Pre-emergent suggestions?

I would like to try using a sprayable pre-emergent herbicide in my apple and pear nursery and around trees in the orchard. Spraying roundup every few weeks is getting old. Which product(s) work well?

I use several pre-emergents on mature trees in the orchard, but I’m not sure any are safe on new trees in a nursery. Sinbar and Alion are the best pre-emergents I have used on Apple and Peach. I also use Surflan and Simizine but they are not as effective. 3 or 4 OZ of Alion will treat a whole acre. It works great, but its expensive (over $400 for 32oz) . Sinbar is sold in a 5 pound bag (about $250 last time I purchased it) Simizine is a lot cheaper and labeled for use on 1 year apple trees I believe. The PHI on most pre is high and Its very easy to kill your trees if your sprayer calibration is not precise. I killed a bunch of Raspberry about 20 years ago with Sinbar when my sprayer calibration was wrong

I’ve had good luck w/Prowl H2O. Related to Surflan and can be mixed w/roundup. It does stain everything yellow it gets on but that will fade in the sun. Check the label for tree age.

I also used Prowl this year for tree fruits. It was helpful but really great. I used Simazine for the blackberries. It seemed to me they both worked about the same. We did have a tremendous amount of rain this spring/early summer which makes it hard for any pre-emergent to work very long. I also used both the Simazine and Prowl at the lowest rates, which probably didn’t help.

One thing about Prowl is that there is no label restriction for using it on young trees. As Blueberry points out, a lot of pre-emergents warn not to use on young fruit trees, but Prowl doesn’t carry that warning. Prowl does warn not to use it on newly seeded nursery stock (I imagine it would keep the seeds from germinating.) As Chikn points out, it is an ugly yellow. It looks like paint.

I’ve seen a video showing how well Sinbar worked on blackberries. Several months after Sinbar was applied, the blackberries still looked very clean. I’ve wanted to try some Sinbar, but the cost has discouraged me. Still Blueberry’s endorsement may make me reconsider. Spraying for weeds after they emerge is a pain.

I was warned about possible Roundup damage to tree fruit a few years ago and I have been using more pre as a result. The current recommendation for my state is no Roundup after June - unfortunately that is when the pre control usually runs runs out and I refuse to use Paraquat in place of Roundup. I looked up the PHI for Simizine on Apples - 150 days, too long for my summer Apples. A combination of simizine and surflan works pretty well on Blackberry, but during a rainy year the control runs out long before the fruit gets picked. Never seen any damage from Surflan and its good on grass, but I did see a little damage to the blackberry plants this year from the Sinbar. This was my first year with Alion on Apples and Peaches. Its expensive, but it has a short PHI and the label allows for more than one application so you can start with a low rate and apply again if the weeds come back. Adjusting for the application rate, I believe Sinbar and Alion cost about the same per acre on Apples and Peaches.

Thanks so much Blueberry for the info. A peach grower friend of mine recommended Alion, so your comments are extremely relevant.

I use paraquat on on non-bearing trees, but I hate to use it because it is so dang dangerous. Burn down herbicides like Liberty are said to work equally as well, but I haven’t used them yet. Liberty is much more expensive compared to paraquat. Still, I may switch to Liberty when I run out of paraquat.

Here the rec is no Roundup after July 15th. One of the commercial peach growers in the area won’t use Roundup at all because he hires a lot of help. He says his help isn’t careful enough to use Roundup, so he uses paraquat with a pre-emergent in the tank mix.

Prowl stunts or stops root elongation close to the soil surface thats why there is no problem with established trees or deep rooted plants. The sun will decompose Prowl if its not watered in within 5 days also because Prowl ties up on surface organic matter. Hope that makes sense. If you use it at a rate of 1.5 ozs./1000 sq ft it gives good control of annual grasses and small seeded broadleaves for 90 days. In our asparagus, we’d use it at 4.5-6ozs and had very clean fields. We used Prowl granular on statice one year right after transplanting. No weeds, nice flowers too, but those plants never grew roots longer than a 1/4" inch.

Need some conversation rate help from you guys. Got some Simazine 90DF to spray as a pre-emegent around my blueberries. Want to spray at 4lb per acre, using my backpack sprayer, what rate per gallon should I use? Thanks!

Hi Chris

You need a pressure gage on your backback to make this work properly. If your rate is too hot you risk killing your plants.

Put a known amount of water on the sprayer perhaps a gallon and spray a known distance (perhaps 100 feet) at a constant pressure (perhaps 35 PSI). Compute the square feet sprayed. Measure the water left over to determine the amount used. From this you can calculate what fraction of an acre can be sprayed with 4 gallons of water.

EDIT. For comparison purposes I can spray about 1/2 acre my 25 gallon 12 volt sprayer at 35 PSI using a single split fan nozzle. I would guess your sprayer would spray about 4/25 or about 1/6 that amount so your 4 gallon backpack should spray about 1/12 of an acre at 35 psi. A desired rate of 4#/acre in a 4 gallon should be something in the range of 4/12 or abut 1/3 pound of material in your sprayer. Please check my math! I always run through the sprayer calibration exercise I described above before I spray. I learned the hard way by killing a bunch or raspberries when I first started