Making a Coconut Crown Spray and Pump Cart for CRB management
Posted on Jan. 29, 2025 / Invasive Species, Nursery, Irrigation , Arboriculture / Subscribe 0
By Alberto Ricordi and Brown Cannon
The RC (Ricordi/Cannon) Crown Spray System was created through a collaboration between Alberto Ricordi and Brown Cannon. We want to thank Brent White for sharing his experience building and operating his own prototype. A walk-thru video of the RC CS System is available on YouTube: https://youtu.be/T18erO8vNxI?si=HJpOTbShFIDihxdA
The RC Crown Spray System was developed to make frequent sprays of the crown of coconut palms (Cocos nucifera) more practical and cost effective, when compared to spray methods that require climbing or a lift to reach the crown of palms for every spray treatment. In the RC System, a stationary halo with spray nozzles is secured on the crown of the palm. This can be easily done when the palm is regularly pruned or trimmed. The halo is connected to a quick coupler near the ground, using a swing pipe that us secured to the palm trunk using 1/2" pipe clamps. For spraying, the quick coupler at the base of the palm connects to a mobile spray system that can service multiple palms using the same quick coupler attachment. This allows for spraying the crown of the palm from the ground, without climbing or a lift.
Recent trials from CTAHR showed that 2.5% Basil essential oil was effective in preventing damage from CRB when sprayed in young palms at a 3-to-4 week interval (Ricordi, 2024). A shorter treatment interval might provide better results in highly infested areas, such as weekly or bi-weekly spray. When a 6% solution of essential oil was directly sprayed on CRB collected from an infested mulch pile in Waianae, the 6% solution caused instant irritation of CRB (see middle row in this short video) and 66% mortality rate after 4 days (Ricordi and Silva, 2023). Previous research from India, where CRB is a native species, showed that several essential oils cause mortality and repel CRB (Ravindran et al, 2019). The RC Crown Spray System can be used for insecticides or repellents with short residual effect, as part of a integrated pest management (IPM) for protection from coconut rhinoceros beetle (CRB) damage, or any other pests.
The RC Crown Spray System can be pre-assembled off-site for easy installation and use on site. It consist of:
- a halo with spray nozzles that is secured to the crown of the palm (Figures 1 and 2);
- a swing pipe connecting the halo to a quick coupler at the base of the palm (Figures 3 and 4); and
- a mobile cart that transports a tank with a booster pump to each palm (Figure 5).
Multiple palms can be connected to a single quick coupler to reduce the number of connections and the time required for treatment, as shown in Figure 4. The quantity of multiple palms per connection will depend on the specs of the pump, height of the palms, and distance between palms. The halo must be adjustment every 4 months or so, as new fronds that emerge can block the spray nozzles. The closer the halo is installed to the central spear, the longer it can stay in place before it needs adjustments. Therefore, proper diameter of the halo is very important. The use of quick couplers makes adjustments easy and non-destructive. We are cautiously optimistic this RC Crown Spray system will work for applications that require frequent spray of the crown, and wish to get information out to the industry so that others can try it and report back on any challenges or innovations. Long term testing and observation will give more clarity on how the materials can withstand the different types of solutions. Nothing presented in this article is proprietary. Everything is experimental and everything can be improved upon. For example, we realized during our first tests that we could add a 1/4" tubing into the halo with a mister at the end and wedged the mister or tubing next to the top spear, similar to what is done with hapu'u in landscaping (native Hawaiian tree ferns). However, climbing a coconut palm can be risk and that's why it is important to share information, so we can move forward efficiently. Managing CRB requires all of us to collaborate and find ways to manage this invasive pest that arrived in 2013. Please do not hesitate to contact [email protected] if you have an idea or innovation that could improve the efficiency of this system, or anything else that could be used to manage CRB.
Figure 1. Group of palms with the RC System's halo installed. The spray halos blend in and are barely noticeable, making it suitable for landscape use.
Figure 2. Close up of a palm with the RC System's halo installed.
Figure 3. Palms with individual quick coupler connections. The swing pipes are installed on the back side of the trunk.
Figure 4. Connecting three (3) palms into a single quick coupler to reduce the time required for spray.
Figure 5. First version of a cart to transport a tank to hold the a solution, booster pump, battery, and hose to connect to the quick coupler at the palms to be sprayed.
Here are the instructions for assembling the RC System and some reference costs:
Spray Halo
The RC Spray system Halo (Figure 6) is made using the following components:
• Swing Pipe
• Two Quick Coupler assemblies
• Three Spray Nozzle assemblies
• Barb fittings
Figure 6. RC System halo components.
Start by assembling the two (2x) quick coupler assemblies (Figure 7):
Figure 7. RC System Halo spray quick coupler assembly.
B1/B2. Barb to 1/2" thread 0.75” Funny Pipe Adapter MPT (FPA-075' $0.39/unit)
PH1/PH2. Pipe thread to Hose thread (AP-106 0.75” x .75” Swivel ADP FIPT x FHT; $3.20/unit)
Q1/Q2. Quick coupler (such as Liluo Tool 3/4” Plastic Water Hose Fitting Male and Female with check valve; 1.20/unit)
A1/A2. Pipe thread to hose thread adapter (Brass .75" GHT Male x .75” NFT Female; $2.50/unit)
Assembling from left to right, make two of the quick coupler assemblies:
1. Attach B to the pipe thread end of PH. Use seven wraps of Teflon tape and attach snuggly.
2. Attach the male end of Q to the hose thread end of PH making sure there is a washer in place in B.
3. Attach the thread end of A to the female end of Q, making sure there is a washer in Q.
4. Finally, wrap the second B with five wraps of Teflon tape and attach it to the female side of the quick coupler Q.
Next, assemble three spray nozzle assemblies (Figure 8, left), and one tee connection to quick coupler assembly (Figure 8, right):
Figure 8. Spray nozzle assembly (left, red letters) and tee to quick coupler assembly (right, green letters).
Parts list from top to bottom:
SN. 4’ Spray Nozzle ADJ 0-360 DEG ($0.93/unit)
SA. PSA-M Plastic Shrub Adapter ($0.38/unit)
SB. FPA-0500 .50” Funny Pipe Adapter MIPT x INS 3400-005 ($0.39/unit)
SP. Swing pipe ($24.03/100 feet)
ST. 1/2” Funny Pipe Tee ($0.49)
Assembling Spray Nozzle Units, from top to bottom. Make three (3) assemblies. Large palms might require additional spray assemblies.
5. Screw on spray nozzle SN to a Teflon taped shrub adaper SA. The Teflon tape will allow for easier adjustment of the spray nozzle direction without leaking. Tip: Fold a strip of 1/2" Teflon tape in half and wrap it once around the threaded end of the shrub adapter SA. Screw the spray nozzle SN on snuggly.
6. Next wrap the threaded end of SB with 5 wraps of Teflon tape and screw it into the shrub adapter SA.
7. Cut off a 2 1/4" piece of Swing Pipe SP and insert it on the barb end of SB. A rubber mallet and/or dish soap makes this task easier.
8. Insert the other end of the 1/2” Swing Pipe SP onto the “Tee” ST. The spray nozzles assemblies are complete!
Assembling tee to quick coupler assembly.
This is the tee that connects the Halo to the swing pipe running down the coconut tree.
HT. halo 1/2" Swing Pipe TWW ($0.39/unit)
HS. halo 1/2" Swing Pipe ($24.03/100 feet)
Assembling from top to bottom
9. Cut a 2 1/4” long piece of Swing pipe HS (from the same roll that was used for the SP pieces) and insert the center of the “Tee” HT into the 2 1/4” long piece HS. Again, a rubber mallet and/or dish soap makes this task easier.
You are now ready to assemble the Halo. See diagram (Figure 9) and assembly steps below for a 19.5" diameter halo.
Figure 9. Diagram of a 19.5" diameter halo. The diameter of the halo will vary depending on the size of the crown.
10. Cut a 52” length of Swing pipe.
11. Insert one of the quick connect couplers to the end in your right had and make sure the brass piece on the coupler is closest to the swing pipe.
12. Measure 4” of pipe from the connection and make a cut.
13. Insert one of the spray nozzle units so the nozzle is above the green lines on the pipe.
14. Attach the other end to complete a circle.
15. Measure 4” again and make a second cut.
16. This time attach the part that goes from the Halo to the tree hose. Make sure it’s pointing down or 180 degrees from where the spray nozzle unit is pointing.
17. Now using the existing spray nozzle unit as a reference, make two marks on the circle of pipe to divide it into thirds and cut the pipe on those two marks. Insert the other two spray nozzles and the Halo is almost complete.
18. The last thing you need to do is connect the quick coupler assembly to the Halo down pipe hose connection (the brass end closest to the halo). In the next step you will disconnect the quick couple and use the bottom half to attach to the top of the Swing pipe going down the tree.
The pipe down the trunk of the palm will be part of a roll of 100’ of Rainbird Swing Pipe. Remove the bottom half of the quick connect on the halo (the quick connect that attaches to the hose running down the tree). Once the climber gets the halo situated he can attach the pipe with the quick connect back on to the halo and secure the pipe to the coconut tree with a 1/2" pipe clamp and two screws. The clamp at the top of the palm can be made tight with duct tape so it will hold the halo in place. Every ten feet or so he can add a 1/2" “D” clamp with screws to secure the pipe loosely down the tree. It needs to be lose so you can push pipe up the tree to allow the halo to be moved to a higher position as the tree grows. The swing pipe resembles a landscape lighting wire conduit once secured to the palm. It is crucial to run the system with water while the climber or lift is up in the tree, to adjust the nozzles (Figure 10). Do not install the halo until you have the entire RC Crown Spray System ready.
Figure 10. It is crucial to run the system with water while the climber or lift is up in the tree, to adjust the nozzles.
Terminating the hose at the bottom of the coconut tree (Figure 11)
Figure 11. Parts for the hose termination valve left to right.
Parts for the hose termination valve left to right.
Q3m. Male end of a quick coupler (Same as Q1/Q2, $1.20/unit)
V1. 3/4" GHT Heavy Duty Plastic Garden Hose Shut Off Ball Valve Standard Water Shut-Off Ball Valve ($2.50/unit)
PH3. AP-106 .75” x .75” Swivel ADP FIPT x FHT ( Same as PH1/PH2 $3.20/unit)
B3. FPA-075 .75” Funny Pipe Adapter MPT (Same as B1/B2, $0.39/unit)
Assembly of Hose Termination Valve:
19. Screw male end of the quick connect adapter Q3m into the female end of the ball valve V1, making sure the washer is inserted into the ball valve V1.
20. Attach the hose pipe end of V1 to the hose pipe end of the hose to pipe thread adapter PH3, making sure a washer has been inserted.
21. Apply five wraps of Teflon to the barb fitting B3 and screw it on snuggly to the pipe thread end of PH3.
Battery Powered Spray Cart (Figure 12)
Figure 12. The first DC powered RC System Cart.
The RC Spray Cart is made using the following components:
C. Cart ($149)
RM. Rubber mat ($15 for 1/2 of a matt)
BP. 12 V DC Water Transfer Pump (such as TDRRICH 70PSI $81.65, must size to site needs)
BT. 12V Lead Acid battery (deep discharge, $200)
ST. Spray tank for spray solution, depending on what will be sprayed and label requirements
V3. Plastics Rain Barrel Spigot, High Flow Valve Core, Large Flow Water Tank Faucet, or Plastic Spigot for 5 Gallon Bucket, 3/4 NPS Inlet x 3/4 GHT Outlet Bulkhead Valve for Outdoor Plastic Bucket ($6)
HS. Hose & Reel ($35 and up)
Y. Y Hose Splitter 2 Ways
This is a part of the system that will vary the most depending on the product to be sprayed, type of cart, pump, etc. Larger properties could use a golf cart or a truck instead of the cart C shown in the picture. However, this cart is suitable for smaller or residential properties because it can store all the equipment and supplies necessary for treatments of up to 20 palms. Based on test sprays, 1 gallon of solution can spray approximately 6 (six) palms. Each palm was sprayed 3 (three) times for a period of 5 seconds each time. The multiple sprays is important to allow the solution to be absorbed and "soak in" instead of dripping as run off. The spray solution is stored in the tank ST. The rubber mat RM reduces vibrations from moving the cart and reduces wear of the plastic components and cart surface from rubbing. The valve or spigot V3 controls flows from V1 is important to o open or close the line that connects the tank V1 to the booster pump T. The battery U powers booster pump T and is controlled with a on/off switch not shown in this image. The splitter Y on the output side of the pump U controls the flow and pressure of solution that is sprayed, via hose X, that connects to the quick coupler installed in each (group of) palm. The other side of the emitter controls a small hose that drains the line into a bucket V2 after each (group of) palm is sprayed. The type of tank, the way the line is drained, and the overall concept will vary depending on the product that is sprayed and label requirement.
Pump Hose Termination Valve (Figure 13)
Figure 12. Parts for the Pump Hose Termination Valve.
Parts for the Pump Hose Termination Valve:
V2 3/4" GHT Heavy Duty Plastic Garden Hose Shut Off Ball Valve Standard Water Shut-Off Ball Valve
Q3f Liulo Tool 3/4” Plastic Water Hose Fitting Male and Female
Assembly of the Termination Valve:
22. Attach V2 to the male end of the hose coming from the DC water Pump BP, making sure the washer is in place.
23. Attach the quick coupler female side Q3f to V2 making sure the washer in Q3fis in place.
This assembly will connect to the quick coupler male side at the end of the line running down the (group of) palm with the Halo.
Operation of the system
- Fill the tank with the spray solution, following the label.
- Connect all the lines and open all valves except for the drain valve at the Y. This drain valve should remain closed when the system is spraying and only be opened when draining the lines or releasing pressure from the system.
- Turn the battery switch SW to on.
- With proper PPE, watch the halo and use the valve at the Y to control the flow to the line to the halo to adjust the spray pressure. Turn the system off as soon as spray run off is visible.
- Wait 30 seconds and run the system again for a few seconds.
- Repeat a third time.
- Close V3 at the spray tank ST.
- Ensure that DT appropriate receptable container is in place to receive the solution from the drain line.
- With V1 and V2 open, and V3 closed, open the drain valve at the splitter Y to drain the spray solution from the hose and swing pipe into DT.
- Close all valves.
- Disconnect Q3f
- Connect Q3f to the next (group of) palm or properly store the system until the next spray.
Again, please share your findings and ideas with us!
Figure 13. Alberto Ricordi (left) and Brown Cannon (right) testing the first RC Crown Spray System, installed December 2024.
Disclaimer: Read and follow pesticide labels thoroughly. Prior to using a pesticide, make sure the product is labeled for the intended use or specific situations. Refer to county and state regulations regarding pesticide use. Mention of a trademark or proprietary name does not constitute an endorsement, guarantee, or warranty by the University of Hawai‘i, Cooperative Extension, or its employees and does not imply recommendation to the exclusion of other suitable products.
References:
Ravindran, P., Subaharan, K., Venugopal, V., Chandran, K. P., Prathibha, P. S., & Sujithra, M. (2019). Essential oil in management of coconut rhinoceros beetle Oryctes rhinoceros L. In Indian Journal of Entomology (Vol. 81, Issue 3, p. 603).
Ricordi, A. and Cannon, B. RC Halo Spray System walk thru. YouTube, https://youtu.be/Jf-shYUcx1I
Ricordi, A. (2024). Field evaluation of essential oils in preventing damage from Coconut Rhinoceros Beetle in young coconut palms. CTAHR Hana’Ai, Volume 55. https://go.hawaii.edu/hSb
Ricordi, A. and Silva, J. (2024). Preliminary Trials on Use of Essential Oils for IPM of Coconut Rhinoceros Beetle. CTAHR Hana’Ai, Volume 52. https://go.hawaii.edu/bS9
Alberto Ricordi, Ornamental and Landscape Assistant Extension Agent, Department of Tropical Plant and Soil Sciences, Cooperative Extension, Oahu County, CTAHR, University of Hawaii at Manoa. [email protected]
Brown Cannon, Graduated from the University of Arizona in 1968 with a Bachelor of Science in Agriculture and has been actively involved in Agriculture for 60 years. http://savehawaiianpalms.com/
Disclaimer: Mention of a trademark or proprietary name does not constitute an endorsement, guarantee, or warranty by the University of Hawaiʻi Cooperative Extension or its employees and does not imply recommendation to the exclusion of other suitable products.
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