Plant Diseases

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Lemon Balm Leaf Issue

Lemon Balm has very few pests or diseases. However, they can suffer root rot if overwatered. This may be the cause for your damaged leaves. Regardless of the cause, you'll want to take several steps to prevent further problems. First, remove the damaged leaves and discard them. As a precaution, if you use clippers, wipe them with alcohol before using them on healthy leaves or plants. You may want to put some organic mulch around your plants, making sure not to allow the mulch to lay next to the plant stems. Not only does that keep any soil born organisms from splashing onto the leaves, it keeps the soil temperature even and reduces water needs. Also, water only when the plants need watering. Feel the soil before watering, making sure it's not already wet. Because all plants in the mint family will begin to droop a little when they need water, that's another good indication that it's time to water. If these measures don't improve your mint's condition, you may want to take several damaged leaf samples to a local nursery for a closer inspection to rule out any other disease process.

Kudos to you for growing lemon balm. It's a great addition to any garden!

By | 2015-12-31T06:20:17-08:00 December 31st, 2015|Plant Diseases|0 Comments
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Leaf Spot On Dogwood

This is a leaf spot but without culturing in a lab it's impossible to know which one. It's not unusual to see leaf spot fungus damage at the end of the season as the plants start to drain their energy into the stems and roots and the green color leaves the foliage and any fungal damage becomes more obvious.

Also, any newly planted trees begin to shut down early since they don't have large, established root systems yet. Although there is nothing that sets off alarm bells in this photo, know that spring flowering dogwoods are prone to dogwood anthracnose, which can be fatal to these plants - if your plant is a Cornus florida (not a Cornus kousa) you might want to take leaves into your garden center or cooperative extension next year if the problem reoccurs.If you have a kousa dogwood anthracnose isn't a concern.

Be sure next year to soak the root system and area just beyond the dripline of the plant deeply once a week. Don't hand water as this is never deep enough. Don't spray the leaves as this is a cause of leaf spot and be sure any automatic watering doesn't hit the foliage and waters deeply (2 hours plus) once a week if there isn't an inch of rain.

By | 2017-09-11T15:49:29-07:00 December 30th, 2015|Plant Diseases|0 Comments
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Petunia Problems

We think that there are several issues with your petunia. 1. It looks like it needs fertilizer. Has it been fertilized since you bought it? Petunias need either a good application of a time-release fertilizer in June or every other week liquid fertilizer used according to directions. 2. This plant looks like it needs deadheading as well. Regular petunias (not Supertunias or Wave Petunias) need to have the developing seeds that are under the wilted flowers snipped off in order to keep blooming. 3. Since this plant is growing in such a small pot it's hard to keep it constantly moist so that can cause wilting problems as well, and since the foliage is so thick it's hard to water without getting the leave wet! In general, water such containers well in the morning, tucking the hose or can just over the rim so that the water runs into the pot but not on the leaves. Then do it again later in the day, depending on the weather. In hot weather a small basket will need watering twice a day - if the temperatures are cooler you can do it once a day. Petunias need to be outdoors in full sun.

By | 2015-12-30T01:22:15-08:00 December 30th, 2015|Plant Diseases|0 Comments
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Spider Mites Or Sun Burn

If the photo were taken just a little closer an identification might be more accurate, however:
1. look on the underside of the leaf and see if there are any webs. They could also be found where the stem meets the leaf and where the stem meets the stalk. If webs are present then you have spider webs and it must be treated with insecticidal soap (available at garden centers and home improvement stores) every seven to ten days until it clears up. You can also place a piece of white paper beneath the leaf. If there any very, very small yellow or red dots crawling around after the leaf is tapped several times, you have spider mites. 2. The foliage also could be from sunburn. Has the plant come from a shady location to a bright light or grown indoors and placed outdoors in bright light? Philodendron xanadu requires filtered indoor light or partial shade outdoors. 3. It could also be from a buildup of unsoluable fertilizer salts in the soil. Take the plant outside (in a shade location) and water the plant five or six times filling the pot up to the top each time and allowing the water to completely drain. This action will "flush" the bad salts from the soil. Afterwards, you might want to think about repotting the plant with good potting soil.

By | 2015-12-29T15:00:42-08:00 December 29th, 2015|Plant Diseases|0 Comments
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Problem With Dieffenbachia

Is this the same dieffenbachia you submitted before? If so, and you followed the advice we gave previously, carefully inspect the leaves for insects or webbing. We think this is a cultural problem, but it doesn't hurt to check. Be sure to only water from below and if the leaves appear to need that humidity sit is on a try of pebbles with water in it. Also if there is any salt built up in the soil (you can see this laying on the top) run water through the plant so you can wash most of that away. The last thing is there are one or two products on the market for indoor plants that is a systemic and will help to control any diseases or pests that may be getting in the soil. Oh, one last thought when was it last repotted? At this point it may not hurt to have some new and healthier soil around it. Any good potting medium that is well drained should work. It is hard to find but we don't recommend potting soils with fertilizers in them but if that is all you can find use it. Guess that covers it for now but always know you can check with a local garden center (not a box store) if they sell indoor plants or your local cooperative extension agent has access to people who know all things plants! Good luck.

By | 2015-12-29T11:59:20-08:00 December 29th, 2015|Plant Diseases|0 Comments
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Powdery Mildew

This appears to be a strong case of powdery mildew. We recommend organic treatment whenever possible. Powdery mildew is unattractive and it can affect the flavor and reduce yields of some fruits and vegetables. Although plants are unsightly and can be weakened by an infection, they do not usually die. Powdery mildew on ornamentals is an aesthetic issue, and not usually worth treating. Prevention and control is more important for vegetables. Powdery mildew can be prevented, and it can be controlled once it appears, but it can't be cured. The key to preventing it is planting mildew-resistant or mildew- tolerant varieties. Resistant varieties get less mildew than susceptible varieties; tolerant varieties may get some mildew, but it shouldn't affect the performance of the plant. Prevention also includes siting plants where they will have good air circulation, and exposing as much leaf surface as possible to direct sunlight, which inhibits spore germination.To control minor infestations, pick off affected plant parts and bag them tightly and put them in the trash. Utilize an organic fungal control like Actinovate or make your own. Home Recipe - Mix 1 part milk with 9 parts water and spray the stems and tops of leaves with the solution. Reapply after rain. Another recipe -
Spraying leaves with baking soda (1 teaspoon in 1 quart water) raises the pH, creating an inhospitable environment for powdery mildew. Best of luck!!

By | 2017-09-11T15:49:30-07:00 December 10th, 2015|Plant Diseases|0 Comments
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Septoria Leaf Spot

This is Septoria leaf spot which is caused by a fungus, Septoria lycopersici. It is one of the most destructive diseases of tomato foliage and is particularly severe in areas where wet, humid weather persists for extended periods.
Integrated Pest Management Strategies

1. Remove diseased leaves. If caught early, the lower infected leaves can be removed and burned or destroyed. However, removing leaves above where fruit has formed will weaken the plant and expose fruit to sunscald. At the end of the season, collect all foliage from infected plants and dispose of or bury. Do not compost diseased plants.

2. Improve air circulation around the plants. If the plants can still be handled without breaking them, stake or cage the plants to raise them off the ground and promote faster drying of the foliage.

3. Mulch around the base of the plants. Mulching will reduce splashing soil, which may contain fungal spores associated with debris. Apply mulch after the soil has warmed.

4. Do not use overhead watering. Overhead watering facilitates infection and spreads the disease. Use a soaker hose at the base of the plant to keep the foliage dry. Water early in the day.

5. Control weeds. Nightshade and horsenettle are frequently hosts of Septoria leaf spot and should be eradicated around the garden site.

6. Use crop rotation. Next year do not plant tomatoes back in the same location where diseased tomatoes grew. Wait 1–2 years before replanting tomatoes in these areas.

7. Use fungicidal sprays. If the above measures do not control the disease, you may want to use fungicidal sprays. Fungicides will not cure infected leaves, but they will protect new leaves from becoming infected. Apply at 7 to 10 day intervals throughout the season. Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate. Follow harvest restrictions listed on the pesticide label. An organic spray would be one containing Bacillus subtilis. It should be sprayed on the plant leaves every 7 days. It should be applied to the undersides of the leaves as well since that is where the fungus resides.

Organic Strategies

Strategies 1, 2, 3, 4 and 6 are strictly organic approaches. Using an appropriate organic herbicide (or removal by hand) would be viable organic approaches to Strategy 5.
There are tomato resistant varieties. Check you favorite seed catalogs for those varieties
Please get a second opinion if you don't agree.

By | 2015-12-10T08:29:51-08:00 December 10th, 2015|Plant Diseases|0 Comments
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Houseplant Leaf Drop

There are numerous reasons for houseplants to drop leaves. Without our staff being there in person to touch the soil and plant we are not able to specifically say what is causing your leaf drop. Houseplants typically drop leaves for many reasons but most are related to improper care or poor growing conditions. What are some of these reasons?

Either too much or too little watering will cause leaf drop. Extremely low humidity will cause sensitive plants, such as gardenia, to drop leaves although most common houseplants will not show leaf drop in response to low humidity only. Plants in pots that are too small will drop leaves. Why? Because there may not be enough root room to support all the leaves the plant tries to form so the oldest leaves drop off. Because the space for the roots is inadequate, the plant may not be able to absorb enough water and nutrients. Some leaf drop occurs when plants are subjected to a big change in environment. Such changes occur when plants grown outside for the summer are brought inside for the winter. Leaf drop brought on by a change in environment should last about three weeks then stop. Chilling is one cause of leaf drop related to environment. Tropical plants are sensitive to low, but above freezing, temperatures. Plants on windowsills may be exposed to chilling temperatures. Hot or cold drafts may be a problem for some plants. Insects and diseases can cause leaf drop but are not as common as the previously listed causes. Some leaf drop on houseplants is normal. The solution may be simple. It may just need more light or fertilizer.

By | 2017-09-11T15:49:30-07:00 December 9th, 2015|Plant Diseases|0 Comments
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Septoria Leaf Spot

This is Septoria leaf spot which is caused by a fungus, Septoria lycopersici. It is one of the most destructive diseases of tomato foliage and is particularly severe in areas where wet, humid weather persists for extended periods.

Integrated Pest Management Strategies

1. Remove diseased leaves. If caught early, the lower infected leaves can be removed and burned or destroyed. However, removing leaves above where fruit has formed will weaken the plant and expose fruit to sunscald. At the end of the season, collect all foliage from infected plants and dispose of or bury. Do not compost diseased plants.

2. Improve air circulation around the plants. If the plants can still be handled without breaking them, stake or cage the plants to raise them off the ground and promote faster drying of the foliage.

3. Mulch around the base of the plants. Mulching will reduce splashing soil, which may contain fungal spores associated with debris. Apply mulch after the soil has warmed.

4. Do not use overhead watering. Overhead watering facilitates infection and spreads the disease. Use a soaker hose at the base of the plant to keep the foliage dry. Water early in the day.

5. Control weeds. Nightshade and horsenettle are frequently hosts of Septoria leaf spot and should be eradicated around the garden site.

6. Use crop rotation. Next year do not plant tomatoes back in the same location where diseased tomatoes grew. Wait 1–2 years before replanting tomatoes in these areas.

7. Use fungicidal sprays. If the above measures do not control the disease, you may want to use fungicidal sprays. Fungicides will not cure infected leaves, but they will protect new leaves from becoming infected. Apply at 7 to 10 day intervals throughout the season. Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate. Follow harvest restrictions listed on the pesticide label. An organic spray would be one containing Bacillus subtilis. It should be sprayed on the plant leaves every 7 days. It should be applied to the undersides of the leaves as well since that is where the fungus resides.

Organic Strategies

Strategies 1, 2, 3, 4 and 6 are strictly organic approaches. Using an appropriate organic herbicide (or removal by hand) would be viable organic approaches to Strategy 5.
There are tomato resistant varieties. Check you favorite seed catalogs for those varieties
Please get a second opinion if you don't agree.

By | 2015-12-09T18:28:53-08:00 December 8th, 2015|Plant Diseases|0 Comments
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Potassium Deficiency On Citrus

This not an infectious disease, nor does it appear to be caused by insects that normally feed on citrus leaves; it does however look like a deficiency of Potassium and probably Iron. Potassium is one of the 3 macro-nutrients, along with Nitrogen and Phosphorous, used by plants in the greatest amounts. The downward leaf-roll is characteristic of a lack of Potassium (in the absence of insects like Aphids and Leaf miner that can cause leaf curl and distortion), and the chlorosis (yellowing) of the upper leaves is caused by a lack of Iron. We've included a link for your reference (scroll down to the bottom to see Potassium), so we recommend asking your local garden center or agricultural supply store for a citrus fertilizer. Apply the fertilizer according to label directions, and time the applications according to the info in this weblink. Citrus should only be fertilized at certain times of year. Watering properly can become difficult when trees are grown in containers. Its easy to overwater if done too often (and especially if the roots have not developed enough to absorb the amount held in the soil/pot size), and easy to underwater if not done frequently enough when the tree is outgrowing the pot size. Make sure your tree is in full sun for 6-8 hours per day for maximum water uptake and movement thru the plant. Under and over watering cause roots to either dry out or rot, and become non-functional which results in insufficient nutrient uptake. Soil and water pH also impact the plants ability to take up nutrients. We recommend you make any necessary adjustments after doing a pH test of the soil when its moist and if the pH is not in the appropriate range of 6.8 -7 you will need to amend with the appropriate materials. You may also consider moving the tree to a different pot (sort of a start-over approach) with new soil.
http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html

By | 2015-12-08T09:26:38-08:00 December 8th, 2015|Plant Diseases|0 Comments
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