ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 101, No. 1 (2014), p. 101–108
Control of ascochyta blight (Ascochyta complex) in pea under Lithuanian conditions
Rūta Česnulevičienė, Irena GAURILČIKIENĖ, Jūratė RAMANAUSKIENĖ
During the period 2008–2010, in different soil and climate conditions: 1) in Middle Lowland of Lithuania in Dotnuva, 2) in Southeast Lithuania in Perloja, experiments were conducted to investigate the peculiarities of ascochyta blight control using seed treatment and fungicide application. Commercial seed from the same lot of the pea variety ‘Pinochio’ was sown in Dotnuva and Perloja. Two seed treatment agents – Raxil extra (a.i. tebuconazole + thiram 15 + 500 g l-1) in a dose rate 2.0 l t-1 and Kinto (a.i. triticonazole + prochloraz 20 + 60 g l-1) 1.5 l t-1 and two fungicides applied at flowering – Signum (a.i. boscalid + piraclostrobin 267 + 67 g kg-1) 1.0 kg ha-1 and Bravo (a.i. chlorothalonil 500 g l-1) 3.0 l ha-1 were used.
Ascochyta blight severity was significantly reduced by pea seed treatment and/or by fungicide application at flowering stage. The values of the area under disease progress curve (AUDPC) of ascochyta blight in the fungicide-applied plots in most cases were significantly lower in Dotnuva compared with those in Perloja. The frequency of detection of the pathogens of Ascochyta complex on pea pods and grain depended on the level of ascochyta blight incidence on plants. With rising infection level, the frequency of detection of pathogens both on pods and grain increased. In Perloja, the fungi of Ascochyta complex on grain were detected in all experimental years, while in Dotnuva only in 2010. The grains of pea crops spray-applied with the fungicides Signum and Bravo in two years out of three were less infected with the pathogens of Ascochyta complex, compared with those from the unsprayed plots. Pea grain yield increments resulting from the use of seed treatment and fungicide application were inconsistent in both experimental sites. It was noted that the values of productivity indicators, 1000 grain weight (TGW) and pod number per plant were higher for the Raxil extra seed-treated plots spray-applied with the fungicides Signum and Bravo; in separate years these values significantly differed from the untreated/unsprayed. In Perloja, in 2008, a significant negative correlation was established between the AUDPC values of ascochyta blight and pod and grain number per plant (P ≤ 0.01), and grain weight per plant and TGW (P ≤ 0.05). Low correlation coefficients were obtained in Dotnuva because of lower ascochyta blight infection there.
Key words: ascochyta blight, Ascochyta complex, AUDPC, fungicides, Pisum sativum, yield.
Full text: 101_1_str14.pdf