Indian Hawthorn Disease

We were talking on the radio this past week about Indian Hawthorn and the disease they

get, so I figured I would expand on this topic this morning, since this plant is so common in the Lowcountry.

The Indian Hawthorn or Raphiolepis have been plagued with leaf spot for years now.  It seems like right after the Red Tips (Photinia) were virtually wiped out by entomosporium leaf spot, the diseased began attacking the Indian Hawthorn.  Indian Hawthorn and Red Tips are in the same plant family as roses (Rosaceae). 

When dealing with a plant that is very susceptible to a leaf spot disease I like to think of several different factors:

·        Is this plant worth keeping in the landscape or should I replace it with another plant that is not susceptible to disease.

·        Is this plant worth spraying ever 14 – 28 days to keep it in my landscape?  To keep an Indian Hawthorn alive, it needs a life-support system.  The plant must be sprayed at least monthly or it will get leaf spot again.

·        What cultural practices can I do to help relieve the pressure of the disease?  The removal of fallen foliage (sanitation) is key when dealing with a leaf spot disease.  Having a healthy soil, as determined by a soil test, is also very important because a stressed plant is more susceptible to disease.  Providing the correct amount of water preferably through a drip system, so the plants are not over-watered or drought stressed.  Proper fertility as determined by the soil test is also important.  Use nitrogen fertilizer very sparingly in small amounts because flushes of new growth are more susceptible to leaf spot.  Choose “resistant” varieties such as “Olivia”.    This does not mean that this plant will never get this disease; it is just more resistant to the disease. Mulch like Cotton Burr Compost will help prevent splashes of water drops that could spread the disease.  Also this mulch will lower the watering needs of the plants. Bioscience products like Messenger should be considered as well. Messenger will thicken the cuticle of the leaf making more resistant to the disease as well as more drought resistant. Good air movement.

·        What control products will work best on this disease?  If you decide to spray, be prepared to spray often.  Honor Guard, Banner, Dithane (Mancozeb), and Kocide are good choices. These products should be used in rotation and according to label. I like the lime-sulphur idea or lime-copper spray for the reason that the original Lamson–Scribner invented this product in an effort to save the French wine crop in the late 1800’s. He called it Bordeaux mix. When spraying these chemicals, an appropriate surfactant should be used. Certain surfactants work better than others with particular products.

I’m in yards all the time and this disease is the most common disease I see in our Lowcountry landscape. I usually recommend replanting the area. I can understand spraying roses all the time. Indian Hawthorn – ah, not so much.

Fireblight nailing Bradford Pears

A bacteria called fire blight seems to be nailing Bradford Pears and Loquats this spring.  Fire blight attacks plants in the Rosaceae family which include apples, plum, cherries, hawthorn, photinia, pyracantha, roses, spirea, pear and many others.  Always plant resistant varieties to ensure you do not get this disease. Remember resistant does not mean immune.

On the Bradford Pear the foliage usually does not fall off the branch and the branch will have a distinct shepherd’s hook curve at the tip. The dead foliage hanging on can sometimes be confused with twig borer damage.

Fire blight often leaves the branches looking burnt or a deep rust color.  This is how the disease got its name.  The bacteria over winters in cankers, then in the springtime the bacteria oozes out of the cankers and attracts insects and bees that help spread the bacteria.  Rain, wind and pruning tools also move the disease from one plant to another or spread the disease on the same plant.  Fire blight usually goes into natural openings on new wood and then moves to older wood, killing the branch. 

To control fire blight, cut out infected limbs 8-10 inches below the signs of damage.  When making cuts on an infected tree, be sure to disinfect your pruning tools with a 10% bleach solution (1 oz. bleach, 9 oz. water).  Since fire blight enters new succulent growth, avoid excessive nitrogen fertilization.  Avoid overhead irrigation or splashing water as this spreads the bacteria.  Consider using a general insecticide in the spring to discourage insects from spreading the disease. 

Since fire blight is a bacteria, an antibiotic such as Agrimycin could be used to reduce infection.  Kocide, Junction and Mancozeb will also help in the control of fire blight.  All these products should be used in the early spring when the plant is blooming and applied according to label rates and intervals of applications. 

A lot of you have new summer flowering annuals and daffodil foliage in your yard.  Both of these will respond favorably to Mighty Plant, Messenger, SeaHume and SUPERthrive.  You will notice a benefit to your summer flowering plants in about two weeks.  By spraying your daffodil foliage, you will notice the benefit next spring when you have bigger blooms on your daffodils.

Fleas have been bad throughout the winter. Protect your pet, your house, and your yard.

Early May 2012

Here is a quick check list of current events in the yard.

Soil tested?  Custom Program written? Apply the products that your soil needs instead of guessing. Doing soil tests are cheaper and provide better results than random applications. Why do you think farmers with hundreds of acres soil test?

Lawn Mower – sharp (new) blade, new oil, new air filter, new spark plug for season?

Prune azaleas, camellias and other spring flowering plants after they bloom? Wait on Gardenias for now.

Trees need pruning? Growing strong out to the tips of the limbs? Plenty of new foliage?

Fertilized your trees and shrubs? 17-00-09, 08-02-04 (organic), Professional?

Fertilize daffodils and spray them with Messenger for bigger bulbs next year. Leave the leaves (foliage) to collect sunlight to refurbish bulb for next year.

Huge fleshy leaves on new growth of camellias and azaleas? Leaf gall? Remove infected leaves and destroy.

Is Powdery mildew attacking roses, crepe myrtles, dogwoods?  Neem PY (organic), Honor Guard

Large Patch Fungus in turf – get an early start – prevention is cheaper than curative. Disarm, Cleary’s 3336, Dual Action Fungicide, and Prophesy are a few chemical controls. Crab Shells, Serenade, and Natures Blend are organic controls that “fix” the problem.

Adult mole crickets are mating – manage them. Lebanon Insect Control

Fire ants are starting to forage – manage them.  Lebanon Insect Control, Baits.

Grubs are near the surface – manage them.  Lebanon Insect Control, Grub X

Scale insects are really bad. It seems like they get worse with all the dry weather. Safari Tree and Shrub for quick knockdown and Dominion for long term control.

For trees and shrubs with perennial insect problems consider Dominion Tree and Shrub.

Get a “jump” on fleas this year. Lebanon Insect Control, Bug Blaster outside. Precor 2000, Inverted Carpet Spray, Alpine Flea Insecticide with IGR or Ultracide all have an adulticide as well as a growth regulator and are labeled for indoor use. Prefurred Plus or Bio Spot to apply to pet.

Plant a vegetable garden?

Plant a flower garden?

If you applied preemergent in February, it is time for your second application (depending on the rate and product you used the first time). Remember the ornamental beds!

The leaves have fallen – new mulch?

Fertilized Palm Trees with 07-00-09 (the most awesome Palm Fertilizer)?

Tested your well water? With over seven years of drought, many are getting salty.

Pruned holly fern, cast iron plant, and monkey grass (Liriope)?

Moles? Mole Patrol, Traps.

'Old Friends' & Large Patch

Yesterday, a neighbor and I were talking about a bike I rode many miles on from the age of 14 until 22 (when someone else thought they needed it more than I). I do not know if it was the look in my eye or the way I talked about that bike, but at the end of the conversation he asked, “it was like an old friend wasn’t it?”

I do not know if it is just me or most gardeners, but I have many ‘old friends’ that I work in the garden with. One of the first items that comes to mind is a pair of Felco #2 hand pruners that I have had since 1987. I have replaced more than a few blades and springs, but they are still getting the job done.

Gloves have to fall in that ‘old friend’ category. When my pants get too frayed or get a hole in them, they go into the wear in the yard pile. I think everyone has had that pair of jeans that just fit a little better than any other pair like an ‘old friend.’

Since I’m now a home gardener with commercial equipment from over twenty years ago, I have many ‘old friends’ in the tool category. Sprayers (store them wet), spreaders (clean the fertilizer off of them), shovels, rakes and even the hose that the ‘hose murderer’ cut to pieces and I mended back to life have all grown into ‘old friends’ over the years.

What are some of your ‘old friends’?

Large patch disease is a big problem in the Lowcountry, knowing that it is a soil borne disease can help you with control strategies.  Being a soil borne disease, you know that it will reoccur in the same areas year after year.  If a leaf blade with Large Patch is moved from one part of the yard to another (lawn mower), this can begin a new infection area; however, these are not spores flying through the air.  As a soil borne fungus, if you map the areas that you have the disease, you can concentrate your control efforts (dollars) into a smaller area, putting less control products into the environment.  If your yard is 5,000 sq ft usually you might have a few infected areas which might total approx. 500 ft.  Instead of buying control products to treat 5,000 sq ft, you can concentrate your efforts into the 500 ft (i.e. 10% of your total yard).  If Large Patch was an air borne fungus with spores, you would have had to treat the entire yard because air borne fungus spreads a lot quicker than soil borne fungus.

As your grass is coming out of dormancy and the temperatures remain cool at night, Large Patch will be ready to attack your grass.  A good granular one-two punch control strategy is Cleary’s 3336 (a systemic fungicide that gets into the plant) and Disarm or Dual Action Fungicide (also a systemic fungicide but a different chemical class).

Large Patch usually likes wet, heavy thatch, improper nutrition, and/or compacted soils.  Culturally you need to manage your irrigation system, raise any low areas, and correct drainage problems.  Reducing thatch, maintaining proper fertility levels, and aerating to alleviate compaction, will also help control Large Patch.  

Aerating

We seem to be in a normal April weather cycle. The daytime high temperatures reaching the 80’s and the nighttime low temperatures dipping into the 60’s. With that weird winter it is nice to see temperatures that look somewhat familiar for the time of year. Unfortunately, brown patch fungus (large patch, zoysia patch) love these nighttime temperatures.

A few weeks ago I wrote about amendments that could be added to the lawn when aerating. That article led to a bunch of questions about aerating in general, so here is some more information.

Aerating does several good things for your lawn, shrubs, and trees. Try to use an aerator that pulls up a plug with a hollow tine instead of a spike type aerator that is just a solid tine going into the ground. By removing cores of soil from your lawn and laying them on top of the ground, all kinds of good things happen. This cultural practice is one of the best for your landscape as a whole. If you can aerate in beds and under trees, that will benefit plants as well.   

Aerating reduces compaction, reduces thatch, increases oxygen movement to the roots, brings beneficial microorganisms to the surface, cuts runners in turf, and allows better penetration of water, fertilizers, or control products into the soil.

Many athletic fields or golf course greens aerate a minimum of once a month during the growing season. Some publications would suggest that a homeowner needs to aerate every three years; however, I think it is such a great cultural practice that I like to see people aerate yearly or every other year.

You can aerate anytime the grass is actively growing. On our programs, I usually recommend in April before your second application of preemergent, just in case any weed seeds are surfaced and try to germinate.

When you aerate, be sure to mark all your irrigation heads, propane lines, cable lines, night lighting lines and any other wire or pipe you might have running through your lawn, so you do not accidentally add to you work load.

If you are a “Do It Yourselfer” most rental stores have aerators for rent. Consider getting a few neighbors together to lower the cost. If you would rather let a professional handle the task, most lawn care companies would be happy to provide this service.

Always read, understand and follow product label. The product label is a Federal Law.