Category Archives: Gardening

Birds are eating my pea plants

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This spring I decided to figure out which bird species are decimating my peas, with the hope that an ID might help me better protect my crop next year. Sneaking up on my allotment so as not to spook the birds, it didn’t take me long to figure out that the culprits were mainly house sparrows. Usually a large flock of them. As proof, here’s Exhibit A, a female house sparrow with a big chunk of a leaf in her mouth.

But I’ve also observed northern cardinals and American goldfinches doing the same, so I can’t blame everything on the sparrows. Indeed, I suspect I’d see additional species helping themselves if I camped out under cover of a bird blind for a day. Pea shoots are just that good.

Naturally, I immediately ran out and purchased bird netting and fully enclosed my trellises in a large box, complete with multiple doors made from overlapped netting, all pegged at the ground with rocks. The netting is delicate and black so it’s hard to see in the photograph below but trust me, it’s there and it covers everything rather tightly.

But after I set it all up the damage to the pea plants continued at pretty much the same level as before. Please refer to Exhibit A, above, and note how the background of the photograph shows the bird netting — the birds just found tiny gaps in the netting, ate their fill, then let themselves out. The cardinals and finches weren’t deterred much, either, and at one point I saw all three species inside, happily munching away.

Below are photographs of the damage in case you’re interested why I’m so worked up about this situation: growth on primary meristems are nibbled off, leaves covered in tiny beak-shaped compression wounds, shoots bent when fat birds perch on the stem while foraging, severed branches left on the ground. When I surprised the birds I could see them flying off with pieces still in their beaks.

I should point out that my allotment is just one of many, and other people have completely unprotected pea plants (gasp!). So I’m wondering, why bother navigating my cage system when there is plenty to eat elsewhere?? Although other people’s plants certainly show damage, whenever I spy on the gardens from afar the birds seem to be on mine plot, on my peas. I’m thinking they must prefer the varieties I’ve planted, all heirloom varieties that climb (‘First 13’, ‘Magnolia Blossom’, ‘Tall Telephone’, and ‘Purple Podded’).

Perhaps the dwarf, self-supporting varieties that most people grow have more lignin and such in the stems and leaves, rendering them less palatable to birds. In support, I’d note that of the varieties I have the birds seem to prefer ‘Magnolia Blossom’, a sugar snap pea (Pisum sativum var. macrocarpon, I think) which Burpee says has “edible tendrils” (tendrils = shoots to pea folks, I think). The Ottawa Gardener, writing about peas with edible shoots and tendrils, says something similar: “I’ve noticed that most recommended varieties are those with edible pods which may be [sic] because the shoots are less fiborous [sic] or sugary.” Andrew Barney says something similar about peas with edible leaves: “any variety with both p / v genes for low fiber in the pod would be a good candidate for this. Plants with lower fiber in the pods also have lower fiber in the leaves,” adding that leafcutting bees (Megachile spp.) also seem to have a preference for tender-leafed types.

So, what to do? I think for this season I’m just going to keep fussing with the netting to minimize the damage. But next year I’ll replace it all with stiffer netting that can be better fastened together with twist ties and such. It will be a lot of work but man I love fresh peas and I don’t like to share.

Anyone have suggestions? I’ve tried a fake owl (birds don’t care at all) but I haven’t yet experimented with holographic tape, threatening mylar balloons, or CDs suspended from monofilament. I’m think none of these will work. What I’d really like to do is leave a hungry cat inside the trellis cage. But I know that would be frowned upon by the locals. Same for the laser defense systems that some vineyards use.

Some insects I found inside dried Turkish figs from Trader Joe’s

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During an online wasp identification course I participated in several weeks ago, there was a fun discussion about whether commercially-produced figs contained fig wasps (Agaonidae, in the Chalcidoidea). Opinions varied, plus some asserted, as do many internet pages, that even if wasps were once inside the figs that ficain (an enzyme) would completely dissolve their bodies. So I purchased a bag of figs and had a look. I found a wasp in the very first fig, in approximately two seconds. And I found much more than that. Photographic details below.

Photograph of a fig being examined under a dissecting microscope

The wasp was small, like most wasps, so here’s a photograph with an arrow pointing out the position. It was wedged in between some of the involucral bracts just inside the ostiole (opening) of the syconium (the “fruit” that is actually an inverted infructescence). I’m not sure whether the wasp was going in or going out.

Photograph of an opened fig with an arrow showing the location of a dead wasp

Here’s a close-up of the wasp, or at least what’s left of it. The shape and positions of the legs seem to be a good match for Blastophaga psenes, the sole pollinator (I think) of Ficus carica. In particular, the middle femorae are much smaller than the front and hind femorae. And the head is wedge-shaped, another attribute of the family.

The species exists in Turkey and in many other places where figs are grown. E.g., it’s in California because it was deliberately introduced there in 1899. This means, of course, that figs grown in California may have wasps in them, too. I’m just the messenger.

Photograph of a dead fig wasp inside a fig

Below is the dorsal side showing (I think) the quadrate scutellum, another family characteristic. The antennae appear to be folded medially into a streamlined position that I assume is useful for navigating the bract maze. I have more pics on iNaturalist.

Photograph showing the dorsal side of a fig wasp

In a different fig, I found two more wasps of a second species. I don’t have a high confidence in my identification but I think they might be Habrobracon hebetor (Braconidae). This species is a regular inside stored figs because it parasitizes caterpillars that eat dried fruit. This wasp, I’m guessing, oviposited into caterpillar-infested figs after they arrived in California (where Trader Joe’s presumably has a warehouse). I don’t know whether the species occurs in Turkey. I have more pics on iNaturalist.

Photograph of tiny dead wasp next to orange frass

Below is a caterpillar in the same fig as the wasp above. Caterpillars were present in several other figs, too, and they were often accompanied by fungal growth. I don’t have an identification guess but if you recognize it please visit my iNaturalist observation.

Photograph of a dead, shriveled caterpillar

I’m not sure whether it’s a different species, but the cocoons below seem to be lepidopterans, too. Here is the iNaturalist link.

Photograph of two caterpillars inside silk cocoons

Here’s the final type of lepidopteran I found, a pupa. Again, I’m not sure what family it might be in. Here’s the iNaturalist listing. The photograph also shows a good quantity of frass, something I found in many of the figs even when I couldn’t locate a caterpillar. The dark color on the left is from fungal growth.

Photograph of a moth pupa next to fig achenes and black frass

The final insect that turned up is a beetle, which I think might be Carpophilus hemipterus, a species native to Asia but now pretty much everywhere. It’s definitely in California. Here’s my iNaturalist observation if you’d like to weigh in on the identification.

Photograph of black and yellow beetle inside a fig

I’d like to point out that insects are extremely common in stored food so the above doesn’t come as a huge surprise to me. And the figs were clearly labelled “organic”, a term that to me greatly boosts the likelihood that there are organisms inside. Unless you have an allergy to chitin or some other insect component (it happens), inadvertent consumption of arthropods isn’t going to harm you.

What did surprise me was how common fungal growth was in this bag of figs. Below is a photograph of what the fungus usually looked like. Not sure what it is (Aspergillus niger?). Some of them were mildly lit up by 356nm UV light, by the way. I think that’s a bad sign.

Photograph of fungal growth next to achenes inside a fig

But a little research turned up what might be the obvious explanation: wasps that manage to crawl into figs via ostiole can be covered with fungal spores in the same way that they are often covered with pollen (that’s the whole point of fig wasps). Indeed, some fig farmers regularly spray anti-fungals onto figs before the females emerge to prevent them from picking up spores and transmitting them to the next fig. Without such treatment (i.e., at organic farms), it’s not rare to find smuts (Aspergillus spp.), endosepsis (Fusarium spp.), and Alternaria rot. Aside from potentially changing the taste of dried figs, I guess there’s a chance you could get a dose of aflatoxins. There’s research on the issue, even articles on the risk from dried Turkish figs.

When fresh figs start to arrive from California I might sacrifice some for a similar investigation. I’d love to find a fig wasp in better condition so I can photograph it. They are bizarre. But per several sources, many (most?) of the figs in California are produced by plants that don’t need fertilization, so finding one might be a challenge. Still, because fig wasps are naturalized in California, I wouldn’t be surprised if they’d still show up inside those varieties. As a demonstration that wasps are alive and well in California, you can order wasp-laden figs online at FigBid.com (e.g., this listing). Note that you don’t order such figs for eating. They are for placing near your crop of figs so that they can get pollinated. Some of the most delicious varieties of figs need such pollination. And some of the varieties that don’t need figs still develop much tastier fruit when they are pollinated by wasps.

Here’s what the California Fig Advisory Board has to say,

“https://californiafigs.com/faq/#:~:text=I%E2%80%99ve%20heard%20that%20there%20are%20wasps%20in%20figs.%20Is%20this%20true%3F

Next on my to-do list is to find the coffee berry borer (Hypothenemus hampei).

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