Plant Diseases

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Shoot Tip Die Back

This tree appears to be suffering from shoot tip die back (as far as we can see from your photo), which could be caused by several things, but is probably a problem originating at the root system. Since you mention this tree is 30 years old, do you know if it was still producing in the recent past? Citrus trees have shallow root systems and roots can easily be damaged and therefore won't be able to provide adequate water and nutrients to the tree. Has anything disturbed the roots at the drip-line recently? Another cause could be high temperatures and lack of water, or application of pesticidal products to water stressed trees. Because there are potentially several potential causes, we recommend you talk to the Citrus/Avo Farm Advisor at the UCCE. We've also included a link, which you are probably already familiar with, and a publication written by a respected UCCE Advisor about citrus tree cultivation.
http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/citrus.html
http://www.mastergardenerssandiego.org/downloads/citrus%20for%20home%20garden.pdf

By | 2016-02-28T05:03:12-08:00 February 28th, 2016|Plant Diseases|0 Comments
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Peach Leaf Curl

You may still be able to salvage the tree, but you will need to control the fungus that is causing the problem. Although symptoms of leaf curl are seen primarily in spring as new leaves develop, there is little you can do to control the disease at this time. Some people remove diseased leaves or prune infected shoots, but this has not been shown to improve control. Normally, diseased leaves fall off within a few weeks and are replaced by new, healthy leaves, unless it is rainy.


If a tree is severely affected with peach leaf curl this can stunt its growth, so consider thinning fruit later in the season. Pruning in fall prior to applying any fungicides can reduce spore numbers overwintering on the tree and reduce the amount of fungicide needed. If leaf curl symptoms occurred on your trees in spring, be sure to treat the following fall and/or winter to prevent more serious losses the following year.

By | 2016-02-27T12:47:44-08:00 February 27th, 2016|Plant Diseases|1 Comment
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Yellow Spots On Camellia Leaves

Sorry for the delay in responding to your Camellia problem. We spent some time on this but cannot say definitively what the cause is. Camellias are susceptible to various diseases, including Oedema (wart like spots that develop on leaves due to environmental conditions), viral pathogen that can cause yellow "mosaic" patterns in leaves, (but yours doesn't really look like that one), and fungal diseases (algal leaf spot). We are also wondering if this could be the result of something applied to or near the plant, like a pesticide or liquid fertilizer, or a weed control product? The best way for you to get a good answer, and what we recommend, is that you take this picture and a plant sample (in a sealed bag) to a garden center, or to your local Dept of Agriculture office, or to your local Master Gardner's Group or to your local farm & home advisor's office (this is one link we found from NCSU - you may be able to find one close to you). Please let us know what you find out! http://wake.ces.ncsu.edu/

By | 2016-02-27T07:50:37-08:00 February 27th, 2016|Plant Diseases|1 Comment
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Powdery Mildew On Lilacs

Powdery mildew is very common on lilac and once you have it difficult to completely get rid of it. Good air circulation is important. After it blooms next year, remove 1/3 of the oldest branches as far down as you can cut it. That might help but isn't a cure. Clean up any leaves this fall and place in garbage. Spray with an organic fungicide labeled for powdery mildew as soon as the plant begins to leaf out in the spring. Just follow the directions.

The good news is that powdery mildew doesn't kill lilacs. It's always worse in dry summers because heavy rains wash some of the mildew spores off - in fact, studies done at Cornell several years back showed that a hard stream of water on the leaves of lilacs once a week was as effective as commercial fungicides! Most people decide to just think of their plants as having gray leaves in late summer, however. If it really bothers you, give the lilac away and plant one of the flowering shrubs that doesn't get leaf diseases.

By | 2016-02-27T03:53:29-08:00 February 27th, 2016|Plant Diseases|0 Comments
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Lime Tree Leaf Problem

There could be a number of problems causing your tree to drop leaves and being non-productive. First though, you'll want to remove the dead leaves from the soil in case they are diseased so they don't infect the soil. You may want to keep several of the leaves in a closed container in case you decide to have a nursery or the local extension agency examine them under magnification. All plants experience some level of transplant shock, that may be part of the problem. However, there is most likely several other issues that need to be checked. Here are some websites with great information on lime tree care and diseases. The first website resource covers growing tips and problems and is very informative - http://citrus.myindoorgreenspot.com/icitrus.htm
The second website is from the University of California and has pictures of actual disease processes and insect damage - http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html

By | 2016-02-26T16:17:27-08:00 February 26th, 2016|Plant Diseases|0 Comments
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Gray Mold On Begonia

Gray mold on begonia plants results from a fungal infestation. The Botrytis cinerea fungus survives in previously infected plant debris as densely packed structures called sclerotia, so it is important to destroy the area that is infected. Gray mold threatens begonias throughout the active growing season and particularly in the enclosed area of the home where houseplants might be grown. As soon as you notice signs of gray mold, remove the infected plant parts. Discourage the disease by spacing begonias to provide adequate air circulation and watering them at soil level early in the day to keep the foliage as dry as possible. Low-nitrogen fertilizer applied weekly at one-quarter strength keeps the plants vigorous without overly stimulating mold-enticing, tender new growth. During cool, humid weather, chlorophyll or mancozeb fungicide applications spaced 10 days apart protect healthy begonias from gray mold attacks.

By | 2016-02-26T03:42:08-08:00 February 26th, 2016|Plant Diseases|0 Comments
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Fasciation Of Lily

This appears to us to be a fasciated stem of either a lily or an alstroemeria. Was this from a florist bouquet? It looks like an example of fasciation, which occurs in many plants randomly. Although we've put it in the category of "disease" on this form it is not - it's a physiological disorder. In fact, there is no one clear reason why some plants become fasciated although it's thought that chemicals, mechanical damage, bacteria, viruses, phytoplasmas, or feeding by insects can all trigger this odd growth. On florist flowers the suspect is often over-application of chemicals used in that industry. Fasciation doesn't spread from plant to plant and there is not any reliable way to promote it, so it's not possible to "breed" a group of plants that always have interesting odd growth. Sometimes fasciated plants are really ugly and over-distorted, while other times the growth is humorous and cool looking.

By | 2016-02-26T02:36:41-08:00 February 26th, 2016|Plant Diseases|1 Comment
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Cactus Scarring

It is very hard to say what's going on - could be fungal, could be bacterial, or none of the above. Many times these dry spots happen and eventually peel off. Try taking something blunt like an eraser on a pencil and gently put pressure on the largest spot. If it seems firm then don't worry about it for now. If it is soft and squishy then you know there is a problem going on. In either case, as a potential stop gap measure, lay the plant on its side with the affected area up. Shake on a good amount of ground cinnamon as you would use for baking. It is a natural anti-fungal, anti-bacterial. We usually use it to dust the surfaces of new cuttings or to pour on a nasty, squishy infection. In your case it is not going to hurt either way. Dump it on good and let the plant sit like that for about 2 weeks. After that stand it up and go about treating it like normal. See if the affected areas have changed or gotten worse. No change, great. If it got worse then it may need bigger guns for the problem.

By | 2016-02-25T08:48:39-08:00 February 25th, 2016|Plant Diseases|0 Comments
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Tomato Leaf Death

This is probably not an infectious disease, bucaused by weather conditions in the recent past. You will want to pay close attention to your plants and maybe provide fertilizer at flowering and fruit set. Keep up with watering, but you may consider watering more deeply at one time and less frequently because tomatoes need water deep in the soil but don't like to have "wet feet" (too much water closer to the surface, which can happen if you water too often). If the water doesn't soak into your soil quickly, you will want to water until just before runoff starts, stop the water, let it soak in, and then apply water again in the same way; you should do this repeatedly until enough water has been applied. This will also help leach salts that can accumulate in the soil with frequent but not deep watering. HIgh salt content in the soil or water can also cause leaf damage or death. Keep the soil moist to dilute the salts, but don't overwater.

By | 2016-02-24T21:06:36-08:00 February 24th, 2016|Plant Diseases|0 Comments
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Rose Stunted Growth

It's difficult to diagnose what may be ailing your roses just by photo alone. However, most rose problems occur because one or more rose growing requirements needs attention. Here are some suggestions and a link to the Oklahoma Extension Agency for more rose growing information - http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-1077/HLA-6403web.pdf

The yellow leaf color suggests that your rose needs nitrogen or is being overwatered. All roses require regular fertilization for proper growth. Refer to the Extension Agency fact sheet for fertilization recommendations. Roses don't like to dry out and need consistent moisture. If the soil is consistently soggy or smells, however, it may be receiving too much water. Also, it's unlikely the coneflower is having any affect on your rose.

We suggest going through the Extension Agency guide to see what rose care basics may be missing or need to altered.

Kudos to you for caring about your roses!

By | 2016-02-24T20:49:24-08:00 February 24th, 2016|Plant Diseases|1 Comment
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