ORGANICALLY SPEAKING
By Don Trotter

 

PEST AND DISEASE CONTROL FOR YOUR ROSES

Hello fellow Earthlings and welcome to the rose garden. Although you were never promised one, many Southern Californians certainly make a point to have a few roses in their garden. This time we are going to explore the natural ways to balance those rascally critters and plagues that seem to love our prized roses. So let's take a walk in the garden.

It is widely known that roses can be a real pain in the - - - - if they want to be or are in any way not attended to. This is not so of a rose that is allowed to grow under natural conditions without nitrogen-fortified chemical fertilizers and harmful insecticides and fungicides. The truth of the matter is that roses can be very easy to tend to if they are cared for with a light hand during the growing season. The fewer things a gardener does to shock a natural balance of things, the fewer problems will arise as a result of that shock.

Chemical insecticides are only effective until the target pest develops a resistance to that chemical. Then it becomes necessary to alternate harmful substances to control an insect population that continually gets worse because of lack of competition and natural predators due to high concentrations of chemicals. The major rose pests that we encounter here in Southern California can be controlled by establishing populations of two beneficial insects and periodic treatments with a bacterial and tree sap extract.

Two beneficial insects are the Green Lacewing and Trichogramma Wasps. These two insects will guard your roses against everything from Aphids to some Scales and Spider Mites. Lacewings are very active and voracious feeders whose host or target prey are aphids, mealybugs, whiteflies of some species, juvenile scale insects, and some spider mites. The tiny Trichogramma wasp is a parasite of caterpillars and some species of the bud worm and will antagonize a number of other butterfly and moth species. These parasites do not have a stinger (no need to fear them); they have an ovipositor that lays her eggs inside the host. As the wasp larvae develop, they use the host as a food supply.

The bacteria that I spoke of is Bacillus Thuringiensis Kurstaki or Berliner. This product is often referred to as BT and is a paralyzing bacteria that affects many species of worm and caterpillar including the leaf skeletonizer worm. By paralyzing the stomach of its host this bacteria is very useful against its target pests.

The tree sap I was referring to is Oil of the Neem Tree of India. The active substance in this sap has been named Azidirachtin after the botanical name of the tree. The extracted oils from the tissue and sap of this tree are very effective at repelling and keeping your rose bushes free of any sign of insects. Although it smells like hazelnut to us, it has the most repellent effect on pest insects. Neem Oil is sold under the name Bio-Neem under the Safer label and Rose Defense under the Green Light label. These two products can be found at any garden supply store.

Controlling diseases in your rose garden is really not very difficult at all. There is no need for harmful fungicides that can cause severe physical problems or have a negative effect on outdoor pets and bees as well as wipe out entire earthworm populations from a single spraying. Balanced nutrition and a couple of minerals can keep your garden disease free without weekly exposure to chemicals.

Most diseases of plants will leave a healthy plant alone. It is the same with us, if we're healthy we don't get sick. Plants also have immune systems. This is where a balanced diet that contains the proper amount of copper, sulfur, potassium, magnesium and calcium will ensure that certain very commonplace and damaging fungi don't get a foothold in your garden.

Potassium is very important for resistance against powdery mildew and rust on roses. Not in some crazy amount that is available to the plant in five seconds after application, but instead, long lasting natural sources from mineral deposits or from other natural sources. When potassium is broken down in the soil by a healthy soil it will actually help to prevent the onset and spreading of powdery mildew and rust, which are tough problems for most chemical gardeners to control.

High calcium levels along with an abundance of naturally available magnesium will cause your roses to produce thick healthy canes without problems with of slow root development in our heavy soils. Copper and sulfur are the two elements which I use as a spray fungicide if absolutely necessary. Other than dormant spraying, minimal spraying should be necessary to prevent fungus and disease if the roses are fed naturally.

In celebration of upcoming Earth Day festivities around the country I offer to all readers of Awareness Magazine who are concerned about their environment a tip on rose feeding. The following recipe for an organic rose food can be obtained at any reputable garden center that carries organic fertilizers. If you can't find the ingredients in your area give me a buzz or send me an E-mail and I'll hook you up with a local source.

Rose food from heaven recipe:
1 part Hoof and Horn meal or Feather meal
1 part Cottonseed meal
2 parts Soft Rock Phosphate or Bone meal
1 part fossilized kelp ( Kelzyme) or Kelp meal
1 part Seabird or Bat guano

Mix these product together to get a rich aromatic rose food that you will only have to apply on your treasured roses every 60 days. The rate of application is approximately one cup per rose. If your roses are really big or you are feeding climbing roses use about two cups. This rose food will change the way you think about rose care and will totally blow those commercial blends away. The best part is that every ingredient is natural and perfectly friendly to the environment. See you in the garden!

Got Questions? Call Don at his toll-free gardener's helpline at 1 (888) 514-4004 or E-mail him at curly@mill.net . Don Trotter operates the Organic Gardener's Resource and Design Centre in Encinitas California.


Return to the March/April Issue Index page