BIG MACS - BIG VOLUMES BUT WHERE IS IT GOING?

BIG MACS,   BIG VOLUMES BUT WHERE IS IT GOING?

Spaced at just over 7 metres inter-row and a tad over 3 metres intra-row. By my reckoning that puts the density at 448 trees per hectare. The trees have been opened up by selective pruning. There are still branches in the way.

This tree gives you an idea of the crown density. The trees are about 7 to 8 metres high.

The problem as expressed by many growers is that the Stinkbugs sit in the top and are not contacted by the insecticde spray.

To see where the spray was going, a six metre PVC pipe with Water Sensitive cards placed at 1 metre intervals was inserted into a dense tree.

The standard spray-rig as supplied was used.   Here are the important data:

Number of nozzle-tips : 26

Total delivery at 15 bar (1500kPa) : 91 litres per minute.  Pressure recorded at the nozzle!

Speed: 92 seconds per 50 metres. Kilometres per hour : 1.96 km/hr

Calibrated volume per hectare : 3'845  l/ha ....3'800 l/ha close enough

Volume per tree : 8.58 l/tree ........... 8 l/tree close enough.

Here are the pics of the WS cards from the bottom up.

The spray-rig.

This pic actually shows the two Adjustable Conejets at the top and the Air Induction AITX's on the right bank. Low resolution pic; sorry.

CHANGING NOZZLES

The top two positions were replaced with the big Adjustable Conejets (AC) to overcome the limited effective height. The remaining right nozzle bank was replaced with Air Induction AITX8004VK Hollowcone tips.

The rig spraying without the trees.

Looks very impressive with all the mist and then the trees spoil the fun.

Note the dramatically reduced drift from the AITX's on the right nozzle bank. No doubt there will be issues with operator safety in the future and there appears to be a move to the air induction nozzles.

It is obvious that where the foliage is exceptionally dense the spray cannot get through.

The Adjustable Conejets - Cone angle adjustment and tip insert size selection will be critical to ensure that the spray gets to the top of 8 and 9 metre high trees.

The left AC should be adjusted to slightly widen the angle.

The real world. Things get tricky.

And another problem! Restricted airflow. 

Once again, notice the reduced drift from the AITX's. Also notice the right top AITX not spraying.....my mistake; turned the wrong cap.

HOT TIP! To improve the angle the right AC should actually be spraying to the left and the left AC to the right. You saw it here first!

More results from the AC and AITX's THIS TIME FROM 2 METRES AND UP AT 1 METRE INTERVALS. REMEMBER; VERY DENSE TREE.

Note : Something to consider.

Somewhere out there in the ether is a graph showing wind speed vs distance from the sprayer outlet. If my memory serves me well the speed drops off dramatically. So just how far does a 100 micron droplet go on a dry hot day? If you have this information or a link to the information it will be appreciated.

Tel Intl  +27 83 289 0327

Tel Natl  083 289 0327

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