Showing posts with label cottony cushion scale. Show all posts
Showing posts with label cottony cushion scale. Show all posts

Thursday, April 5, 2012

Random Garden Thoughts and Pictures



Cottony Cushion Scale on a Mandarin tree
A favorite pest of citrus, pittorsporum and nandina here in California: cottony cushion scale. This sucking insect protects itself from most predators with a cottony covering. Also guarding the scale: ants, which harvest the secretions of the scale for food. Control the ants with ant bait; control the scale with either a blast of water from the hose or an application of horticultural oil. Avoid harsh chemical insecticides which may deter one of the few beneficial insects that feeds on this scale: the vedalia beetle.

According to  the UC Davis Integrated Pest Management website: do not apply imidacloprid (Merit or Bayer Advanced Citrus Fruit and Vegetables) for cottony cushion scale control. Although imidacloprid has scale insects listed on the label, it doesn’t kill cottony cushion scale. 

The Tumbling Event at the Scale Olympics
To make matters worse, imidacloprid is very toxic to vedalia beetles. The beetles are poisoned when they feed on cottony cushion scale that have ingested imidacloprid. Cottony cushion scale outbreaks have been observed following use of this insecticide because the vedalia beetles were removed and the insecticide didn’t control the pest.

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Magic Kingdom Beehives?

Seen at Disneyland. Clever use of alyssum in the shape of a lantern or beehive.

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Easy source of baby greens? Start them from seed in smallish containers (3" pots, perhaps). Keep them on an outside table near the kitchen window for an easy meal reminder. Snip 'em as you need 'em!


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As seen at the National Heirloom Exposition, Sept. 2011:


The National Heirloom Exposition and Pure Food Fair in Santa Rosa last September was Disneyland for Grow-it-Yourselfers. Here, the Redwood Empire Chapter of the California Rare Fruit Growers had this beautiful pear on display, the Conseiller de la Cour.

From the book, "The Fruit Manual: Containing The Descriptions And Synonyms Of The Fruits And Fruit Trees Of Great Britain" comes this description of the Conseiller de la Cour: "Fruit, large, sometimes very large, being near four inches and a half long, and three inches and three-quarters wide; oblong pyriform, pretty even in its outline, but slightly undulating. Skin, thickly covered with cinnamon-coloured russet, so much so as to be encrusted with it, and permitting only very little of the pale yellow ground to show through it. Eye, large and open, with long, stout, and somewhat woody segments, set in a moderate depression. Stalk, from an inch to an inch and a quarter long, inserted on the wide, blunt apex of the fruit without depression. Flesh, yellowish, very tender, melting, and buttery, with an abundant richly flavoured juice, which is sweet, sprightly, and with a fine perfume.This is one of the finest pears in cultivation, and ripens about the end of October and beginning of November. The tree is hardy, vigorous, and an abundant bearer, forming fine pyramids and standards. Mr. R. D. Blackmore says it is 'a very fine pear. Coarse from a wall. I have grown it to weigh 18 oz.'"

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 Also from the National Heirloom Exposition at Santa Rosa last September: this first place winning tomato, Pink Berkeley Tie-Dye. Annie's Annuals describes it: "With metallic green stripes this port-wine colored beefsteak (avg size: 8-12 oz) boasts an excellent sweet, rich, dark tomato flavor. Rated higher than ‘Cherokee Purple’ for taste & HIGHLY RECOMMENDED  FOR THOSE OF US WITH COOL SUMMERS. Alice Waters of Chez Panisse calls them 'Tomatoes you’ll never forget!'”

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Here's a red meat watermelon radish, from Heirloom Organic Gardens in San Benito County. It was a crowd stopper at the National Heirloom Exposition. They sell their fresh produce at Farmers Markets in the Bay Area.

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All gardening is local; so, be wary of falling in love with a plant when you're on vacation. This stunner is the Pink Rice Flower (Pimelea ferruginea), an Australian native plant as seen at Cambria Nursery and Florist, in Cambria, CA. Cambria is located in California's Garden of Eden, also known as the Central Coast, near Morro Bay. Frosts seldom happen there. Unlike here, in the Sacramento area.

From the online plant description: "The Pimelea ferruginea needs a minimum temperature superior to 15°C." 
For us Fahrenheit heads, that translates to 59 degrees F. Considering that our average nighttime low temperature is below 59 for 8 MONTHS A YEAR, this would not be a good choice as a perennial for Sacramento. Summer annual, perhaps.

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Pictures do not do justice to the brilliant hues of red-orange on this Chinese Pistache, "Keith Davey". On a clear, fall day, you can see this tree a mile away.

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I was impressed with the performance in 2011 of the Shock Wave Coral Crush Petunia. A great cascading plant with no insect problems (at least here!) with an extended bloom season. Even better, the petunia plant in that container with the Kumquat tree survived our freezing winter, and is greening up again.

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Garden quiz time. 
The reason winegrape growers place rose bushes at the end of their vineyard rows:
a) To alert them to a powdery mildew outbreak;
b) To alert them to an insect infestation;
c) Red roses mark the rows of red winegrapes; white, the white wine.
d) They're pretty.

 d) is correct. Different strains of powdery mildew attack roses. Insects that bother both would attack the grapes first. And if the color of the rose indicated the varietal, then an apricot colored rose would mean that they are growing Boone's Farm Strawberry Hill wine!


Sacramento County Farm Advisor and Viticulture specialist Chuck Ingels says the practice may have been tried in France a long time ago to detect powdery mildew early, but it doesn't work because the mildew of grape is a completely different species from that of the rose and they have different temperature requirements.  And roses get aphids but grapes don't.


Powdery mildew on grapes: Erisiphe necator.
Powdery mildew on rose: Sphaerotheca pannosa
Downy Mildew On grapes: Plasmopara viticola
Downy mildew of roses—Peronospora sparsa

Viticulture instructor Andy Walker at UC Davis says that roses are planted strictly for aesthetics.

One blogger took a trip to the vineyards of Italy where the winemaker discussed the issue:

"Singore Razzi explained how they grow the grapes for their wine. We wondered why there were rose bushes at the end of  each row of grapes and found out that very sophisticated tests were done by scientists on the soil and after those tests the rose bushes were  planted to tell the wine master how the soil is doing. If the roses stay fresh and perfect they know the grapes are doing just as well...when a bush is 'sick' they know those grapes growing in that row are 'sick" also.'
No winemaker is going to rely on roses to tell them about the quality of the wine. But it certainly impresses visitors; and, they probably bought more wine because of their sophistication!"

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Old broccoli that should be pulled? A closer look...


Bees in Flowering Broccoli


This is why I take my time before yanking out spent winter vegetables that have bolted. The flowers attract beneficial insects, such as honeybees and bumblebees. And that flowering broccoli comes at a time (early spring) when you want a lot of bees in your yard for pollinating fruit trees.
Here's more on attracting beneficials to your yard.


Tuesday, January 10, 2012

Controlling Sooty Mold



From the garden email bag, Gus from Lodi wants to know: “We have a great crop of oranges now despite the fact that many of the fruit and leaves are coated with a black substance that is easily washed off of the fruit. The fruit tastes great. Can you help? Thanks.”
 
 
That substance may be sooty mold, which is a fungus that results from the excrement of sucking insects such as aphids or scale.

 





According to the UC Davis Integrated Pest Management experts, sooty molds do not infect plants but grow on surfaces where those excrement deposits accumulate. This excrement, also known as honeydew, is a sweet, sticky liquid that plant-sucking insects excrete as they ingest large quantities of sap from a plant. Because the insect cannot completely utilize all the nutrients in this large volume of fluid, it assimilates what it needs and excretes the rest as honeydew. Wherever honeydew lands - leaves, twigs, fruit, yard furniture, concrete, sidewalks, or statuary - sooty molds can become established.

Although sooty molds do not infect plants, they can indirectly damage the plant by coating the leaves to the point that it reduces or inhibits sunlight penetration. Without adequate sunlight, the plant’s ability to carry on photosynthesis is reduced, which can stunt plant growth. Coated leaves also might prematurely age and die, causing premature leaf drop.
 
And as you pleasantly discovered, fruits or vegetables covered with sooty molds are edible. Simply remove the mold with a solution of mild soap and warm water.

To thwart any new outbreaks of sooty mold, do not overprune, overfertilize or overwater your pest-prone plants, says the University of Florida Ag Service. These bad habits can create weak, succulent new growth on the plants, a delicacy for sucking insects.


Beginning of sooty mold. Note the small white mass of scale on the stem.
To control sooty mold, you have to control the pests. On citrus, soft scales, such as cottony cushion scales, are the usual culprits. This scale can be controlled with a light horticultural oil when the scale are in their crawling stage.
Cottony cushion scale on mandarin branch

Sooty mold can attack any plant that may have an infestation of other sucking insects, especially aphids, leafhoppers, psyllids, and mealybugs.

The UCD IPM pros also advise against using insecticides containing the active ingredient imidacloprid for controlling this pest. Although scale is listed on the label as a pest that it can control, it is not effective against cottony cushion scale. 

Photo courtesy UC IPM

 To complicate matters, imidacloprid will reduce populations of the beneficial insect, the vedalia beetle. Both the adults and larvae of the Vedalia beetle feed exclusively on the cottony cushion scale on a variety of plants including rose, acacia, magnolia, olive, and citrus.







One product that can help control many of these pests, while washing off the sooty mold from leaves or fruit, is insecticidal soap. Even a blast of water from the hose can help wash off the sooty mold without harming any beneficial insects that might be trying to help you out. Horticultural oils or Neem oil can also suppress scale populations.

Also, look for ants crawling up and down the tree. Control the ants, and you can control the pests...as well as the sooty mold. Ants herd and protect sucking insects from beneficial insects, in order to harvest the honeydew for the ant colony.

Baits containing boric acid placed around the base of the tree will control ant populations in a couple of weeks. Sticky substances, such as Tanglefoot, although messy, can stop ants. See this previous post on ant control.

 



For plastic or painted surfaces that might have sooty mold, the USDA recommends this cleaning solution:





1/3 cup powdered household detergent 
1 quart household liquid bleach
2/3 of a cup of Trisodium phosphate
3 quarts of water. 

Be sure to wear rubber gloves when cleaning with this solution.