2018: The Year Squirrels Discovered our Pomegranate Tree

One could complain that this blog allots way too much space to two topics: tidying up and complaints about squirrels. At the risk of repetition, let’s discuss the squirrel issue this morning beginning with a year end review of our fruit harvest totals:

Fuji apples: 0
Winter banana apples: 0
Fuyu persimmons: 0
Hachiya persimmons: 0
Peaches: 0
Pomegranates: 6
Figs: 20?
Avocados: 20? but with a few bite marks

So not a total loss in the pom department but a long ways from my days of thinking that the hard skin of pomegranates are squirrel proof.

This is the point in my squirrel complaint blog post where I lazily link to UC Davis’ squirrel management notions. It’s also the paragraph in which I claim to have discovered a miracle squirrel cure in the form of a lame old man joke. Now you’ve got a bad case of earworm. Go ahead and suggest dogs and rifles in the comments and you’ll see us soon on a PETA billboard.

Spider Bite!

My sincerest apologies for beginning your week with a picture of two festering arachnid bites, but that’s what Mondays are for.

These particular arachnid bites belong to UCSD alumni pal Professor Nic, who is visiting us from Canada, the greatest of nations. The bites sent him to the very same Kaiser emergency room that saved Kelly’s life last year. Unfortunately, modern medicine lacks any kind of test that would reveal the scientific name of the perpetrator.

Kelly and I immediately pinned the blame on the infamous Brown Recluse spider (Loxosceles reclusa). But, according to the LA County Natural History Museum’s extraordinarily useful book Insects of the Los Angeles Basin, the Los Angeles basin has no brown recluses in residence. According to that same book, the most likely perp is the Long-legged Sac spider (Cheiracanthium species).

When disturbed they draw the pair of forelegs back and in, forming a cage around the body . . . These spiders have relatively strong, long fangs and have been known to bite humans, causing a wound that is painful and slow to heal.

Professor Nic captured a photo, in his Corian® bejeweled Airbnb, of the likely perp when he got back from the ER and it looks exactly like the Long-legged Sac spider in the NHM book. Don’t worry, he later released it to the hipster wilds of Echo Park.

Unlike the Brown Recluse, Long-legged sac spiders employ reputation management consultants to keep their nefarious activities out of the news. They live in the corners of rooms and even, according to the NHM book, take up residence in household appliances. So dust out that Vitamix periodically!

Lest we fall into a spider hating hole, allow me to close with some of my own, unpaid spider reputation management. I believe that we should give our our children plush, stuffed spider toys for Christmas instead of teddy bears to instill in them a love of all things Araneae. Spiders are a vital part of the web of life (pun intended) . We should cast off our fear of them and respect the work they do in keeping down the population of other insects. In Southern California the only spider to treat with caution and respect is the Western Black Widow (Latrodectus hesperus). While a spider bite from a Long-legged Sac spider is painful, it’s not going to cause serious consequences.

Defeating Squirrels With Tech

After watching a squirrel chew up every single peach on our little tree, despite deploying yards of bird netting, I found myself pondering extreme and deadly measures. Then I found myself fantasizing about what I would do if I were Elon Musk. First, I’d give up on the mars idea. Mars is, after all, a lifeless, barren speck of dust lacking life’s essentials such as breathable air, plants, cats and Parmesan cheese. Why bother? How about, instead, turning that technical know-how towards the most important issue of our time: squirrel deterrence.

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As it turns out I’m not alone. At a Python programming conference, back in 2012, software engineer Kurt Grandis presented a research project he entitled, “Militarizing Your Backyard with Python: Computer Vision and the Squirrel Hordes.” Grandis’ motivation was a squirrel attack on his peach tree and, worse, his kid’s pumpkin patch. The full lecture details Grandis’ attempt to create a program that would differentiate between squirrels and birds and then deliver a carefully aimed blast of water at just the squirrels. It’s worth viewing in its entirety just to hear how Grandis resolves the image recognition question, “What is squirrelness?” If you’re impatient you can fast forward to the 16 minute mark for the video. Spoiler alert: it works, at first, and then the squirrels quickly learn to ignore the blasts of water.

It leaves me wondering if a scary clown strategy might work better such as it did with this bear:

Kidding aside, two Southern California biologists are using high powered lasers to dissuade ravens from attacking endangered desert tortoises. The biologists are also speculating about the possibility of “gamifying” this task by opening it up to anyone who wants to take a potshot via the internet. Which leads to my question of the day. Would you readers be interested in a gamified laser squirrel shoot in the Root Simple backyard? Time to learn Python!

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Polyphagous Shot Hole Borer and Avocados

Multiple entry holes on avocado trunk. Photo credit: Eskalen Lab, UC Riverside.

Multiple entry holes on avocado trunk. Photo credit: Eskalen Lab, UC Riverside.

Of all the plants in our yard the one I care most about is our avocado tree. I’d be despondent if anything happened to it. Which is why I panicked when I first heard about the Polyphagous Shot Hole Borer (PSHB), a beetle that spreads a fungus Fusarium euwallacea. First noticed in 2003 here in Southern California, the PSHB seems to damage some trees more than others.

Concerned about losing my avocado tree I wrote Akif Eskalen, a plant pathologist at the University of California, Riverside. Dr/ Eskalen’s lab has done a lot of work on the PSHB and what to do about it. I asked him specifically about avocados and here’s what he had to say in an email,

My lab has been conducting a continuous survey on PSHB on infested and non-infested avocados in California since 2012. Based on the preliminary results from our survey the beetle PSHB seems to be attacking and causing damages on primary and secondary branches of avocado only. We have also seen attacks on the trunk of the trees but somehow the beetle is not successful establishing galleries there which could cause of quick death of the tree. I believe with a proper orchard sanitation you can reduce the damage of the beetle and also keep the beetle population down in the orchard . . . we are still continuing experiments with different insecticide and fungicides on avocado against this beetle and their fungi. An insecticide (Hero) has already registered under Section 18 that could be used by growers in CA.

He provided a link to a short publication his lab put out on orchard sanitation best practices as well as a link to information for avocado growers on the use of Hero. Hero is a pyrethroid-based pesticide.

For my own backyard tree I’m going to:

  • Make sure pruning tools are disinfected before use. This is one of the main reasons we use a qualified arborist.
  • Avoid moving firewood around. I’m going to have to think carefully about the wood I import for my pizza oven.
  • Use mulch that has been chipped to less than 1 inch.

I’d sure hate to lose a tree that provides six months worth of free and delicious Fuerte avocados.

What’s the Most Squirrel-Proof Fruit?

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Depending on my mood I see our yard either as a sort of groovy, permacultural exercise in “abundance” or as an overpriced rodent feeder. It occurred to me this morning that we’ve been, inadvertently, running an experimental squirrel fruit buffet for ten years.

Perhaps it would be informative to see what trays in the buffet have any fruit left for the resident hominids. Towards that end, I’ve created an annoying, animated emoticon scale ranging from one to five squirrels with five being the most favored fruits and one being the least favored.

In the give up all hope category:

Figs: Squirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by Alephron
Everyone loves figs. Raccoons, squirrels, rats and even Roman emperors. I’ve even seen raccoons, in the middle of the day, feasting on our delicious Mission fig. It’s easy to see why. There’s nothing like a fresh fig. And fig season is so frustratingly short. Kind of like our youth!

Apples: Squirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by Alephron
We have two trees, a Winter Banana and a Fuji. The squirrels are welcome to the mealy Winter Banana apples. But those Fujis are just about the tastiest apple I’ve ever eaten. The squirrels usually manage to get them all.

Persimmons: Squirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by Alephron
We have both the non-astringent and astringent types of persimmons. The squirrels like to take a bite out of them before they are ripe, thus leaving them to rot on the tree. Persimmons take so long to mature that I doubt I’m going to get any this year before the squirrels get to them.

Peaches: Squirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by AlephronSquirrel Icon by Alephron
I managed to harvest a few thanks to throwing some netting over the tree. But I was so stressed out by the prospect of finding the tree stripped of fruit that I became unpleasant to live with.

On the more hopeful side:

Avocados: Squirrel Icon by AlephronSquirrel Icon by Alephron
The damage here is more from rats than squirrels, I think. Typically, I’ll find an avocado with one bite near the stem on the ground. The good news is that those partially chewed avocados are, usually, still edible.

Pomegranates: Squirrel Icon by Alephron
I think this is the real winner in the squirrel/human fruit buffet fight. I’ve found squirrels trying to eat them but they have to chew through the thick and unappetizing skin. Plus the tree has hidden, wicked thorns. The downside is that these two qualities also make them difficult to harvest and eat. I use what we call the pomegranate spanking method to release the seeds. Squirrels have not yet figured this out.

What fruits do you manage to wrestle from the squirrels? What have you noticed in your garden?