International Journal of Plant Protection

C. M. Ginoya ¹, N. M. Gohel ¹

Affiliations
1 Department of Plant Pathology, B.A. College of Agriculture, Anand Agricultural University, ANAND (GUJARAT), IN

Abstract

Cultural and morphological variability studies on seven different media viz., potato dextrose agar, host leaf extract agar, host fruit extract agar, oatmeal agar, Richards' agar, Czapek's Dox agar and Rose Bengal agar revealed considerable variation among the isolates of A. alternata indicated the existence of variability in the pathogen. Moreover, Oatmeal agar and potato dextrose agar were found as an excellent media to support the growth and spore formation of isolates of A. alternata, respectively. In case of isolates, Ahmedabad isolate (Aa-7) (61.90 mm) and Rajkot isolate (Aa-8) (61.71 mm) were at par in supporting the mycelium growth and Anand isolate (Aa-1) supports the sporulation abundantly. Among eight isolates of A. alternata, distinct differences in terms of conidial length, breadth, beak length and number of septa were recorded. The average conidial length varied from 16.93 to 59.24 μm and breadth ranges from 6.90 to 14.98 μm with beak length of 3.25 to 44.07 μm. The transverse and longitudinal septa varied from 2 to 10 and 0 to 4, respectively. In the present studies, glaring differences in conidial size were noticed among the isolates even when same medium was used for the growth of the isolates. It can be assumed that variation in the isolates may be inherent since isolates were collected from diverse agroclimatic zones of Gujarat. Hence, these variations in the conidial size indicated the existence of variability in this pathogen.

Keywords

Alternaria alternata, Fruit Rot, Chilli, Capsicum annum, Cultural And Morphological Characterization.

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C. M. Ginoya ¹, N. M. Gohel ¹

Affiliations
1 Department of Plant Pathology, B.A. College of Agriculture, Anand Agricultural University, ANAND (GUJARAT), IN

Abstract

Among the ten newer fungicides evaluated under in vitro condition by poisoned food technique against Alternaria alternata revealed tebuconazole, hexaconazole and azoxystrobin (18.2%) + difenconazole (11.4%) at all the three concentrations (500, 1000 and 1500 ppm) completely inhibited the mycelial growth of the pathogen and proved to be most effective. Based on in vitro screening, five promising fungicides were selected and reevaluated under field condition against fruit rot of chilli and the result revealed that two foliar application of tebuconazole (50%) + trifloxystrobin (25%) (75 WP) @ 0.05 per cent at an interval of 15 days, commencing from the initiation of disease was most effective in reducing fruit rot intensity and increasing fruit yield over control. Tebuconazole which was found effective under in vitro but could not reduce fruit rot intensity effectively under field conditions.

Keywords

Fungicides, Alternaria alternata, Fruit Rot, Chilli, Capsicum annum, in Vitro, In Vivo.

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