sulfur kills fungal spores and mites. Just so you know, lime sulfur smells like rotten eggs, but it works great.
Step two, for fruit insects and diseases, is your combination fruit tree spray. This is a product that is labeled for fruit trees and has both an insecticide and a fungicide. These usually contain the fungicide captan, with malathion and/or carbaryl (sevin) for insects. The first spray should be at bud swell. That’s when you first see a little green. The second spraying should be when the flower buds are pink, showing color, but not yet open. The next spray should be when you’ve got 80% or better flower loss. Then after that, you’ll spray per label instructions until harvest. Normally, that’s every 10-14 days. The label will tell you when to discontinue spraying before harvest. It is important that you stay on the program. Missing an application can quickly result in fungal diseases attacking your fruit. I like to alternate products occasionally just to prevent anything building up a resistance to a particular product. I’ll use chlorothalonil for a fungicide with permethrin for an insecticide. Organic alternatives would be neem oil, which works both as an insecticide and a fungicide, a rotenone/pyrethrin combination or spinosad for insects and copper soap for fungal problems.
Step three is controlling borers. On apples and pears, you can use imidacloprid as a soil drench in December or January to control borers for a year. On peaches, cherries, plums, nectarines and apricots, spray the trunk, main branches and the ground beneath the tree with permethrin per label instructions which is normally about once a month.
For pecans, use imidacloprid as a soil drench in December or January to control insects. (You can apply it anytime the ground isn’t frozen, but it works quickest if applied in late fall or early winter so it’s present when the sap rises quickly towards spring.) Pecan phylloxera, the small round galls on leaves and stems is likely to be at least partially controlled by imidacloprid. It is labeled as a soil drench for other insects on pecans and has a commercial spray label for phylloxera on pecans, so I see no reason why if the chemical is present, it would not work. Severe infestations of phylloxera will reduce this and next year’s crop so I would treat a pecan tree just as a precaution since it controls other insects also. There is not a systemic organic substitute. For phylloxera control with an organic or with any non-systemic insecticide, spray when the buds begin to swell and two more applications 7 days apart.
Are many of your pecans black on the inside or not fully developed? Many people think this is a disease, when actually it’s a zinc deficiency that causes it. It’s called “rosette”, because it causes the leaves to be compacted together giving a rosette appearance, and it causes leaves to be discolored, twigs to die and the kernels to be dried up and black. Apply 3 – 5 lbs of zinc sulfate on mature trees each year and about 1 lb on young trees. Spread it evenly 10 feet either side of the dripline.
For cane fruits like blackberries and raspberries, fungal problems are our biggest concern. Spray with lime sulfur when they are dormant to start clean and use copper soap once the foliage has sprouted. Use permethrin should you need an insecticide. A rotenone/pyrethrin combination is a good organic choice for insects.
For grapes, use lime sulfur as a dormant spray and then the combination fruit tree spray in season. I like to alternate fungicides on grapes also. Every third spraying, use Bordeaux mix. Bordeaux mix is a copper fungicide that works particularly well for black rot on grapes. Use the same organic recommendations for grapes as cane fruits.
For blueberries, use chlorothalonil for fungal problems and permethrin for insect problems, though blueberries are relatively problem free in the Mid South. Neem oil would be a good organic choice for blueberries.
For strawberries, most combination fruit tree sprays can be used. For gray mold, alternate a copper soap or Bordeaux mix. Use permethrin for spot insect problems. An organic option would be a rotenone/pyrethrin combination for insects.
For most vegetables, carbaryl or permethrin will control most insects, chlorothalonil or mancozeb will control just about any disease. B.T., a bacterium that kills caterpillars, is a great choice for tomato hornworms, corn earworms and cabbage loopers and is available in both a liquid and a dust. Neem oil would be a good organic alternative but use with caution when the temperatures rise above 90°. Any oil could cause foliage burn in high temperatures, especially if the plant is drought stressed. Switch to the rotenone/pyrethrin combination for insects and wettable sulfur for diseases, in high temperatures.
Now the ornamentals…
Virtually every tree and shrub we grow in the Mid South is a potential host for some type of boring insect, but ornamental cherry, plum, dogwood, cherry laurel, elm, hickory, birch, oak and pine top the list. Borers are most likely to attack a stressed tree or shrub so keeping your plants watered and fertilized is very important. Most boring insects are the larval stage of beetles and can be controlled with an imidacloprid soil drench which protects the plant for a year if applied in December or January. Some borers are caterpillars, the larval stage of a moth. Imidacloprid has little effect on caterpillars, so a monthly application of permethrin is a good idea if you’re not sure what type borer you have. Cherry, plum and cherry laurel get both types of borers so an application of both products is advisable. Dogwood borers are controlled by imidacloprid. An organic option would be spinosad applied every 7 days from early April through June. The reason for weekly applications is because most borers have very short life cycles and when they hatch depends on the type of borer and the weather. We want to make sure the plant is protected during the 90 days that most borers hatch.
Euonymus…truly a plague on humanity. The evergreen (or ever yellow) varieties will get euonymus scale and powdery mildew. The more you shear them, the worse it will get. You can use an oil spray to kill scale whenever the temperature is above 32° and below 90°. Imidacloprid will give you season long control. Use acephate, a systemic insecticide, in the summer for 3-4 weeks control. For powdery mildew use propiconazole, a systemic fungicide for up to 4 weeks control. Neem oil would be an organic substitute except in very hot weather. The undersides of the leaves must be coated with Neem, but it’s not necessary with the systemic products above.
Azaleas planted in the sun will usually get lacebugs. If they are damaged now, you should be on a spray program to prevent repeated damage next year. Use imidacloprid for season long control or use acephate monthly beginning in late April and continuing through August. A rotenone/pyrethrin spray would be the best organic choice but again you must spray the undersides of the foliage.
Roses... Want to grow them in the Mid South? Then you have to spray them. I’m not talking about Knock-Out shrub roses that are low maintenance. I’m talking about floral quality, long stem, fragrant, “I’m so sorry, forgive me” type of roses. They are going to get black spot, powdery mildew, aphids, thrips, cane borers…get the picture? I like acephate for insects and propiconazole for diseases but I alternate it with mancozeb occasionally in the summer. Use liquid copper for fungal problems and neem or the rotenone/pyrethrin combo for insects as an organic option.
Photinia x fraseri or red tip as it is often called is a member of the rose family. It makes a spectacular hedge but is susceptible to Entomosporium leaf spot. The more plants you have and the more they are sheared, the more likely you are to get the disease. To prevent the disease, start spraying in mid March before the new growth appears and continue until fall. Use propiconazole every 3 to 4 weeks. Liquid copper once a week in the spring, and every two weeks in the summer, should give good control if you avoid overhead watering.
Otto Luyken, Schip, Zabel and cherry laurels often get shot hole disease here. It starts with a small reddish brown spot which ultimately dries, then falls out leaving small holes. Good cultural practices will help limit the effect. Avoid overhead watering, plant them in areas with good air movement and some morning sun and avoid shearing them so air can move through the plant. The disease is usually caused by a combination of a bacteria and fungus, so propiconazole would be the best protection with the least work. Start spraying by early April and continue every 3 – 4 weeks through June. By July, the conditions usually aren’t favorable for the disease to set in.
Gardenias often have a problem with whiteflies. You can’t kill every whitefly. Spray right now, kill them all and in a few minutes, more have migrated from surrounding plants and yards. Protecting the plant should be our focus, not killing the insect. The best control is with a systemic. Imidacloprid applied in December or January, should give you season long control. Acephate sprayed every 3 weeks at the first sign of a whitefly will give good control also. Contact insecticides like permethrin would quite well but need to be sprayed much more often. Use Neem or the rotenone/pyrethrin combo spray for an organic alternative.
Remember to…
Read and follow all label instructions. There is important information on the label about rates, frequency and how close to harvest a product can be used.
Refrain from the tendency to think “if a little does good, then twice as much should do better”. It doesn’t work that way. A bug can only be so dead!
Don’t spray on windy days or just prior to a rain. Wear the correct protective clothing when you spray. Flip flops, shorts and tank tops aren’t it!
Never spray a dry plant. Try to water the night before you spray if your plants are dry.
Avoid spraying in extreme heat. Any product sprayed in 100°+ temperatures may cause some foliage burn.
Spray the ground around the plant when you spray the plant.
Mark your calendar through the spring and stay on the program to protect your plants. I can remember if I sprayed today, I can’t remember what I did last week. Write it down; know when you’ve sprayed and when to spray.
You might ask “Why would anyone use a short time control when imidacloprid will control insects for a year?” Cost is the main reason. Imidacloprid is less work but more expensive to use. It’s a wise choice for a select specimen or two in your yard, but may be cost prohibitive for your whole yard. That’s why I’ve tried to give you some other options.
Where can you get these fine products? By jingy, we just happen to have them.
Here are the product names to look for…
Dormant oil - ferti-lome Dormant Spray and Summer Oil
Lime sulfur - Hi-Yield Improved Lime Sulfur Spray
Combination fruit tree spray - Bonide Fruit Tree Spray
Imidacloprid - ferti-lome Tree & Shrub Systemic Soil Drench
Propiconazole - ferti-lome Systemic Fungicide
Chlorothalonil - Hi-Yield Vegetable, Flower, Fruit and Ornamental Fungicide
Copper Soap - Natural Guard Copper Soap Liquid Fungicide
Neem oil - ferti-lome Triple Action Plus
Permethrin - Hi-Yield Garden, Pet & Livestock Insect Control
Bordeaux mix - Hi-Yield Bordeaux Mix Fungicide
Rotenone/Pyrethrin - Bonide Liquid Rotenone-Pyrethrin Spray Concentrate
Spinosad - ferti-lome Borer, Bagworm, Tent Caterpillar & Leaf miner Spray
B.T. - American Thuricide (liquid) or ferti-lome Dipel Dust
Acephate - Bonide Systemic Insect Control
Mancozeb - Bonide Mancozeb
Carbaryl - ferti-lome Liquid Carbaryl Garden Spray (aka as Sevin)
This was the mystery plant for November. It is Rhus toxicodendron, poison ivy!
I heard once that an early explorer saw this attractive vine covered in berries, collected some and sent them back to the Queen of England. I also heard he chose not to return to England.
Here’s December’s mystery plant. Picture on the left is summer leaf coloration; picture on the right is fall coloration. Hint: It’s closely related to the plant above.
The contest ends on December 15th. Drop by either store to enter or you can email your entry to questions@danwestonline.com. One winner, selected from all correct entries, will receive a $25 Dan West Gift Certificate.
Best wishes to all of you this holiday season.
Your friends at Dan West.