Landscape Contractor / Design Build Maintain

AUG 2012

LC/DBM provides landscape contractors with Educational, Imaginative and Practical information about their business, their employees, their machines and their projects.

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Virus Attacks Kansas City- Area Roses Above: Fire blight is a contagious tree disease caused by a bacterial infection (Erwinia amylovora) that makes flowers, shoots and leaves appear scorched. The disease has destroyed whole orchards in a single growing season. Plant Diseases A ! BACTERIAL INFECTION CALLED hFIRE BLIGHTv AND AN AN THRACNOSE FUNGUS HAVE INFESTED SOME -ISSOURI TREES AIDED BY A COOL AND WET SPRING &IRE BLIGHT BACTERIA IS NAMED FOR THE BURNT OUT APPEAR ANCE IT CAUSES IN FOLIAGE !PPLE CRAB AND "RADFORD PEAR TREES ARE SUSCEPTIBLE TO THE BACTERIA n TYPICALLY SPREAD BY BEES DURING POLLINATION n AS WELL AS 2OSACEAE PLANTS LIKE COTONEASTER HAWTHORN AND SPIREA 0RUNING INFECTED BRANCHES IS THE BEST DEFENSE AS PESTICIDES AND ANTIBIOTICS CAN HELP BUT CAN ALSO CREATE TREATMENT RESISTANT STRAINS )N CONTRAST ANTHRACNOSE PRIMARILY AFFECTS ASH OAK SYC AMORE AND MAPLE TREES 7ARMER WEATHER SHOULD TURN THE FUNGUS DORMANT BUT LANDSCAPERS SHOULD DISPOSE OF INFECTED LEAVES TO LIMIT SPREAD AND TREAT TREES WITH FUNGICIDE EARLY NEXT SPRING TO LIMIT FURTHER OUTBREAKS WORKS AS FUNGICIDE s !DD v LAYER OF MULCH NOT TOO MUCH s 2EMOVE AND DESTROY ANY INFECTED PLANTS s 3TERILIZE TOOLS SHOES AND HANDS TO PREVENT DISEASE SPREAD Left: Anthracnose fungus causes discoloration and premature leaf drop in various shade tree species including maple, oak, elm and walnut. Yearly infections will cause reduced growth, less shade and a weakened tree susceptible to further injury. Impatiens Downy Mildew Found in Louisiana Left: Characteristics of impatiens downy mildew include discoloration of the upper leaf and downy mildew growth on lower leaf surfaces. )MPATIENS DOWNY MILDEW A SCOURGE OF SUMMER BED DING PLANTS ACROSS THE NORTHERN 5NITED 3TATES HAS MADE ITS FIRST APPEARANCE IN ,OUISIANA )NFECTED PLANTS WERE TRACKED TO TWO DIFFERENT NATIONAL CHAIN STORE GARDEN CEN TERS SUPPLIED BY WHOLESALERS FROM TWO NEIGHBORING STATES 4HE MILDEW APPEARS AS A GRAY DISCOLORATION ON NEW GROWTH OR A YELLOWING OR DOWNWARD CURL OF THE LEAVES !IRBORNE DISEASE SPREADING SPORES BREED ON THE UNDERSIDE OF INFECTED LEAVES AND APPEAR AS A WHITE POWDERY GROWTH &REQUENT OVERHEAD IRRIGATION CAN SPREAD THE PATHOGEN IF OVERHEAD IRRIGATION IS UNAVOIDABLE EXPERTS RECOMMEND WATERING IN THE MORNING SO THE LEAVES CAN DRY QUICKLY )MPATIENS walleriana ARE MOST SUSCEPTIBLE TO THE MILDEW WHILE .EW 'UINEA IMPATIENS ARE TOLERANT HOWEVER THE LATTER STRAIN IS LESS HEAT TOLERANT AND ARE MORE PRONE TO ROOT ROT )F MILDEW IS DISCOVERED FALLEN LEAVES AND INFECTED PLANTS IN THE IMMEDIATE VICINITY SHOULD BE UPROOTED AND DESTROYED AS SYMPTOMS MAY NOT SHOW FOR UP TO TWO WEEKS 10 LC DBM wet spring and changing weather conditions in the first half of the year can lead to a variety of airborne diseases that can be unsightly, if not deadly, to local plants and trees. Fire Blight & Anthracnose Fungus Hits Missouri Trees Prevention Tips s 0LANT DISEASE RESISTANT STRAINS LIKE 2OSA "ANKSIAE +OREAN $OGWOOD 7ESTERN 2ED #EDAR s 0RUNE AND OR TRIM STEMS TO INCREASE CIRCULATION s 3PRAY WITH BAKING SODA MIXTURE Above: Experts recommend digging out and destroying plants infected with rose rosette, since the disease is nearly incurable. Rose rosette is lethal to many rose species, including those usually disease-resistant. ,ANDSCAPERS IN +ANSAS AND -ISSOURI ARE BATTLING ROSE ROSETTE A VIRUS THAT INFECTS ROSE PLANTS AND IS CURRENTLY INCURABLE !T LEAST FOUR ROSE BEDS ALONG TRAFFIC ROUTES AND OUT SIDE CITY BUILDINGS IN /VERLAND 0ARK NEAR +ANSAS #ITY -O HAVE BEEN REMOVED DUE TO THE VIRUS AND SOME HOME GARDENS HAVE ALSO BEEN AFFECTED 3YMPTOMS VARY DEPENDING ON THE ROSE INFECTED AND EXPERTS RECOMMEND DIGGING OUT AND DESTROYING INFECTED PLANTS SINCE THE MITES THAT SPREAD THE VIRUS ARE WIND BORNE #ONTAMINATED PRUNING SHEARS CAN ALSO SPREAD THE DISEASE AND MITICIDES ARE ONLY MARGINALLY EFFECTIVE AS THE MITES BURROW DEEP INTO THE ROSE S TISSUES Disease Keys Fire Blight: s 7ILTED BURNT LOOKING LEAVES s "LACKENED BRANCH TIPS Anthracnose Fungus: s ,ESIONS ON LEAVES WHERE WATER COLLECTS s $ISCOLORATION AND DETACHMENT FROM TREE Rose Rosette: s 2EDDENED FOLIAGE s %XCESSIVE THORNS s 5NCONTROLLABLE STEM GROWTH Impatiens Downy Mildew: s 'RAY DISCOLORATION ON NEW GROWTH s 9ELLOWING OR CURLING LEAVES s 7HITE POWDERY GROWTH ON UNDERSIDE OF LEAVES

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