Sri oh fount of knowledge, thank you. Also to all who have posted suggestions. As suggested by Sri, here is background.
We have 108 plants which are 2 years old - most seriously affected and now at a stage where we won,t be able to look into the acils as they are almost 8-10 ft. Next we have 42 plants which are 18 months old - the beetles are found in these too. The last lot of 100 are just 8 months old and starting to attract the beetles. We noticed the first attack when the plants were about 6 months old.
Immediately we mixed fine river sand with thimet and poured down the axils.
We set up 6 pheromone lures per acre. This reduced the count from 5-6 a day to about 3.
Next we fermented castor seeds and along with the solution placed them in sunken pots all over the field. They worked but only reducing the count of beetles but not eliminating them.
We used naphatlene balls.
Along with this we have been pouring a mixture of 1 liter of monocrotophos + blue copper every month for over 18 months now. We have also replaced mono with lambdacyhalothrin. We found this more effective than mono.
We have hung bags of thimet in fine cloth around the axils.
I hope to have covered all the tricks by now. Everyday 2 staff go scout with long needles around each tree and pierce the beetle out. Surprisingly they are of uniform size of about 5 cm. Wonder where is the rest of the crowd ?
As said before the 2 year old plants are going out of reach now and we fear there is nothing we can do to stop this relentless attack until we find the source of these beetles.
To clarify - there are no FYM or vermi compost yards nearby.
I went thru the links and I think the red palm weevil is different from rhinoceros beetle in looks.the only bit of new info I gathered is to use marotti oil cake with sand.
But i would still like to know how we can get and fix tracking devices on these little guys