Sweet watermelons

July 15, 2011 under CANR News

Delaware watermelon connoisseurs are enjoying the moment – local watermelons are now ripe and ready to enjoy. Local watermelons are sweeter and tastier than the out-of-state melons available earlier in the summer, claim their aficionados.

“Local watermelons do taste pretty sweet. And buying local produce when it’s in season helps to support our local growers,” notes Phillip Sylvester, agriculture agent for Kent County Cooperative Extension.

The state’s watermelon crop typically ripens by July 10 and continues through Sept. 25, with the most active harvest period in mid-August.  Delaware’s watermelon industry has declined slightly in recent years but is still strong.  There are more than 2,700 acres of watermelon in Delaware, down from 3,000 acres five years ago. Crop production is currently valued at $11 million annually.

Sylvester always plants watermelons in his home garden in Felton but the bulk of commercial growing takes place further south, in and around Laurel. The well-drained, sandy soils in western Sussex County are excellent for watermelon growing.

This area has been the seat of Delaware’s commercial melon industry since the 1850s, when schooners loaded with watermelon traveled the Nanticoke River to Baltimore and points beyond. More recently, the Laurel Farmers’ Auction Market opened in 1940 to bring wholesale watermelon buyers and sellers together. At one time the price of virtually every Delaware watermelon was negotiated at the Laurel Market. Today, supermarket chains send brokers directly to growers but the market is still used by small- and medium-sized buyers.

Sylvester grows “Crimson Sweet” watermelons because he says they have an exceptionally sweet taste. But this striped heirloom melon will never win any popularity contests, tasty as it might be, because of what some view as an unforgivable downfall – its seeds.

“I don’t care if a watermelon has seeds,” says Sylvester, “but most people do.”

In the 1990s, less than 1 percent of watermelons were seedless. Today, about 75 percent of the watermelons sold in the U.S. are seedless varieties. A seedless watermelon plant contains three sets of chromosomes and is sterile so it must be pollinated by a second plant to set fruit. As a result, growers must pay strict attention to the pollination needs of their seedless watermelon crops. Most growers rent or own honeybee hives but some have started to use bumblebees. UD bee researcher Debbie Delaney and Cooperative Extension fruit and vegetable specialist Gordon Johnson are working with watermelon growers this summer to see if bumblebees improve crop productivity.

Kate Everts also is conducting watermelon research but her projects focus on combating Fusarium wilt. This pestilent pathogen causes one of the most economically significant watermelon diseases worldwide. It causes wilt and plant death early in the season and again when the plant is in fruit. Once a field exhibits severe Fusarium wilt, it’s off limits for watermelon growing for 15 or more years.

Everts, who holds a joint appointment at the University of Delaware and the University of Delaware, collaborates closely with Extension specialists Emmalea Earnest and Gordon Johnson. Her research team focuses on several areas: they’re developing plants resistant to Fusarium wilt, exploring chemical disease measures, and looking at how cover crops can suppress this nasty fungus.

Sylvester is diligent about helping commercial growers obtain maximum yields but when it comes to his own watermelon plot, he adopts a laidback attitude. Though the ag agent know his way around a garden, sometimes pests or weather get the best of his watermelons. Every spring he tells himself “maybe we’ll have watermelons, maybe we won’t.”

However, this summer he hopes for a bumper crop because his 1 1/2-year-old son, Henry, shows a liking for watermelon. What could be better than a “Crimson Sweet,” grown in the backyard by Dad?

Article by Margo McDonough

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Nature’s Fireworks

July 11, 2011 under CANR News

 Annelid worms do it. Certain species of centipedes and millipedes do it. Even a tropical land snail can do it.

But here in Delaware, fireflies and glow worms are the only terrestrial creatures that light up the night with their own built-in flashlights.

Bioluminescence results from a chemical reaction in which chemical energy is converted to light energy, according to Doug Tallamy, chair of the University of Delaware’s Department of Entomology and Wildlife Ecology in the College of Agriculture and Natural Resources.

Fireflies (Lampyridae) aren’t actually flies and glow worms (Phengodidae) aren’t really worms. Both are considered to be beetles and are closely related species.

The fireflies’ glow adds beauty to a summer night but there are several pragmatic reasons for bioluminescence, too. Fireflies and glow worms light up to attract the opposite sex. Adult fireflies, both male and female, flash coded messages to attract prospective mates. Males fly about while they flash, females usually flash while hanging out in bushes. It’s all about “speed dating” not lengthy courtships — there’s no time to waste since adulthood only lasts for about two weeks.

There’s another reason why fireflies light up, at least in the case of juvenile larvae. Almost a decade ago, UD scientists led by Tallamy discovered that baby fireflies light up to keep predators at bay.

Previous studies had shown that mice and other would-be predators shun adult fireflies because of a compound in fireflies’ body that produced a bitter taste. The UD study demonstrated that baby fireflies flash to advertise that they also exhibit this bitter taste.

“A flashing neon sign may lure hungry humans to an all-night diner but the bioluminescence of firefly larvae sends a very different message to would-be predators,” says Tallamy.

Summer season

This summer is shaping up to be a good but not spectacular season for fireflies.

“Lightning bug populations at my house have been strong but not record-breaking,” says Tallamy. “In general, populations fluctuate from habitat availability more than from weather. However, if we get a bad drought during the summer and fall that does impact the population of lightening bugs the following summer.”

Fresh strawberries for a few short weeks around Memorial Day. Carnival rides at the State Fair for 10 days in July. Like other summertime pleasures, firefly season is short-lived.  “Nature’s fireworks” begin a few weeks before July 4th and are at their peak now. By the end of July they’re gone, save for a few stragglers.

Where to find different species

Several species of fireflies can call themselves native Delawareans. The beach region of Sussex is home to the coastal firefly, which prefers sandy, even salty, soil and generally stays close to the ground. Inland Sussex and Kent counties are home to yet another species. But the greatest diversity in firefly species is found north of the Chesapeake and Delaware Canal, says Tallamy.

“Fireflies are especially abundant in the Piedmont region, in the northernmost part of Delaware,” he says. “Most firefly species favor ‘old field habitat.’ In New Castle County, that type of habitat is most commonly found around the White Clay and Red Clay creeks and along the Brandywine River.”

At first glance, one species of firefly may not look much different from another. But pay close attention to fireflies as they begin to light up. “If you look closely, you’ll start to notice some distinct variations in their flash pattern,” says Tallamy.

There are three characteristics that differentiate firefly species:

  • Where the fireflies are located. Some species like to be close to the ground; others prefer shrubs and low trees.
  • The flight track, or style of flying, varies from species to species. Some fly in a “J” pattern then swoop down low, others take looping flights.
  • The pattern of the bug’s flashing. Think of the flashes like Morse Code — do they resemble a dash-dash-dash pattern or dash-dot-dash?

If your kids like to catch fireflies and put them in a jar, go for it, says Tallamy, as long as you punch some holes in the lid and release the fireflies after a few hours. Fireflies are beneficial insects; in their larval form they feed on garden and crop pests.

Article by Margo McDonough

The article can also be viewed online on UDaily.

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Changing seasons provide varied birding opportunities

January 10, 2011 under CANR News, Cooperative Extension

One of the things that Derek Stoner likes most about living in Delaware is that every season brings new things to see and enjoy outdoors. Birding is a great example of nature’s diversity throughout the year.

“Birding in January, when owls are breeding, is a lot different than birding in July, when shorebirds flock to the Delaware Bay during their southward migration,” notes Stoner, the past president of the Delmarva Ornithological Society.

Here are some of the avian highlights that each season brings. How many of these birds will you spot in 2011?

Winter

As the New Year begins, the woods come alive with the calls of owls. Delaware’s most-common woodland owl, the great-horned owl, begins nesting now. Listen for its territorial hooting calls at night. The Eastern screech owl is also active and makes a trilling call. So how do you identify all those trills and hoots? Before heading out, Stoner suggests listening to owl calls at this website.

In February, take part in the Great Backyard Bird Count, a citizen science project throughout the U.S. and Canada. Last year’s count tallied more than 11 million birds of 602 species. Beyond the important scientific data that’s collected, the count generates excitement for birders, notes Chris Williams, UD assistant professor of wildlife ecology. Get involved by visiting this website.

Spring

In late April and the first half of May, birders flock to White Clay Creek State Park, where warblers, tanagers, orioles and other migrants are attracted to the large expanse of healthy woodlands. The best time to see lots of migrants, says Stoner, is after a night with steady winds from the south.

If you want to see red knots in the spring, there’s one place to go — Mispillion Harbor on the Delaware Bay, which attracts up to 90 percent of all the red knots in the world during this time period. Red knots fuels up on horseshoe crabs at the harbor. Check them out from the observation deck of the DuPont Nature Center. For a map and directions, visit the DuPont Nature Center website.

Summer

Summertime to Carrie Murphy means the return of the American goldfinch. This small finch is attracted to native perennials in her garden, including echinacea, black-eyed Susan and hardy ageratum. In its spring plumage, the brilliant yellow-and-black male looks like he belongs in a tropical rain forest instead of a Delaware backyard. Murphy, horticultural agent for New Castle County Cooperative Extension, says the goldfinch also likes annual sunflowers.

In July, look for blue grosbeaks, gorgeous blue birds with silvery bills. Doug Tallamy finds a pair nesting in his dogwood tree every July. “The male sings from May to September every morning for two hours,” says Tallamy, the chair of UD’s Department of Entomology and Applied Ecology.

Want to attract blue grosbeaks to your own yard? “Blue grosbeaks like to include snake skins in their nests, so if you hang a snake skin up on a fence, you’re more likely to get them,” notes Tallamy.

Late summer is prime time for migrating shorebirds all along the Delaware Bay. Visit the impoundments at Fowler Beach and Broadkill Road of Prime Hook National Wildlife Refuge to see black-necked stilts, black-bellied plovers and many varieties of sandpipers.

Fall

“I like watching hawks fly out of trees to kill unsuspecting rodents during the fall,” says Brian Kunkel, an entomologist with UD Cooperative Extension. If the thought of watching hawks feasting on rodents makes you lose your lunch, just keep your eyes skyward. The northern tip of Delaware is the place to see hundreds of migrating broad-winged hawks on their way to South America. Check out the Ashland Hawk Watch page.

In November thousands of ducks, geese and swans funnel into the First State to take advantage of the abundant food and resting places. Places like Thousand Acre Marsh, Woodland Beach Wildlife Area and Silver Lake in Rehoboth offer great viewing.

Wrap up the year by taking part in the Christmas Bird Count, the world’s longest-running biological survey. Seven Christmas Bird Counts take place in Delaware. Learn more at the Delmarva Ornithological Society website.

Article by Margo McDonough

This article can also be viewed online on UDaily by clicking here.

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Fireflies light up the summer sky

July 7, 2010 under CANR News

Fireflies may not light up the sky as bright as Fourth of July displays but this season they’re putting on quite a show.

“This is a fantastic year for fireflies, probably because we got so much rain last summer,” says Doug Tallamy, chairperson of the Department of Entomology and Wildlife Ecology at the University of Delaware. “As larvae, fireflies like moist leaf litter and things stayed moist last year.”

“Nature’s fireworks” continue long after July 4th — fireflies are at their peak now and stick around Delaware until the end of July.

Although most of us call them fireflies or lightning bugs, these luminescent creatures are more properly known as Lampyridae, which in Latin means “shining fire.” And they are actually beetles, not flies, says Brian Kunkel, an entomologist with UD Cooperative Extension.

Summer out West certainly has its pleasures, such as less humidity in most places than here in the Mid-Atlantic. But one thing you can’t enjoy in Beverly Hills or Boise is fireflies.

“Fireflies aren’t found west of the Rockies,” says Kunkel.

There are several species of fireflies native to Delaware. The beach region of Sussex County is home to the coastal firefly, which prefers sandy, even salty, soil and generally stays close to the ground. Inland Sussex and Kent counties are home to yet another species. But the greatest diversity in firefly species is found north of the Chesapeake and Delaware Canal, says Kunkel.

“Fireflies are especially abundant in the piedmont region, in the northernmost part of Delaware,” he says. “Most firefly species favor ‘old field habitat.’ In New Castle County, that type of habitat is most commonly found around the White Clay and Red Clay creeks and along the Brandywine River.”

At first glance, one species of firefly may not look much different from another. But pay close attention to fireflies as they begin to light up. “If you look closely, you’ll start to notice some distinct variations,” says Kunkel.

There are three characteristics that differentiate firefly species:

  • Where the fireflies are located. Some species like to be very close to the ground; others prefer shrubs and low trees.
  • The flight track, or style of flying, varies from species to species. Some fly in a “J” pattern then swoop down low, others take looping flights.
  • The pattern of the bug’s flashing. Think of the flashes like Morse Code — do they resemble a dash-dash-dash pattern or dash-dot-dash?

As for why fireflies light up, it’s for the same reason that tight clothing and flashy jewelry are a staple at nightclubs — to attract the opposite sex. Adult fireflies, both male and female, flash coded messages to attract prospective mates. Males fly about while they flash, females usually flash while hanging out in bushes. It’s all about “speed dating” not lengthy courtships — there’s no time to waste since adulthood lasts just two weeks.

There’s also another reason why fireflies light up, at least in the case of juvenile larvae. Almost a decade ago, UD scientists led by Tallamy discovered that baby fireflies light up to keep predators at bay.

Previous studies had shown that mice and other would-be predators shun adult fireflies because of a compound in fireflies’ body that produced a bitter taste. The UD study demonstrated that baby fireflies flash to advertise that they also exhibit this bitter taste.

“A flashing neon sign may lure hungry humans to an all-night diner but the bioluminescence of firefly larvae sends a very different message to would-be predators,” says Tallamy.

If your kids like to catch fireflies and put them in a jar, go for it, says Kunkel, as long as you punch some holes in the lid and release the fireflies after a few hours. Fireflies are beneficial insects because they may feed on insect pests in the garden so it’s important not to harm them.

Article by Margo McDonough

You can also see this article and accompanying photo on UDaily by clicking here.

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Carvel Research and Education Center beats the heat with UDairy Ice Cream

June 30, 2010 under CANR News, Cooperative Extension, Events

Making a three hour trip just to get ice cream may seem a bit over the top, but after hearing and reading great reviews about the delicious ice cream from the College of Agriculture and Natural Resources’ UDairy Creamery, Barbara Stephens didn’t mind the round trip from Georgetown to Newark to share the best of Townsend’s sweet cuisine with her colleagues. Stephens works at the Elbert N. and Ann V. Carvel Research and Education Center, home of Sussex County Cooperative Extension and satellite agriculture research campus.

And the Carvel staff, many of whom work outside in the research fields, were very happy she did!

Stephens suggested to Carvel Director Dr. Mark Isaacs that an Ice Cream Social might be a nice alternative to their recent practice of getting together each summer for a staff – family picnic. The change to tradition couldn’t have been timed better, considering the persistent heat wave.

“Barbara’s idea of an ice cream social was excellent!” said Isaacs. “It gave our staff an opportunity to sample the delicious UD ice cream from our college, and provided a much welcomed treat from the heat and humidity.”

All three flavors featured at the ice cream social – chocolate marshmallow, strawberry, and traditional vanilla, were a big hit. Several people tried a three scoop sampler – most took advantage of the wide variety of toppings – but some enjoyed their ice cream in its pure, delicious state.

The creamy, cool delights, made from UD’s 100 Holstein cows, were a welcome respite to those who have been working outside in temperatures nearing 100 degrees in the past week. Thursday, June 24, the day of the social, was the hottest day of the week.

UD alumna Corryn Barnes, currently a science teacher in Harrington, is working her second summer with Extension IPM Specialist Joanne Whalen. Barnes enjoyed the break in her outside duties and for the opportunity to relax.

“This was the perfect day for a nice summer treat,” Barnes said. “It’s very nice to get together with the different departments and meet people you normally don’t get to meet. Are they going to have it again?”

That seemed to be the question on everyone’s mind. The general consensus among the 60 or so in attendance was the hope that the ice cream social would be repeated often during the summer. Some even suggested once a week would be ideal.

“I’ll take that into serious consideration,” Isaacs said, with a wink.

For photos of the ice cream social visit the REC’s Flickr page by clicking here.

Article by Michele Walfred

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