- Author: Alison Collin
If you have fruit trees you are probably now getting a little tired of raking up fallen fruits which are the result of a natural occurrence known as the “June Drop”. This year the phenomenon is extending well into July, to the point that one wonders if there will be a crop left to harvest. So what is normal, and when do our trees need help?
Apples and pears produce several flowers on each cluster in spring, and depending on pollinator activity, and the local availability of another apple to cross pollinate, many, many flowers may set fruit. However, there will also be numerous little fruitlets that did not get pollinated properly, are damaged by insects, or require more carbohydrates than the tree can produce, and these fruits wither and fall off, frequently in large numbers.
As the remaining fruits begin to swell many more get attacked by codling moth, are affected by lack of sufficient water, or otherwise get damaged, and since the tree can only support a certain sized crop it goes through another round of shedding, usually beginning in June and continuing until early July, often resulting in carpets of larger fruit on the ground - frustratingly too immature to use for any practical purpose.
It is thought that warm nights may cause the fruit drop to be excessive since the respiration rate of the tree causes more carbohydrates to be consumed during the hours of darkness, leaving less available for fruit production.
Another factor could be lack of nitrogen, so a careful fertilization regime should be followed, being aware that too much nitrogen can also cause fruit drop and excessive growth. For information on fertilization see: http://homeorchard.ucanr.edu/The_Big_Picture/Fertilization/
In areas such as ours lack of water will also be a factor, so make sure that you check your irrigation system and remember to seasonally adjust the amount. A mature semi-dwarf tree can produce over 400 pounds of apples which, after all, are made up mainly of water!
On a large, heavy cropping tree, thinning young fruits early in the season reduces the natural shedding, and picking off any obviously damaged fruit as the season progresses will also help, but not eliminate the problem entirely. If a fruit is scarred or misshapen this will only grow with the fruit, so one might as well remove it and save the tree from wasting resources trying to get it to maturity. Infected fruits should be properly disposed of so that they do not create a source of infection. For information on thinning: http://homeorchard.ucanr.edu/The_Big_Picture/Fruit_Thinning/
Generally speaking, if the tree looks healthy and has a heavy crop of fruit falling in mid-summer should not be cause for concern.
If you open up a pest management guide for apple or pears—those books really exist, by the way—the first insect listed is always the dreaded codling moth. These are the creatures responsible for turning an apparent bountiful harvest of fruit into a brown, wormy mess in late summer. Codling moth is the main insect pest that attacks apples and pears in our region.
After overwintering as larvae, the moths emerge in spring, mate and then proceed to lay eggs on the fruit. These eggs hatch into tiny larvae that eat their way into your fruit, ruining it in the process. Fully grown larvae fall out of the fruit, pupate into adult moths (usually on the ground), and the process repeats. In the Owens Valley, there are usually two generations that we worry about controlling. Their development is mostly driven by temperature.
The first generation of adults usually emerges in April, and egg laying follows in a few weeks. The exact timing varies each year and by location, north or south, in the valley. The second generation lays its eggs over an longer period, but it is usually in July. Most of the complaints of ruined fruit by gardeners are from this second generation.
Because there are at least two generations to be concerned with, it is essential to get control during the first generation so that you have fewer moths to fight later on.
While it's possible to achieve control by just using continual sprays through the season with insecticides, this isn't usually how we deal with this pest since that's wasteful and carries risks. Codling moth is usually controlled through a combination of means.
Commercial codling moth control is a complex topic. There is a great body of peer-reviewed literature on the subject. In the home landscape it really isn't possible to implement a full, successful control program. UC has a simpler set of guidelines for landscapes and gardens here.
The approach I would recommend to is to watch your fruit closely. Ideally you should learn what a codling moth egg looks like and learn to identify it. If you want to control with sprays, egg laying is the only feasible time to apply an insecticide, Organic or otherwise.
Codling moth eggs are tiny and hard to see. They look like tiny translucent pancakes about as big around as a pencil's lead. These are usually laid near the blossom end of the fruit. I find them easier to see in the morning or late afternoon when the sun is low in the sky. They are slightly reflective and having sunlight reflecting on them is a big help. Check those fruits you can reach easily from the ground for the eggs by turning the fruit and looking around the blossom end. The third week in April is a good time to start looking in our area. Continue this through mid-May. Remember that Bishop is about 1 week behind Lone Pine in timing. Check for eggs again in late June through July. Egg laying is your best shot for applying controls.
If your eyes aren't good, you'll have a hard time knowing when to time sprays by finding eggs, but there are other options. A favorite home control technique of mine is to remove all fruit of the first generation that has a worm. This alone can go a long way in getting control, especially if you're not surrounded by neighbors with wormy fruit.
If you really want to have clean fruit, in June you can bag fruit to protect them from insect attack. Garden supply companies sell bags for this purpose, but you can improvise as well. Have bags on fruit before egg laying commences. Since we have wind issues, you'll need a way to secure the bags onto the fruit. Bagging is a lot of work! Anytime you see fallen or damaged fruit on the tree, you should remove it immediately whether you bag or not.
Unless you are committed to bagging fruit, most homeowners who demand high levels of control will need to spray some product. These vary from biological organisms that kill the target pest as well as naturally or synthetically derived insecticides. Because these products and recommendations change so often, I'll direct you here for current recommendations. (See bottom of that page.)
Codling moth control is definitely a challenge, but you can expect reasonable control with a little effort on your part. Even if you lose some crop each year, you should still have enough to make growing apples and pears worth your while.
All over our region we are receiving reports of fire blight occurring on fruit trees. This bacterial disease primarily infects pears, apples, quince and pyracanthas in our area. While there are a few other species out there that can be affected, it is unusual to see them attacked. Peaches, plums and cherries are not affected by this disease.
Fire blight is a bacterial disease. It usually gets its start during the bloom period of susceptible hosts. Early on it looks like wilted shoots and flower buds. Most gardeners do not notice the disease until it has turned entire shoots black. This burnt appearance happens suddenly which gives the disease its name.
By the time you see burnt shoots, it is too late to do anything to stop it. You're too late now. This summer, plan on pruning out all diseased wood. If you miss any, remove the remainder this winter. Removal of diseased material is important in controlling the disease in the future. The disease is primarily spread through flies and bees interested in the flowers. By removing sources of infection via pruning, your chances of getting the disease diminish. Sometimes this means pruning out a lot of the tree.
Disease growth is favored by a certain range of temperatures that occur in spring. In our area this coincides with turning on irrigation which raises humidity. Late spring storms, even if they don't bring rain, do often raise humidity as well.
There isn't really an effective spray option available to homeowners. Even farmers have a hard time with sprays of this disease. The UC IPM program has a brief summary of spray options at the end of this informative fact sheet. If you do spray, this occurs during the infection season as a means to prevent the disease. After-the-fact sprays have no effect. Don't bother trying.
There are great differences in susceptibility to fire blight by cultivar (variety). If you find that your pear or apple is always being afflicted with fire blight, consider replacing it with a more-resistant cultivar. Usually catalogs point this out.
As our nation expanded from sea to sea, homesteaders took apples with them. And eventually some of those settlers ended up in bear-infested Arkansas. The hilly terrain of the Ozark region wasn’t well suited for row crops, or much else for that matter, but it did grow apples well. At one time Benton County was the known as a leading apple producing region and not as Wal-Mart's headquarters.
Arkansas's heyday of apple production has long since passed, but there are a few remnants of the past that are still around Ozarks including a annual festival in Lincoln, whose orchards have since been converted to houses. It may sound surprising but there is a large following of enthusiasts of antique apple varieties, all of which seem to have a backstory. (Well, maybe it's not that surprising. If there are folks that get excited about daylilies, anything could be interesting to someone out there.)
Gardeners interested in heirloom varieties should consider growing ‘Arkansas Black’ apples. This apple was found in a nursery in Benton County around 1870. Most experts in these sorts of things believe that this variety was a chance seedling of ‘Winesap’, another favorite with heirloom aficionados.
‘Arkansas Black’ is named for its famously dark skin color. Other than color the other defining characteristic of this variety is its extreme firmness. At harvest in October, ‘Arkansas Black’ could probably substitute for a baseball. Ozark farmers would raise this apple and then store it in straw-lined pits for months before attempting to eat it. Long storage was definitely a positive attribute in those days, and in January the fruit was soft enough for the dentally challenged to enjoy the flavor of this apple.
My grandfather grew this apple in his front yard in Lake County. He lost his teeth in WWII and couldn't bite this apple with his dentures, so several times he tried to graft it to a softer-fleshed variety. As far as I know, his tree still survives.
Today 'Arkansas Black' has reemerged as a popular hobby variety. While not everyone appreciates an apple that bites back, like fine wines the unique flavor and firmness of ‘Arkansas Black’ mellows with age.
I have this variety in my back yard in West Bishop. It seems to do fine in the Owens Valley, assuming your kids don't do you a favor and harvest your crop in July. As it ripens in October, it probably isn't the most reliable choice at higher altitudes. Last year mine were perfect November 15, but they probably should have been harvested before Halloween.
The widespread planting of apples in this country is testament to the simple demands of the apple tree on the gardener. Like roses, a gardener can make apple growing a complex endeavor with spraying and pruning, or they can elect to let nature run its course and see what happens. Of course the most satisfactory results are usually found in well-tended orchards.
As a rule, apples need to be planted with a pollinator in order to set fruit. Most apple varieties will suit this purpose so if you already have an apple or crabapple, you should get good pollination assuming you do not kill bees with insecticides during the bloom period. If you need to get a pollinizer and can't decide which to use, I would suggest ‘Golden Delicious’. While it is not the most remarkable or unique apple variety, it has a long bloom period and produces a lot of pollen.
Apple trees will grow in all sorts of light levels, but if you want any fruit, you will need to plant them in a place they will continue to get lots of sun. A good rule of thumb for a home orchard would be to space trees as far apart as the canopy will be tall. An apple tree on its own roots can easily get 30 feet tall so this wouldn’t leave a lot of room in most yards.
The solution to finding enough room for an apple tree comes from selecting the correct rootstock. Gardeners can easily find rootstocks that can keep a tree 11 to 18 feet tall and pruning could further influence the ultimate height.
Most garden catalogues sell dwarf plants which are usually on a rootstock called M9, but home gardeners seldom have the option of selecting a specific rootstock. While full dwarfing is a nice convenience, home gardeners would be well-advised to select one of the taller semi-dwarf rootstocks such as M106 or M111 if given the option. They provide better anchorage and drought-tolerance: a real benefit here with our wind and dryness.
There are as many opinions as to the best way to train an apple as there are apple growers, but generally the best results come from a tree shaped like a Christmas tree. Whatever shape you choose the important thing is to be consistent every year. It's hard to go from a vase to a pyramid.
‘Arkansas Black’ is a unique heirloom variety that has a lot to offer the amateur orchardist. Excellent storage, great fresh flavor, and good cooking characteristics make it an apple well-suited for gardens. And it tastes different from what you'd get at the store.