How It Works

Chemjet Tree Injector

The aim of tree injection is to utilise the trees natural transport system to distribute pesticides, fungicides and fertilizers to the areas where they are most effective without releasing any of these chemicals in the environment. In addition compounds can be injected which boosts the trees own defense mechanism.

The Chemjet® Injector is a spring-loaded device, with a 20mm tapered `nozzle’ to assist when placing the injector into the tree. Like a syringe the chemical is `drawn’ into the `chamber’ of the injector in measured 10, 15 or 20ml quantities. The injector is then `locked off’ by turning the handle in a clockwise direction.

The injectors are placed in the tree by drilling a 4.2mm or 11/64″ (wood dependent) hole 50mm deep then utilising the tapered nozzle to secure the injector firmly in place. Turning the handle anti clockwise will then release the device and inject the tree with the desired amount of chemical.

A tree’s circulatory system can be likened to that of a human. The tree takes up carbon dioxide and energy from the sun through the leaves where it photosynthesis’ it’s food. The food (sugars and carbohydrates) then dissolve in the sap and are carried downwards through the inner bark. This food is then distributed to every living cell in the tree including the root system. Applying chemicals to the plant tissue by spraying is inefficient especially in the fight against root pathogens.

Tapping into the trees natural circulatory process allows chemicals to dissipate rapidly and effectively, minimising wastage yet maximising efficiency by distributing to vitally important elements of the tree’s infrastructure.

Note the flow of the chemical as is it introduced through the trunk. The chemical reaches every element of the tree including the fine root hairs. Tree injection is also an economical alternative to other methods. The tree receives the chemical ‘directly’ therefore wastage is minimised.

Finally and most importantly, injecting the tree is the environmentally sound option when compared to alternate methods of treatment. Simply, a tiny fraction of conventionally used chemical is injected directly into the tree, without any release of chemicals in the environment.

Specific Instructions for Sudden Oak Death and Oak Wilt

Preparation of Tree Injectors

Spray a silicone lubricant down the barrel from the plunger handle before use.

1. Wear eye protection and gloves.
2. High speed cordless drill.
3. 11/64” normal steel shank drill bit.
4. Select Injectable product.
5. Mixing container
6. 5 gallon Bucket to carry loaded injectors.
7. A spray bottle of HEB – “All Purpose Disinfectant” or Lysol “Kitchen Spray” work equally well.

Note: Always spray your drill bit from tree to tree, and any other tools you may use.

1. Prepare the solution – For Oak Wilt – prepare a 50/50% solution of Propiconazole. For S O D – 11 oz of Potassium Phosphite and 22 of Water
2. Measure the tree to determine the number of injectors for placement. FOR OAK WILT: Place 1 injector every 3” equidistance around the trunk stem. FOR S O D: Place 1 inject every 4” to 5” apart
3. Draw the solution into the syringe and lock the plunger handle.
4. Drill the 11/64” holes in the trunk between the bark crevices 1 ¼ deep on a 45 degree downward angle.
5. Push the injector nozzle firmly into the drill hole. Note: Drill one or two holes at a time. This prevents over heating the drill bit. NOTE: The screw thread is for strength. DO NOT rotate the syringe like a screw this may cause damage or break the nozzle.
6. Hold the injector body down with one hand and at the same time unlock the plunger handle by ¼ turn.
7. While still holding the injector and with the open palm of your hand, give the plunger handle a firm, but gentle nudge to better seat the nozzle. You will hear a click noise. This will indicate a tight seal.
8. Work your way around the tree, repeating steps 4, 5, 6, and 7.

Now, the injectors start the safe and environment friendly injection process. It feeds the liquid with a low infusion 23 lbs pressure, to the sapwood (xylem) of the tree.

For injecting Oak Wilt, normal uptake is within 3-5 hours. In oak trees, the water movement up the trunk is 92ft/hour.

For injecting for SOD , uptake is relative fast, 5 to 45 min.

Injection Maintenance – – – “ Water your trees prior to treatment !” At the end of the day, pull the empty syringes from the trees and place them in your bucket ready to clean. For Oak Wilt … Wash with plain Hot Water (120 degrees) and let stand for 5 or 10 min,… drain and let dry.

The pathogen is heat sensitive and 95 degrees destroys the pathogen. For SOD, and other application rinse in hot water with disinfectants. DO NOT USE CHLOROX Put the injector tip into the solution and pulling up and down the plunger a number of times.  If you change products, always follow this practice.

Allow the injectors to dry. Spray a silicone lubricant down the barrel from the plunger handle.

Chemjet Instructions

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Donovan Family Investments is a leading avocado producer in Central Queensland with over 45,000 trees growing on our four farms. We have been using Chemjet tree injectors for over 20 years as our preferred method to control Phytophthora with phosphonic acid. During injecting season, our crews use 1000+ Chemjet tree injectors up to five times daily to provide environmentally friendly delivery of phosphonates to the trees’ root system. Over the years, we have found that the team at Chemjet provides us with exceptional customer service, quality products and replacement parts as required.

Lachlan Donovan
Donovan Family Investments

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