Many small, pen-sized papaya side shoots were formed after injecting a BA/GA, solution into the bases of stems of one-year old plants of the 30-year old clone `Honey Gold', followed by topping the stems a day later. Standing small leafy cuttings in various fungicidal solutions for 10 or 30 minutes resulted in phytotoxic basal burn, whereas a short immersion gave good results. Benlate® and Folicur® were best, especially with the addition of paclobutrazol. There is a distinct seasonal variation in the rooting of cuttings, with those that have been exposed to cold winter conditions giving poorest results. For best results (95% rooting in 4 weeks in perlite with intermittent mist), stock plants are maintained in a protected environment, especially in cool weather. Uniform side shoots, are harvested regularly, leaving stubs to produce new shoots, while maintaining enough leaf canopy.
Peter Allan and Bridgette Hazelhurst
Peter Allan, Alan George, and Robert Nissen
Low chill `Flordaprince' peach trees were grown in subtropical Australia, either following paclobutrazol application to dwarf the trees, or extra nitrogen to invigorate them. Fruits were thinned uniformly. Paclobutrazol significantly reduced the competing spring shoot growth and gave earlier maturity of larger, better quality fruits. It reduced the spring, but increased the autumn root flush. Stage 2 of fruit growth was slightly longer in vigorous trees, resulting in delayed seed growth and greater dry mass of the embryos. Starch reserves were greatest in the roots, followed by the trunk, shoots and leaves. The reserves were lowest during the second half of fruit development, but rose again after the end of shoot extension growth. Leaf N, P, and K levels decreased through the season while Ca and Mg increased. There were significantly lower K and higher Ca and Mg levels in dwarfed trees.
Darren E. Robinson, Nader Soltani, Allan S. Hamill, and Peter H. Sikkema
Combining herbicides and fungicides can improve production efficiency; however, there is little information on the effect of these mixtures on weed control and processing tomato crop response. Six field trials were conducted from 2002 to 2004 in Ontario to study the effect of rimsulfuron and thifensulfuron applied alone or in combination with metribuzin and with or without chlorothalonil or copper fungicides on processing tomato. There was no visual injury or reduction in marketable yield of processing tomato with rimsulfuron or thifensulfuron alone or when tank-mixed with chlorothalonil or copper hydroxide. Rimsulfuron, thifensulfuron, rimsulfuron plus metribuzin, and thifensulfuron plus metribuzin could be tank-mixed with chlorothalonil without a reduction in weed control. However, efficacy of rimsulfuron and thifensulfuron were reduced when tank-mixed with copper hydroxide. The reduction in weed control incited by adding copper hydroxide was overcome with a low rate (150 g·ha–1 a.i.) of metribuzin for thifensulfuron but not rimsulfuron. Application of rimsulfuron and thifensulfuron alone or with low rates of metribuzin and chlorothalonil could provide tomato growers with a single-pass treatment for the control of troublesome weeds and diseases.
Cheryl-Ann L. Corbett, Nader Soltani, Allan S. Hamill, Peter H. Sikkema, Stephen Bowley, and Darren E. Robinson
Trials were conducted over 2 years at three locations in Ontario to determine the tolerance of three sweet corn hybrids to postemergence application of nicosulfuron (25 and 50 g·ha–1), bromoxynil (280 and 560 g·ha–1), and nicosulfuron plus bromoxynil (25 + 280 g·ha–1 and 50 + 560 g·ha–1). All hybrids showed injury 7 days after treatment (DAT). The crop largely recovered from the injury in most treatments, as indicated by the ratings completed 14 and 28 DAT. However injury from the tankmix of nicosulfuron plus bromoxynil at both rates still appeared to be synergistic at 7, 14, and 28 DAT. Visual injury, height reductions and yield loss in the nicosulfuron plus bromoxynil (50 + 560 g·ha–1) treatment were more severe than in the other herbicide treatments. Yield of BSS5362 was significantly decreased in the nicosulfuron (50 g·ha–1) and nicosulfuron plus bromoxynil (50 + 560 g·ha–1) but was not affected by any other herbicide-hybrid combination. Caution must be exercised when using this tankmix combination, as there is potential to cause significant visual injury, height reductions and yield loss.