Abstract
Using bioassay and fluorescent tracer techniques it was demonstrated that more fungicide was retained on mature leaves of summer salad onion crops if 1 kg/ha iprodione wettable powder (w.p.) formulation plus wetting agent was sprayed at 280 1/ha than at 560 1/ha or 1120 1/ha.The lowest spray volume (280 1/ha) with four sprays of iprodione w.p. (0.5 kg in October, November, December and January) gave effective control of Botrytis cinerea and significantly increased plant stand and yield. More fungicide was required to obtain equivalent results using a mixed programme of two thiram (4 kg/ha total) and two iprodione w.p. (2 kg a.i./ha total) sprays at the same application volume and intervals. Where the mixed programme was applied at 1 1 20 1/ha, 1 2 kg a.i. (total fungicide) was necessary to achieve equivalent disease control.At 280 1/ha, retention and persistence of iprodione on onion foliage was greater with the oil‐based than with the wettable powder formulation. In summer especially this resulted in improved Botrytis control and greater numbers of marketable onions. In winter onions, oil and w.p. formulations were equally effective and gave equivalent improvements in plant stand and yield.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call