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  • Author or Editor: P.S. McManus x
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Studies were conducted in 1988 and 1989 to evaluate the influence of planting time and method on plant establishment and yield of fall broccoli. In 1988, plant establishment of direct-seeded broccoli was not improved with application of vermiculite (63 kg/ha). a cross-linked polyacrylamide polymer (17 kg/ha), or both as anti-crustants over the untreated check (37.6%, 32.2%, 24.6%, and 31% of target population, respectively). In 1989, transplants were compared with double-seeding (planting two seeds 25 mm apart). With seed. germination of 55% in the early planting (8 Aug.). plant populations of double-seeding and transplants were similar, but 42% germination of double-seeding in the late planting (28 Aug.) resulted in lower plant populations than from transplants. While yield reflected differences in plant populations, the percentage of marketable heads from transplants was significantly greater (90.6%) than from seedlings (78.9%). These data suggest that broccoli transplants are a viable option when high soil temperatures may be detrimental to seed germination.

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The effectiveness of a disease-warning system and efficacy of reduced-risk fungicides for management of sooty blotch (Peltaster fructicola, Leptodontium elatius, Geastrumia polystigmatis) and flyspeck (Schizothyrium pomi) (SBFS) of apple (Malus × domestica) were evaluated in Illinois, Iowa, and Wisconsin in 2001 and 2002. Warning system-timed applications of the second-cover fungicide spray occurred when 175 h of leaf wetness had accumulated; wetness data were derived either from a sensor placed beneath the canopy of apple trees (on-site) or according to remotely sensed estimates. In replicated experiments, using sensor measurements as inputs to the warning system saved one to three (mean 1.8) and zero to four (mean 2.3) fungicide sprays per season in 2001 and 2002, respectively. Because remotely estimated wetness hours accumulated more rapidly than did on-site measurements, the warning system using remotely sensed wetness data saved only zero to one (mean 0.3) and zero to two (mean 0.7) sprays per season in 2001 and 2002, respectively. SBFS incidence in the integrated pest management (IPM) plots did not differ significantly from that of conventional calendar-based fungicide sprays plots in 11 of 12 site-years. When on-site wetness measurements were used in demonstration trials at 14 cooperating commercial orchards in 2001 and 2002, the SBFS warning system saved one to six (mean 2.6) and two to seven (mean 3.1) sprays per season, respectively. Incidence of SBFS in IPM plots did not differ significantly from trees managed with cooperating growers' conventional fungicide schedules in 16 of 28 siteyears. The on-site warning system was more consistently successful in Illinois and Iowa than it was in Wisconsin in both replicated experiments and in cooperating commercial orchards. The reduced-risk fungicides kresoximmethyl and trifloxystrobin provided control of SBFS equal to conventional fungicides (benomyl or thiophanatemethyl) in all trials. Potassium bicarbonate controlled SBFS less effectively than either conventional fungicides on a calendar-based or disease-warning schedule, or treatments incorporating reduced-risk fungicides.

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