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

Client Request:  Hi...I am looking for some help. I have a pomegranate tree that I have enjoyed since moving in my home in 2006. Last year I noticed some large bugs which I later found out were called leaf footed bugs. They are hideous and ruined my fruit last year. I was advised to spray neem oil on the tree periodically starting in the spring. I've done so, and even sprayed the tree last night. However, today I found 1/2 dozen or so of the bugs on the tree this evening. How do I get rid of these bugs? I've already noticed dark spots on my fruit. Any advice is welcomed. I have included a picture of the bugs on my tree. Thank you.

Help Desk Response:  Thank you for contacting the UC Master Gardener Help Desk with your question about the large bugs on your pomegranate tree. You're right, they are leaf-footed bugs. Your photos are helpful and show adults on your pomegranate fruit.

The following website has useful information about these bugs and how to manage them: 
 http://ipm.ucanr.edu/PMG/PESTNOTES/pn74168.html    

The adults can cause small blemishes on the surface of the pomegranates, with brown spots inside the fruit. The adults are common now because the fruits are getting close to harvest time. As noted in the website, insecticides are usually not warranted but they can be used if an infestation is particularly severe. If your infestation reaches a level at which you conclude you need to apply an insecticide, you'll find recommendations about the type of insecticide to use and when to apply it in the attached document. You will want to be cautious about the use of insecticides if you want to consume the fruit. If you do apply a pesticide, make sure that you follow the instructions on the label regarding the time period to wait between applying the pesticide and harvesting the fruit. Also, wash the fruit before eating it.  Additionally, keep in mind that spraying with insecticides may be harmful to bees and other beneficial insects. 

Control of the bugs using more physical measures may be helpful. You can get the nymphs and adults out of the tree by shaking the branches or by using a stream of water from the nozzle on the hose. You can squash the bugs once they are on the ground. Because some adults may fly away, you'll want to repeat this process every week or so. You may also be able to pick the bugs off the plants by hand and crush them, wearing gloves to avoid the odor of the bugs.

As you'll see on the website, the adult leaf-footed bugs can overwinter and then re-emerge in the spring to lay eggs. Each adult female can lay up to 200 eggs over a two-month period in the spring. Given this life cycle trait, a good management approach is to try to eliminate places where the insects can overwinter. In your fall cleanup, you will want to remove all the fruit from the tree and clean up debris below the tree to help remove overwintering populations. The adults also overwinter under woodpiles so if you maintain a woodpile you might want to inspect it carefully to remove any of the insects you can locate. In the springtime, the adults feed on weedy plants, so eliminating or mowing woody plants in the vicinity of your pomegranates can also be a good strategy for reducing populations.

Good luck with you pomegranate tree. 

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

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Note:s Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ignore.edu/HortCoCo/ You can also subscribe to the Biog.

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

Help Desk Request:  I'm delighted you're available to help diagnose garden problems! Below are four pictures of a grape leaf problem. I have four old vines - Flame and Thompson seedless - that grow against a south-facing solid fence. The vines are close enough that they are co-mingled across the fence. The problem currently is located in one area of the vines and was not visually noticeable three weeks ago. All the vines are vigorous and seem healthy except for the affected leaves. I have cut most of the leaves and vines that are visibly distressed and placed them in my green waste bin. In the 15+ years I've had the grapes I have never had this problem; however, this year I was VERY, VERY late in pruning back the vines, and did not complete the pruning until the new vines had grown a couple feet long. Perhaps the evil villain over-wintered because of my tardy pruning?

Any idea what the problem is - fungus, bug or insect critter, bacteria?  I have not seen anything crawling on either side of the leaves.  And, what is your recommended approach and treatment? Thanks in advance for your help!

Submitted Representative Images of Affected Grape Leaves (below)

   

  
MGCC Help Desk Response:  Thank you for contacting the UC Master Gardener Help Desk with your issue of ‘bumps and holes' on your grape leaves.

Thank you for the pictures and note that the blister is on the top of the leaf and the bottom shows fuzzy white. We were able to diagnose simply from the damage itself. The bumps are the result of mites – specifically grape erineum mites. The good news here is that even though the mites infest the leaves, no management is necessary as they rarely lead to any crop losses.

Erinium mites are wormlike, light yellowish white and microscope so you really would need magnification to see the actual mites themselves.

Young leaves show bright pinkish or reddish swellings on upper surfaces. Corresponding areas on lower surfaces are concave and densely lined with a felty mass of plant hairs

The mites overwinter under outer bud scales and move to unfolding leaves in spring. They associate in small groups to feed on lower leaf surfaces; the result is production of masses of enlarged leaf hairs inside a blisterlike area on the leaf. On the undersides of the leaves, beneath the swellings, are concave, densely lined, felty masses of oversized leaf hairs in which the mite populations develop. As the population increases, some move to new areas or to other leaves. From mid-August to leaf drop, there is a movement back to the overwintering site underneath the bud scales.

You indicated that this is new to you and that you were a bit late pruning. I cannot explain for sure why this year and not prior years and I cannot be sure the late pruning added to this situation.

Following is a link to a UC Pest Management website on the subject but it does not really add to the information I have provided above.   http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/grerineummte.html

Good luck and enjoy those grapes, and do not hesitate to contact us again with garden problems.

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

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Note:  UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, 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 Biog.

Wisteria Vein Mosaic Virus

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

Client's Question:  This spring I planted 4 wisteria vines around our pergola and they've grown well but now two plants have bumpy leaves and one has brown curl at the end of a few leaves. I worked the soil well and added compost before planting. Any ideas? Thank you.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk regarding your wisteria plants.  Your photos are very helpful in showing the damage you mentioned.  You mentioned that one plant has a few leaves with brown tips and curling, and 2 plants have “bumpy” leaves.

On those “bumpy” leaves, I see some yellow patches, and my research leads me to believe it is Wisteria Vein Mosaic virus. This virus affects a wide variety of horticultural and vegetable crops — roses, beans, tobacco, tomatoes, potatoes, cucumbers and peppers — This Mosaic is a viral disease found throughout the United States.

The virus is transmitted mechanically and by grafting. Cuttings or divisions from infected plants will carry the virus. It can be introduced into landscapes on new plants that were infected during their production. Other wisteria can become infected if it comes into contact with infected sap from a plant with the virus. For example, using the same tool for infected and non-infected plant without disinfecting in between use. Mosaic virus over winters on perennial plants and is spread by insects that feed on them. Aphids, leafhoppers, whiteflies and cucumber beetles are common garden pests that can transmit this disease. Soil, seed, starter pots and containers can be infected and pass the virus to the plant. 

Once a plant becomes infected with the virus, it usually remains infected throughout its life. 

Aside from discoloring foliage and distorted leaves, the virus does not seriously harm wisteria or significantly reduce the vigor of infected plants. There is no cure or treatment, and generally none is needed if the plant's cultural needs are met and it is otherwise healthy. 

Here are a few precautions to take:

• Do NOT save seed from infected crops.
• The virus can be spread through human activity, tools and equipment. Frequently wash your hands and disinfect garden tools, stakes, ties, pots, greenhouse benches, etc.
• Avoid working in the garden during damp conditions (viruses are easily spread when plants are wet).

Here is a reference link from UC on the virus.  Take a look at the photo attached to the article, it looks very similar to your photos. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/wisteriavirus.html

If you are interested, here is an article describing first report of Wisteria vein mosaic virus in Wisteria sinensis in the United States of America. https://www.plantmanagementnetwork.org/pub/php/brief/2008/wisteria/

Plant virus symptoms look similar to many nutrient deficiencies. The following conditions will also cause the brown tips and curling leaves that you see:

• Too much fertilizer/salt in the soil. 
• Soil too wet and/or poor drainage.
• Other nutritional deficiencies. 

You mentioned that you planted 4 plants and only one has brown tips.  Take a look to see if that plant receives more sun than the others which might explain the brown tips.  

Here is a reference on how to manage pests in wisteria. I recommend reading the articles under Environmental Disorders (on the right side of the screen), and there is also information on good cultural practices. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/wisteria.html

It is difficult to say whether the Mosaic virus is the cause of both the “bumpy” leaves and the brown tips and curling leaves or they are also caused by cultural practices (e.g. excess fertilization/salt, overwatering). 

Since your plants are new and only planted in the spring, it is possible that the plants were already infected with the virus when you bought them.  You might want to talk to the nursery and see if they would replace them. 

I hope this information is helpful in managing your wisteria.  I have a wisteria myself and it is such a joy to see the flowers in the spring. Please do not hesitate to contact us if you have further questions.

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

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Note:  UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, 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 Biog.