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Invertebrates

 

Invertebrates

By Jutta Thoerner  UCCE Master Gardener

 

What can I do now to reduce damaging insect's populations in my garden prior to spring?  Erika in Grover Beach

 

You probably heard the Master Gardeners talk about fall and winter clean up in the garden. The main reason we encourage gardeners to remove fallen leaves and other discarded plant material is to minimize the potential for insects to overwinter in your garden litter. There is a huge difference in providing “clean” mulch which is properly prepared compost versus spreading insect infested plant debris throughout the garden.  Another source of spring insect trouble is the expired fruits and nuts left hanging on trees. These old and shrunken fruits are called tree “mummies”. Apple moths, walnut husk flies, and almond  navel orangeworm  are just a few examples of insects whose numbers can be greatly reduced by simply cleaning up on and around trees. Play it safe and dispose of all discarded plant material. Move it an operating composting system, or add it to the green waste can. Many insects can overwinter happily with our low or no frost zones. 

When you lay out your vegetable plots this winter, dedicate one corner for a beneficial insectary planting and another area to attract the harmful insects. By providing a constant source of blooming plants (insect food) in your beneficial corner, you'll get a head start on developing a population of pollinating insects. You might be able to attract those tiny beneficial wasps that feed on or parasitize certain damaging insects like aphids and tomato hornworms.  To attract harmful insects, think back to which plant attracted the most insect pests? In my garden, certain cabbage, some winter greens, and beans are the sacrificial plants. They get planted earlier than my main crops and I have very good luck shaking the plants and seeing many of the chewing insects drop in my soapy pale.

Lastly, invest today in row covers for your small seedlings. Garden catalogs sell several models in a range of thicknesses to best suit your climate. They completely protect your tender shoots until it is safe to uncover them and let the pollinators do their job.

For more information and photos of beneficial insects, visit http://www.ipm.ucdavis.edu/PMG/NE/index.html

Posted on Thursday, November 27, 2014 at 1:58 PM

Thanksgiving Herbs

Thanksgiving is tomorrow, so I am sure you have all the ingredients you might need for your upcoming feast. Lots of herbs make their way off the shelf and into this wonderful meal, so I thought this would be a great time to discuss some of the most popular herbs used in the traditional Thanksgiving meal, and give some tips on growing and storing them. If you don't already have any or all of these three herbs in your garden, you might consider planting some once spring rolls around.

Rosemary

Rosemary is always a popular herb - and a popular decorative shrub in our area as it is hearty and drought-tolerant. For Thanksgiving use, you can use a rosemary-salt blend to rub your bird, or finely chop and combine fresh rosemary with butter and rub that on your bird. Whole sprigs can also go straight into the cavity of the bird. Rosemary roasted potatoes are also a delicious side dish.

You might already have rosemary, either creeping or upright, in your landscape. If you don't, and would like to grow some, you should! Rosemary is very easy to care for. It prefers 6-8 hours of sunlight per day and thrives in our warm climate. Rosemary likes dry soil - so be sure not to overwater and let the soil dry out between waterings.

Thyme 

Thyme is a popular herb to combine with poultry, but this lemony herb also goes well in baked goods. You can rub some thyme on your bird, throw some sprigs inside the cavity, or even toss some thyme into your piecrust dough.

Much like rosemary, thyme can make a great decorative accent in your garden. Many gardeners believe that the flavor of thyme improves the more it is neglected - meaning poor soil and little water suit thyme just fine.

Sage 

Sage complements pork very well. It also adds a savory flavor to browned butter, and who doesn't love sage stuffing?

There are many types of sage, and not all of them are edible. These varieties are all edible: garden, purple, tri-color, golden and common sage. Another giveaway for edible sage is the botanical name "salvia officinalis." Sage prefers full-sun and is drought-tolerant once established. It prefers well drained soil and does not like to have wet roots.

Harvesting and Storage

As far as harvesting goes, you can cut sprigs of rosemary, thyme and sage as needed to use fresh, or you can cut and hang sprigs to dry. Once dry I do recommend removing the needles or leaves from the stem and putting them in a jar or bag of some sort, as no one likes dusty herbs!

 

 

 

 

Posted on Wednesday, November 26, 2014 at 7:00 AM

Growing wine grapes without irrigation possible for some, not all

It's easier to grow wine grapes without irrigation in the Napa Valley, which receives more rainfall than the San Joaquin Valley.
California's ongoing drought is raising the interest of wine grape growers in dryland farming, reported David Pierson in the LA Times. Pierson interviewed Napa Valley growers who are already dry farming their vineyards. While it may be feasible to rely solely on rainfall in the Napa Valley, San Joaquin Valley growers would have a hard time setting a grape crop without irrigation.

"If you don't water in the San Joaquin Valley, you're not getting a yield," Larry Williams, a professor in the Department of Viticulture and Enology at UC Davis and based at Kearney Agricultural Research and Extension Center, told Pierson.

Last month Sacramento Bee columnist Mike Dunne used Williams' study of water use of chardonnay grapes in the Carneros Region to refute the amount of water a Dutch researcher claimed was required to produce a single glass of wine. “In California vineyards and cellars, is 29 gallons of water to produce a single glass of wine a realistic estimate?” Dunne asked Williams, who explained that California grape yields per gallon of water are much higher than in Europe.

“The mean yield of wine grapes in Europe ... is around 1.8 tons per acre using data I've gleaned from research papers,” Williams says. “The mean chardonnay yields across California are 7.4 tons per acre.”

Based on Williams' research, Dunne wrote, “Vines of the dry-farmed portion yielded 4.9 tons per acre, while vines on the irrigated portion produced 6.3 tons per acre. The upshot was that 14.2 gallons of water was needed in the dry-farmed block to produce a typical 4-ounce pour of wine, while 15.3 gallons of water was needed in the irrigated parcel to produce a 4-ounce pour of wine, totals far lower than the figure calculated by the Water Footprint Network.”

Posted on Tuesday, November 25, 2014 at 4:34 PM

Grapes, Roses, and Pierce's Disease

Help for the Home Gardener from the Contra Costa Master Gardener Help Desk

Client's Questions and Problems:
Client lives in a condominium/town house complex in central Contra Costa County that permits individual gardens. The client grows both roses and grapes. Immediately adjacent, the Homeowners Association (HOA) maintains a privacy/sound wall covered in ivy (maybe English or Boston ivy). Client brought samples of the plants into the CCMG Help Desk for assistance identifying the plants' problems and what could be done about correcting them. All the plants look distressed with maybe a fungus or possible insect activity, the roses looking somewhat the same and also with black spots on the leaves, and the grape showing signs of distress including discolored leaves and withering. Several days after the client brought samples of the plant problems, and before CCMG could analyze plants for the problems, the client contacted the CCMG Help Desk again to inform HD that after reading an article in California Agriculture (2014, Jan-June, volume 68, page 20), it appeared that the grape leaves may be infected with Pierce's Disease (PD). Based upon the article, the client was concerned that all the grape vines should be removed. 

 

   

Pierce's disease is caused by a strain of the bacteria Xylella fastidiosa, which blocks the water-conducting system of a grapevine, leading to vine death 1 to 5 years after the plant becomes diseased.
(Photos from California Agriculture, 2014, Jan-June, Volume 68, page 20)

 

 

 



CCMG Help Desk Response:
This is a follow-up to your recent discussion with our MG volunteer, and a follow-up voicemail regarding the discoloration and die-back of your grape leaves and roses. 

I. Grapes
You are correct that it looks like your grapes have contracted Pierces' Disease. The photographs you viewed on line and the photos we have viewed in our library certainly seem to confirm the presence of the disease. 

I don't know how many grape vines you have, but in case you have more than the one infected plant, here are some of the symptoms to look for: 

Symptoms
According to our Pest Management resources: 

“In vines that are infected in spring, symptoms of Pierce's disease first appear as water stress in midsummer, caused by blockage of the water-conducting system by the bacteria. The occurrence of the following four symptoms in mid- to late summer indicates the presence of Pierce's disease: (1) leaves become slightly yellow or red along margins in white and red varieties, respectively, and eventually leaf margins dry or die in concentric zones; (2) fruit clusters shrivel or raisin; (3) dried leaves fall leaving the petiole (leaf stem) attached to the cane; and (4) wood on new canes matures irregularly, producing patches of green, surrounded by mature brown bark. Delayed and stunted shoot growth occurs in spring following infection even in vines that did not have obvious symptoms the preceding year.  

Leaf symptoms vary among grape varieties. Pinot Noir and Cabernet Sauvignon have highly regular zones of progressive marginal discoloration and drying on blades. In Thompson Seedless, Sylvaner, and Chenin Blanc, the discoloration and scorching may occur in sectors of the leaf rather than along the margins.  

Usually only one or two canes will show Pierce's disease symptoms late in the first season of infection, and these may be difficult to notice. Symptoms gradually spread along the cane from the point of infection out towards the end and more slowly towards the base. By mid-season some or all fruit clusters on the infected cane of susceptible varieties may wilt and dry. Tips of canes may die back; roots may also die back. Vines of susceptible varieties deteriorate rapidly after appearance of symptoms. Shoot growth of infected plants becomes progressively weaker as symptoms become more pronounced.  

Climatic differences between regions can affect the timing and severity of symptoms, but not the type of symptoms. Hot climates accelerate symptoms because moisture stress is more severe even with adequate soil moisture.  

A year after the vines are infected some canes or spurs may fail to bud out, and shoot growth is stunted. New leaves become chlorotic (yellow) between leaf veins, and scorching appears on older leaves. From late April through summer infected vines may grow at a normal rate, but the total new growth is less than that of healthy vines. In late summer leaf burning symptoms reappear.” 

Outlook

Vectors of Pierce’s disease include the blue-green sharpshooter
(Graphocephala atropunctata), top, and the nonnative glassy-winged sharpshooter
(Homalodisca vitripennis), bottom.
Unfortunately, Pierce's disease is a lethal disease of grapevines. It is spread by certain kinds of leafhoppers known as sharpshooters. In our area, the blue-green sharpshooter is the likely culprit (also known as the “vector”) with the potential of the grassy-winged sharpshooter, an even more potent pest.

Management and Control
Control of sharpshooters is not effective, although removal of alternate hosts might help. Some alternate hosts are Bermuda grass, blackberry, and willow. There are many hosts though, so removal of these might not be effective either.

Removing diseased vines as soon as possible when Pierce's disease first appears is critical to help reduce infection of other vines.  I would not recommend putting them into your own personal compost bin. If there is a large volume, you might want to consider burning it. 

Remove the grapevines as they become unproductive. You could replant with less susceptible cultivars such as 'Sylvaner', 'Thompson Seedless', and 'Ruby Cabernet'. 

Certain plants have been identified as preferred breeding hosts for the blue-green sharpshooter (places they will lay eggs). These plants should be avoided if possible.

Blue-green Sharpshooter Breeding Plants
Blackberry Fuchsia
Eldeberry Periwinkle
Ivy Geranium
Virginia Creeper Liquidamber
Roses

As you can see, roses are one of the preferred breeding plants. Although Pierce's Disease doesn't infect roses, it is quite possible given that the sharpshooter prefers roses, and you mentioned that your rose is close to your grapes, that the plant is showing the effects from sharpshooter feeding. 

Currently, the only other recommendations with respect to plant selection are to plant conifers, or to establish a non-irrigated xeriphytic (i.e., dry) landscape. These plants should not be attractive to blue-green sharpshooters. 

Further information on identifying Pierce's Disease can be found at http://www.ipm.ucdavis.edu/PMG/C302/mt302sppiercedis.html

II. ROSES
From the sample you gave us, and a search of other photos we have, it appears that your rose might be suffering from a couple of things – black spot and the effects of the sharpshooters. 

Black Spot Symptoms
According to our resources, “Black spot causes black spots to develop on the upper surface of leaves and succulent stems. The spots have feathery or fiber like margins and no powdery growth on the undersides of leaves. Small black fruiting bodies are often present in spots on upper sides of leaves. Yellow areas develop around the spots. Leaves may drop.”

Spots on upper surfaces of rose leaves
   
Yellow areas develop around spots

Solutions
The black spot fungus requires free water to reproduce and grow, so leaves should never be allowed to remain wet for more than 7 hours. (When hosing off aphids, do so in the morning so leaves have a chance to dry by midday.) Provide good air circulation around bushes. Remove fallen leaves and other infected material and prune out infected stems during the dormant season. Black spot is usually not a problem during California's dry summers unless overhead sprinklers are used, but the disease can be serious where rainy summers prevail or in cooler areas. Miniature roses are more susceptible than other types, although a few varieties are reliably resistant to all strains of black spot. A combination of bicarbonate of soda plus light horticultural oil can be used to manage black spot (as well as powdery mildew). Use about 4 teaspoons of baking soda per gallon of water with a 1% solution of narrow-range oil. Avoid getting on open blossoms. Neem oil can also be effective. Preventive sprays of fungicides such as triforine or chlorothalonil may also be effective. 

A UC IPM Pest Note (free), that will give you some more information on rose pest management can be found on the web at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7463.html 

I hope this helps. Thank you again for bringing this problem to us. It was a lot of fun to research.

*********************************************************************
Follow-up:  Further Questions and CCMG Help Desk Response:

From the Client: 
Thanks for all the helpful information. I see that I'll have my work cut out for me in taking out all the vines, cutting back the roses, and trying not to spread this further. I'll let my HOA know also, because I believe there is an extensive outbreak of something that has affected most of the ivy in the HOA's 30 acres. The ivy within a foot of my grape vines has all died off—and within 10 feet is a Liquidamber tree, and of course geraniums – all of the plants you listed as being breeding plants for the insects. My last question is should I be notifying the county ag department or vector control about this infection?

Follow-up Response:  from CCMG Help Desk:
We did some checking and Pierce's disease is not a reportable problem in Contra Costa County, so you don't need to notify anyone. 

We also don't think your HOA's ivy dieback is caused by PD, even though ivy is considered a host plant. There are also other insects and diseases that affect ivy, as well as cultural problems. I've been seeing many patches of ivy in the area that appear sunburned and water-stressed and even many drought-adapted plants are having serious problems this year. Here is information from UC that covers pest and diseases in ivy: http://www.ucdavis.edu/PMG/GARDEN/PLANTS/ivy.html. This may help your HOA trouble shoot the ivy problem.

Please feel free to call again if you have more questions.

Contra Costa Master Gardeners' Help Desk


Editor's Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday 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, and we are on the web at http://ccmg.ucanr.edu/

Posted on Monday, November 24, 2014 at 12:04 AM

Beetles Have an Eye Out for Figs

Help for the Home Gardener from the Contra Costa Master Gardener Help Desk

Client's Problem:

Black Mission Figs
photo: treesofjoy.com
The client has a Mission Fig tree that is about 5 years old. It has produced just fine until this year. The client is seeing little black insects that look like fleas on branches, but thinks they may be little beetles. Additionally, something is infecting the figs. About half of them are getting black inside. The client thinks it could be a fungus. The client wants to know what this is and how to control it.

CCMG Help Desk's Response:
I'm responding to your telephone inquiry yesterday about a problem with your Mission Fig. I under stand that you have observed little black insects on the tree branches which are about the size of a flea but may be beetles. You also reported that something is infecting the figs. Some figs are getting black inside and may have some fungal growth.

It is likely that the small insects that you have observed are the cause of the problem with the rotting figs. The insects may be dried fruit and/or sap beetles. There are several closely related species of this insect. The adults are small brown or black beetles with or without lighter spots on the wings, depending on the species, They range in size from 0.1 to 0.2 inch long and have clubbed antennae. The wings do not cover the last two to three abdominal segments. The larvae are white and 0.1 to 0.2 inch long when mature. Here are photos showing two different species of such beetles: 

Dried Fruit Beetle
photo: UC IPM
  
Adult Confused Sap Beetle
photo: UC IPM

As figs mature, the fruit often develops an entry point at the eye of the fig which the beetles use to gain entry into the soft fruit tissue. They can also enter the fruit at other openings in the fruit caused by mechanical injury or by other insects. After they enter the fruit, the beetles transmit spoilage organisms that cause the fruit to sour and ferment. The rotting figs in tum can attract other pests such as vinegar files and navel orange worms. The beetle larvae feed inside the fruit until they are mature enough to emerge and drop to the ground where they pupate and emerge as adult beetles.

To manage an infestation of the beetles the University of California recommends that you promptly remove and destroy all infected fruit. You may want to dispose of the rotting fruit in a plastic bag in your garbage to stop reproduction and spread of the beetles. You should remove any infected fruit from the tree and also promptly and thoroughly remove any fruit that drops to the ground.

UC also recommends trapping the beetles in a container with an inverted cone top. You can find a link to a drawing of such a container at this UC Davis website: http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/PESTS/driedfrtbeetle.html. You bait the trap with fermenting figs and water. You could also add some bakers yeast to speed up the fermentation process in the trap. If you decide to try traps, check them every couple of days and remove trapped beetles. Also replenish the water if needed.

As new figs start developing on your tree, check them carefully to try to detect and remove any that may have been invaded by the beetles. You may want to try harvesting on the early side of ripeness to reduce the chances that the beetles will have gained entry into the fruit.

UC also reports that fig varieties with small eyes (like a Mission fig) are less likely to be infected by the beetles than fig varieties with large eyes. The fact that your Mission fig appears to have been attacked by the beetles demonstrates that even they are not immune to attack.

As a final caution, the beetles can also infect other fruit such as stone fruits (e.g., peaches, plums, cherries, etc.) and citrus. So if you have such trees, keep an eye out for a problem. Early removal of any infected fruit and thorough and quick clean-up of fruit that drops to the ground would also help manage the problem in other fruit trees.

Hope this information is helpful. You are welcome to contact us again if you have further questions.


Contra Costa Master Gardeners' Help Desk


Editor's Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday 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, and we are on the web at http://ccmg.ucanr.edu/

Posted on Saturday, November 22, 2014 at 12:03 AM

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