ask-tom-pictureHello Tom,

Thank you very much for your article about spotted wing drosophila in the OGS newsletter.

My partner and I own a small berry patch that is only about 75′ by 75.’  That comes to about 0.13 acres. Using your spraying charts I calculate for 0.13 acres we would need about 0.6 ounces of Entrust for a season.

Looking up Entrust I find it is very expensive (between $505 and $600 per pound), and I also don’t want to purchase too much and have to dispose of it later. Apparently the EPA prohibits the selling of Entrust in amounts smaller than a pound, so I have two questions for you:

  1. Do you know if, rather than buying Entrust, I can buy the active ingredient Spinosad in amounts more appropriate for my size of berry patch?  If so, how do I know the correct strength of Spinosad?
  1. Do you know of small scale berry producers going together on the purchase of Entrust?

Any information or advice you can provide is very much appreciated.

— Gordon

 

Gordon –

I also had sticker shock when I looked more closely at the Johnny’s Catalog.  $600 is a lot for a product that might work on SWD.ask tom  You also raise a good point about disposal problems when a small grower is unlikely to use a pound in a season or two.

Another product containing spinosad (the active ingredient in Entrust) is Monterey Garden Spray. A third is Captain Jack’s Deadbug Brew. Reems Creek Nursery has both products and Fifth Season has the Monterey product. Monterey is OMRI approved and Captain Jack’s is not. My plan is to try the Monterey product. 

Here is a comparison chart.

Product

Container Size

Spinsad Concentration

Approx.Cost

OMRI Approved?

Cost per 1% Spinosad

Entrust

16 oz dry

80%

$650

Yes

$81

Monterey Garden Spray

16 oz

0.5%

$25

Yes

$50

Capt. Jacks Deadbug Brew

16 oz

0.5%

$25

No

$50

 

For a little more background, the State of California describes Spinosad as “a naturally occurring insecticide with stomach poison and contact activity. It activates the central nervous system of insects through interaction with the nicotinic acetylcholine receptors.” http://www.cdpr.ca.gov/docs/emon/pubs/fatememo/spinosad_fate.pdf

Ruth Gonzalez with Reems Creek Nursery cautions that to avoid bee damage, Spinsosad should be sprayed very early or late in the day when bees are less active. Once Spinosad dries, there may be less risk because bees don’t feed on the foliage. 

Here is a Washington State apple spray program that suggests several Spinosad products. While a different program will apply to berries, this information may be useful. http://www.co.chelan.wa.us/pc/data/organic_spray_apples_pears.pdf

Thanks for your question. Happy berry harvest.

 

— Tom

 

Tom Elmore

Tom Elmore

Tom Elmore is co-owner and operator of Thatchmore Farm in Leicester NC. He has grown certified organic fruits and vegetables for 25 years and serves on the Boards of the NC Greenhouse Vegetable Growers Association and the Organic Growers School.