- Author: Ben Faber
Diadasia bituberculata – Digger Bee
The hills are alive with the sound of BEE-EEZZE. And often they are found crawling on the ground, as is the case of Digger Bees. At this time of year, they might be seen along the margins of avocado orchards, near hiking trails or in undisturbed areas of citrus orchards. They are called Digger Bees commonly, but this is just a generic name for a large group of bees that nest in the ground. There are many genera and species and because of the general lack of study of these bees they are lumped under the name Digger for lack of any greater knowledge and naming of them. In the case of this bee find reported here, they are possibly Diadasia bituberculata – as suggested by Robin Thorpe, retired UCD entomologist. They are uncommon in the rest of the world, but found here in California and western US.
There are several kinds of small hairy or metallic bees that dig into the soil to nest, hence the common name, digger bees. They are a diverse group that comes from different families and the term digger bee can include the andrenid bees, halictid bees, and colletid bees such as the plasterer and yellow-faced bees. These are solitary bees and native pollinators that are active early in the season. Each female digs a cylindrical underground tunnel as a nest where she reproduces (as opposed to social bees such as honey bees where only the queen reproduces and maintains a colony with the help of sterile workers). Although solitary, they form colonies that may have several hundred nests in one spot, but all nests are independently owned.
The subterranean nest is provisioned with a mixture of nectar and pollen collected from nearby flowering plants. This "bee-bread" is food for the bee's offspring (larvae) that develop in the underground chamber and emerge as adults the following year.
Digger bees are 1/4 to 1/2-inch-long and variable in color (mostly shiny metallic or dark, but some with markings of white, yellow or reddish brown). There is one generation of digger bees per summer and once the adults finish perpetuating the species by laying eggs of the next generation there will be no activity till the following spring.
Digger bee nests are commonly located in areas where grass and mulch are scarse, either from too much shade, previous drought conditions or other stress. Most of them like to fly around their airspace at different times of the day, something to do with mating, air temperature or staking territory. They often travel great distances to forage.
The threat of being stung by digger bees is unlikely. The bees are docile and not likely to sting unless handled or threatened. There is no nest guarding behavior or attack behavior like there is with social insects such as honey bees and yellowjacket wasps.
Image: Digger Bee "Colony", Thanks to Pest Control Adviser Jane Delahoyde's friend.
- Author: Christina Herrick
This article is from Florida Grower News. Thanks for Jim Lloyd-butler for pointing it out.
FLG-Editorial@MeisterMediaww.com
A sister species of the Varroa destructor mite is developing the ability to parasitize European honeybees, threatening pollinators already hard pressed by pesticides, nutritional deficiencies, and disease, a Purdue University study says.
Researchers found that some populations of Varroa jacobsoni mites are shifting from feeding and reproducing on Asian honeybees, their preferred host, to European honeybees, the primary species used for crop pollination and honey production worldwide. To bee researchers, it's a grimly familiar story: V. destructor made the same host leap at least 60 years ago, spreading rapidly to become the most important global health threat to European honeybees.
While host-switching V. jacobsoni mites have not been found outside of Papua New Guinea, Purdue researchers Gladys Andino and Greg Hunt say vigilance is needed to protect European honeybees worldwide from further risk.
“This could represent a real threat,” said Andino, a bioinformatics specialist with Information Technology at Purdue. “If this mite gets out of control and spreads, we might have another situation like V. destructor.”
Varroa mites are obligate parasites, meaning their lifecycle is inextricably entwined with that of their bee hosts. The mites can do serious damage to their hosts' health due to their relatively large size – “think of a tick as big as your fist,” Hunt said. Mites latch on to bees and feed on their hemolymph, insects' rough equivalent to blood, leaving behind open wounds that are susceptible to infection. They can also transmit diseases such as deformed wing virus and have been linked to colony collapse disorder.
To gain insight into the biology behind V. jacobsoni‘s host switch, Andino and Hunt, professor of behavioral genetics and honeybee specialist, studied the differences in gene expression between V. jacobsoni mites that fed and reproduced on Asian honeybees and those that parasitized European honeybees. Knowing which host cues mites respond to and the genes involved could lead to potential control strategies, the researchers said.
“If we can understand the mechanism, we might be able to disrupt, block, or manipulate that,” Andino said. “But first we have to understand what is happening and which genes are involved in allowing the mites to shift to a new host.”
Andino and Hunt said the mites' leap to European honeybees likely occurred within the last decade. Previously, V. jacobsoni mites were occasionally found on European honeybees but seemed unable to produce healthy offspring, limiting their destructive capacity.
Catching the host transition in its early stages will allow researchers to continue to investigate the complex genetic details behind the shift and monitor infected European honeybees, Hunt said.
“This happened once with one species of mite, and it looks like it's happening again. Maybe if we catch this as it's beginning, we'll be able to figure out why it's happening or, down the road, stop it.”
The paper was recently published in BMC Genomics.
Funding for the study and an ongoing genome-sequencing project was provided USDA's-Agricultural Research Service and the USDA National Institute of Food and Agriculture.
This article is from Florida Grower News
- Author: UC Statewide IPM Program
Various insects, birds, and other animals pollinate plants. Bees, especially honey bees, are the most vital for pollinating food crops. Many California crops rely on bees to pollinate their flowers and ensure a good yield of seeds, fruit, and nuts. Pesticides, especially insecticides, can harm bees if they are applied or allowed to drift to plants that are flowering.
Our mission at the University of California Agricultural and Natural Resources (UC ANR), Statewide Integrated Pest Management Program (UC IPM) is to protect the environment by reducing risks caused by pest management practices. UC IPM developed Bee Precaution Pesticide Ratings to help pest managers make an informed decision about how to protect bees when choosing or applying pesticides. You can find and compare ratings for pesticide active ingredients including acaricides (miticides), bactericides, fungicides, herbicides, and insecticides, and select the one posing the least harm to bees.
Ratings fall into three categories. Red, or rated I, pesticides should not be applied or allowed to drift to plants that are flowering. Plants include the crop AND nearby weeds. Yellow, or rated II, pesticides should not be applied or allowed to drift to plants that are flowering, except when the application is made between sunset and midnight if allowed by the pesticide label and regulations. Finally, green, or rated III, pesticides have no bee precautions, except when required by the pesticide label or regulations. Pesticide users must follow the product directions for handling and use and take at least the minimum precautions required by the pesticide label and regulations.
A group of bee experts in California, Oregon, and Washington worked with UC IPM to develop the Bee Precaution Pesticide Ratings. They reviewed studies published in scientific journals and summary reports from European and United States pesticide regulatory agencies. While the protection statements on the pesticide labels were taken into account when determining the ratings, it is important to stress that UC IPM's ratings are not the pollinator protection statements on the pesticide labels. In a number of cases, the ratings suggest a more protective action than the pesticide label.
The UC IPM ratings also include active ingredients that may not be registered in your state; please follow local regulations. In California, the suggested use of the bee precaution pesticide ratings is in conjunction with UC Pest Management Guidelines (for commercial agriculture) and Pest Notes (for gardeners). Each crop in the UC Pest Management Guidelines has a link to the Bee Precaution Pesticide Ratings database and provides guidance on how to reduce bee poisoning from pesticides.
For more information on protecting bees from pesticides, see UC IPM's Protecting Natural Enemies and Pollinators, and use the Bee Precaution Pesticide Ratings.
Bee Guide
“According to a UC Berkeley news report,about one-third of the value of California agriculture comes from pollinator-dependent crops, representing a net value of $11.7 billion per year.”
- Author: Ben Faber
We hear about the decline in honeybees (non-native, from Europe and the most commonly managed bees), but native bees are declining too and in many instances these are the pollinators of California avocado. The loss of any pollinators is a loss for agriculture as well as the environment. But here are the loss charts.
file:///C:/Users/Ben%20Faber/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/TL5O596C/Wild%20Bee%20Decline%20Threatens%20U%20S%20%20Crop%20Production.pdf
file:///C:/Users/Ben%20Faber/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/TL5O596C/Number%20of%20wild%20bees%20drops%20where%20theyre%20needed%20most-%20Science%20News.pdf
file:///C:/Users/Ben%20Faber/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/TL5O596C/Wild%20Bee%20Declines%20Threaten%20US%20Crop%20Pollination.pdf
file:///C:/Users/Ben%20Faber/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/TL5O596C/National%20Analysis%20of%20Wild%20Bee%20Abundance%20Highlights%20Areas%20of%20Concern.pdf
http://ucanr.edu/blogs/bugsquad/index.cfm?tagname=Claire%20Kremen
Next year will be better.
Bumblebee doing its thing
- Author: Ben Faber
Two years ago we set out to study the impact of native bees on avocado fruit set. We applied for several grants unsuccessfully and turned to growers to see if there was interest. We raised $6,000 to start the project and have established 4 sites in Ventura and Santa Barbara counties. in the meantime have gotten a Sustainable Agricultural Research and Extension grant. This grant does not start until October 2014. We need bridging funds to continue this study. Below is the original request from growers for funds. If you would help contribute it will keep this study going until the larger grant comes through. Thank you.
Dr. Gordon Frankie at UC Berkeley is teaming with Dr. Ben Faber from the Ventura County UCCE Extension to jointly work on a pollination study for avocados. Dr. Frankie is studying how to increase native bee pollinators in avocado orchards. To do this, we plan on surveying the native bees that are in the area, identify the plants that they are foraging on and then plant those species in orchards to lure indigenous bees + pollinators in to the orchards. These plants will also be monitored for their attractiveness to beneficial insects which could control avocado thrips, persea mite along with other pests. We will need some startup money to cover the costs of native plants plus travel for Dr. Frankie and his assistant to be able to come down to monitor the project. They are ready and willing to come do this important study. We have applied for UC grants and will apply to CA Avocado Commission and CDFA Specialty Crops for money, but we will not see that money until summer 2014 at the earliest. We need your help. It would help to plant the natives before the winter rains. They need the rain to bloom; so the sooner you can help, the sooner we can plant. We are trying to cobble together donations of about $3,000. Thank you in advance. Any contributions are tax deductible and can be made to: UC Berkeley Foundation (with a notation at the bottom of the check: Gordon Frankie Bee Lab) and sent to Dept of Environmental Sciences, UC Berkeley, 130 Mulford Hall #3114, Berkeley, CA 94720.