Natural events: orchard edition, July 2017

Featured this month:

  • Harvesting
  • July weather
  • What are the big problems in the orchard?
  • Mammals
  • Woodpeckers
  • Japanese Beetles on:
    • Perennials
    • Annuals
    • Wild plants
  • June quiz answer
  • A few orchard insects

Harvesting this month: One of our goals is to get a steady stream of fruit from our plantings, and that didn’t quite happen in July. Blueberries normally produce in July, but they were done in June this year. Peaches produce in July; our blossoms were killed by frost, but we did acquire some from another source. Blackberries came on eventually, but yields were disappointing, in part because of damage by Japanese beetles. We ate some nice William’s Pride Apples (left photo), along with a number of slightly messed up apples (mostly William’s Pride and Initial) that dropped off the trees for one reason or another. Towards the end of the month, we had a few small bunches of grapes; the variety is Bluebell, and it has been the most vigorous of four vines that we planted a few years ago. The bunches may look a little pathetic, but given the Japanese Beetle pressure each year since they’ve been planted, along with the young age of the vines, we’re pretty excited to get anything at all. And they are really, really tasty.

July temperature: It was July. It was hot. (Enough redundancy.) The maximum temperature was a brutal 103º F, though it could have been worse, as that’s 7º F below the record high for that day, and 10º F below the record high for Columbia. The month also had a number of reasonably pleasant days, with 8 days topping out below 85º F.

July precipitation: Rain came on a decent schedule, but the total for the month was a bit under 2 inches, which is less than ideal.

What are the big problems in the orchard? When we shifted the focus of this series of natural events posts to the orchard for 2017, we had grand plans of sleuthing out the insect- and disease-based afflictions of all sorts of fruit by consulting pest ID books, finding and raising insect larvae from within the fruit to an identifiable adult stage, and so forth. What left the frass in the grapes (left photo)? What made the Asian pears (center) shrivel and drop off the tree? What insects lurk in the wild plum crop (right)? We don’t have complete answers to those questions, and we’ve come to accept that we’re not going to figure out everything in one year. But, we’ve also come to realize that the problems shown above are not the biggest threats to our fruit, at least not until we solve the top three July problems, which our experience to date suggests are mammals, birds, and Japanese Beetles.

Mammals: In our experience, mammals (probably raccoons, likely groundhogs, and possibly opossums) can do more damage to tree fruit in less time than any other biological pest. (Let’s just not think about the bad hailstorm…or the herbicide drift…that could outdo these.) Fortunately, mammals can be fenced out pretty easily with the help of a temporary electric net fence. The perimeter orchard fence exists to exclude deer, but it’s really hard to make gates impervious to smaller mammals, so we didn’t try. Instead, our strategy is to put up net fences when crops become attractive to critters. This is the same strategy we use for strawberries, sweet corn, and melons, and we’ve gotten pretty good about knowing when to put those up: early enough to provide protection but late enough to minimize the amount of vegetation that will grow up on the net while it is in place. Unfortunately, being less experienced with tree fruit, we have not learned the appropriate timing quite so well. But we now have firm evidence that waiting until July 1 is TOO LATE, at least when it comes to early bearing apples such as William’s Pride. In future, the summer solstice might be a better target date.

Woodpeckers (and other birds): The photo on the left shows a cut-open apple with bird damage, probably woodpecker, along with some ants. The ants aren’t a primary problem, they only follow the woodpecker damage. Are the woodpeckers just following other insect damage? In some cases, perhaps; the apple on the right has some other problems, and perhaps the woodpeckers were attracted as a result. But it’s pretty clear that woodpeckers really like the fruit itself. This is a problem, particularly since their ripeness standards are lower than ours, and they can slowly destroy the fruit in a young diverse orchard, particularly one in which multiple varieties of apples and pears ripen in slow succession. Hopefully, someday there will be enough fruit to shrug off the damage by woodpeckers, but we’re not there yet. So, in the meantime, we’re painstakingly covering fruit with cloth bags, pieces of old cheesecloth, or cut up pieces of old socks held on by a twist tie. Annoying? Yes. Effective? Seems to be.

Japanese Beetles: If mammals destroy fruit by a single visit, and woodpeckers by a thousand pecks, then Japanese Beetles do so by about a billion nibbles. As noted in June, this year’s beetles were the worst we’ve ever seen. They ate (as photographed, left to right and top to bottom) blackberries , rhubarb , sorrel, jostaberry, gooseberry, June berry, asparagus, aronia, elderberry, and more. Blueberries, apples, grapes, cherry, chestnut, and ostrich fern also had damage. A coating of kaolin (Surround) on the plants sort of worked some of the time, but the numbers were so overwhelming that at times it didn’t seem to have much protective effect.

Beetle numbers were very high right through the end of the month (dropping somewhat with the arrival of August, though they’re still present in lower numbers as I write this). The feeding dynamics of the beetles are fascinating and something we don’t fully understand. They eat annuals and perennials, natives and introduced species, though they generally seem to prefer some plant families over others. A high concentration of beetles feeding on a favorite plant sometimes seems to cause individuals to spill over onto less favored species, so paying attention to everything they’re eating (and how much they favor it) seems helpful in the quest to understand them. We thought their preferences for vegetation changed somewhat as weeks passed. In many cases, we thought we didn’t notice beetles on a given plant species until that plant reached the flowering or fruiting stage. In addition to plant preferences, there also seems to be a swarming behavior; huge numbers will accumulate in one place for days, only to disappear with relative suddenness (sometimes in association with rain). However, sometimes plants that have been abandoned (the blueberries are safe, we thought!) will be recolonized later in big numbers again (oh, no, not the blueberries again). Hot weather also seems to increase their activity; we literally had Japanese Beetles bouncing off the windows on some of the hot days of July.

Annual crops affected by Japanese Beetles: Kentucky Wonder Beans (upper photo) are a Japanese Beetle favorite; the Rattlesnake Snap Beans immediately next to these were only minimally touched. The Malvaceae family is popular with the beetles, including Burmese Okra (center row, left) and Thai Red Roselle (center). A variety of annual flowers were nibbled, including Zinnia (center row, right), with even more damage on Cosmos and Morning Glory (not shown). Kale, corn, and peanuts (lower photos) all got munched. Soybeans, which we aren’t growing this year, are also a beetle favorite. We wonder, do the conventional soy fields to our north affect the beetles that are present here?

Wild plants affected by Japanese Beetles: In addition to the wild plants shown last month, here are some more: clover (upper left), smartweed (upper right), Common Milkweed (lower left), Trumpet Creeper (lower center), and tick trefoil (lower right). This list is not comprehensive!

We don’t have a solution to the Japanese Beetle problem. Kaolin (Surround) can help. Parasitoids and other ecological checks will hopefully kick in eventually. In the meantime, emphasizing fruits that aren’t bothered so much by beetles is perhaps a sensible option. Asian pears, strawberries, and annual crops of watermelon and musk melon qualify here (as far as we’ve seen).

June quiz answer: Aaron Templemire was quick to answer last month’s quiz with the correct answer. The seedling is a pecan. Look up pecan in a tree book, and it will show the compound leaves of an adult, but the seedling’s first few leaves are simple. Compound leaves come along soon, though, as seen in the photo on the right.

Wild hickories: Speaking of nuts, 2017 seems to be a bumper year for wild hickories. Perhaps we’ll get to taste a few later in the year. (Note the compound leaves, similar to the pecan above.)

A few orchard insects: Here are a few photos of random orchard insects from July. I set up a black light one evening, and this large beetle (finger tip for scale) showed up. It seems to be Orthosoma brunneum. Upper right is a praying mantis on the trunk of an Asian pear tree. Lower left is a fruit fly of the genus Euaresta. that I saw sitting on an apple leaf. Lower right is a bit of a mystery: The orchard hosts lots of seedling and resprouts of Shingle Oak trees. While weeding around fruit trees, I noticed that the lower few inches of many of the Shingle Oak sprouts were encased with some sort of organic matter that housed aphids and ants tending them. We haven’t been able to find more information on this…so, readers, any ideas?

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