Web Author: Dr. Beth Grafton-Cardwell, conducts research in the San Joaquin Valley on insect and mite pests of citrus. These web pages provide up-to-date information about the pests and their natural enemies, including basic biology, hosts, distribution, monitoring methods and management tactics. Please join us in exploring this subject through blogs, information and resources.
Citrus Bugs Blog
November has arrived, and before you know it we'll be ringing in 2018! For those who hold a license or certificate from the Department of Pesticide Regulation (DPR), and have a last name starting with the letter M through Z, this is your year to renew.
DPR is urging license and certificate holders to mail in applications now to avoid late fees and to allow enough time for processing so that you can receive your new license or certificate by the beginning of the new year. Renewing early gives DPR time to notify you if you are short any continuing education (CE) hours and allows you time to complete any additional CE courses without having to retest.
If you need more hours to complete your renewal application and don't have time to attend an in-person meeting, then check out the online courses available from the UC Statewide IPM Program (UC IPM).
The following UC IPM and UC Agriculture and Natural Resources online courses have been approved by DPR and are available whenever and wherever you want to take them.
Laws and Regulations
- Proper Pesticide Use to Avoid Illegal Residues (2 hours) $40.00 charge
- Providing Integrated Pest Management Services in Schools and Child Care Settings (1 hour Laws and Regulations and 1 hour Other)
- Citrus IPM: California Red Scale (1 hour)
- Citrus IPM: Citricola Scale (1 hour)
- Citrus IPM: Citrus Peelminer (1 hour)
- Citrus IPM: Citrus Red Mite (1 hour)
- Citrus IPM: Cottony Cushion Scale (1 hour)
- Citrus IPM: Forktailed Bush Katydid (1 hour)
- Pesticide Application Equipment and Calibration (1.5 hours)
- Pesticide Resistance (2 hours)
- Tuta absoluta: A Threat to California Tomatoes (1 hour)
- Urban Pesticide Runoff and Mitigation: IPM – Pesticide Properties (1 hour)
- Urban Pesticide Runoff and Mitigation: Impact of Pesticides - Urban Pesticide Runoff (1 hour)
- Urban Pesticide Runoff and Mitigation: Water Quality and Mitigation: Bifenthrin and Fipronil (1 hour)
- Urban Pesticide Runoff and Mitigation: Herbicides and Water Quality (1 hour)
For those of you with last names A through L (or those of you who want to get a jump on your CE hours), look for new online courses from UC IPM coming in early 2018.
View the list of all DPR-approved online or in-person courses. For more information on the license and certification program and renewal information, visit the DPR website.
For more information about pest management and other training opportunities, see the UC IPM website.
Pollinator Week, June 19–25, 2017: Bee Knowledgeable!
—Stephanie Parreira, UC Statewide IPM Program
Bees are the most important pollinators of California agriculture—helping us grow field crops, fruits, nuts, and vegetables. Honey bees receive most of the credit for crop pollination, but many other kinds of bees play an important role as well. There are 1600 species of bees in California! Take time during Pollinator Week to learn about the different kinds of bees and what you can do to help them flourish.
Why should I care about other kinds of bees?
Bees other than honey bees contribute significantly to crop pollination. For example, alfalfa pollination by alfalfa leafcutter bees is worth $7 billion per year in the United States. Other bees can also boost the result of honey bee pollination—in almond orchards, honey bees are more effective when orchard mason bees are present. The more bee species, the merrier the harvest!
While growers often rent honey bee colonies to pollinate their crops, some wild bees pollinate certain crops even better than honey bees do. For instance, bumble bees are more effective pollinators of tomato because they do something honey bees do not: they shake pollen out of flowers with a technique known as buzz pollination. Likewise, native squash bees are better pollinators of cucurbits—unlike honey bees, they start work earlier in the day, and males even sleep in flowers overnight.
How can I help honey bees and other bees?
When it comes to land management and pest management practices, some bees need more accommodations than others. That's why it is important to know what bees are present in your area and important to your crop, and plan for their needs. Use this bee monitoring guide from the University of California to identify the bees present on your farm.
You can help all kinds of bees by using integrated pest management (IPM). This means using nonchemical pest management methods (cultural, mechanical and biological control), monitoring for pests to determine whether a pesticide is needed, and choosing pesticides that are less toxic to bees whenever possible. Check out the UC IPM Bee Precaution Pesticide Ratingsto learn about the risks different pesticides pose to honey bees and other bees, and follow the Best Management Practices To Protect Bees From Pesticides.
Bees also need plenty of food to stay healthy and abundant. Plant flowers that provide nectar and pollen throughout the year. See the planting resources below to find out which plants provide year-round food for specific types of bees.
Like honey bees, native bees need nesting areas to thrive. Bumble bees, squash bees, and other bees nest underground. Ground-nesting bees may require modified tilling practices (such as tilling fields no more than 6 inches deep for squash bees) or no-till management to survive. For aboveground nesters like carpenter bees and mason bees, consider planting hedgerows or placing tunnel-filled wooden blocks around the field. See the habitat resources below for more information about native bee nesting in agricultural areas.
Enjoy your “beesearch!”
Bee Habitat Resources
- Habitat for Bees and Beneficials
- Managing Wild Bees for Crop Pollination
- Native Bee Nest Locations in Agricultural Landscapes
- Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms
- Hedgerow Planting for Pollinators: Central Valley, Central Coast, Southern California
- Conservation Cover for Pollinators: Central Valley, Central Coast, Southern California
- The Integrated Crop Pollination Project: Tools for Growers
- Insect Pollinated Crops, Insect Pollinators and U.S. Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009.
- Native bees are a rich natural resource in urban California gardens. (PDF)
- Honey bees are more effective at pollinating almonds when other species of bees are present.
National Invasive Species Awareness week: February 27 – March 3, 2017
—Stephanie Parreira, UC Statewide IPM Program
Invasive species are plants, animals, fungi or microbes that are not native to an area, but can quickly establish, multiply, and become pests. These species can hurt the environment, agricultural production, and even human health in some instances (e.g. the mosquito Aedes aegypti). According to the USDA, invasive species are responsible for $137 billion per year in economic losses in the United States.
In agricultural systems, invasive species may reduce yields, render crops unmarketable, or make rangeland unfavorable to livestock. In natural areas, they may squeeze out native species, change soil quality, and increase the frequency or intensity of wildfires.
Some of these species have been introduced intentionally (e.g., yellow sweetclover, which was originally imported from Europe as a forage species for livestock), while others arrived by accident (e.g., the glassy-winged sharpshooter which came to California inadvertently through nursery stock shipments).
Just one species can be detrimental to crop production and revenues. The invasion of spotted-wing drosophila, for example, caused conventional raspberry growers in California to lose $36.4 million in revenue between 2009 and 2014, and would have reduced California raspberry yields by as much as 50% without control efforts.
The spread of invasive pests has become more prevalent in recent decades, and is linked to several factors, including global travel, produce trade, and climate change. Many invasive pests spread by human movement—medusahead, for example, has long awns on its seeds that easily attach to clothing and animal fur, to be carried to other locations. A recent study by UC scientists also determined that due to climate change, invasive weeds are shifting their ranges at a faster rate than native plants, and will likely cause more problems in agriculture and natural resources in the future. The yellow starthistle, an invasive plant that dries out soil and degrades rangelands, is one of the pests that will expand its range further north in California (and beyond) due to climate change.
While invasive pests can be a major challenge to growers and land managers, there are successful stories of stopping exotic pest invasions with well-coordinated eradication efforts. Recently, the California Department of Food and Agriculture (CDFA) declared the European Grapevine Moth eradicated from California after no moths were found in the state from 2015 to 2016. This was due to a rapid response, largely by the UC Cooperative Extension scientists after the moth was discovered in Napa vineyards in 2008.
As the graph shows, degree day unit accumulations for California red scale were not quite as bad this year as the previous two years, but were still well above the 30 year average. Which explains why California red scale is so difficult to control lately - an extra generation! If we get prolonged cold this winter and average daily temperatures (max + min divided by two) stay below the scale's developmental threshold of 53oF, then two things will happen: 1) the scales will stop developing until the weather warms in March, and 2) younger instars will experience overwintering mortality, leaving mostly adult females and males. A synchronized scale population is easier to control with insecticides, because crawler emergence occurs over a short period of time in the spring and summer and crawlers are the easiest stage to kill with insecticides.
During 2014 and 2015, abnormally warm weather generated a rapid accumulation of degree day units, well above the 30-year average, that allowed an additional generation of California red scale to complete their development. In addition, the excessively warm winters we have had during those years allowed California red scale, and other pests, to continue to develop during the winter in the San Joaquin Valley. This is quite unusual. While the 2016 season was well above the 30-year average through August, the accumulated degree day units at the end of the season were less than the last two years. Hopefully we will have a cold (but not freezing) winter that will prevent California red scale populations from continuing their development and cause mortality to the younger instars.