How to Use Back Pack Sprayers In Forestry Applications Prepared by Dan Green for 2017 Tree School
What we are going to cover in 90 minutes Forestry Applications Types of Sprayers Piston or Diaphragm Brands of sprayers Solo, others What comes with a sprayer Modifications and accessories nozzles and booms Spot spraying Area spraying and calibration Waving Wand Chemicals Mixing, cleanup and storage
Way, way too much to cover We cannot do justice to all that I would like to cover. But you will at least be exposed to possibilities that you can explore on your own. Ask questions as we go, please.
Forestry Applications This presentation assumes you are using the back pack sprayer to spray forest ground or perhaps mixed forest and pasture. Using a back pack sprayer around your house or garden may involve additional or different techniques not mentioned today.
Types of Sprayers Piston or Diaphragm Usually it doesn t matter which pump you have. They both work fine. Piston pumps in your sprayer work best with liquid formulations and can produce higher pressures, should you need them. Powder formulations can be abrasive (damaging) to a piston pump. Diaphragm pumps work best where higher pressures are not needed. Abrasive formulations do not bother a diaphragm pump. Some brands of sprayer are available in either type of pump, some are not.
Brands of Back Pack Sprayers Solo Comes in either piston or diaphragm Handle threads are US Pipe standard threads (convenient) Others Many good brands and designs Handle treads are usually not US Pipe standard which is inconvenient when you want to build a boom or change nozzles. Prices in the range of $75 seem pretty common for all brands.
Five Things that Come with a Sprayer Pump Handle..switchable for left handers in some brands Straps..should be comfortable for long days Off/On Handle.. thread size as discussed already may be important Wand.. thread size may be important Nozzles..usually plastic, sometimes several different nozzles
Modifications and Accessories Nozzles Flat Spray or Fan, different angles and flow rates Cone, fixed or adjustable, different flow rates Flood jet Nylon, brass, stainless steel Booms Usually need to be self made, publication available at Extension Connecting booms to the sprayer handle can be a challenge
Spot Spraying Mix as directed on the chemical label, usually a percentage. 1% is about one ounce per gallon, 4% is 5 ounces per gallon Don t make stronger than the label directs Spray at a pressure that is just enough to make the nozzle form its pattern. TOO MUCH PRESSURE CAUSES FINE PARTICLES THAT DRIFT Spray just until you can see that most of the foliage of what you want to kill is moist. DON T OVER APPLY. Chemical dripping off foliage is wasteful and may be harmful to desirable plants
WARNING Spot Spraying is Not Safe with All Chemicals Read the label on the chemical you are going to use. Herbicides like Roundup, 2,4 D, Crossbow, Garlon can be used in a spot spray. Insecticides can usually be spot sprayed but be very careful. Read and follow label instructions carefully and completely. They can be dangerous. Herbicides like atrazine and Velpar are not good candidates for spot spray. It can be done but it is very easy to over apply them. Damage to nontarget plants is likely. Some herbicides (Oust, Escort and others) cannot be safely applied as a spot spray.
Maximum per Acre Restriction You are not allowed to spray more chemical per acre than the label allows. If you have a heavy stand of weeds and you insist on spot spraying, you may apply more chemical than you should. Spot spraying is for spots. Area spraying should be done as follows:
Area wide spraying This is a huge subject that cannot be handled in any detail in this class. But it is a terribly useful skill if you have much spraying to do. You can learn it by reading a publication or taking other classes. Start off spraying just water on your driveway and learning to determine your application rate.
You Can Area Wide Spray With A Single nozzle Multiple nozzle boom Waving wand Requires CALIBRATION Generally any herbicide can be applied area wide. Don t apply insecticides area wide with a back pack sprayer. It is far too dangerous for the applicator.
Calibration we will practice this outside If you are 1. Using an 8003 nozzle 2. At the lowest pressure that will form a fan (about 15 psi) 3. Holding it about 2.5 feet above the weeds and 4 Walking at 200 feet per minute You should be applying 15 gallons of water per acre. An acre is 43,560 square feet (208 ft X 208 ft)
At 15 gallons of water per acre Mix no more that three gallons of mix at a time. It is more convenient and not so heavy to carry. For a chemical that needs one quart of chemical applied to each acre you would need 20% of one quart of chemical to make up a three gallon mixture. This means 20% of 32 ounces or 6.5 ounces of chemical mixed in 3 gallons of water. 2 quarts per acre is 13 ounces in 3 gallons, 1 gallon per acre is 26 ounces in 3 gallons of water (again, assuming you are spraying 15 gallons of water per acre)
Other Options You can change nozzles, walking speed, use multiple nozzle booms or any number of things to make the job easier. Each change involves the need to recalibrate your equipment. A very good resource is the TeeJet catalog which you can find on line. Or Extension publications
Check what you actually did with the first tank You should check how much you actually covered with your first tank. Three gallons of mix should cover 20 % of an acre (in our example). A spray swath is 2.5 wide (in our example) so it should cover about 3,500 lineal feet or about 8,700 square feet. If you covered more than that, you need to add more chemical to the mix. If you covered less, reduce the chemical.
Waving Wand Technique The Waving Wand technique is very useful for area spraying of soil active chemicals (Oust, Velpar, Atrazine, Escort). It is quite different than what we will cover today. If you would like to know more about it contact me out of class.
Dedicated Sprayers Sprayers used for Oust or Escort CANNOT BE USED afterwards in nonforestry uses. Mark dedicated sprayers clearly with permanent marker. Don t succumb to the temptation to spray dandelions in your lawn with a sprayer that has held Oust, Escort or other chemicals that are forestry only. Buy another sprayer instead.
Chemicals Insecticides Can be dangerous to people. Their use in back pack sprayers should be strictly limited to smaller jobs where the plants sprayed are waist high or shorter. Wear full protective gear as required on the label. Herbicides Tend to be low in toxicity. Almost all of this presentation assumes we are talking about herbicides. Read and follow the label. Wear proper protective clothing and shoes as specified on the label. Fungicides Tend to be low in toxicity. Fungicides are seldom used in forestry applications. Read the label.
Mixing Chemicals should be mixed with the water IN A BUCKET OR JUG not in the sprayer tank. Mix just enough for one sprayer full or less (My opinion, not the law) Wear proper protective clothes for the chemical you are mixing. Read the label. Be careful of splashes, especially into your eyes. Wear rubber gloves and goggles at a minimum. Again, read the label for requirements. Use all of what you mix so you don t have to store mixed chemicals
Cleanup and Storage Clean your sprayer each time you are done using it. The rinse water from most chemicals can be sprayed over the ground where you were killing weeds but read the label for special precautions your chemical may require. A triple wash of all parts for the sprayer, inside and out, is usually sufficient. Clean up immediately after you are done spraying. Store your sprayer out of direct sunlight. Store unmixed chemicals in a safe, preferably lockable area where they are not subject to freezing or extremely high temperatures. Avoid having left over mixed chemicals so you don t have to store them.
Let s Go Outside and Spray Please organized into teams of two and grab a sprayer. Meet me outside and we will practice whatever you want using just water. The best way to learn how to spray is by spraying water on a dry driveway. Don t be in a hurry to start spraying the chemical. Learn with just water first.
Call me if you need help Dan Green 503 655 7366 greentreefarm@msn.com