## Backpack Mistblower and Tristar Example

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**Determine how many trees per planted acre farmer has (see inset)****Determine the volume of spray per tree:**- Fill up mistblower with known amount of water
- Spray the complete amount of water at trees as if you were treating.
*This is called ‘volume of spray disbursed*’ - Count the number of trees you treated

**Determine the volume of spray per acre of trees:**- Multiply
*volume of spray disbursed*by number of planted trees in an acre - Divide that number by number of trees treated

- Multiply
**Read formulation label****If target Ai per acre is in lbs per acre, convert to ounces per acre so farmer can more easily measure material****Determine target oz of formulation per acre by dividing target oz of Ai per acre by % Ai in formulation.****Determine oz of formulation per volume to spray in backpack mistblower by dividing 6 by 3**

## Example

**Determine how many trees per planted acre farmer has (see inset)**

*in this example**the**farmer has 5 x 5 spacing, so 1742 trees per acre*__Trees per planted acre__#### Formula:

#### ft

^{2}in an acre ÷ ft^{2}spacing1 acre = 43560 ft

^{2}**4**×**4 spacing**= 16 ft^{2}43560 ft

^{2}÷ 16 ft^{2}=**2722 trees****per planted acre****4.5**×**4.5 spacing**= 20.25 ft^{2 }43560 ft

^{2}÷ 20.25 ft^{2}=**2151 trees per planted acre****5**×**5 spacing**= 25 ft^{2}43560 ft

^{2 }÷ 25 ft^{2}=**1742 trees****per planted acre****Determine the volume of spray per tree:**- Fill up mistblower with known amount of water.
*3 gallons* - Spray the complete amount of water at trees as if you were treating.
*This is called ‘volume of spray disbursed*’ - Count the number of trees you treated

*100 trees are sprayed with 3 gallons of water with backpack mistblower*

- Fill up mistblower with known amount of water.
**Determine the volume of spray per acre of trees:**- Multiply
*volume of spray disbursed*by number of planted trees in an acre - Divide that number by number of trees treated
\(\frac{\mathrm{Volume\ of\ spray\ disbursed}}{\mathrm{Number\ of\ trees\ treated}}=\frac{\mathrm{X} }{\mathrm{number\ of\ trees\ per\ acre}}\)

\(\frac{3\ \mathrm{gallons}}{100\ \mathrm{trees}}=\frac{X\ \mathrm{gallons} }{1742}\)

\(\left(100\right)\left(X\right)=\left(3\right)\left(1742\right)\)

\(100X=5226\) or 52.26 gallons per acre

- Multiply
**Read formulation label:**

Tristar:

8.5% Ai in formulation (weight)

.76 lbs Ai per gallon (volume)

Target Ai per acre: .154 lbs Ai per acre (weight)**If target Ai per acre is in****lbs****per acre, convert to ounces per acre so farmer can more easily measure material**

*.154**lbs**Ai per acre*(16 oz/ 1lb) = 2.46 oz**target**Ai per acre***Determine target oz of formulation per acre by dividing target oz of Ai per acre by % Ai in formulation.**

*2.46 target Ai per acre ÷ .085 = 28.98 oz of Tristar formulation.*

To achiever our target Ai (2.64 oz per acre) farmer must spray 28.98 oz Tristar formulation per acre with the farmer’s backpack mistblower**Determine oz of formulation per volume to spray in backpack****mistblower****by dividing 6 by 3**

*28.98 oz Tristar per acre**÷**52.26 gallons per acre**sprayed by backpack**mistblower**in 5*5 spacing = .554 oz per gallon*

**Therefore, the farmer in this example must add ~.5 oz of Tristar per gallon in a Stihl backpack mistblower in order to apply target .154 Ai per acre**

Publication date: March 6, 2024

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