What is eating/removing young fruit from my lemon and orange trees?

Question

I live on the upper Gulf coast, just inland of Galveston Bay. For the past three weeks my improved meyer lemon tree, and two satsuma orange trees have been in glorious bloom. The bees went crazy, and all three trees were covered with little tiny fruit.

Over the past week disaster has struck. Something has eaten or caused to fall off almost every tiny fruit from the lemon tree. It appears that leaves are also being stripped off. I've been watching this closely, and one day a branch will appear healthy, and the next its fruit and some leaves will be gone. While there are some leaves on the ground, and some old blossoms, those numbers are small compared to what is missing from the tree.

I might assume that the culprits are caterpillars, but I don't see any pests of any kind on the tree. I'm stumped.

I have included a picture of a branch that was previously bearing fruit and leaves, and which is now mostly stripped. Over the past several days this appears to have started happening to the orange trees as well.

What is happening, and what can I do to limit the damage to the orange trees before I lose that crop as well?

Here are more pictures. This one is of the lemon tree. Note that there are still many leaves, though some are missing. The fruit from these branches is almost completely gone.

Here is the base of one of the orange trees. As you can see, there is a good deal of dropped fruit on the ground, but almost no orange leaves. (Those leaves in the picture are from mulch from last fall.)

This last picture is from the orange tree as well. Many leaves are still on the branches, but a lot of fruit has dropped.

Maybe it's just the trees dropping their fruit, but I am certain that many leaves are gone as well. These trees otherwise seem quite healthy, and in past years I have not seen them lose this much fruit. I should also mention that the orange trees do have a lot of fruit still on the branches. I want to keep it that way, which is why I am so concerned about the loss of fruit.

Finally, I will also mention that my young grapefruit tree (3 years old), which is nearby, initially had 30 or so immature fruit on it (which I was going to pick off), but has dropped all but one. That was the first tree that exhibited this behavior.

Stormy asked for picture of the entire trees. Here are the two orange trees.

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OK, I originally posted this in the spring, and now its falls (mid-October). I answered my own question, suggesting that it was a spring cold spell that caused the budding fruit to drop.

Now that it is fall, I have to say that I was a complete worry wart. We've never had a crop so prolific as this. In a normal year we'd be picking fruit in late November. This year, however, we've been eating oranges, small ones, to be exact, since September - every day!

So here is what's going one. The trees are laden with fruit. In August we noticed that the trees where dropping green fruit. One day I peeled a green orange that had fallen, and found it to be edible. Since that day, we've pretty much been having oranges. It's hard to describe how unusual this is.

Nowadays, we are picking to help the tree with the weight, mostly picking the ones that are beginning to show some signs of color. Nonetheless, we are eating oranges every night, which is great. The fruit is continuing to mature, and at some point we expect the fruit to be normal (large, orange, and easy to peal). So far, they have been small and mostly green, but even so the pulp has been sweet and more than ready to be eaten. By late November, I expect the remaining fruit to be large and delicious.

What a change! What I thought was a major loss of fruit turned out to be an abundance that I could not imagine.

Thank you for everyone who lent an opinion to the original post. It turns that our loss of blossoms was not a tragedy. What remained burdened our trees to the point that I worried about the weight of fruit, and we've been harvesting steadily in order to help the trees along their journey towards winter respite.

Take a look:

Answer 1

My vote are deer. Need to see more pictures, see the environment where your plants are situated, how big your plants and pots are...but cleanly eaten leaves are usually by deer that aren't so starving. They just adore juicy leaves.

This is just my initial answer to the little information we could use. Please look closer for chewed leaf bits, chewed stems with leaves, leaves with teeth marks, tracks in the potting soil? Do you have rabbits or raccoons?

Are we talking about potted lemon/orange trees? I am assuming they are on your deck, patio or close to the home? Do you know what deer track looks like?

The more we know the better we can give a more accurate answer. Wish we could just BE there like teleported from the Star TreK teleportation deck? Grins!

There is deer fencing that is very cheap to install around your patio? It is a plastic mesh similar to bird proofing mesh for blueberry bushes. There are also motion sensor sprinklers to scare anything big enough to cause the sensors to trip...work real well.

Need to get out the detective tools and look just a wee bit closer. To be responsible we need to correctly ID the culprit first before guessing. Thanks...

Answer 2

Ok, until Stormy posts the correct answer I'll post this answer. Once Stormy has posted an answer I'll change my acceptance of the answer from this answer to Stormy's answer.

In short, after having ruled out damage from animals, Stormy suggested that the trees might have been dropping the fruit on their own, and that might have been the result of a late cold snap. Well, we've had a weird winter and spring here on the Gulf Coast. We had an unusually cold winter. Several times this winter I had to cover my smaller citrus trees and provide a source of heat (a light bulb or heater). The larger satsuma orange trees are mature enough to handle the cold, but I was worried about them.

Fortunately, everything survived, and come spring the lemon and oranges were covered in blossoms, and subsequently small fruit. But spring was also colder than normal, and we had a couple of days where it got no warmer than 38 F (though no frost and nothing below 32 F). Nonetheless, one of those cold snaps did occur after the fruit appeared. And, that apparently was enough to cause the trees to drop their fruit.

There is one significant piece of evidence that supports the "cold snap" conclusion. The grapefruit and lemon trees were in a less protected position in the yard, and they lost most of their fruit. Portions of the orange trees that were less protected lost most of their fruit, but those portions that were more protected are still covered in fruit.

So, thanks for the suggestion, Stormy. Once you post your answer I will select yours as the correct one.