sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

SDÜ ORMAN FAKÜLTESİ DERGİSİ
June 30. On each date, the number of leaves per twig was assessed, and twigs were
sprayed until runoff with each treatment (up to 5 mL per twig, but depending on
the number of leaves and leaf sizes). A plastic board was held behind each twig
while spraying to prevent overspray onto other twigs. There were nine chemical
treatments and a water control (Table 1).
Table 1: Treatments applied to 2 m tall maple trees at the Guelph Turfgrass Institute,
Guelph, Ontario, Canada, in Spring 2008 for control of tar spot.
Treatment Common Name Product/ L
Water control water 0 ml
Banner MAXX propiconazole (15.6%) 0.245 mL
Compass 50WG trifloxystrobin (0.16%) 0.175 g
Daconil Ultrex chlorothalonil (82.5%) 1.5 g
Dithane DG mancozeb (75%) 3 g
Eagle WP (Nova) myclobutanil (40%) 0.34 g
Heritage WG azoxystrobin (50%) 0.3 g
Rovral Green GT iprodione (25%) 10 mL
Senator WP thiophanate-methyl (70%) 1 g
Sulfur sulfur (92%) 10 g
The number of spots per leaf was assessed weekly from the start of the trial
until the end of June, and then assessed monthly until the end of September. The
morphology and phenological state of the maple leaves was also recorded during
each assessment.
3. RESULTS AND DISCUSSION
As observed in previous years (Hsiang & Tian 2008), the first symptoms of tar
spot on Norway maple in Southern Ontario appeared in late June as small, round,
light green, chlorotic spots, 2 mm across. Spots enlarged to 15 mm by mid-August,
and developed small black tar-like raised structures on the adaxial surface with a
yellow margin. Conidia, which are considered non-infective and possibly
spermatizing, appeared as a shiny layer on the black stroma at this time. By early
September, the individual spots merged into a circular black spot up to 2 cm across.
Overwintered Norway maple leaves collected in March 2007 and 2008, had
stroma, paraphyses and asci (56-80 µm × 8.5-10.6 µm), but no ascospores were
visible. By the middle of April, the asci were still undifferentiated, but were found
to contain globular vacuoles or bodies. The asci became swollen as spores
developed, and filiform ascospores were first observed in early May, averaging 55
× 2.0 µm. By late May, after soaking in water, slits in the hysterothecia (modified
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