Sk. Sugha et al., EFFECT OF HEAT-TREATMENT OF BULB AND SPRAY OF FUNGICIDES IN MANAGEMENT OF PURPLE BLOTCH NALTERNARIA-PORRI) OF ONION (ALLIUM-CEPA), Indian Journal of Agricultural Sciences, 63(5), 1993, pp. 303-305
An experiment was conducted during winter seasons (rabi) of 1989-90 an
d 1990-91 to study the effect of heat treatment of bulbs alone and in
combination with a spray of metalaxyl + mancozeb (Ridornil MZ) for the
control of purple blotch [Alternaria porri (Ellis) Cif.] of onion (Al
lium cepa L.). Heat treatment to onion bulbs at 35-degrees-C for 8 hr
before sowing followed by single prophylactic spray of metalaxyl + man
cozeb @ 0.25% at bolting stage or only 3 sprays of metalaxyl + mancoze
b @ 0.3% at 15-day intervals (from the appearance of disease) gave the
most effective control of purple-blotch disease. Heating of bulbs at
40 and 45-degrees-C reduced the crop growth. Spray of metalaxyl + manc
ozeb @ 0.3% proved superior to those of copper oxychloride 0.25%, capt
afol 0.2% and mancozeb 0.25%.