You'll have a better chance of getting a beautiful and disease-free poinsettia, mum, or begonia in a few years as scientists get a fresh view of the world of horticultural pests. 
Armed with space-age technology similar to that used to photograph the surface of Mars, agricultural scientists are peering into the surface topography of nursery crop leaves to see what pesticides and biological control organisms work best. But instead of a NASA mission control center, this work is emanating from the newly created Molecular and Cellular Imaging Center. The center-a joint venture between ARS and Ohio State University (OSU)-has four of the newest generations of microscope: two types of scanning electron microscope, a transmission electron microscope, and a confocal laser scanning microscope that produces three-dimensional fluorescent images. The microscopes have digital imaging features originally developed for telescopes and cameras in the space program to study the surface of planets and their moons. The center also houses a DNA high-throughput sequencer, so scientists can perform genetic and molecular studies. These advanced microscopes and related equipment allow Krause and colleagues to peer closely into the ecology of the leaf surfaces of plants, a world inhabited by fungi and bacteria good and bad. Krause views fungicides, bactericides, insecticides, and herbicides flowing through the waxy peaks and valleys of the leaf surface, just as water flows on planet Earth. The scientists are tracking pesticides to see whether they reach the underside of plant leaves, where diseases and other pests tend to begin their attack. The plant samples come from the many Ohio commercial nurseries and greenhouses that Krause and colleagues work closely with. The capabilities offered by the new center will help the scientists better assess how well a particular pesticide is reaching the pest, how uniform the pesticide application is, and how well the sprayers and other applicators are working. Krause agrees: "We'll be seeing things we could only infer before." He's already used the microscopes to see the spores of the fungus that causes apple scab disease as they emerge from crabapple leaf surfaces. And next to the spores he has seen crystals of a fungicide that controls those spores. Once the spores emerge, they spread by being blown in the wind; washed off by rain or irrigation; or brushed off by insects, animals, or people. Krause has also seen gray mold disease up close. Caused by Botryis cinerea L., it's a common disease that is costly to greenhouse producers. Infecting fruits, flowers, and trees, gray mold looks like gray fuzz and is found on aging blossoms and soft ripe fruits. It first attacks dead or dying plant parts, then moves to the healthy parts. When infected flowers or leaves are plucked, a grayish-white cloud of fungal spores can usually be seen. 
These are just two of the many fungal or bacterial pests that rob a fair share of the nursery and floriculture industry's returns of $12 billion a year¡ªone of the fastest growing areas of U.S. agriculture. They are also the pests that can brown up a golf green and destroy precious landscape plants, not to mention corn, soybeans, wheat, and other major food crops. The new scanning electron microscopes and related equipment offer the scientists an opportunity for much greater magnification-up to 450,000 times, compared to 75,000 times for conventional scanning electron microscopes. e plants that beautify our homes and neighborhoods. 


