Strategus Aloeus: Tis the season for the ox beetle.

[Ed Askew]

Well I am prepared for my annual battle with the dreaded killer of small palms, Strategus Aloeus, the ox beetle. If you have seen little perfectly round burrows about the size of a quarter within 12 inches of a palm less than 36 inches high, and then the palm died, this was done by Strategus. Last year I tried Spectracide (Triazicide) as prophylaxis against attacks. The results were multiple burrows on 5 palms out of about 60 palms. 3 of the attacked palms were protected by a rock barrier I installed when planting them (see some of my earlier post regarding this). None of those burrows were successful for the beetle. I was able to catch one in the act and kill him. I lost both of the palms that were attacked and not protected by a rock barrier.

There were no controls, but my guess is that Spectracide is partially effective if applied every two weeks to the roots from June 15th to August 1st. Downside is having to apply it every two weeks, and I'm pretty sure it's killing scale predators. I had a heck of a scale problem last year and I think that's why. After using Spectracide, I could find none of the little black lady beetles we have here that keep scale in check.

Also, I did build a light trap and I caught only one beetle. It may have been too late in the year by the time I had it working. Two palms were attacked while the light trap was operational. Thousands of innocent bystander beetles were killed by it.

Again none of the palms that I have growing in an area where they are mulched with pea gravel were attacked, even though they are close to the woods. My palms planted next to the woods are the first and most frequently attacked.

This year I only have about 30 palms that are of the size that they are vulnerable to attack. All but about 10 of those were planted using the rock barrier. So my battle plan for this summer is to use no insecticides at all. I have cut 3 inch high rings out of a scrap section of 12 inch corrugated polyethylene drain pipe. I then cut through one end of each ring so I could open it, and drilled holes on either side of that cut in order to run a cable tie through it and re-close the cut once I worked each ring around the base of all of my smaller palms. I removed every bit of organic material not part of the palm itself within each ring, and filled them all with pea gravel. I will just sit back and wait. Come mid June I'll make my rounds and if I see any burrows I'll just use a garden hose and flood them. That is often all it takes to roust out the insect.

I don't know why the beetle hasn't attacked the palms mulched with pea gravel, but I have a hypothesis. I believe that when it tries to initiate a burrow in the pea gravel that the burrow collapses. The pea gravel won't hold up. If the beetle persists in digging down into it I think it would suffocate. The beetle is about as large as an insect can get, and their size is limited due to problems with oxygen transport. This large beetle probably can't survive in any limited oxygen environment. (Their grubs live underground of course, so maybe I'm completely wrong here) That's probably also why the rock barrier works, as although they have no problem removing and digging around rocks, the burrow ends up crooked and there's a ventilation issue because of that. Also probably why they don't attack palms over 36 inches high, because the entry point into the palm bud is too deep. I've noted when probing burrows with rebar that every one is exactly 20 inches deep.

So that's the plan for this year. I'll come back late summer and report on my success or failure.

Ed.

[Ed Askew]

This appears to be a complete failure. Last night we had four burrows, all in the palms mulched with pea gravel. We flushed two beetles out with a garden hose. One of the burrows was right next to a palm in a large area I have mulched in about 3 inches of pea gravel. The whole idea was based on the fact that palms in this area had not been attacked in the past. We've had heavy rains here the past few days which softened the soil and made it easy for the beetles. The pea gravel may have been more sticky due to the moisture keeping the burrows from collapsing. I'll probably fill these rings with larger rocks and see if that's any more effective.

Ed.

[DoomsDave]

Thank heaven we don't have that problem here, though I'll give you pocket gophers, if you want them . . . .

Let us know how it goes.

You're providing important information.

[Ed Askew]

So far I've had 6 of 29 palms that are of the vulneralbe size for the beetle that have been attacked. We have been able to flush 12 beetles altogether out of burrows. I have found that there are always at least 2 beetles in each burrow (if there are any, i.e. if you find them in time). The female is always the first to emerge, but the male will stay in the burrow as long as he can sometimes up to 45 minutes with it completely flooded. We have to keep the hose running the whole time to keep the burrow full of water until they are out. My wife flushed out 4 beetles from a single burrow the other day. The beetles seem to like certain of the palms and attack the same ones repeatedly. They have not attacked any that were planted with the rock barrier as decribed in my previous posts. I have had the pea gravel ring on top of the rock barrier. Also on those not planted with the rock barrier I have replaced the pea gravel with larger rocks inside the ring, then filled pea gravel in to occupy the space between the large rocks. None of these palms have yet to be attacked, but we have had no rain in almost 2 weeks, so we'll see what happens after another heavy downpour.

[rozpalm]

We have these in Florida and I've never known them to be anything but a minor problem.

[Ed Askew]

Well for our particular local, this beetle is not a minor problem. It's also not going to kill every single on of your plams either. I understand in certain parts of east Texas it will kill every single small palm. So far, in the last 4 years, I have lost about 20 palms from Strategus. In my experience, if you are able to get the bettle to come out of the hole, the palm has about a 50% chance of surviving. Otherwise, it's a 100% mortality rate. To date we have had 7 palms attacked and have killed 14 bettles flushed from the burrows (on one palm my wife had 4 bettle emerge). From research I've done on these beetles and talking to other people in my area (Southern Mississippi) I've come to believe that if you have street lights around your place they are not a major problem. They're attracted to the lights and they are a very juicy meal for lots of insectivores who know they and other insects are attracted to lights. I killed one that was floundering under one of my porch lights I had accidentally left on for a couple of hours one night last month. I live way out in the country though, have no street lights and have no lights on within 1/4 mile of my house. I know I could just leave on some lights but I like it without the lights. We have an awesome display of fireflies all summer you don't get in town and just a lot of other benefits from not having light pollution. I think I've got this problem licked now as none of the palms I planted with the rock barrier and have the gravel ring as well have been attacked so far this year. One beetle did get past the big rocks in the gravel ring (this one not planted with the rock barrier.) We just had a very heavy rain today though; the first rain in 3 weeks. Tomorrow morning will tell the tale on how well my defenses have worked. Right now is the absolute peak of Strategus activity.

[John Case]

Ed, I might suggest the installation of some solar lighting to place around your vulnerable trees if you think that as a result of light these beetles might get eaten by a predator. Just a thought....

[richtrav]

Ed, I didn't realize they were a problem that far east. In Central and South Texas they are a very real problem, in fact well into Mexico they are known trouble makers on tequila plantations. They definitely favor some palms over others and will eat the spears of a number of monocots. I think agaves are probably their favorite. They certainly seem to favor some palms over others and some species seem able to recover better; Sabal texana and palmetto can often survive a mild attack if they are large and healthy enough while S. mauritiiformis are almost always killed. They generally go after palms that still have their growing points at or near ground level and usually don't bother if the plants aren't "meaty" enough (Rhapis are fine). So far I know of no bullet proof solution, imidacloprid (Bayer Tree and Shrub) seems to work OK but gets expensive if you have a lot of plants. They are generally not a problem in town and even in more suburban or rural areas you'll often get a few years of good growing before they "find you", but once they're established they never want to go away. I've known people to try almost everything from rocks and gravel to the giant buffer pads from floor polishers to buglight zappers.

[Ed Askew]

They were here before I planted any palms. I didn't know what they were intially. Hundreds of burrows down in a holler below my house near an intermittant stream. Thought they were crawfish. Imidacloprid was my first treatment and it was highly effective. The problem is imidacloprid kills scale enemies, but it doesn't kill hard scale. I had a horrendous scale problem on all my palms (sabal louisianas, meds, and large sabal palmettos) after using imidacloprid that took 2 years to get under control. So far this season we have flushed 24 beetles out of burrows. They have attacked 9 (I think, about 9 anyway) of my palms, one a very large sabal louisiana over 6 feet tall with a short trunk. I was surprised to see that palm get hit. The beetles hit the same individual palms repeatedly. Must be some pheromone trail. I have an idea for an underground trap that I'm going to try next season and I'm going to bait it with beetles I capture this season, and frozen palm hearts from any of my palms that die.

So far the combination of palms planted with 2" of large (1-2") gravel below grade in a 12" circle around the palm, and then a 12" diameter 3" high plastic ring filled with pea gravel on top of that has not been breached this season. I'll replace any palms that die with palms planted in that way.

Ed.

[Ed Askew]

I think I can safely report final results for this season: Of 29 palms of the size normally attacked by the beetle protected with the pea gravel ring 8 palms were attacked. We flushed a total of 24 beetles out of their burrows. No insecticides were used. Once I realised the beetles were getting past the pea gravel on all palms not planted with the rock barrier I switched the gravel to larger gravel about 1" size plus pea gravel in between and this seemed to be a superior deterrent but was breeched twice on palms that had been previously attacked. I noticed the same palms were repeatedly attacked by different beetles leading me to hypothesize that some pheromone is left by the beetles when burrowing that attract more beetles.

I was dismayed to find two large palms more than 36 inches high were attacked. That's a first for me. One was my largest Sabal Louisiana.

It's too early to say for sure but my guess is that I'll have a low mortality rate on the attacked palms. All seem to be growing, but one has some browning of the spear leaf. That one will probably not make it. It was one of the smaller palms attacked. We were able to flush beetles out of the burrows farily quickly this year. The gravel ring made burrows obvious.

Lastly the best news is that of none of the palms (about 20) planted with a large pebble barrier (about 1"- 2" average size gravel) 2" deep and in a radius of 6" around the palm at planting, with sticky red clay sprinkled on top and watered in at planting time, then later having the pea gravel ring (12" diameter plastic ring 3" high filled with pea sized gravel) later installed above grade were attacked this year. That's 0 for 20. I suspect this will prove an effective detterent. Any palms I have to replaced will be planted in this way.

One PS here is that coffee grounds may be a detterent. We have a scale problem and have read that coffee grounds help. My wife has been dumping them around the palms we have that had scale last year. None of those palms were attacked by Strategus.

Ed.

[eevans]

Thanks to posts like this on the PT forums, I've finally discovered this to be the likely culprit in the mysterious deaths of some of my "bulletproof" palms (4 windmills, 1 Sabal brazoria, and maybe even one of my beloved pindos). Over the years I have found their holes immediately adjacent to base of several of my palms - never anywhere else, never next to any other plants. I eventually figured out what they were after finding living or dead adults next to the holes.

This year I've decided to prepare for the attack. I like your rock-filled ring idea, but a couple of my palms are in locations where that isn't practical. So I bought some steel mesh (1/4 inch holes) and trimmed it to create "rings" that cover the ground to about 8 inches from the base of each trunk. The mesh is way too tight for ox beetles to get through. And since these palms already have trunks, they won't get any wider, so I figure the mesh won't hurt them.  Here is what it looks like after being cut out, and then after installation. I just covered it back up with mulch afterwards so the mesh isn't visible.

[Swolte]

Any report on how the mesh idea worked? Other experiences are welcome too!
:)

Edited June 12, 2020 by Swolte

[eevans]

Hard to be certain.  I can say that on those palms to which I applied the mesh, I have not had any new tunnels. But I only did this on three palms so it isn't a big sample.

I can say that I have cut my self on the ragged mesh edges at least once, since it is covered in mulch and I sometimes forget when I'm poking around in there; e.g., weeding, spreading new mulch, etc. It's like the way I cut through a mulch-covered soaker hose with a shovel at least once every year : (

For the other small palms I used piles of "egg stones" bought in bags from home-improvement stores. In the past couple of years the only palms attacked by the beetle have been Sabal minor. The beetles always seem to find a way around the stones, maybe because the bases of S. minor are always changing as the old leaf bases press down and out.  Also, mine are mostly planted in groups, which causes even more nooks around the bases.  On the plus side, I've never actually lost a S. minor to these attacks. They have grown stunted leaves for a year or so afterward, but they always seem to recover somehow.

In fact, over the years I have only had Sabal minor, Sabal "brazoria", Butia capitata (odorata?), and young windmall palms attacked by the ox beetle. They mostly hit the S. minors.  They have not bothered my other small in-ground palms: Arenga engleri, Rhapis lady palms, and some Chamaedoreas, all of which I presume are all too small for them.

[PricklyPearSATC]

On 6/11/2020 at 9:03 PM, Swolte said:

Any report on how the mesh idea worked? Other experiences are welcome too!

It's a good idea to remove the steel mesh at the end of each growing season and re-apply the next season!  I have palms that grew into it! 
 

[Reyes Vargas]

I hate those beetles.  They killed two of my Livistona decora palms.

Here is the decora that I dug up.  You can see the hole that it made.

I'm this picture I'm holding the head of the beetle that was still in the hole.  It's a little hard to make out since it's covered in dirt.

Another picture of the hole it created with the head just to the left.

[Reyes Vargas]

Well the ox beetles are starting to wake up for the season.  Time to try and protect the palms.  

Do ox beetles attack only young palms or can they go after older palms?

[PricklyPearSATC]

6 hours ago, Reyes Vargas said:

Well the ox beetles are starting to wake up for the season.  Time to try and protect the palms.  

Do ox beetles attack only young palms or can they go after older palms?

They're weird.  I believe palms are not a true "host" for these beetles, so they can exist without palms.  I think palms are "candy" to them.  When they attacked one young palm in my yard, they attacked a different one every night for 5 nights.  This was in 2008.  (They have not destroyed palms since, but am worried this year with loss of their habitat from the freeze. )
I believe palms are an "opportunistic host" for them, so they go where it is easy for them to go.   Hence, young palms are more at risk. 

Edited May 2, 2021 by PricklyPearSATC

[Reyes Vargas]

Well I was inspecting my last livistona decora and sure enough there was a huge hole at the base of the palm.  For some reason they are attracted to my decoras.  I have a couple chinensis and they don't bother those.

Here is the hole at the base.

Here is the size of the trunk.  My question is, is this palm big enough so that the ox beetle will not kill it?

I didn't know what to do so I poured some malation in the hole since that was all I had.  Stinks like hell.  I'm not buying any more of that stuff.

[Swolte]

Please keep us updated on how the mesh works as beetle time has arrived in Texas!

I just had an attack on a rare Sabal Guatemalensis juvenile (not trunking yet). I had an egg-rock barrier but it wasn't bothered by it (still not sure if it helped or not as who knows how many would have attacked without it). Must have dug about a foot deep. I poured some insecticide in the hole and flooded it with water (I know this works from a friend). Unfortunately, I had kid-duty so everything was hasty and I couldn't wait around, take pics, and/or get a body.  

Edited June 18, 2021 by Swolte

[Ed Askew]

The Palm Fortress

So beetle season is just starting, and I don't know for sure how this is going to work, but early indications are that it is effective as long as the edges don't wash out.  Last year I lost I think 5 palms and one or two are questionable.   We killed 38 beetles.  All my palms are S. palmetto, which I grow myself from seed.  This year I had twenty 5 gallon Sabal palmettos that I should have planted last year, but I wasn't ready to plant them.  So they were extremely root bound.  I made 20 of these palm fortresses.  Each palm fortress consists of four 7x7x1.5" square tiles with a 3x3" hole in the middle, and there is notch in one corner that is 1/2x1/2".  In the center is a 6x6" square of galvanized hardware cloth.  These tiles are made from concrete, and the mesh is glued on there with Locktite (formerly PL brand) urethane construction adhesive.  So I made 80 of these tiles.  The reason I did this instead of using just the hardware cloth alone, which of course is going to be easier, is that I know from past experience with different barriers that the problem is the beetle will just crawl under the mesh.  Also, the palm will grow into the mesh and impale itself.  This way, the palm pushes out the tiles.  As it gets bigger, you can insert thin tiles in between and enlarge the central gap.

[Ed Askew]

Exactly how these palms are planted is very crucial.  First off I dig a hole that is more than twice the diameter of the pot.  Then, when I remove the palm from the pot, I use a hose and I wash off about 1 or 2 inches of the potting soil from the top of the palm.  I put the palm in the hole, and then I pack the local soil around the root ball, and fill in the hole around the outside up to about 4" from the top, leaving a trench that is 4 inches deep around the root ball.  I water that in gently.  Then, I pour in a bag of pond rocks in that trench, put some more dirt in there to fill in the cracks between the rocks, and water that in.  There is now still a 1 or 2 inch space under ground level that I place the palm fortress tiles in.  You made need to trim off the dead petioles of the palm to allow it fit in the central gap of the tiles, and you may need to chip off some concrete gently with a mason's hammer.  The fit has to be tight enough that a beetle can't fit between the tiles and the palm. Once you have the palm fortress situated, fill in dirt around it, so dirt inside the center of each hole, up to ground level and water it in.  Ideally, the palm fortress is just barely above ground level; it's mostly buried but the mesh part is just above ground level.  So I planted 20 palms this way.  We have had torrential rains and a tropical storm already in Mississippi, and the rains washed out the dirt from several of my new palms, and two have been attacked so far by beetles that were able to crawl underneath the exposed edge of a tile.  None have successfully attacked a palm where the palm fortress remained at least buried on all four sides.  I have found multiple aborted burrows along the edges of several palms, where the beetle digs in and encounters the buried rock ring.  The palms all look healthy, have recovered from transplant shock, and have grown roots up under the tiles that I can see after the rains washed the soil away.  So this is kind of an involved project and it's not worth anyone else doing it I don't think until this is proven effective.  If it is, I'll go into all the details for how they were made if anyone is interested. 

[Swolte]

Thanks for sharing, Ed, that's quite the impressive setup... 
 

I haven't tried the mesh (just bought some) yet but you're the first to claim that the beetles will just go underneath it! That's news. 

You're saying the rocks are only 3" deep (with 2" underground?) and that, thus far, has had them abort tunnels? Just curious, have you tried to have some of the mesh bent and underground?

[Ed Askew]

No, I haven't tried mesh per se, but I did try landscape fabric with rocks on top, and they went right under it.  I have no doubt they will just go underneath mesh, and then the other problem is the roots of the palm will grow through the mesh and the mesh will not be able to move to accommodate the growth of the palm.  There was someone from San Antonio who tried mesh and said there was a problem with the palms growing into it.   The rocks are 4" thick and underground, and right underneath the tiles.  I found several burrows that ended in the rocks and were aborted.

[Ed Askew]

Yesterday we had 1.5 inches of rain, and it should have been a big night for beetles.  I got one.  This one was a little male, and he managed to squeeze his way into the central gap between the tiles and the biggest and prettiest of the palms I planted this spring.  I don't think he got far, because when I turned the water on him, he came up immediately.  I remember planting this particular palm, and I had to enlarge the corner indentation on each of the 4 tiles with a mason's hammer, and I got a little carried away and made the hole a little too big.  So, any barrier has to be snug against the palm for it to work, and it has to be heavy enough that the beetle can't move it.  This is my 4th beetle and the third of 20 newly planted palms with the palm fortress that were attacked.  This is the first time a beetle got to the palm when the palm fortress was buried on all four sides.  The other 2 happened because the rains washed out dirt exposing the under surface of the fortress, and the beetle was able to crawl underneath.  These beetles are very strong, and you'll find that out when you handle one.  They are a determined enemy, and I don't believe anything will be 100% effective against them.  Last year I had planted 10 palms, and I believe almost every one was attacked.  We flushed out the holes and killed 38 beetles, and I lost half of those palms.  I'm just hoping to improve on that.  Last year was the worst year ever for me and beetles.   So, last night I had one hit, but I saw on my rounds a half dozen aborted borrows that ended in the underground rock barrier that is at the periphery of each palm fortress.

Edited June 25, 2021 by Ed Askew
Failed to include some important information.

[Cindy Adair]

Thanks so much for all your excellent information!

Have you tried your palm fortress on palms already planted? 

[Ed Askew]

No.  I don't think it would work.  The outer edge has to be buried where the beetles can't crawl underneath.  I've thought about it and usually I notice that the older palms have sort of a mounded contour to the dirt around them.  I don't think it would work.  Plus, I've used all I have made.

[Swolte]

On 6/24/2021 at 8:23 PM, Ed Askew said:

I have no doubt they will just go underneath mesh, and then the other problem is the roots of the palm will grow through the mesh and the mesh will not be able to move to accommodate the growth of the palm. 

Thanks for sharing this information. This is extremely helpful!

I meant a 4" (? this is what I am trying to determine) ring of mesh underground in addition to a mesh above. I am not worried about the palm roots being blocked as palm roots generally don't get large like with woody plants and should be able to grow right through it. As far as I am concerned the mesh can remain under the ground. If the palm has to move, I will need to dig it out anyway. I read that these meshes can stay strong under the ground for even longer than above ground (25+ years, depending on moist levels, acidity, etc...). 

I think the palm bases growing into the mesh can be remedied by either adjusting the size every year (this is what the original poster mentioned) until the palm is at its final size and/or having some sort of snug, rubber, barrier in between the mesh and the palm (for experimentation, I bought some of that thick double stick gorilla duct tape to layer it on).
 

[Cindy Adair]

I see we are all thinking hard about this issue and it really helps to hear about the experience of others. 

Thanks so much!

[Ed Askew]

Well, the palm is going to get wider, and the barrier will need to move to accommodate that, and the palm is going to grow into the mesh and it won't be able to move.  I made, years ago, something like what you have there, Cindy.  I had a piece of 12" diameter plastic drain pipe, and I cut into small sections only 3" long, cut those sections in one spot to open the ring, and drilled 2 holes on each side of the cut to cinch them up with cable ties.  I put this around my palms and filled it with rocks.  That worked to some degree.  Beetles do rarely dig outside that 12" circle, and they come into the circle and move the rocks.  Anyway the palm as it grows makes it so those rocks are a lot harder for the beetle to remove as it puts them under tension, and ultimate it will lift the ring above the ground and break it.  By then it's a big palm and won't be harmed by the beetle.

[Cindy Adair]

Ed, when I entered the only easy to reach supply store I was strongly considering making something like you describe. I even had a saw in my car to cut a pipe to fit for transport. 

The landscape edging I purchased instead was an impulse buy, based largely on my current shoulder pain. The the idea of using a saw, electric or not, seems daunting.

As it turns out, cutting the landscape edging  is also hard one handed so I may need to ask for assistance either way. 
 

It sounds like you did not use hardware cloth under the rocks with your pipe surround trials?

I too am concerned that wire mesh will injure the stem but wanted maximum protection. So initially I am protecting very vulnerable small palms already in the ground near my house where I am more likely to monitor frequently. 
 

By the way these were treated in the pot at least 2 weeks before planting 3/21 with the Bayer product yet at least two have beetle holes. They show no sign of damage to the plant yet and when retreated I have seen no beetles exit so perhaps just an entry hole leading to a quick beetle exit! This happened just a few days ago.

 

[Ed Askew]

The landscape edging should work, but I would make the diameter of the circle at least 12".  No, this is my first try with mesh in any way.  I don't know for sure it will be problematic.  I just came back from beetle patrol, and I noticed one of those pipe sections running up a couple of my now huge Sable Louisianas, and took a picture of that all stretched out now, I was able to get it off no problem.  The other picture shows one I took off a dead palm earlier that the beetle killed some time ago.  Then I caught this little guy today; he hit a palm that I think was really killed last year since it hasn't made a spear leaf since the winter.  He wasn't too big but he has some impressive horns.  I left his burrow open, and I'll use that palm as a beetle trap, flushing the burrow daily for a while.

[Ed Askew]

The other two things I am trying this year are two different traps.  One is a light trap, and the other is a pit trap.  The light trap just has a blacklight mounted next to two pieces of plywood 3'x3', painted white, one screwed into the center of the other making a "T", and a wooden frame, and sitting on top of a 5 gallon bucket that I buried so that the top is at ground level, and there are holes drilled in the side of the bucket about 4 inches from the top so water drains out.  It's about half full of water.  The other trap is a pit trap.  It's made from a plastic jar, a scrap piece of smart siding, and a short piece of 1 1/4" PVC pipe.   I drilled a hole to accommodate the pipe in the smart siding and the lid, screwed the lid to the smart siding, pushed the pipe through until one edge is flush with the smart siding, and protrudes partially into the jar.  The jar is buried and the smart siding is flush with the ground.  Both of these traps are baited with a partial Strategus male aggregation pheromone.  The pheromone is 98% methyl ethyl ketone, 1% sec butyl acetate, and 1% diethyl ketone (aka 3 pentanone).  MEK you can get at any hardware store and I was able to get sec butyl acetate, but I couldn't convince anyone to let me buy 3 pentanone.  So, I made two version, one just MEK and a tad of sec butyl acetate, and another with those two and a tad of acetone, which is very close to 3 pentanone in chemical structure and supposedly has the same odor.  Don't mess with these solvents unless you have the proper protective equipment, which includes an organic vapor mask and gloves.  So far, I haven't caught anything but a lot of little beetles, not Strategus.  I would imagine they would attract females.  I haven't seen a female yet, they always come later.  But, I'm going to abort this pheromone for now and try methyl salicylate.  Supposedly, that's a chemical released by injured plants.  I've used this to lure lady beetles and it did seem to work.  Strategus must be able to sense a recently planted palm, or an palm that is in distress, because they always attack those first.  They must be attracted by some chemical. 

[Cindy Adair]

Your work with pheromones is interesting and I hope it works! 

It is raining here so I have done what I can do with garden scissors to prepare 30 barriers. Tomorrow hoping to get help to cut the landscape edging and get more than just my prototype in place.
 

Interesting that my circle using the 36 inches I had selected will create an 11.5 inch diameter circle, so very close to the minimum of 12 inches you mentioned. 
 

A few more questions for now Ed. Do you have an idea of the diameter of palm trunk (assuming a trunking species) which is likely to survive beetle attacks? Also do you see higher survival with clumping palms as I think I have?

Lastly, do you see the distorted multi heads on some survivors? These are mainly from before I had a clue and was doing nothing. I don’t give up, even with spear pull and I do pour hydrogen peroxide in the spear hole at least once. 
 

Thanks again!!

[Swolte]

A couple of notes from what Oscar (buddy dealing with the same issue for longer than me) and I have learned:

- They also attack Yucca. I found a couple (male and female) in a Yucca Recurvifolia variagata and there was a hole in a nearby Yucca Carnerosana (this was a small one and 'spear pulled' - RIP).

- Though I TRULY HATE to use this, layering Triazicide closely around the base seems to really work. None of my palms that had this spread around them have been dug into so far, whereas those that did NOT have a layer (or did so poorly) were attacked. I also found beetle bodies 1-3 ft from palms that had the insecticide protection. Until I have experimented with more mechanical protections, this is the one to use.

- We're looking into acquiring fungal strains of Metarhizium anisopliae (like F52) that may attack these beetle and may be a more thorough, more eco-friendly, long-term solution. So far, its all out of stock. Has anyone looked into these yet? 

[Ed Askew]

Do you have an idea of the diameter of palm trunk (assuming a trunking species) which is likely to survive beetle attacks?

Any diameter can survive, as long as the beetles are gotten out in time, but if not, I'm guessing, 5 or 6 inches.

Also do you see higher survival with clumping palms as I think I have?

All I have is S. palmetto, S. Louisiana, and Med palms.  They've never bothered the Med palms.

Lastly, do you see the distorted multi heads on some survivors? These are mainly from before I had a clue and was doing nothing. I don’t give up, even with spear pull and I do pour hydrogen peroxide in the spear hole at least once. 

Yes.  Sometimes that will go on for a season or two, and then the palm will recover.  However, somehow the beetle knows which palms are weak, and if you have one of those, they'll get it again the next season.  I had one that was attacked every year for probably 8 years, and had really bad scale and recovered from all of that, was growing really well and got a thick truck, like 6", and I wasn't even checking it and then it just up and died last year.  I went digging around through various vines and stuff growing around it and found the ground was riddled with beetle holes.  Usually, if there are a bunch of vines and stuff growing around a palm, they leave it alone.  It may be that the beetle makes galleries underground, and then they emerge as new born adults using old burrows next to these palms.  They would rather use an old burrow than dig a new one.

[Ed Askew]

"layering Triazicide closely around the base seems to really work. None of my palms that had this spread around them have been dug into so far, whereas those that did NOT have a layer (or did so poorly) were attacked. I also found beetle bodies 1-3 ft from palms that had the insecticide protection. Until I have experimented with more mechanical protections, this is the one to use."

Yeah I've sprayed insecticides around the base, and it will help a lot.  I had to quit doing that because of scale.  My scale problems became bigger than my beetle problem.  You're killing an important scale control which is also a scarab, and that's the twice stabbed lady beetle, Chilochorus stigma.  They live in the debris underneath the palm, and come out in the evenings and eat scale all night long. It may be where I live, which is a Southern Yellow Pine forest, the scale is really bad. Those trees are loaded with scale.  However I have some citrus, and no scale on those, or my camellias. 

The people that really know how to control Strategus don't speak too much English and they run oil palm plantations in South America.  They spray for them, and they remove all the dead vegetation from the palm plantation possible.  Also they dump a creosote solution down any burrows they find, in addition to flushing the beetle out like I do.  I think the reason I have so many beetles is all the debris in the woods.  I can never get rid of all that, without a controlled burn which is probably what I need to do.  Plus I don't have any lights at night, except for my light trap which I just started using.  I haven't caught a Strategus, but I see a carcass from what was probably a Strategus in the vicinity, and I see armadillo activity. 
 

[Cindy Adair]

It is already rhino beetle season in Puerto Rico and the first failure of my barrier trial. Ever the optimist it is way too early to see if the beetles just laugh at my attempts. 
 

I am guessing you are much more dry so safe another couple of months?

[Swolte]

I haven't encountered a single beetle yet here in Central Texas. They usually arrive on June 1st, like clockworks. Now, its *crickets*. We've had an unusual warm (and dry-ish) spring so that's probably it.  

[Ed Askew]

Happy April fellow Strategus fighters!  Are you ready?  I think I am.  I can report that since my last post I have had an 80% survival using the Palm Fortress.  The new palm grove I planted with those is really too far for me to be washing the beetles out of their holes when I find them, so last year I didn't do that at all.  What I did do that might have worked was I would, if I found a hole, spray just a little Bengal Roach spray with the little plastic tube like you have with WD-40 down the hole.  I didn't go crazy, just a quick blast and maybe repeated it every couple of weeks or so.  I have found that beetles emerge from underneath the Palm Fortress sometimes.  No way did they enter from above.  The Palm Fortress gets pushed apart as the palm grows, so I cover the cracks with rocks, bricks, etc.  I have two pictures, and here's the first of my new palm grove.  This is an area about 100 feet south of our house that a few years ago we cut some timber that was shading the house, and I decided to plant palms there.  I'm not going to make it into any kind of formal area.  I live in the country.  You see the palms I planted this year are the little ones on the left.

Edited April 25, 2023 by Ed Askew

[Ed Askew]

Now, picture two is my SECRET WEAPON.  A couple of years ago, I tried to catch some of these beetles with a light trap, and I never caught any, but I noticed somehow the activity was markedly reduced.  I live in the country and normally I have no lights at night.  I like a dark night sky and enjoy nature, all sorts of night critters.  However, somehow light disrupts these beetles so during beetle season only, I have this extremely bright mercury vapor light that comes on this year.  We'll see how good it works.