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Fooling with Pheromones–or Moths Keep Following Me Home

Pheromone Tie

Most orchards must deal with two serious insect offenders, the Oriental Fruit Moth and the Codling Moth. They can have multiple generations every summer, and each fertile female lays approximately 100 eggs per generation. That’s a lot of worm damage. Neither of these moths is native to the United States, nor do they have any “natural” enemies to reduce their numbers. As a preventive measure, we use pheromone disruption in early spring to confuse male moths so they do not mate. Suspended from fruit trees in a pattern particular to our orchard, pheromone laden wire ties saturate the atmosphere with the scent of female moths. In turn, the smell disrupts mating, averting egg and worm damage in our apples and peaches. Worth the extra expense, this organic strategy helps us eliminate several insecticide applications annually.

Because of its effectiveness, pheromone disruption has been part of our IPM program for many years, but it is not foolproof. To ensure Oriental Fruit and Codling Moths stay within a manageable range, we routinely scout (our daily dog walks), monitoring for pests and pest damage. This is also a good time to check our moth traps. Concurrent with mating disruption, we hang traps containing pheromone lures that attract male Oriental Fruit and Codling Moths. If we catch more than five per trap per generation, we exceed the minimum damage threshold, prompting us to determine our best control measure. Codling Moth Granulosis Virus is an organic material that we apply sparingly when necessary, and it specifically targets Oriental Fruit and Codling Moths, allowing beneficial insects to progress unharmed. To synchronize this control, we first must establish the number of days until egg hatch (a time period determined by a degree day temperature model).

Almost invariably, pheromone disruption arrests any need for further action against the moths. We choose instead to monitor traps and accept some damage rather than to depend on a calendar based spray schedule that may stamp out all insects–the good, the bad, and the ugly.

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Our Ozark Orchard–Gone Native

Foraging bumblebee in redbud blossoms

I live in the country, on an orchard, so I must be an authority on matters farm-related. Not so. Small town suburbia is my rightful domain, and rural life is unfamiliar. Twenty years in and I’m still learning about what not to take for granted–solitude, birdsong, night sky, bees.

If pressed to choose the insect I’d most like to resemble, I might pick one of the many thousands of bee species native to North America. Perhaps I’d imitate the fast flying Agapostemon, a bright, metallic green bee better known as the sweat bee; or maybe the dread cuckoo who can steal into other bees’ nests masked by pheromones; or possibly the Megachile Campanulae, a leafcutter who lines her home with petals, leaves, and recycled plastic?! John, of course, would choose the blue orchard mason, a bee as fruit obsessed as he.

Many types of these bees call the Ozarks home, and they go largely unnoticed while assisting the local ecosystem. Our orchard, in fact, relies exclusively on wild bees. Their strength and diversity is vital to us considering without these bees, we would have a lot less fruit. Nevertheless, I have underappreciated them. Every spring I stand in the dizzy bee frenzy of full-bloom nectarines, but only now have I contemplated our native bee population, realizing suddenly our good fortune and our responsibility.

Native bees’ requirements are basic: food (pollen and nectar) and shelter (nesting sites). Better habitat, indigenous plants in a number of settings, encourages heterogeneity. This is a big win because a mix of bees ensures an assortment of flowers. Here at the farm, some of our pollinator plantings result by chance and others by careful design, and it’s this array of fields, forest, fencerows, pond banks, ditches, edges, and orchard blocks that protects and feeds our wild bee community. Standing dead trees remain in the wooded areas of our farm, and small, untidy meadows break up the neat, straight rows of apples and peaches. These features lend important nesting prospects by supplying dry, sunny, open spots for ground-nesting digger and bumble bees and hollow rock and tree cavities for feral honey bees. And once cut, the ill-planned stands of bamboo growing thick beside our home will make fine tunnels for leafcutter and mason bees.

Nonetheless, we are delinquents rather than do-gooders indulging our expanse of lawn. However sensuous and fresh and green, it fails to provide the varied terrain necessary for native bee homebodies who spend most of their time inside their nests or, when searching for food, close to their nests. As pollinators then, they are especially appealing because native bees forage in a tighter radius, transferring the “right” pollen from flower-to-flower. This behavior is a boon to orchardists but puts pressure on habitat; bee resources need to be nearby and need to coincide. Blossoms and fallen fruit yield adequate farm forage much of the year, and despite our lawnscape, even our yard proper attracts wild bees. A haphazard collection of trees and shrubs and plants mostly characteristic of an Ozark broadleaf forest, beautyberries, irises, goldenrods, black-eyed susans, and asters grow with abandon–lucky rather than calculated wild bee preferences.

My inattention to bee specific blooms spills over to the beds nearest our front door. Although filled with fragrance and color, they were planted with other pollinators in mind, so to the butterfly bushes, I’ll add more salvias, sunflowers, and penstemons, accommodating wild bees’ penchant for yellow, white, and blue. These casual, carefree plantings defy my minimalist partiality, but a variety of flower shapes will suit the tastes and tongue-lengths of many different bees. More native plants also should draw wild bees nearer to the spots I frequent, giving me opportunity for closer scrutiny. I’m curious to know what bees reside here, where they build their nests, and how they carry pollen. By late fall, my bee count notebook will detail entries that can help me assess and improve their environment.

I trust the bees will accept my invitation to forage and nest in our gardens and at our farm long-term. More intentional care to enhance their diminishing habitat is an easy exchange for the value they supply. Our farm is an ongoing experiment that asks how we can maintain a productive orchard within a recovering ecosystem, and our wild bees have been helping with this effort however invisible to us.

 

Resources

The Xerces Society – A nonprofit dedicated to invertebrate conservation. Look for the pdf read Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms.

The Pollinator Partnership – An organization devoted to pollinators–protection of their habitat and their future. The ecoregional planting guide is helpful (Arkansas and Missouri fall into the Eastern/Ozark Broadleaf area).

The Great Sunflower Project – Dedicated to habitat improvement, the site provides a good start for anyone interested in keeping a pollinator count.

Speaking of habitat, Debbie Hadley’s 12 Things You Can Do to Help Native Bees and Michael D. Warriner’s The Buzz on Native Bees are two articles that address ways to better our pollinators’ environment.

A recent find is my soft copy of Heather Holm’s Pollinators of Native Plants: Attract, Observe and Identify Pollinators and Beneficial Insects with Native Plants that details insect interaction with prairie land, woodland, and wetland plants.