Indian Hawthorn (Rhaphiolepis indica)-Leaf Spot
Cause The fungus Diplocarpon mespili (asexual: Entomosporium mespili), is most active during prolonged periods of cool, wet weather in the spring. Fungal spores overwinter on infected leaves or juvenile shoots. High humidity, cool weather, crowded plants, and splashing water from rain or overhead irrigation provide an ideal environment for disease spread. Host range is wide including Indian Hawthorn, photinia and quince.
Symptoms Leaf lesions arise as minute dots on newly developing leaves in spring. Lesions enlarge to form gray-brown, irregularly shaped spots with a red or brown border. Leaf spots mature as circular, brown lesions, 0.25 inch in diameter, with raised black fruiting bodies (acervuli) in the center of each spot. Leaf lesions can be few and scattered or can become so numerous that they coalesce to form large dead areas. Defoliation can be heavy with the onset of severe outbreaks of the disease. Infected areas on older leaves frequently have a gray-white cast due to the production of spore masses when leaves are wet. Infection of older leaves in late spring may also appear as white “ghost spots” on leaves when higher temperatures abort the progress of infection.
Cultural practices Careful inspection of container-grown plants in early spring helps identify early signs of leaf spot.
- Avoid overhead irrigation or apply such that plants are not wet for extended periods of time.
- Spacing of container plants helps prevent spread of disease to healthy plants.
- Take cuttings for propagation only from pathogen-free plants.
- Discard diseased cuttings and container stock. Remove and destroy diseased leaves and other debris from production beds.
- Rhaphiolepis x delacourii (hybrids) and the cultivars Clara, Eleanor Tabor, Indian Princess, Olivia, Ovata, and Snow White have shown resistance.
Chemical control Begin protective fungicide treatment before the casual fungus spreads and symptoms appear. Continue preventive applications at 10- to 14-day intervals until new shoot growth is finished. During heavy rain, shorten the spray interval to 7 to 10 days. Tank-mix and/or alternate products with different modes of action to prevent the build-up of resistant fungi. Limit the use of any one group during crop production.
- Banner MAXX at 5 to 8 fl oz/100 gal water. Group 3 fungicide. 12-hr reentry.
- Broadform at 4 to 8 fl oz/100 gal water. Group 7 + 11 fungicide. 12-hr reentry.
- Concert at 22 to 35 fl oz/100 gal water. May cause injury to buds, blooms or tender new growth. Landscape use only. Group 3 + M5 fungicide. 12-hr reentry.
- Compass O 50 WDG at 2 to 4 oz/100 gal water. Do not use organosilicate additives. Group 11 fungicide. 12-hr reentry.
- Copper-Count-N at 2 to 4 quart/100 gal water. Oregon only. 48-hr reentry.
- CuPRO 5000 at 3 to 5 lb/A. Group M1 fungicide. 48-hr reentry.
- Daconil Weather Stik at 1.4 pints/100 gal water. Group M5 fungicide. 12-hr reentry.
- Eagle 20 EW at 6 to 12 fl oz/100 gal water. Group 3 fungicide. 24-hr reentry.
- Heritage at 1 to 4 oz/100 gal water plus a non-silicone-based wetter sticker. Group 11 fungicide. 4-hr reentry.
- Insignia SC at 6 to 12 fl oz/100 gal water. Do not use with organosilicate-based adjuvants. Use preventively only. Group 11 fungicide. 12-hr reentry.
- Junction at 2.5 to 5 lb/A. Spray solution pH should be above 6.5. Group M1 + M3 fungicide. 48-hr reentry.
- Monterey Liqui-Cop at 3 Tbsp/gal water. H
- Mural at 4 to 7 oz/100 gal water. Group 7 + 11 fungicide. 12-hr reentry.
- Nu-Cop 50 DF at 1 lb/100 gal water. Group M1 fungicide. 48-hr reentry.
- Phyton 27 at 1.5 to 3 oz/10 gal water. Group M1 fungicide. 48-hr reentry.
- Spectro 90 WDG at 1 to 2 lb/100 gal water. Group 1 + M5 fungicide. 12-hr reentry.
- Zyban WSB at 24 oz/100 gal water. Not to be confused with the smoking cessation drug. Group 1 + M3 fungicide. 24-hr reentry.
Entomosporium Leaf Spot
A fungal disease of photinia, hawthorns, and other related plants. It primarily hits large monoculture plantings. It can be controlled by improving soil conditions and avoiding susceptible plants. It is most active in spring and fall. Use the Sick Tree Treatment and try to avoid watering the foliage. Although it shows up on the foliage as round dark purple spots, it is really disease of the root system. Baking soda or potassium bicarbonate spray will stop the spotting on the leaves if caught early. Improving the health of the root system with aeration, compost and rock powder is the long range cure. Products for the soil containing alfalfa will also help. Use the Sick Tree Treatment for ultimate control. Drenching the soil with mycorrhizal laced compost products is the most effective solution if only one treatment is to be done.
ENTOMOSPORIUM LEAF SPOT OF PHOTINIA AND INDIAN HAWTHORN
“There is no effective control for this very damaging disease.” That’s what is often said when the purple spots and yellow leaves show up on photinia and hawthorns. But – it’s not true.
First of all, understand that neither photinia nor Indian hawthorn can stand “wet feet” or tolerate poor drainage. Red tip photinia (Photinia fraseri) are particularly susceptible to root fungal diseases in poorly drained soil. Damage from root diseases can weaken plants making them more susceptible to problems such as leaf spot fungus. Fallen leaves can be removed, as they are a potential source of future infections, but are not the most significant source. Moving them could cause dispersal of more spores. I never do that. You may try covering fallen diseased leaves with cedar mulch to accelerate their decomposition and suppress the fungus.
For treatment, use a potassium bicarbonate spray on the foliage (1 rounded tablespoon per gallon water), 1% hydrogen peroxide or corn meal juice. It may be good to remove severely diseased plants that have also been damaged by cold injury and replace them with other plants not susceptible to the disease. For plants that remain, aerate the root zone and while the holes are open, apply the soil amendments we use for bed preparation – compost, rock minerals like lava sand, greensand, zeolite and sugars like dry molasses and cornmeal. That’s basically the Sick Tree Treatment
Although I wouldn’t plant any more red tip photinia, my photinia program, which evolved into the Sick Tree Treatment, can save the plants and bring them back into health. If the root system of the plant is too damaged, then the plant may need to be removed. The reason for the acceleration of photinia problems is over-planting and the continued use of harsh synthetic fertilizers and toxic pesticides. Not only do those products not solve the problem, they make it worse. The real problem is not the spots on the leaves, the subsequent chlorosis and then foliage die back. These are merely symptoms of the real problem. Unhealthy roots are the problem.
Red tip photinia breeding led to this fatal flaw – weak roots that are highly susceptible to root fungal diseases. When the roots get in trouble, the symptoms start to appear on the foliage. Only the organic products that stimulate beneficial biological activity will help. Many people have saved their plants with the Sick Tree Treatment and the basic organic program keeps them happy long term. For more details see – Sick Tree Treatment on https://www.dirtdoctor.com.
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DEAR NEIL: I have five well-established Indian hawthorns in a row. Late August, one developed a small area of dead, brown leaves. I removed the dead leaves and observed a brown streak in them and others, also in some of the other shrubs. It did not appear to be leaf spots, but a nurseryman identified it as a fungal blight.
Fungicide spray seemed to help for a while, but now all the leaves on the first plant are brown. It appears to be dead. Should I replace it with another Indian hawthorn? I’m sorry I can’t send a photo.
Dear Reader: I really can’t identify your problem without seeing it. Entomosporium fungal leaf spot takes on many different appearances, and that may be what is involved. It certainly is the most likely candidate.
If you want to replant, you really need to be sure that’s not the problem. I have a difficult time recommending hawthorns any longer due to that disease for which we have no reliable control. I suggest use of one of the dwarf hollies instead. While they may not flower, they’re handsome all year, and they don’t have the problem with a fatal disease.
Your best option in diagnosing this issue would be to send a sample of one of the dying branches from one of the other plants to the Texas Plant Clinic at Texas A&M in College Station. Its website will have all the details of collecting and sending the sample.
DEAR NEIL: I have dug up a 12-inch-tall sapling of a sweetgum in East Texas. What can I do to transplant it successfully into the alkaline soil of Central Texas?
Dear Reader: I’m assuming you look to me for honest answers. I needed to say that, because others might tell you to dig a large planting hole and use lots of organic matter to keep the planting mix acidic. Sweetgums, after all, need more soluble iron than alkaline soils will allow.
And that answer would keep your little tree healthy for a few years. That gives those people ample time to get out of town before you discover that organic matter decays and loses its acidity. Plus, trees outgrow their original planting holes.
The result of it all: The tree begins to show iron deficiency, and there is no practical way of stopping it. They rarely last more than five or eight years in alkaline soil. I’m sorry for the bad (but honest) news.
DEAR NEIL: I have two red climbing roses, one in front and one in the backyard. Both lost their leaves weeks before it got cold. What would have caused that? They’re completely bare right now.
Dear Reader: That certainly sounds like old-fashioned black spot, the fungus disease that begins with yellow blotches that soon become dark brown before causing the entire leaves to fall. There are fungicidal sprays available to arrest the disease, but they’re only effective when you can get ahead of the infection and stay ahead of it by spraying weekly in spring and fall.
DEAR NEIL: My purpleheart plants froze completely. Will they come back in the spring? I was under the assumption that they were perennials.
Dear Reader: Yes. Like many other perennials, purpleheart plants freeze to the ground. They’ll come back vigorously in late March and April. Don’t disturb the soil where they’re planted.
DEAR NEIL: We have tall nandinas that really ought to be trimmed back from our windows. How can we do it? The plants have lots of berries. When can we prune them without ruining the berries?
Dear Reader: It sounds like you have the old-fashioned standard nandinas. There is an odd pruning technique that is rather specific to them. You want to sort through their stems and select the tallest one-third of the stems. Cut those canes clear back to the ground, leaving the other two-thirds intact.
Those cut canes will send out new sprouts that will fill in from beneath, giving the plants a fresh, rejuvenated look. If they’re really overgrown, you could even cut the tallest half of the canes back to the ground.
DEAR NEIL: When do we need to fertilize our asparagus bed? It’s been planted for two years, and we should get a good harvest this next year. What should we use?
Dear Reader: Apply an all-nitrogen fertilizer such as 21-0-0 at the rate of ½-pound per 100 square feet of bed space. Fertilize in early to mid-February, in anticipation of the new growth. Water the fertilizer in deeply to get it immediately to the plants’ roots.
You can also make a similar application after you finish harvesting. Otherwise, just keep the plants well mulched and moist.
Have a question you’d like Neil to consider? Email him at [email protected] Neil regrets that he cannot reply to questions individually.
Why Are Leaves Turning Brown And Falling Off On My Indian Hawthorne?
Maple Tree · Gardenality Genius · Zone 10A · 30° to 35° F
Hi Joe-Are these shrubs older and well establish or fairly young shrubs? When did you prune the shrubs and were they pruned back quite a ways to control their size? Do you remember is you had any cold or freezing temperatures after the pruning? The indian hawthorn, which is what i’m assuming you have, are extremely hardy and can accept any hard pruning even rejuvenation pruning within 6 inches of the ground and recover well. I’m thinking at this time your pruning may not have had anything to do with the plant browning and losing leaves. Were any of the leaves yellowing or browning prior to your pruning? Have you had a lot of rain that may have kept the soil saturated for a period of time. Has there been any fertilizing of this plant or any weed killers or other chemicals used for any reason nearby? Check the leaves closely for any damage to the leaves or appearance of any insects. Discoloration and spotting, before browning and dropping could indicate insect or disease causing the browning and dropping of leaves. Evergreen shrubs such as these will also lose many of there older leaves this time of year especially more so with some plants after the unusually cold winter many have had. Scratching small spots through the outer bark with a sharpe knife or fingernail and observing the tissue under the bark will indicate whether the stems are still alive or not. If the tissue under the bark is green and not brown the limb is still alive. If brown that part of the stem is dead. If you could upload a picture of the shrub and a close up picture of the affected leaves it may help to lead us to the problem. To the right of your name below your question you will see where you can upload your pictures.
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Pathogen-caused leaf spot diseases, particularly those of stone fruit trees and such vegetables as tomato, pepper and lettuce are of two types, those caused by bacteria and those caused by fungus. Leaf spotting of either kind is generally similar in appearance and effect. Prevention and treatment of both kinds often involve the same practices.
Infected plants have brown or black water-soaked spots on the foliage, sometimes with a yellow halo, usually uniform in size. The spots enlarge and will run together under wet conditions. Under dry conditions the spots have a speckled appearance. As spots become more numerous, entire leaves may yellow, wither and drop. Members of the Prunus family (stone fruits, including cherry, plum, almond, apricot and peach) are particularly susceptible to bacterial leaf spot. The fruit may appear spotted or have sunken brown areas. Bacterial leaf spot will also attack tomato and pepper crops in vegetable gardens.
Fungal leaf spot attacks lettuce and can also occur on brassicas and other vegetables including such as cabbage, cauliflower, Chinese cabbage, broccoli, Brussels sprouts, kohlrabi, kale, turnip and rutabaga. For more on vegetables susceptible to bacterial and fungal leaf spot, go here.
Bacterial leaf spot will also infect some annual and perennial flowering plants including geraniums, zinnias, purple cone flowers and black-eyed Susan. Fungal leaf spot will infect aspen and poplar trees. Leaf spot will also cause problems for strawberry plants.
Both types of leaf spot are most active when there is plenty of moisture and warm temperatures. During the summer months, especially if plants are watered by overhead sprinklers, sufficient moisture may be present for infection when the bacteria are splashed or blown on to leaves. Wind and rain transmit the bacteria to plants.
This disease overwinters in the soil around infected plants as well as on garden debris and seeds. It will also remain in the twig cankers, leaves, stems and fruit of infected trees.
- When selecting fruit trees, choose resistant varieties if possible.
- Keep the soil under the tree clean and rake up fallen fruit.
- Use a thick layer of mulch to cover the soil after you have raked and cleaned it well. Mulch will reduce weeds and prevent the disease pathogen from splashing back up onto the leaves.
- Prune or stake plants to improve air circulation. Make sure to disinfect your pruning equipment (one part bleach to 4 parts water) after each cut.
- Leaf spot among vegetables is most often introduced through infected seed or transplants. Make sure your seeds and transplants are from leaf spot-free stock.
There is no cure for plants infected with bacterial leaf spot. Preventive, organic measures include:
- Spraying with a baking soda solution (a tablespoon of baking soda, 2 1/2 tablespoons of vegetable oil, a teaspoon of liquid soap, not detergent, to one gallon of water), or neem oil (do not use when pollinating insects including bees or other beneficial insects are present). Baking soda may burn some plant leaves. Spray only a few and then check for a reaction before applying applications every two weeks.
- Apply sulfur sprays or copper-based fungicides weekly at first sign of disease to prevent its spread. These organic fungicides will not kill leaf spot, but prevent the spores from germinating.
- Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
- Containing copper and pyrethrins, Bonide® Garden Dust is a safe, one-step control for many insect attacks and fungal problems. For best results, cover both the tops and undersides of leaves with a thin uniform film or dust. Depending on foliage density, 10 oz will cover 625 sq ft. Repeat applications every 7-10 days, as needed.
DON’T LET FUNGUS HAVE A FIELD DAY WITH YOUR INDIAN HAWTHORN.
Q: My once brilliantly green and thriving Indian hawthorn now has yellowed foliage marred with brown mottling and spots. What is this and how should I treat it?
A: Your Indian hawthorn has Entomosporium, or fungal leaf spot. It’s a common problem during our frequent summer rains, exacerbated by high humidity and damp conditions. In Indian hawthorn, fungus often first appears as a yellowing of the leaves followed by visible spots. These spots may be small, large, few or many, and occasionally can consume the entire leaf. Affected leaves may turn tan or red and even fall off if left untreated. How does it happen exactly? Fungal leaf spot occurs when airborne spores are deposited on wet foliage. The water activates the spores and they begin to grow.
To stay ahead of the fungus game, plant varieties of Indian hawthorn that aren’t susceptible to leaf spot, such as Olivia, Eleanor Tabor, Indian Princess, Gulf Green, Georgia Petite and Georgia Charm. Use drip irrigation, if possible. Be sure to remove severely infected leaves and throw them away (that goes for fallen leaves, too). Fungus prefers to infect tender, young leaves, so hold off on pruning and fertilization. Both practices encourage new growth during the growing season (translate: more spores).
Fortunately, a broad-spectrum fungicide can successfully treat and help prevent leaf spot and other fungal diseases. Don’t let fungus have a field day with your Indian Hawthorne. Apply a fungicide as soon as new growth appears each year to keep your plants healthy and looking their best.
Filed Under:: Fungus
Tagged with: best practices for Indian hawthorne, fungal leaf spot, fungicide, Indian hawthorne pests, plant disease, plant fungus