What I Learned at CAPCA's Annual Conference

How far do honey bees forage?  Do some ag chemicals hide your trees from bees?  Can weeds be managed with burn-down herbicides, only?  Answers to these timely questions and many more were delivered by expert speakers at the annual conference of the California Association of Pest Control Advisors (CAPCA).Dr. Gordon Wardell, Bee Biologist with Paramount Farming Company in the south San Joaquin Valley, described the structure of honey bee colonies, their food sources and what his company is doing to maintain the health of these essential partners of almond growers.How far do bees forage?  Honey bees commonly forage from a quarter mile to a mile and a half from the hive, with some foragers traveling two to three miles in search of food – nectar, pollen, and water for the hive.  Forager bees report back to the hive and direct worker bees to food sources.Can certain ag chemicals interfere with the foraging/feeding process of honey bees?  Dr. Wardell reported that very recent research shows that organo-silicon spray adjuvants can wipe forager bee memory, confuse bees and may keep worker bees from find an orchard sprayed with one of these materials.  To maintain bee health and ensure the best possible pollination conditions in a given year, Paramount Farming Company is doing the following things:

• Improving conditions at bee loading/unloading sites.
• Using no bloom sprays unless absolutely necessary and then sprays are applied at night.
• Planting supplemental foraging for bees. Bees need a range of different food sources.
• Providing fresh water buckets in the orchard.  Water is dumped and replaced regularly.
• Providing scientific support for almond and bee industries.

Kurt Hembree, UC Farm Advisor in Fresno County, talked about proactive weed management to counter the growing problem of herbicide resistant weeds.  To control weeds now and in the future, he recommended a four-step program:

• Don’t let weeds go to seed.  Pull “escapes” from your field.  You’ll be glad you did.  Resistance in a weed population starts with just one or two individual plants.  Pull them when you see them.
• Do a good spray job -- the right rate, spray volume, calibration and good to excellent spray coverage.
• Rotate herbicide chemistry.  Repeated use of the same material will lead to resistance.  Numbers indicating the mode of action of each herbicide are on the label.  Read the label.
• Diversify control tractics – rotate chemistries, mixtures, and timing.  Consider pre-emergent herbicides as they have different modes of action than burn-down (post-emergent) materials.  A burn-down only program is hard to do effectively over time and only a few different modes of action are available.

Surveys have shown that PCAs are the first-line source of information for California farmers.  The CAPCA conference is a great opportunity for PCAs (and growers) to learn from leading researchers and each other.