Abstract
An in 'fro evaluation of the fungitoxicity of various fungicides against As-cochyta rabiei revealed Sunlate, Topas C-50, Dithane M-45, Rizolax, Daconil and Pencozeb to be the most effective, in that order, in inhibiting rnycelial growth of the fungus. Foliar application of fungicides to field grown gram plants revealed Topas C-SO and Daconil to be the most effective in reducing gram blight ratings, the effec-tiveness of former being better than that of the latter.
INTRODUCTION
In gram (Cicer arielinion L. with the present low yield level, the best way of con-trolling gram blight disease, caused by As-cochyta rabid (Pass.) Lab. is through the use of cultivars which possess durable resistance (Reddy, 1980). Efforts to develop gram cul-tivars resistant to blight infection, either through conventional breeding methods or through mutation breeding procedures, are on their way in Pakistan. Although these efforts have consequently led to the devel-opment of some partially resistant cultivars (liaq et al., 1981; Anon, 1986), still it will be a long way to follow when durable resistance against gram blight disease will be achieved and incorporated into our commercial gram cultivars. Until gram cultivars with durable resistant to gram blight disease are devel-oped, fungicidal control of the disease is an alternative possibility which will help either to avoid crop losses or to produce, at least, disease-free healthy seed for the next season crop. In view of this, some of the available fungicides were evaluated for their corn par-ative effectiveness against the gram blight disease.
MATERIALS AND METHODS
In-vitro evaluation or Fungicides: The com-parative fungitoxicity of each of the eleven fungicides was evaluated by poisoned food technique. A weighed quantity of each fungicide was amended into autoclaved gram seed meal agar (GSMA) to obtain 5,10,20 and 50 Agiml concentrations. GSMA without fungicide served as the con-tml, The composition of GSMA was:
Gram flour Dextrose Agar agar Distilled water
20g 20 20 up to 1000 tril
Twenty millilitres of the amended and non-amended medium was poured in each of the four 90 mm diameter petriplates. Af-ter the agar medium was solidified, 6 mm agar plugs containing A. rabiei mycelium were cut from a 25-day-old GSMA culture plate, using sterile cork borer and placed in the centre of petriplates. The inoculated petriplates were incubated at 22 ± 2 C and radial growth (mm) of the fungus was recorded alter 21 days of incubation.
