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From the UC Blogosphere...

Trouble in the Almond Orchards

Beekeepers and almond growers are concerned--and rightfully so--about the some 80,000 bee colonies that died this year in the San Joaquin Valley almond orchards. In monetary terms, that's a loss of about $180,000. But the loss isn't just financial. It could have long-term effects.

Beekeepers believe that pesticides killed their bees after the almond pollination season ended but just before they could move their bees to another site. This is a serious blow to both industries. Growers need the bees to pollinate their almonds. Now some beekeepers are vowing this is it; they'll never to return for another almond pollination season.

Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology talks about the issue in his latest edition of from the uc apiaries, published today on his website.

"When should the colonies be allowed to leave the orchards?" he asks. "When pollination no longer is happening. That does not mean that the bees should remain in place until the last petal falls from the last blossom."

"Why might beekeepers desire to move their hives out of the orchards 'early?' Once the almonds no longer provide nectar and pollen for the bees, the bees find replacement sources of food. Unfortunately, those sources may be contaminated with pesticides that almond growers would never use when the bees are present. Some common pests that surge right near the end of almond bloom include Egyptian alfalfa weevil larvae and aphids in alfalfa, and grape cutworms in vineyards. Delayed dormant sprays sometimes are being applied in other deciduous fruit orchards, even when the trees are in bloom. Often blooming weeds in the crops are attracting honey bees. If the year is really dry, the bees may be attracted to sugary secretions of aphids and other sucking bugs."

Mussen says it's "not difficult to see that accidental bee poisonings often happen. Despite our California regulations requiring beekeepers to be notified of applications of bee-toxic chemicals within a mile of the apiaries, bees fly up to four miles from their hives to find food and water. That is an area of 50 square miles in which they may find clean or contaminated food sources. Thus, growers whose fields are 'nowhere near' any known apiary locations may accidentally kill many bees with chemical applications."

"It seems," Mussen says, "that a combination of exposures of colonies to truly bee-toxic insecticides, followed by delayed effects of exposure to fungicide/IGR mixes during bloom, really set the bees way behind. The problem proved so severe that a number of beekeepers stated that they were never returning to California for almond pollination. That is not a good thing, since we really don't have too many colonies coming to almonds as it is."

In his newsletter, Mussen goes into depth about when and how bees pollinate the almonds and what could be causing the problem and how it can be resolved.

His take-home message? "Our honey bees cannot continue to be exposed to as many toxic agricultural products as they are, or we will not have enough bees to fill the pollination demand for our nuts, fruits, vegetable, forage and seed crops."

That's serious business.

A honey bee packing pollen as it forages on almonds. (Photo by Kathy Keatley Garvey)
A honey bee packing pollen as it forages on almonds. (Photo by Kathy Keatley Garvey)

A honey bee packing pollen as it forages on almonds. (Photo by Kathy Keatley Garvey)

Almond growers need bees. Without bees, there would be no almonds. (Photo by Kathy Keatley Garvey)
Almond growers need bees. Without bees, there would be no almonds. (Photo by Kathy Keatley Garvey)

Almond growers need bees. Without bees, there would be no almonds. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, April 23, 2014 at 9:21 PM

New FREE Publication on Sustainable Landscaping in California Available for Master Gardeners


New free publication on sustainable landscaping by Janet Hartin, Pam Geisel, Ali Haravandi, and Rachel Elkins
University of California Cooperative Extension (UCCE) Master Gardeners have been at the forefront of promoting sustainable landscape practices.  UCCE Master Gardeners now have a new free powerful publication at their disposal, “Sustainable Landscaping in California: How to Conserve Resources and Beautify your Home Landscape” (ANR Publication 8504). 

This in-depth publication provides research based information for individuals interested in adopting sustainable landscape practices. These practices include: plant selection, water conservation, pest management and providing wildlife habitats.

The free publication contains helpful figures, photos, and references for individuals looking for detailed and more complex information. “Sustainable Landscaping in California” can be a powerful tool for new volunteers working at a helpdesk or for developing workshop content or use in a presentation.

The sustainable landscaping publication is available as a free downloadable Adobe PDF from the UC Agriculture and Natural Resources (ANR) Catalog.  Don't forget to check-out some of the other high-quality gardening publications available. Ask a local UCCE office about publication discounts for volunteers!

Posted on Wednesday, April 23, 2014 at 2:26 PM
  • Author: Aubrey Bray

A Bee That's a Delight to See

Male green metallic sweat bee. (Photo by Kathy Keatley Garvey)
What's that on the Coreopsis?

Could it be--a bee?

Yes, that's the metallic green sweat bee, also called an ultra green sweat bee, Agapostemon texanus.  This one  (below) is a female. Males and females are easily distinguishable.  The female is all green, from head to thorax to abdomen, while the male (right) is green on the head and thorax but not on the abdomen.

Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, talked about them at the recent UC Davis Pollinator Gardening Workshop, sponsored by the California Center for Urban Horticulture.

The Agapostemon are members of the Halictinae family. They are "often called sweat bees because in hot weather they are attracted to human perspiration, which they lap up, probably for the salt it contains," according to the book, Bees of the World, by Christopher O'Toole and Christopher Raw.

Some of the family's many genera, including  Agapostemon, are restricted to the New World. Halictus and Lasioglossum "are common to the Old and New Worlds," the authors write.

Coreopsis, also called tickseed or coreopsis, is a genus of flowering plants in the family Asteraceae.

We spotted the female metallic green sweat bee at the Loch Lomond Marina, San Rafael. We captured the image of the male several years ago on a seaside daisy at the Mostly Natives Nursery, Tomales.

Green sweat bees will be among the bees featured in the book, "California Bees and Blooms: A Guide for Gardeners and Naturalists," to be published in the fall of 2014 by Heyday Press. It's the work of Gordon Frankie of UC Berkeley; Robbin Thorp of UC Davis; photographer Rollin Coville of the Bay Area; and Barbara Ertter of UC Berkeley. It will contain nearly 30 of the most common bee genera in California.

Frankie, Thorp, Coville and Ertter (and others) also published "Native Bees Are a Rich Natural Resource in Urban California Gardens" in California Agriculture.

Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey)
Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey)

Female metallic green sweat bee, Agapostemon texanus, on coreopsis. (Photo by Kathy Keatley Garvey

Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey)
Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey)

Female metallic green sweat bee peers at the photographer. (Photo by Kathy Keatley Garvey) Keatley Garvey)

Posted on Tuesday, April 22, 2014 at 8:01 PM

Fruit Tree Thinning Workshop

 

Fruit Tree Thinning Workshop

By Jutta Thoerner    Master Gardener

 

I had a lot of small fruit last year and much of the fruit dropped prematurely. How can I prevent this from happening again? Robert, San Miguel

 

 This premature fruit drop is referred to as “June drop”, which occurs in our area around May. It is a natural process that thins fruit in an attempt to prevent overbearing – or a crop load that the tree cannot successfully support.

However, this natural thinning is sometimes not enough. Signs that too much fruit is produced by the tree include broken branches laden with fruit, small fruit or alternate bearing of crop.  In this extreme drought year, thinning your fruit is particularly important.  Manually thinning will help your tree to get through this season less stressed, minimizing susceptibility to diseases and even sunburn. Some examples of trees that benefit from thinning include apples, Asian pears and certain European pears. These trees produce flower clusters from each bud and each flower can become a fruit. Thin these pome fruits to one or two fruit per cluster and at least 6-8 inches apart. The size of the fruit should be 0.5 inches to 1 inch in size at the time of thinning.

Stone fruits such as apricots, plums, peaches and pluots produce one fruit per bud and often, for example with apricots, on the entire length of the branch.  Thin all the fruit clusters to just one fruit and leave 2-4 inches between each fruit. Thin when the fruit is ¾ to 1 inch in diameter.  

If you have small trees or believe in keeping your trees small with summer pruning, hand thinning is the easiest and also produces the most accurate results. If you have a large tree and ladder climbing is no longer your hobby, attach a short rubber hose or cloth to a long pole. Strike individual fruit or clusters once or twice to break the fruit up and it will drop. Remember to clean the dropped fruit off the ground to lessen the spread of diseases. If you want to see a demonstration on “How to thin fruit”, join the Master Gardeners on April 23rd @ 1 30 pm for a one hour workshop in the Demonstration Garden (Garden Of The Seven Sisters).   

Posted on Tuesday, April 22, 2014 at 4:18 PM

Earth Day conservation tips come from UCCE

Substituting drought-tolerant plants and mulching the soil surface are other ways to conserve water.
Small changes in irrigation habits can result in big water savings said an Earth Day report in the Merced Sun-Star written by Thaddeus Miller.

The article focused on the Earth Day festivities at UC Merced, but the water-savings tips came from David Doll, UC Cooperative Extension advisor in Merced County. A large fraction of home water use happens in the yard. Doll said reducing lawn watering time and fixing broken sprinklers are important first steps to water conservation.

Grass lawn can use more water than many agricultural crops - including almonds, walnuts and tomatoes. Generally residents can cut back lawn irrigation and keep it green.

Doll shared a simple test to prevent excessive landscape irrigation. Pinch the soil between the thumb and index finger. If dirt crumbles and falls away, it needs water. But if it forms into a ribbon one-inch wide or longer, it can go another day or two without water, Miller reported.

Water conservation is part of the citizen science project being launched May 8 by UC Cooperative Extension to mark its 100th anniversary. On the Day of Science and Service all Californians are asked to report their water saving strategies. To participate, go to http://beascientist.ucanr.edu.

 

 

 

 

Posted on Tuesday, April 22, 2014 at 1:57 PM

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