Jan 30, 2014Apple pollination driven by honeybee management
Operating a flourishing family farm near Shelburne, Mass., keeps owner Tim Smith on a busy schedule. Among the important tasks is overseeing Apex Orchards’ apple pollination and honeybee management.
Smith spoke about the topic on Dec. 18 at the New England Vegetable and Fruit Conference in Manchester, N.H.
Housed on more than 200 acres, Apex Orchards grows a wide variety of tree fruits, apples, peaches, nectarines, apricots, quince, pears, Asian pears, blueberries, table grapes and kiwi. It sells produce at stores throughout the area, at farmers’ markets and at the farm itself.
“This is without a doubt one of the top fruit-growing areas in the world,” Smith said. “The soils, the microclimates, the varieties all combine to give our customers the best-tasting fruit possible.”
In order to help make that happen, Smith pursues a healthy apple-flowering effort because he recognizes the number of seeds set per fruit increases the size of the apple.
“It allows the apples to mature more evenly,” he said. “We always try to set king bloom. For that you need flower sets of 5 to 10 percent for a commercial crop.”
He said bees tend to work close to the hive for the first day or two after being moved. Bees will work up to two miles from the hive foraging, and they are likely to work the most attractive crops available.
“Bees will continue to work the same crop they started working,” he said. “They tend to work up and down the rows in a high-density planting. Much of the pollen transfer for cross-pollination takes place within the hive.”
Changes in beekeeping patterns have brought challenges, such as a proliferation of varroa mites that infest honeybee colonies.
Varroa mites are external honeybee parasites that attack both the adults and the brood, with a distinct preference for drone brood. They suck the blood from adults and the developing brood, weakening and shortening the life span of those on which they feed.
Emerging brood may be deformed, with missing legs or wings. Untreated infestations of varroa mites that are allowed to increase will kill honeybee colonies. Losses due to these parasitic mites are often confused with causes such as winter mortality and queenlessness if the colonies are not examined for mites.
Smith said beekeepers use pesticides within the hives to control mites, but negative impacts can occur from using pesticides, as well as not controlling mites.
He pointed to ongoing concern for Nosema ceranae, a fungal disease that is difficult to control and may be interacting with other viruses.
Nosema ceranae is a microsporidian, a small parasite that mainly affects Apis cerana, the Asiatic honeybee. It may cause nosemosis, also called nosema (Nosema apis, the most widespread of the adult honeybee diseases). The dormant stage of nosema is a long-lived spore that is resistant to temperature extremes and dehydration.
He said the evolution of beekeeping practices includes a focus on nutrition, including the intensity of required feeding schedules for honeybees.
Hive replacement is seen as an essential way to manage honeybee pollination efforts, Smith said.
“Replacing hives is a constant operation for all commercial beekeepers,” he said. “Most beekeepers are replacing 100 percent or more of their hives every year.”
He urged caution when interacting pesticides with miticides the beekeeper is using for mite control. Use of the chemical fluvalinate, which slowly permeates the hive over a 40-to 50-day period, or SI fungicides “may increase toxicity to bees by 2,000 times.”
Smith said it’s important for growers to spray during pre- and post-bloom only, acknowledging that extended bloom makes this approach difficult.
“Time sprays to allow for king bloom pollination,” he said.
Smith believes almost all pesticides have some repellency to bees.
“Never spray when bees are foraging, even fungicides,” he said. “Spray early morning or evenings if necessary during bloom. Try to eliminate SI and strobilurin fungicides during bloom.”
Focusing on hive replacement, Smith said the number of hives used per acre is a “risk management decision. How warm will it be; how rainy will it be during bloom? What are the chances of frost during bloom?
“Plan on one hive per acre or per 1,000 bushels of expected production as a minimum,” he said.
When placing hives in the orchard, they should be in a place with exposure to morning sun. They should be located near a windbreak in groups to increase competition and cross-pollination.
It is important to inspect hives that growers rent, Smith said. Growers should be looking at hive strength, the frames of the brood and bees and the overall quality of the hives.
“It’s always more cost effective to rent stronger hives of bees for pollination,” he said.
A four-frame hive will produce 4,000 flying bees. An eight-frame unit will house 15,000 flying bees.
“Two weak hives will never equal the field force of one strong hive,” he said.
Inspecting at least a percentage of the rented hives is crucial.
“Consider using a quality-based contract,” Smith said. “Work with your beekeeper to get the strongest hives for apple pollination.”
Alternative pollinators to honeybees include Osmia (mason) bees and bumblebees.
“Both are good pollinators, but both are prohibitively expensive,” he said.
“Always rent strong hives of bees. Don’t be afraid to check the hives you are renting. Always decide how many hives per acre based on how much risk you’re willing to accept.”