Natural events: orchard edition, April 2017

Featured this month:

  • Baby fruit
  • Temperatures
  • Spring leaf-out comparison
  • Frost/freeze damage
  • Precipitation
  • Blackberry pests part 1
  • Blackberry pests part 2
  • Long-horned beetle
  • Bluebird babies

Baby fruit: There won’t be a Chert Hollow-grown peach this year, and the apple prospects are sparse, but late April offers hope for a good variety of fruit. Pictured above (left to right, top to bottom) are strawberry, sour cherry, blueberry, June berry, mulberry, apple, and Asian pear. Our second-year gooseberry plants also have some berries. Other fruits haven’t flowered yet, including blackberries, raspberries, and elderberries. Two new fruit-bearing additions to our plantings (grafted pawpaws and persimmons) are too young to produce but are also late-season bloomers. This diversity of timing in flowering and fruit set is helpful when it comes to dodging damaging cold spells. And, yes, we had more of those in April:

Temperature: We had hard frosts on April 7 and April 23 (as well as a light frost in low spots on April 24). The official record at the airport didn’t drop below 35ºF during the month, but we had considerable frostiness in our valley and even up the entire orchard slope. To reiterate what we said last month, those temperatures are well within the “normal” range and shouldn’t have been a big problem. However, because of the overall warmth this winter and spring, vegetation in general and orchard fruits in particular have flowered and leafed out quite early. For example:

Spring leaf-out comparison: The photo on the left was taken in our woods on April 25, 2007. The photo on the right shows approximately the same view one decade and one day later, on April 26, 2017. The overall warm spring this year has resulted in a very early leaf-out. Using 2007 as a “baseline” is not entirely fair, since 2007’s leaf-out was ahead of schedule in March before getting zapped by record-setting cold that April. However, both our records and our memories confirm that spring leaf-out has been particularly early this year.

Freeze/frost damage: Open blossoms and freezing temperatures aren’t a good combination. The photo on the left shows a healthy strawberry blossom; the photo in the center shows a blossom that has been killed by cold, as indicated by the black center. Fortunately, strawberries are relatively easy to protect from cold, as a piece of row cover or old sheets can be stretched over the plants and weighted down with rocks for effective protection from all but the most severe cold; the warmth from the ground radiates back up and helps to provide protection. The only trick is reading the forecast to know when to do this. For us, if the forecast is for 42ºF or below with a clear sky and little wind, then we typically expect frost, though we’ve gotten frost even with a 44ºF forecast. Unfortunately, fruit trees can’t be readily protected in the same way, and we lost most of the apple blossoms in April. Blueberries are the biggest plants we’ve covered with some success.

Precipitation: The end of March was wet, and that wet spell continued into early April before drying out during the middle of the month. Then the wetness resumed, bringing record-setting floods to a number of rivers, particularly in the Ozarks region of Missouri and Arkansas. Each of the last six days of the month brought measurable precipitation. This long, wet period raised our level of concern about plant diseases; during this period Cedar Apple Rust fungi on Eastern Red Cedar trees put out their orange tentacles and the fruit trees experienced extended periods with wet leaves. Concern about fungal infection in the orchard is, at least, a relatively minor concern compared to the many problems from flooding that folks around the region had to contend with. We didn’t experience any damage, just extreme sogginess.

photo of Red-necked Cane BorerBlackberry pests, part 1: Swollen stems on blackberry plants indicate the presence of the Red-necked Cane Borer (Agrilus ruficollis). According to various sources (such as this and this), the adult lays an egg on the cane during the summer, the larva bores into the cane, does some tunneling, overwinters as a larvae, pupates in the spring, emerges as an adult, and repeats. I spent some time looking for larvae in a number of canes (a more challenging task than I had expected), and I eventually found a tunnel above a gall in the cane photographed above. In the upper horizontal photo, the gall is at right, and the top of the cane is to the left; the gouge near the gall is a result my use of a knife to dig around in search of an insect. Several inches above the gall I found a tunnel, and at the end of the tunnel I found remains of a larva. The lower photo shows a zoomed-in view. I’m assuming this was a Red-necked Cane Borer larva, but the cause of its demise is a mystery. Perhaps a parasitoid did it in? A small triumph, but there are plenty of Red-neckeds still on the loose.

Blackberry pests, part 2: We have an aging planting of Chester Blackberries that is still productive enough that we’ve been reluctant to retire it. At the base of the plants are some stumps of old dead canes that have been pruned out over the years, and as I was working around the plants, I discovered that some of those stumps are wobbly and rotting. I dislodged one of these, turned it over, and discovered the critter at left. This is pretty clearly a borer, a term for an assortment of moth and beetle larvae that chew into the stems and roots of a variety of plants and are notorious for causing damage in orchards. Getting a good look at borers can be very difficult, because the most damaging ones chew through the living parts of plants. In this case, the borer is in a dead part of the cane, and it is not entirely clear whether it or its companions are also hanging out in the live part of the crown. In any case, I put it in a jar with a very lightly dampened piece of paper towel, and now I have a pupa, which is ~5/8″ long, shown above at right. At this point, I’m reasonably certain that it is a long-horned beetle (Family Cerambycidae); the long, curving antenna is visible in the photo. I’ll have to wait and see if it emerges as an adult to get a more specific identification.

photo of Painted Hickory BorerLong-horned beetle (not the one from the larva above): I found this adult long-horned beetle hanging out in a pile of concrete blocks in the general vicinity of the orchard, and since I associate long-horned beetles with borers, I collected it for identification. This appears to be the Painted Hickory Borer (Megacyllene caryae), and the MO Bugs blog has a nice write-up about it, noting that this borer species uses dead wood, not live trees.

Baby Bluebirds in a nestBaby bluebirds: Soon after Eric put a cedar nest box on a post in the orchard in March, a pair of Eastern Bluebirds started nest construction in the box. Young hatched in April; this photo from April 23 shows four fluffy nestlings. Bluebirds primarily eat insects, though they will also eat small fruit and berries. (Alternative fact: Eating blue berries is how they become blue birds. See, the young aren’t blue yet because the blueberries aren’t ripe yet.) We hope that someday the farm will produce enough fruit for us to have our fill even after the birds have had theirs. Until then, we’ll have to continue to make use of bird netting to exclude birds from blueberries and other fruits that are practical to protect with netting. Meanwhile, the mulberries are a more-or-less intentional offering to the birds, and elderberries are a less-intentional offering.

The good news? Birds that eat berries plant berries. As of a few years ago, we had no bearing mulberries or elderberries here; both have started to bear in the last couple of years, and various birds ate virtually all of both last year. Not coincidentally, we’re starting to see seedlings of both showing up in various locations. We’re all in favor of an increase in wild or semi-wild mulberries and elderberries, particularly if these fill a niche that might otherwise get taken over by invasives such as bush honeysuckle. Will these bluebird babies grow up to disperse native fruit while also cleaning up insects? Who knows, but for now they’re very cute.

One thought on “Natural events: orchard edition, April 2017

  1. We definitely got some of that frost as well. Only one apple tree will fruit this summer, and it cost me a couple tomatoes that I was a little early on putting out. This is the second spring in a row we’ve had an early leaf-out and lost a lot of buds. Hope this isn’t becoming a trend.

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