Messenger - Vol. 4, No. 3, Page T-1
On Technology
Planting new ideas

     At the touch of a button, Agricultural Sciences Prof. John
Frett's computer screen displays a full-color photograph of a red
maple tree in all its glory. Another click of the button calls up a
page of text describing the tree's botanical name (acerubrun), leaf
structure and other characteristics. With one more click, Frett's
computerized database of plants even offers help for those who can't
pronounce acerubrun: "a-cer-RU-brun," the computer says, providing the
proper pronunciation in a synthesized voice.
     Along with the red maple tree, Frett's database-known as the
University of Delaware Botanical Gardens Hypermedia Map-now describes
more than 200 plants. Anyone who uses the Internet can take an
electronic 'tour' of the gardens.
     An associate professor of horticulture, Frett developed the
database, with help from research associate Betsy Mackenzie, because
he wanted to provide students and the general public with information
about plants growing in the UD's Botanical Gardens. He also wanted to
give students greater access to the photographic slides of plants he
regularly shows during his classes. Horticulture instructors typically
maintain vast libraries of slides and other images, Frett explains.
Unfortunately, he adds, students often have only one opportunity to
view each slide in the classroom.
     "Our whole society is image-based," Frett says. "For a lot of
students, if they can just store an image of a plant in their memory,
that's worth 15 minutes of rote memorization. Images stored in a
database give students a quick way to review essential information
about plants."
     Frett and Mackenzie are still adding images to the database by
converting slides into digital data that can be stored on a compact
disc and then fed into a computer. Ultimately, Frett's database may
include enough images and facts to describe up to 1,700 plants.
     Frett also is working with Dewey Caron, professor of entomology
and applied ecology, to incorporate information on insects into the
database. "It would be great if we could show what insects affect each
plant," he says.
      Another computerized database helps University students learn to
diagnose plant diseases by studying images and electron micrographs
accompanied by text. Stored on a videodisc, the database-created by
Thomas A. Evans, associate professsor of plant pathology, with
associates at the University of Massachusetts and Clemson University
and funding from the U.S. Department of Agriculture-contains almost
10,000 images of plant diseases and pathogens.
     Images of powdery mildew, for example, show how this plant
disease appears on such common hosts as roses, vegetables and turf
grass. Beneath an image of a begonia afflicted with powdery mildew,
text points out that "the fungus obtains its nutrients from the plant
by sending haustoria into epidermal cells." And, if a student is still
confused, a built-in glossary explains that an haustorium is a
"specialized absorptive structure of a parasite." Another, more
detailed image shows the student how powdery mildew might look through
a microscope's lens.
     Students probably won't learn to diagnose every possible plant
disease by studying videodisc images, Evans says. But, they should
begin to recognize the basic categories of plant diseases-including
those caused by fungi, nematodes, parasites, bacteria, viruses and
abiotic (non-biological) agents. Compared to a faculty member's
personal collection of slides, Evans adds, the videodisc offers
students a broader range of information. High-quality slides for the
videodisc were contributed by plant pathologists at universities
throughout the country and by the American Phytopathological Society
     "After our students graduate, they might go to work in Malaysia
or California or Florida," Evans says. "We don't want to train them to
work only in limited crop disciplines. We want them to work
productively in any geographical region of the world."
     Copies of Evans' videodisc may be borrowed for individual study
at workstation computer laboratories maintained by the College of
Agricultural Sciences. Prof. Robert B. Carroll makes use of the
videodisc for classroom presentations, too. "Plant pathologists have
traditionally been forced to fumble through stacks and stacks of
slides and try to bring into the classroom whatever live materials
were available," says Carroll. "The videodisc makes a greater number
of slides available to students many more hours each day. This has
been especially helpful in introductory plant pathology and diagnostic
plant pathology lectures and labs."