Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request:  I'm finding these “new” bugs on my tomatoes. I don't remember seeing them on the tomatoes in prior years. Would you please tell me what they are and what I should do about them. Thank You.

MGCC Help Desk Response:  Thank you for contacting the UC Master Gardener Program Help Desk with the photo of your bugs. These are leaffooted bugs in the nymph stage.

Leaffooted bugs seem to be an increasing problem in our gardens. They are not new to California, but they seem to be occurring more commonly in the past several years. Adults overwinter, often in large groups, in protected spots such as woodpiles, palm fronds, under peeling bark, or in tree cracks. In the spring or summer, they move into gardens looking for fruit that's ripening so they can lay their eggs. Tomatoes seem to be one of their preferred crops.

Leaffooted bugs have piercing-sucking mouths they use to suck plant juice. When they feed on small tomatoes, the fruit will sometimes fall off prematurely. Feeding on mature tomatoes can cause a slight discoloration that doesn't really harm the tomato--they are still edible.

For control of leaffooted bugs right now (July), hand pick them when you see them (wear gloves because they don't smell very good), and look for and remove eggs which are usually laid in a chain on the underside of leaves. If you experience a heavy infestation this year, remove overwintering sites, clear weedy areas around your garden site where the adults feed before the fruit ripens, and next year, you can try using row covers to protect crops if you see the problem again. Use of an insecticide for control is rarely warranted. 

This link will take you to more information about leaffooted bugs from the University of California:   http://ipm.ucanr.edu/PMG/PESTNOTES/pn74168.html. 

Please do not hesitate to contact us if you have more questions.

Happy gardening!

Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/). 

Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Subject: More Summer Tomato problems  as well as Crop Rotation and Fertilization 

Client brought tomatoes from her garden with “production problems” to the Help Desk.

Response from the Help Desk: Thank you for bringing your tomato plant samples to the UC Master Gardener Program Help Desk office. You mentioned that you have been planting tomatoes in the same area for a number of years and have not had problems before this year. We found 3 different conditions in your samples that could explain why your plants are not thriving.

First, the leaves that are pale with a purplish cast on the undersides have symptoms of both nitrogen and phosphorus deficiency. Nutritional deficiency can make plants susceptible to other problems like pests and diseases. To remain healthy, tomato plants may need light applications of nitrogen every 4 weeks, and they also frequently need phosphorus. A good organic vegetable fertilizer will supply these nutrients and release them slowly. More detailed recommendations for how to fertilize tomato plants can be found here http://ipm.ucanr.edu/PMG/GARDEN/VEGES/CULTURAL/vegefertilizing.html .

Tomato Russet Mites (microscopic)
pix: UCANR

Second, your plants are infested with a microscopic pest called a tomato russet mite. Mites suck plant juices, weakening the plants. Heavy infestations can cause severe defoliation (loss of leaves). Growing tomatoes in the same
place year after year can favor a build up of this pest. The pest can also persist in petunias, morning glory, and other plants in the tomato family like potato, peppers and eggplant. We recommend that you remove the infested plants, all fallen leaves and weeds in the area, and put them in your green waste container (not in a compost pile). This will reduce the potential that russet mites will still be in your yard next year.

Additional information on the russet mites can be found here http://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/tomrusmite.html. 

Sulfur dusts can be used to reduce an infestation of russet mites but will not help if the pest has already killed most of the plant. If you do decide to try a treatment anyway, safety warnings applicable to the use of sulfur include wearing eye protection, long pants and long sleeves, and a hat, and avoiding contact with eyes and skin.  Additional information on sulfur is here http://ipm.ucanr.edu/TOOLS/PNAI/pnaishow.php?id=67 . 

Third, at least one of your plants has a bacterial disease, called pith necrosis, that is attacking the inside of the stems, hollowing them out. Unfortunately, this disease will kill the plant and there is no treatment for it. To prevent a re-occurrence of this disease next year, do not plant tomatoes in the same area year after year. Also, reduce stress to your plants by watering and fertilizing them adequately, but do not add excessive amounts of nitrogen (follow label directions). Finally, wait to transplant tomatoes until early May when the soil should have warmed to at least 60 degrees because colder soil favors the development of this disease.

Finally, we strongly recommend that you not plant tomatoes or other plants in the tomato family listed above in the same area more than 2 years in a row. Rotating your vegetables will help reduce the pests and diseases that you have been experiencing this year. You may also be interested in a good overall UC reference on growing tomatoes in the home garden that can be found (free) at http://ucce.ucdavis.edu/files/repositoryfiles/8159-54222.pdf

Please feel free to contact us again if you have additional problems with your garden.

Help Desk of the UC Master Gardener Program of Contra Costa County (JL)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/).

Advice from the Help Desk of the
UC Master Gardeners Program of Contra Costa County 

Client: I'm having some early summer problems in my garden. I'm reluctant to use pesticides in my garden since I have several small children. Would you please provide some recommendations to either cure and/or minimize the problems:

1. Tomato plants are doing reasonably well but there are some funky looking lower leaves that I'm concerned about.
2. My roses' leaves are mottled with brown-red markings.
3. The flowering pear tree's leaves are mottled and dropping; an arborist recommended injecting a chemical into the tree to cure the problem
4. I suspect that my garden soil is too alkaline (i.e. previously tested pH@7.1). How can I test it and what can I do to reduce pH? Will just adding compost reduce pH? 

UCMGP's Help Desk Response: Thank you for the photographs, which were very helpful. Our responses follow:

Tomatoes:  Your tomato plants look mostly healthy, but do have a very common disease called early blight seen on a lower leaf. This disease is caused by a fungus, and is spread by wind and splashing water. Disease development is favored by cool, humid conditions. To reduce the spread of the disease, avoid overhead irrigation. You may want to cut off the diseased leaf at the bottom of the plant to reduce spore production. These cultural methods should be sufficient to reduce the impact of the disease on your plants. Since you have small children and are concerned about the toxicity of pesticides, you probably will not want to use any pesticides on your tomato plants. Additional information about early blight can be found here http://ipm.ucanr.edu/PMG/GARDEN/VEGES/DISEASES/tomearlyblight.html. 

Roses:  Your roses are infected with rust, another common fungal disease in our county. Rust is favored by mild, moist conditions, and is less common during hot weather. However, once a leaf has become infected, it will not recover, and many infected leaves will drop prematurely. Avoid overhead watering or splashing onto leaves. Fungicides can protect new growth but do not eradicate the fungus from leaves that are already infected. Commercial products (when labeled for the care of rose rust) as well as Neem oil should be effective as a preventive when used before infection starts. Clean up all fallen leaves and put them in your green waste container (i.e. do not add to the compost pile). Since one of your roses is almost completely defoliated, you may want to consult with a rose specialist. You can find one here: http://www.ncnhdistrict.org/CRs/districtcr.html. Rust resistant roses are available. Additional information on rusts can be found here: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/rusts.html. 

Flowering Pear Tree:  The photograph from the flowering pear confirms that it is infected with Entomosporium, another fungus that is spread by splashing rain. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/entomoslfspt.html. We do not think that this disease warrants fungicide treatment. I do not know what chemical the pest company was

recommending for injection, but any chemical that has systemic activity would be transported to the leaves.  The infected leaves do fall prematurely, but the tree grows a new set of leaves later. Hot dry weather protects the new leaves from infection. The fungus survives from season to season in the fallen leaves, so it is recommended to clean up all the fallen leaves and put them also in your green waste container (i.e., again do not compost). This cleanup is made easier if there is no other vegetation under the tree and the soil is left bare. The University of California says that in special cases fungicides can be applied, but neither of the UC recommended fungicides have activity when injected, only when sprayed on the leaves. Generally, we do not recommend spraying any type of pesticide on large trees, because the chemical, applied under pressure, is bound to drift onto other plants where children, pets, beneficial insects and wild animals can be exposed. Further, since this disease is mostly a cosmetic problem and not likely to kill the tree, using fungicide is hard to justify.

Soil pH:  Home test kits for soil are fairly reliable as long as the instructions are followed carefully. A pH of 7 - 7.5 is borderline satisfactory, but may go up over time because our municipal water tends to have high pH. We recommend that you wait until the plants have been harvested and then add garden sulfur to the soil in the fall according to label directions. Lowering the pH with sulfur takes time (i.e., months), so you must be patient. Adding compost will not lower the soil pH.

I hope that this information is helpful. Please do not hesitate to contact us again. Good luck on a successful summer garden.  

Editor's Notes:  It is likely that the tomato, rose, and flowering pear tree problems may have been caused by the late rains creating conditions conducive to fungus: cool, humid conditions. Warmer, drier weather should minimize these types of fungus infestations provided there is adequate air circulation and not overhead watering early evening.

Help Desk of the UC Master Gardener Program of Contra Costa County (JL)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/). 

 

Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County


Thank you for contacting the Help Desk of the UC Master Gardener Program of Contra Costa County. Your recent email had three related questions:

1. Growing watermelons and tomatoes in large containers…what is the best soil composition for successful growth?
2. What type of soil is best for your tomatoes that will be grown in wine barrels in 8 hours of hot sun?
3. Your compost material has lots of worms in it. The compost will be mixed into a wine barrel in the hot sun. How can you keep the worms alive and well in wine barrels planters in full sun?

Potting Mixture For Watermelons And Tomatoes. Regarding an appropriate potting mixture for your watermelons and tomatoes, either the mixture of soil, compost and sand (plus some coconut coir for improved water retention) or the use of a commercial potting mix combined with compost and coconut coir would provide a good growing medium.

Here are some additional thoughts about each approach as well as some notes on the benefits and disadvantages of each approach.

Soil, sand, compost and coconut coir. If you use this approach, it would be best to use a loamy garden soil. Silty loam would be the best. Sandy loam could be used, but in that case you should use less sand in the mixture. Clay soils are generally avoided for watermelon culture because they drain poorly, but they can be productive if irrigated with care to prevent prolonged saturation of the root zone (a condition that favors the development of root rot pathogens) and to allow good drainage between irrigations. Adding plenty of organic matter (e.g., compost or coconut coir) would make both the clay and sandy soils more productive.

If you use garden soil, keep in mind that it can contain insects, weed seeds and disease organisms. For this reason, it would be best to heat the soil in an oven for 1 hour at 210°F to kill any bacteria, fungi, insects, or weed seeds before the soil is combined with the compost and sand.
 
This soil mixture will be heavier than the commercial potting mixture. Added weight is sometimes a disadvantage for containers. However, since the containers may become a bit top heavy if you have a good crop of large watermelons or tomatoes growing upward on a support structure, the added weight could be an advantage. If you want the planter to be lighter, you could replace the sand in the mixture with either perlite or vermiculite. Those amendments will aid in drainage just as the sand does but would produce a mixture that weighs less than one that includes sand.

tomato growing in barrel

If you use sand, be sure that it doesn't include residual salts (as could be the case if it is collected from an ocean beach). Neither watermelons nor tomatoes would grow well if the soil is too saline.

Commercial Soil Mixture Combined With Compost And Coconut Coir. Usually a commercial soil mixture does not include any actual soil, but they can still provide a very good growing medium. If you use an available commercial soiless mixture, it would probably not be necessary to add either compost or coconut coir. This commercial mixture's ingredients already include compost, and the peat moss would function in much the same way as coconut coir to improve water retention. Adding compost and coconut coir wouldn't detract but would add to the cost.
 
One disadvantage of the mixture is that it uses peat moss which is less sustainable than the coconut coir alternative. Peat comes from very slow-growing, slow rotting plants and it typically takes 1,000 years for a bog to add 1 yard to its depth. Coconut coir is a byproduct of the coconut industry and is more easily renewed than peat.

If you want to make your own potting mixture that does not include garden soil or peat moss, you can use a combination of one-third each of compost, vermiculite or perlite and coconut coir. Measure the volume of the coconut coir only after it has been soaked in water since its volume will increase significantly once it absorbs the water. I've have been regularly growing vegetables in containers for many years and always use this potting mixture. It would work well for both the tomatoes and the watermelons.

For additional information on growing watermelons, I suggest you look over the information found at:http://anrcatalog.ucanr.edu/pdf/7213.pdf . For information about growing tomatoes in containers, see http://ccmg.ucanr.edu/files/229047.pdf.

Compost Worms In Containers. In our research, there are varying opinions about the viability of worms in containers. Considering that you mentioned having worms in your containers that will be in the hot sun for 8 hours per day, the worms would not survive in this environment. They prefer moist, cool soil which might be hard to manage in your situation. However, experimentation is always a great learning experience (although maybe not for the worms). For example, you could consider using some shade protection on very hot days. Possibly you could set it up in a way that shades the container but not the plants. Also, be sure that the soil mixture has plenty of peat and/or coconut coir to help retain water.

Thank you for contacting the Help Desk. Feel free to check back with us if you have additional questions.

Help Desk of the UC Master Gardeners Program of Contra Costa County (tkl)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/).