Email Print Site Map
Cooperative Extension San Joaquin County
University of California
Cooperative Extension San Joaquin County

Posts Tagged: Eric Mussen

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

Rapini! Rapini! Rapini!

Billy Synk in the rapini he planted. (Photo by Kathy Keatley Garvey)
Honey bee population declining?

You wouldn't know it if you were to visit the two rapini patches in front of the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, University of California, Davis.

“The bees love the rapini,” said Laidlaw manager and staff research associate Billy Synk, who planted the seeds given him by Project Apis m.

Project apis m., a moniker derived from Apis mellifera, the scientific name of the European honey bee, funds and directs research to enhance the health and vitality of honey bee colonies while improving crop production. It's based in Paso Robles, Calif.  Take a look at the organization's website:  "We've infused over $2.5 million into bee research since our inception in 2006 to provide growers with healthier bees resulting in better pollination and increased crop yields.  We have personal relationships with the nation's commercial beekeepers and with the top bee scientists in the country."

"We fund research studies, purchase equipment for bee labs at our universities, support graduate students and provide scholarships to young bee scientists to encourage their pursuit of science-based solutions to honey bee challenges." 

Its eight-member board includes beekeepers and industry leaders. Extension apiculturist Eric Mussen of UC Davis is a longtime scientific advisor.

And rapini? It's a green cruciferous vegetable from the mustard family. The leaves, buds and stems are edible and often served in restaurants throughout the world. If you were in Italy, you'd eat the cimi di rapa or rapini. In Naples, it's known as friarielli and sometimes broccoli di rapa, according to Wikipedia. If you were in Rome, broccoletti. And in Portugal and Spain, grelos.

The bees know it as simply food for their colonies. Good stuff.  (In addition to rapini, PAm encourages folks to plant lovers, vetch, allysum, and native wildflowers as bee pasture.)

One thing's for certain: If you plan to participate in the UC Agriculture and Natural Resources' pollinator count for a three-minute period on Thursday, May 8 your eyes will tire from counting all the bees in the rapini!

Like to participate?  See the UC ANR's website, Day of Science and Service. You can also photograph pollinators and post the images on the website for all to see and enjoy.

A honey bee foraging on rapini at the Harry H. Laidlaw Jr. Honey Bee Facility. (Photo by Kathy Keatley Garvey)
A honey bee foraging on rapini at the Harry H. Laidlaw Jr. Honey Bee Facility. (Photo by Kathy Keatley Garvey)

A honey bee foraging on rapini at the Harry H. Laidlaw Jr. Honey Bee Facility. (Photo by Kathy Keatley Garvey)

Honey bee takes a liking to the rapini.  (Photo by Kathy Keatley Garvey)
Honey bee takes a liking to the rapini. (Photo by Kathy Keatley Garvey)

Honey bee takes a liking to the rapini. (Photo by Kathy Keatley Garvey)

Multi-tasking honey bee cleaning its tongue and packing its pollen load. (Photo by Kathy Keatley Garvey)
Multi-tasking honey bee cleaning its tongue and packing its pollen load. (Photo by Kathy Keatley Garvey)

Multi-tasking honey bee cleaning its tongue and packing its pollen load. (Photo by Kathy Keatley Garvey)

A large pollen load. (Photo by Kathy Keatley Garvey)
A large pollen load. (Photo by Kathy Keatley Garvey)

A large pollen load. (Photo by Kathy Keatley Garvey)

Posted on Monday, April 21, 2014 at 9:48 PM

Targeting the Varroa Mite

Varroa mite on a drone pupa. (Photo by Kathy Keatley Garvey)
Beekeepers know the varroa mite as "Public Enemy No. 1."

And it's an enemy to be reckoned with, Extension apiculturist Eric Mussen told students in the UC Davis "Biology of Parasitism" class, taught by forensic entomologist Robert Kimsey and nematologist Steve Nadler, Department of Entomology and Nematology.

Guest-lecturing at a special session held at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis, Mussen talked about the varroa mite--its history, biology, damage and control methods--and then opened several hives at the apiary.

The Varroa destructor, a native of Asia, is now found in hives throughout the world except in Australia. It was first detected in the United States in 1987.

The eight-legged reddish-brown parasite, about 1–1.8 mm long and 1.5–2 mm wide, is a blood sucker that's difficult to control, Mussen said. Mites transmit viruses (there are now some 22 named RNA viruses) that can wipe out a hive. A familiar mite-transmitted disease that beekeepers see is DWV or Deformed Wing Virus. Mites are also known lowering the protein level of a bee's blood, and reducing its weight and life span.

Mussen said that mites spread from colony to colony by phoresy (animal-to-animal transport). They ride on flying drones (males) and adult worker bees (females). They also spread changing hosts on flowers.

"A mite enters a honey bee cell just before or during the time it is being capped," Mussen said. "It feeds on older larva or prepupa. Sixty hours later, the mite lays its first egg. The egg will hatch in about 24 hours."

"The number and release of offspring depend on the length of the pupal stage. The queen is pupa for 8.5 days (no mites). The worker is pupa for 12.5 days (1.3 mites) and the drone is pupa for 14.7 days (3 or 4 mites)," he said. Thus, due to the longer time required for drone development, drone pupae get the worst of it.

"When maturing, the newly emerged mites climb onto adult bees and feed by puncturing the intersegmental membranes and sucking the bee blood," Mussen related. "Often these are nurse bees that stay around the brood nest. Sometimes the hosts are drones and older foragers that are flying from the hive every day. Eventually the new mite climbs off the nurse bee onto a comb in the brood nest and enters a cell. The reproductive cycle starts and within 6 days, 44 percent of the young mites have moved into the brood cells; within 12 days, 69 percent of the mites are in the brood cells; and within 24 days, 90 percent of the mite are in the brood cells."

"If there is no brood, the mite has to feed on adult bee blood every six days or so to remain alive," Mussen said. "Mite life expectancy in summer is around 60 days; bees about 42 days. Mite life expectancy in the winter is up to 9 months; bees about six months."

Mussen also discussed how to detect mite infestations through non-chemical and chemical methods,  and listed chemical treatments being used throughout the nation. Mites are developing resistance to a few chemical treatments, he pointed out. And, some of the chemical treatments not only kill the mites, but damage or kill the queen and the brood.

Beekeepers who try to go organic, figuring that "if the bees can't make it on their own--if they're not fit--let them die" are really doing a disservice to neighboring beekeepers, Mussen said. The mite will overrun a colony and then  infest other colonies.

Public Enemy No. 1--definitely a force to be reckoned with.

Extension apiculturist Eric Mussen (second from left) talks to a UC Davis class in the apiary of the Harry H. Laidlaw Jr. Honey Bee Research Facility. Third from left is forensic entomologist Robert Kimsey, one of the two class instructors.(Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen (second from left) talks to a UC Davis class in the apiary of the Harry H. Laidlaw Jr. Honey Bee Research Facility. Third from left is forensic entomologist Robert Kimsey, one of the two class instructors.(Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen (second from left) talks to a UC Davis class in the apiary of the Harry H. Laidlaw Jr. Honey Bee Research Facility. Third from left is forensic entomologist Robert Kimsey, one of the two class instructors.(Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen shows a frame to the students. (Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen shows a frame to the students. (Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen shows a frame to the students. (Photo by Kathy Keatley Garvey)

Varroa mites are reddish brown. (Photo by Kathy Keatley Garvey)
Varroa mites are reddish brown. (Photo by Kathy Keatley Garvey)

Varroa mites are reddish brown. (Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen reaches for a smoker as a bee (far left) buzzes off. (Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen reaches for a smoker as a bee (far left) buzzes off. (Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen reaches for a smoker as a bee (far left) buzzes off. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, April 16, 2014 at 5:18 PM

Honey, Let's Go Honey Tasting!

Eric Mussen
Want to sample some honey?

How about almond, yellow starthistle, leatherwood, cultivated buckwheat, safflower and wild oak?

Those are the varieties that will be offered by Extension apiculturist  Eric Mussen of the UC Davis Department of Entomology and Nematology at Briggs Hall on Saturday, April 12 during the 100th annual campuswide UC Davis Picnic Day.

Mussen will be offering honey tasting to one and all--come one, come all--from 10 a.m. to 3 p.m. And it's free. You grab a toothpick, poke it in the honey dish, and enjoy.

Folks don't usually like the bitter taste of almond, Mussen says. That's why you won't find it sold in stores. His favorite? Starthistle. It's an invasive weed, but don't tell that to the bees. They love it.

It's also a good time to ask Mussen about honey bees and check out the glassed-in bee observation hive in 122 Briggs. There you can look for the queen (she's the one with a number on her thorax) and watch the colony at work. In addition, the UC Davis Department of Entomology and Nematology is planning scores of educational displays and fun activities. You can learn what an insect is--how it differs from spiders and other critters. You can create maggot art, follow the termite trails and "bet" at the cockroach races.  You can learn about  forensic, medical, aquatic, apiculture and forest entomology.  Like pollinators? Learn about the major pollinators in your backyard. Like fly fishing? Tie a fly.

At the Bohart Museum of Entomology, home of nearly eight million insect specimens, you can see insects have been recently discovered and insects that are threatened and extinct. You can also hold Madagascar hissing cockroaches and walking sticks (live!) in your hand.

All in all, it plans to be a fun day for picnickers who love bugs--or want to learn more about them and what they do.

Fish-eye view of the honey tasting at Briggs Hall during the UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)
Fish-eye view of the honey tasting at Briggs Hall during the UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

Fish-eye view of the honey tasting at Briggs Hall during the UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

Evan Marczak of Davis samples honey. (Photo by Kathy Keatley Garvey)
Evan Marczak of Davis samples honey. (Photo by Kathy Keatley Garvey)

Evan Marczak of Davis samples honey. (Photo by Kathy Keatley Garvey)

Briggs Hall will be busy on Saturday, April 12 during the annual campuswide UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)
Briggs Hall will be busy on Saturday, April 12 during the annual campuswide UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

Briggs Hall will be busy on Saturday, April 12 during the annual campuswide UC Davis Picnic Day. (Photo by Kathy Keatley Garvey)

Posted on Thursday, April 10, 2014 at 7:25 PM

Bees and Onions Go Together: Pollination Partners

The University of California, Davis, is a world leader in seed, plant and agricultural sciences. Some 100 seed and seed-related companies are located near UC Davis and benefit greatly from its proximity, but the influence of UC Davis extends throughout the USA and far beyond.--Seed Central

So it stands to reason that Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology will keynote a Seed Central-affiliated conference on Thursday, April 10 on the Davis campus. He'll speak on "Honey Bees in Seed Crop Pollination" at 6 p.m. in the UC Davis Conference Center.

Mussen serves as the Extension apiculturist for the entire state, but is also involved at the national and global level.

Seed Central is co-organizing the two-day conference (which ends April 10) with the UC Davis College of Agricultural and Environmental Sciences. This is the Veg Research and Development Forum, an annual meeting of the research managers of vegetable seed companies with breeding activities for the North American market.  Its purpose, according to the Seed Central website: "to enable discussion among research managers of long-term, pre-competitive research topics and research-related policy issues of importance to the North American vegetable seed industry. Attendance includes invited participation with university scientists, technology providers to the seed industry and members of the downstream agriculture and food industries."

If you've ever seen honey bees pollinating an onion umbel (flowering head), they're a joy to watch. The bees come in twos and threes, buzzing up, around, over and under. It's their world on a string. A globe on a stalk. A bee-covered ball.

Nevertheless, there's concern among the onion growers and beekeepers about decreasing seed production due to the increased use of insecticides to control onion thrips. This insect vectors the pathogen, iris yellow spot virus.

Hybrid onion seed is indeed a small specialty crop in California, but an important one. To get acquainted with what's going on in the industry, read the UC Agriculture an Natural Resources (UC ANR) publication (No. 8008) on "Onion Seed Production in California," published in October 2013. One of the experts on onion seed production in California is Yolo County Farm Advisor Rachael Long, who directs the Yolo County Cooperative Extension, Woodland.  

Honey bees on an onion umbel. (Photo by Kathy Keatley Garvey)
Honey bees on an onion umbel. (Photo by Kathy Keatley Garvey)

Honey bees on an onion umbel. (Photo by Kathy Keatley Garvey)

Honey bees circling the
Honey bees circling the "globe" (onion umbel). (Photo by Kathy Keatley Garvey)

Honey bees circling the "globe" (onion umbel). (Photo by Kathy Keatley Garvey)

Posted on Wednesday, April 9, 2014 at 10:31 PM

Next 5 stories | Last story

Webmaster Email: mdhachman@ucdavis.edu