Tolerance to organic controls observed in California SWD population

Mark Bolda, Santa Cruz, Monterey & San Benito UC County Farm Adviser, has reported on recent laboratory assays conducted in California demonstrating tolerance to Pyganic (pyrethrins), an organic insecticide used against spotted wing drosophila (SWD). The assays were conducted on a population that had been treated in the field with Pyganic many times.

Organic management tools for SWD are very limited. Entrust (spinosad) and Pyganic (pyrethrins) are the two most effective organic control methods, but both have short residual control times and must be applied frequently. This means that SWD are exposed to pesticides over multiple generations, which is a recipe for resistance development. The same situation exists with conventional insecticides, but there are more modes of action available to rotate, which lessens the likelihood of short term resistance development.

The two-year period from SWD detection to potential pesticide tolerance development is definitely short term and only highlights the fact that we need to manage SWD on a system-wide scale: optimizing non chemical/cultural management to reduce populations, wisely selecting pesticides, and rotating modes of action.

More information
Suspected Tolerance to Pyganic (pyrethrin) Found in Spotted Wing Drosophila - Strawberries and Caneberries Blog

Grape Root Borer*Volunteer Monitoring Network trapping data now available

The Grape Root Borer*Volunteer Monitoring Network (GRB*VMN) has been up and running for a month, but the first, substantial trap captures occurred last week. The network consists of 10 locations in 7 North Carolina counties. Trap captures from these sites will be available here through the end of October, when the grape root borer flight is expected to end.

2011 GRB*VMN sites. Sites are only identified to the county level and assigned a number for record keeping purposes when there are multiple sites per county.

Monitoring locations and trapping data are listed below, from east to west:

Jones County 1

Rowan County 1

Rowan County 2

Davie County 1

Yadkin County 1

Surry County 1

Surry County 2

Surry County 3

Wilkes County 1

Haywood County 1

The highest number of trap captures is currently in Davie County with a few other locations catching a few moths. It is interesting that our flight appears to be occurring so late in the year, since reports of moth captures begin in July last year. We are monitoring the grape root borer flight in North Carolina to better understand when and where our highest populations occur. This information is important when making grape root borer management decisions, in particular whether or not to use currently labeled pesticides, which must be used either 30 days before harvest or after harvest. If you are interested in monitoring grape root borer yourself, see here for more information.

More information Do it yourself - Grape root borer monitoring

Southeastern strawberry preplant meetings underway

The 2011 strawberry preplant meetings are underway, and I will be attending the Sandhills meeting tonight in Carthage, NC. You can find a list of all upcoming strawberry preplant meetings here. Tonight I will be discussing spotted wing drosophila (SWD) biology and significance in strawberries and strawberry clipper considerations.

Strawberry clipper is a relatively infrequent pest in the southeast, but the North Carolina Sandhills is a clipper hot spot. I am planning an on farm trial in this region next spring to address some of the key questions about strawberry clipper management. Namely, how much does clipper damage impact strawberry yield, and how do southeastern strawberries respond to damage?

For those not able to attend preplants, the SWD slides I will be covering are embedded below. Bear in mind that the maps in this presentation are current as of July 2011 and are subject to change.



I will also be attending the South Carolina preplant on August 18, 2011 where SWD will be the main topic.

More information
Preplant meetings and fumigation resources - NC Strawberry Association
Strawberry clipper posts - NC Small Fruit & Specialty Crop IPM