.

Field evaluation of fungicides against alternaria porri (Ellis) Cif., causing purple blotch of Onion ( Allium Cepa l. )

Table 3 Field evaluation of fungicides against purple blotch of onion – pooled analysis

PDI

Yield t/ha

Treatment

% decrease

% increase

Pooled mean

B:C

over control

Captan 50% WP

45.21

21.63

24.11

16.64

6.26

Chlorothalonil 75% WP

40.98

28.96

30.81

49.06

14.15

Copper oxy chloride 50% WP

41.22

28.55

26.59

28.64

9.85

Mancozeb 70% WP

27.18

52.88

39.71

92.09

33.85

Propineb 70 WP

39.04

32.33

30.13

45.78

16.25

Difenconozole 25% EC

43.89

23.93

27.62

33.63

9.27

Triademorph 80% EC

37.02

35.83

31.80

53.85

20.91

Hexaconozole 5% SC

44.65

22.60

26.60

28.69

12.31

Propiconozole 25% EC

43.72

24.22

27.88

34.87

12.48

Pyraclostrobin 6.7% + Dimethomorph

31.81

44.86

33.31

61.16

7.23

12% WG

Pyraclostrobin 5% + Metiram 55% WG

31.22

45.89

34.62

67.50

7.90

Cymoxanil 8% + Mancozeb 64%

26.04

54.86

37.06

79.27

20.67

Metalaxyl-M 4% + Mancozeb 64% WP

32.43

43.79

34.82

68.47

17.51

Control

57.69

20.67

Discussion

effective against A. alternata causing leaf blight of

The fungal diseases are spreading rapidly and are

groundnut (Kantwa et al. , 2014). Chlorothalonil and

becoming epidemic in many crops due to changing

Mancozeb were effective in reducing the leaf blight

environment. Fungicides are capable of controlling

caused by A. alternata causing Chrysanthemum

the disease; however indiscriminate use of fungicides

leaf blight (Arun Kumar et al. , 2011) and both were

builds resistance in pathogen and necessitates the

recommended for purple blotch (Gevens 2011).

evaluation of new molecules to combat disease.

Chatage and Bhale (2011) showed the effectiveness of

Alternaria blight disease severity varies with the

Mancozeb and Chlorothalonil against A. pluriseptata

micro-climatic conditions at the particular location.

incitant of IVY ground fruit. Mancozeb was reported

Application of fungicides at critical stages of 45 and

as highly effective fungicide in the management of

75 days after sowing has been reported to minimise

purple blotch of onion (Chethana and Kachapur

losses due to the disease and increase benefit for the

2010, Shahnaz, 2013). Meena et al. , (2011) proved

users (Meena et al. , 2004).

the efficacy of Mancozeb in a multi-location trial in

different states of India against Alternaria blight in

The effectiveness of Captan was noticed against

Indian mustard. It was effective against A. tenuis

purple blotch disease of onion (Sharma, 1986),

(Begum et al., 2010), A. solani (Chaudhary et al. ,

A. cassia on cowpea seed (Noelani et al. , 2002) and

2010, Gondall et al. , 2012), A. alternata (Kantwa et al. ,

A. brassicae (Khan et al. , 2007). Effectiveness of

2014). The effectiveness of Mancozeb against several

Chlorothalonil in the management of purple blotch

Alternaria species is in accordance with the present

of onion was reported and recommended as foliar

work. Gholve et al. , (2012) reported Mancozeb

application at fortnightly interval (Abhinandan et al. ,

as least effectiveness of against A. macrospora

2004). These works are in agreement with our studies.

affecting cotton, which is in contrast with our work.

In contrast, Captan and Chlorothalonil were least

Wickramaarachchi et al. , (2004) stated Propineb