How to cut moss losses by pvb52213


TURF                  TALK
                                              How to cut moss losses
                                                                What's the latest on            Cook's applications all took place
                                                                moss control? We           between October and May. The high
                                                                have the worst prob-       iron applications did not injure turf, but
                                                                lem in September on        they reduced moss infestations.
                                                                our greens, and this            Copper toxicity is a problem where
                                                                year looks as bad as       repeat treatments are made for more
                                                                usual.                     than one year at rates in excess of 0.2
                                                                                           pound of copper per 1,000 square feet
                                                              About two years ago, the     per application. The result is spots simi-

                                              A               dish detergent Dawn Ultra
                                                              was credited with killing
                                                              off moss on greens (even
                                                              though the product is not
                                                              labeled for that use). But
                                              Oregon State University researchers
                                                                                           lar to dollar spot.
                                                                                                "You also get a shortened root system
                                                                                           so as soon as you get heat stress, your
                                                                                           grass starts to wilt," Cook says. But at
                                                                                           copper rates of 0.1 and 0.15 pound per
                                                                                            1,000 square feet, turf wasn't damaged.
                                              couldn't get the same result with the             "If you try the copper stuff, remem-
                                              detergent.                                   ber you want copper hydroxide, you do
                                                  "It actually increased the percentage    not want copper sulfate and you do not
                                              of moss over time," says Tom Cook,           want zinc sulfate;' Cook warns. "We did
                                              associate professor of horticulture. "I      an excellent job killing grass with both
                                              think people are going out with spot         of those."
                                              squirt guns and they're just blasting it,         Cook's best moss control           has
                                              so Lord knows what their rates are.          occurred with the fatty acid H02.
                                              When we took published rates ... we               "With the fatty-acid materials we've
                                              didn't control any moss, we just injured     been able to get 100 percent control with
                                              the turf."                                   as little as two to three applications,"
September can be a bad month for moss             Some superintendents       recommend     Cook said. "The weak link right now is
infestations.                                                                              spray volumes. We're looking at some-
                                              spot applications of moss with Dawn
                                              Ultra under full sunlight at tempera-        where between 12 and 75 gallons per
                                              tures between 55 and 80 F.                    1,000 square feet with a drench."
                                                  Infestations of greens-type moss              The H02 treatments caused a slight
                                              (Bryum argenteum) get worse through-         yellowing of the turf. That could be
                                              out summer and are worst in fall, Cook        remedied with iron, however.
                                              says. He has found other products that            "What we have actually started doing
                                              kill moss in creeping bentgrass (Agrostis     is: We alternate a fatty-acid treatment
                                              palustris) at "astronomical" application     with an iron treatment," Cook says.
                                              rates:                                            "We're in the preliminary stages of all
                                              • Ferric sulfate or ferrous sulfate           this, so don't go home and try this on
                                                 applied five to seven times at 0.2        your home greens."
                                                 pound of iron per 1,000 square feet,
                                                 every two weeks.                                       -   Mark Kind, GCM technical editor
                                              • Copper hydroxide (with or without
                                                 Mancozeb) applied five to seven times
                                                 at 0.1 or 0.2 pound of copper per
                                                 1,000 square feet, every two weeks .
                                              • H02 (a proprietary fatty acid salt)
                                                 applied three times at 15 to 20 ounces
                                                 of active ingredient per 1,000 square     Contact Turf Talk c/o Information Services, 1421
                                                 feet every two weeks.                     Research Park Drive, Lawrence, KS 66049-3859, or
                                                                                           mention Turf Talk in an e-mail message to
                                                  "You wouldn't put two-tenths of a Questions are also taken from the
                                              pound of iron on in a whole year in a        members' discussion forum on GCSAA's Web site
                                              normal sequence;' Cook says.                 ( or generated by GeM editors.

48   Golf Course Management   •   September   2000

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