The year can be thought of as a cycle. We will start the year in the orchard with Spring, the season of rebirth. When Spring arrives it seems as though dozens of tasks need to be done at once to get ready for the growing season. Pruning which has been going on all winter needs to be finished. Brush which has accumulated beneath the trees as a result of pruning is raked into row centers and chopped or pushed into piles and burned. Fertilizer is spread underneath every tree according to leaf and soil analysis. New trees are planted. Scion wood from desirable varieties may be grafted to existing trees of less desirable varieties as a quick way of making the varietal change.
Then comes bloom, the real beginning of the apple growing process and an event that excites the veteran grower and the novice alike. We depend upon bees to carry pollen from one flower to the next so that apples will develop. With most varieties pollen must come from a different variety in order to get a good fruit set. If you plant a seed from a McIntosh apple, it will not produce a McIntosh tree because the pollen that fertilized the flower was probably not from a McIntosh flower. There are native bees and other insects flying during bloom, but in order to insure that we have adequate pollination, most apple growers lease hives of bees from a beekeeper during bloom at the rate of approximately one hive per acre. In addition to an adequate number of bees, good pollination weather is necessary to have a good fruit set. The honey bee is particular and does not like to fly if the temperature is below 60 degrees or if it is very windy. Cold, rainy, or windy weather has kept many a good bloom from living up to its potential to produce a good crop.
Apple growers spend lots of money to lease hives of bees, wish for really good pollinating weather, and then they wander around the orchard after bloom wondering if perhaps the fruit set is too good. How can the fruit set be too good? Too good a fruit set results in lots of small apples. Each bud opens to reveal a flower cluster of five blossoms. There is one large central blossom called the king with four somewhat smaller ones around it. The king will make a larger apple than the other blossoms. Ideally growers would like just the kings to set fruit and during a good bloom, and only a relatively small number of those. Apples should be spaced every four or five inches along a branch. It is more desirable to have the strength of the tree go into growing a moderate amount of large apples than a large amount of small apples. A bushel of large apples may be worth twice what a bushel of small apples is worth, so that it matters a lot that too good a fruit set not be allowed to remain.
Thinning is the solution. Thinning is usually accomplished by chemical means. There are a few chemicals that if applied shortly after bloom will cause a percentage of the little apples to drop from the tree. The difficult part of this process is the decision concerning how much to thin. Right after bloom it always looks as though almost every blossom cluster has produced five little apples. It hasn't, but it takes a few weeks to tell which are going to develop into apples and which are going to shrivel up and fall off. This falling of un-pollinated applets is called "the June drop." In Maine it happens in early July. Therefore the decision to thin has to be made several weeks before one can really know how much thinning is needed. An educated guess is made based on the number of flowers, the weather and temperature during bloom and how active the bees were. If the educated guess wasn't quite right or if weather conditions weren't conducive to effective thinning, growers may hand thin in July when the apples are about an inch in diameter. Thinning also promotes return bloom. Many apple varieties have a tendency to produce an apple crop only every other year. Thinning counteracts this tendency.
Pest control starts in the spring and continues throughout the summer. It will be discussed at some length in a later section. During July and early August the orchard is mowed at least once, usually twice. It is a job like housecleaning, never ending and as soon as everything has been mowed once it is time to start over again. Weeds right under the trees are considered pests because they use water and nutrients needed by the trees, and they harbor insects harmful to the tree or fruit. They are particularly bad competition for young trees. Weeds are mostly kept under control by the use of herbicides, but other means are available such as under tree cultivation and mulches. A clean strip under the trees reduces rodent habitat.
In July and August many growers have crews doing summer pruning in which the cuts are restricted to new upright growth no greater than three quarters of an inch in diameter. Its purpose is to let in light and allow the sun to color the apples so that they can be picked in a timely fashion. The grade, and hence the value of a red apple variety depends on its percentage of red color.
In late July and August some varieties of apples ripen and are ready to harvest. The early varieties are often very tasty but are not good long term keepers so they are picked, packed and marketed immediately. The intense flurry of activity usually lasts about a week and a half for each variety and serves as a good dress rehearsal for the main harvest.
This starts in late August or early September. Although many varieties are grown, McIntosh is the most important commercial variety in Maine. It is known nationally and it does better in our Northern climate than it does further South. We have just three weeks to pick McIntosh before there is significant loss to drop. Labor to harvest the apples is provided by local people and workers who come from far away. Many are brought in from Jamaica and some come from Mexico.
Experienced skilled workers are very important, because pickers make the difference between a bushel of apples fit only for processing and one graded as extra fancy that may sell for eight times more than processing apples.
The intensity of the short harvest season is hard to imagine unless one has experienced it. The pickers work eight hours a day seven days a week during good weather, while the support crew works about 10 hours daily. This crew includes the foreman, quality checkers whose job it is to make sure that the apples are picked carefully and not prematurely before enough red color has developed; record keepers whose job it is to record the hours worked and the amount picked by each picker, and tractor drivers who move the wagons hauling the apple bins through the orchards while they are being filled by the pickers and drive them to the apple storage when they are full. By the end of each days work all apples picked that day should be in refrigerated storage rooms being cooled. Prompt cooling after picking increases storage life.
The first apples picked are put into special cold storage rooms which are nearly airtight when sealed shut. These special rooms are called controlled atmosphere storages, because the oxygen in the room is reduced to between 3% and 5% and the carbon dioxide is kept within a similar range. The temperature is kept at about 36F for McIntosh and 32F for Red Delicious. The room's atmosphere is tested daily and normal air is let in through a port if it gets to the lower limit of the allowed amount. Since apples use oxygen and give off carbon dioxide, limiting the amount available slows the ripening process, but it also means the amount can get too low if not checked daily. These specially stored apples are destined to be marketed later in the year, from December on. The later picked apples, are riper and more flavorful but will not keep as well. Therefore they are marketed first and kept in refrigerated rooms that are not sealed. They are stored at 32F. These apples are referred to as cold storage or regular storage fruit.
Unless apples are sold directly from the orchard through a "pick your own" operation, they must be graded or sorted according to a quality standard that conforms to state and federal law. They are generally stored just as they are picked, and then graded and packed as orders are received for them, shortly before being marketed from a retail operation on the premises or before being shipped to supermarkets for resale. Grading, packing and shipping of apples goes on from a few weeks to 12 months depending on the size of the orchard and the manner of marketing the orchard uses. Some orchards have the facilities to store, grade and pack all their own fruit. Others have all or part of their crop stored and packed by a cooperative facility.
After harvest there is still work to be done before winter arrives. Any equipment left in the orchard needs to be collected and put under cover. Sprayers and tractors that will not be used until next spring need to be made ready to withstand freezing temperatures and stored for the winter. Tree limbs broken by too heavy a fruit load need to be sawed off. One last mowing is done to keep the grass from providing too much cover to rodents. The main rodents that apple growers are concerned with are voles that will eat apple bark at or below ground level girdling a tree and thus killing it. Damage is limited by reducing their numbers by an application of poison bait after harvest, by trying to make the orchard habitat unattractive to them, and by protecting the tender bark of the trunks of young trees with guards of various types, and by cheering on the predators. We like foxes and coyotes.
Winter is not a time for apple growers to take long vacations to southern climates as many people seem to think. Apples are graded, packed, and marketed all winter as previously mentioned. The other major job done in the winter and early spring is pruning. Major cuts are made when the trees are dormant. Every tree should be pruned every year. Trees are pruned to renew fruiting wood, to let light into as much of the tree as possible, to encourage moderate vigor, and to maintain the tree at a convenient height and shape. The mad scramble to finish up pruning always seems to run right into the need to perform those jobs belonging to beginning of the growing season when the cycle starts again.
Integrated Pest Management
The above description of a year in an orchard glosses over pest control, other than rodents and weeds, because it deserves several paragraphs of its own. Apples are unfortunately attractive to a large host of organisms besides humans: insects, fungi, tiny arachnids called mites, deer and birds are the most common. Deer we attempt to keep separated from apple trees by means of fences. Birds we mutter and swear at, but in most years the damage is an annoyance but not a major financial calamity. In the 1995 growing season bites and tears by red squirrels caused significant crop damage in many orchards, but this is not usual. The remaining pests: fungi, insects, and mites we try to keep under control by a combination of horticultural practices, biological controls, naturally occurring predators, and when necessary chemical pesticides targeted to very specific problems. This approach to control of pests is called integrated pest management.
A grower does not look at a calendar to decide when to spray. Instead, consideration of past and future weather, the stages of fruit development and pest development, and the pest population determined by scouting and trapping are all considered before a spray is put on. Scouting is done by apple growers or technicians who monitor traps and check a percentage of trees in each block for pests or pest damage. Various traps are used to attract specific insects by means of visual or pheromone odor lures. When the insects light on the traps they are entangled in a sticky substance. There they remain waiting to be counted. Research has established the number of catches that can be tolerated before significant damage occurs to the crop. When the threshold is crossed a grower will spray a chemical targeted to control that pest.
Chemicals are applied by means of air blast sprayers pulled by tractors or, sometimes early in the season when the ground is too muddy to drive on, by an airplane. It is often done at night or early in the morning, because that is when there is usually very little wind. This is important if the material is to land where it is directed. All people who use restricted use pesticides must either be a licensed pesticide applicator or have undergone pesticide handler training and be supervised by someone who has a license. The license from the Maine Board of Pesticides Control is initially obtained by passing a written test and renewed by attending lectures on safe pesticide handling, life cycles of various pests, recent research, and other topics that will help growers do an effective and safe job growing a clean, marketable crop.
The pesticides used have been extensively tested for their effectiveness and safety There are restrictions concerning their use near harvest. The Food and Drug Administration samples fruit after it has been picked for pesticide residue. Residue on Maine apples has been non-existent or negligible.
Growers have come to appreciate the help given by naturally occurring predators and so try to use pesticides that will be as benign to beneficial insects or mites as possible. In Maine in the case of aphids, at least, predators will adequately control the problem if given time enough and so almost no Maine apple growers spray for aphids. Mites are little spider-like creatures that destroy the green tissue of the leaves, and if a large enough population develops, will weaken the tree to the extent that it will drop most of its fruit too early. Natural predators will usually not be sufficient to control mites, but will provide significant help in keeping the population in check until late in the season. A healthy predator population depends upon using chemicals for other problems that are not toxic to the predators.
Horticultural practices such as keeping trees well pruned and open to air movement help combat problems by allowing for good drying conditions and good penetration of spray. Keeping surrounding woods and fields free of alternate hosts for pests will also lessen the need to spray. Early season mowing discourages two spotted mites.
Research into the life of the pests in question has cut the use of pesticides. For example apple scab, a fungus that growers spend more time and money combating than any other single pest, has been extensively studied with respect to the conditions necessary for an infection to occur. Scab spores which over winter in the apple leaves which fell the ground the previous autumn are released by rain at a time when the spores are mature and ready to shoot. Infection depends upon the temperature and the length of the wetting period.
Growers get information from University Extension specialists about the current maturity of scab spores, monitor the temperature during rain and the length of the wetting period and then look on a chart to determine if conditions were right for an infection. If so measures can be taken to combat it. Some growers use spore traps that face into the wind, suck in the air and deposit any spores on a microscope slide. The trap has a switch that is activated by moisture and so turns on when it rains. The other approach used is to watch weather forecasts for approaching rain and to make sure that the trees are covered with a protectant fungicide ahead of time. Research has been done determining the time of day when infections take place. It may be that rain at night during scab season is not as great a threat as a daytime rain, if major infections take place only during daylight hours.
Current research is studying ways to reduce the dose of scab spores available on the orchard floor waiting to be released and infect the trees. One such approach is the chopping of the leaves in the fall and application of urea to help them rot. The more knowledge available, the more effectively and sparingly pesticides will be used. Maine apple growers who belong to the Maine State Pomological Society support research with their dues.
Integrated Pest Management is the approach used by apple growers in Maine. Its widespread adoption has often resulted in reduced use of chemicals which is better for the environment and definitely better for apple growers' pocket books. It is an approach that is continually being refined.