Walnut (Juglans regia L.) is a very important and appreciated species from the group of nuts for fruits rich in nutritional principles (minerals, vitamins, fats and so on). Bacteriosis (Xanthomonas juglandis) is one of the main diseases of the walnut. The present study used image analysis methods to evaluate the degree of bacterial attack on walnut leaves. The total leaf area (TLA), healthy leaf area (HLA) and affected leaf area (ALA) were determined. For image analysis, the Scan Sick & Healthy Leaf application, made in Processing with Java code lines Java, was used. There were analyzed 15 case studies, represented by walnut leaflets with different degree of bacteriosis attack. The single factor ANOVA test was used to evaluate the variance in the experimental data set. PAST software was used for statistical analysis. The total leaf area (TLA) studied ranged from 35.89 cm2 in sample 4 to 92.35 cm2 in sample 7. The healthy leaf area (HLA) ranged from 29.85 cm2 for sample 14 to 90.13 cm2 for sample 7. The area affected by bacterial attack (ALA) varied between 0.26 cm2 in case of sample 1 and 9.24 cm2 in case of sample 15. The healthy leaf area (HLA) as a percentage, compared to the TLA, recorded values between 81.24% (sample 14) and 99.58% (sample 1). The leaf area affected by bacteriosis (ALA) recorded percentage values between 0.42% (sample 1) and 18.76% (sample 14). The relation that accurately described the distribution of ALA values against HLA values (%) is given by a linear equation, under conditions of R2 = 1, p << 0.001, which indicates a very high accuracy of determining the two types of surface ( HLA, ALA) in relation to the total surface of the studied leaves. The Scan Sick & Healthy Leaf application can be extended to evaluate other attacks by plant pathogens, at different plant species, cultivated or in spontaneous flora.

bacteriosis, Java, leaf area, Processing, walnut, Xanthomonas

environmental engineering

Presentation: oral