What’s doing this to our apples?
For weeks, we’ve been finding cavities dug out of our young apples, often with some kind of rot starting within the excavation. We don’t find any insects or caterpillars inside the cavities, nor any frass. Generally the cavities have smaller wounds nearby. This damage devastated the fruit on our William’s Pride tree, damaging over half the fruit. As they were nearly ripe, we were able to carve around and eat some of the damaged fruits, but still lost a lot of apples. About the time the William’s Prides were gone, the same thing started happening on the two nearby Liberty trees, a worse loss because Liberty doesn’t ripen until September, so the fruits are way too underripe to eat. Not being able to identify any insect behavior linked to this has been maddening, until a belated two-part aha moment cleared things up.
First, we cataloged what we knew:
- No insects observed, nor insect traces like frass.
- The flesh seemed eaten away, but the skin seemed to fold into the cavity.
- The damage around the cavities looked like small puncture wounds, sharp slits again with the apple’s skin folded in.
- Larger cavities seemed to be rotting, but the rot didn’t extend more than a tiny distance from the excavation; the flesh would be pure just beyond.
Then we really considered the exact shape of the small holes: take a close look at those on the second apple from the left, above. See that almost V-shaped hole? Bird beak. Now it all fell into place. Bird’s beaks would easily puncture skin, folding it in without chewing it away. Birds would enjoy sweet apple flesh without leaving any frass or other traces.
But we’d yet to actually see birds in the apple trees. Sure, we have lots of birds around the orchard, eating insects and such, but we hadn’t seen meaningful activity within the trees. And the birds most commonly listed as apple pests, like crows or starlings, are species we just don’t see here with any regularly and certainly hadn’t lately.
Then, in a random mid-afternoon glance toward the orchard, Eric saw them: four Blue Jays flew into the worst-afflicted Liberty tree and started kicking up a ruckus, flapping around within the tree, the branches bouncing up and down as they did their work. Blue Jays.
Now several more things fell into place. Looking at new damage, we realized that it was always concentrated on the upper side of apples, and/or the side nearer the branch, as in the photo above. One can easily imagine a bird perched on that branch, pecking away at the sweet treats within easy reach. This also explains the rot; we’ve been having very wet conditions for a long time, and these upturned cavities capture rain water and dew, naturally beginning the rotting process as they don’t dry out. What to do?
Birds are difficult to control. They’re illegal to shoot, not to mention pointless with something as common as Blue Jays; you can’t trap them; putting netting over an orchard of apple trees is unworkable….so what can you do? We settled on two approaches.
First, we’d try to spook them. Various sources report mixed success hanging shiny dangly things from fruit trees; we have a supply of worthless CDs, which now hang from the branches, twisting in the breeze and casting sharp reflections in all directions. One seemed particularly relevant to the task at hand.
Second, many of the branches were weighed down with fruit (even after a serious thinning this spring), and were near-horizontal. Most of the damage seemed to occur along these horizontal branches, which were easier for large birds like Blue Jays to land and perch on. So we tied support strings to T-posts, hauling the branches back toward the vertical, as seen in the before-and-after photos above. We hope this has the dual benefit of better supporting the weight of the apple crop and hopefully dissuading Blue Jay landing zones.
We don’t know if these measures will work, but they’re an efficient start on the problem.