Influence of Seasonal incidence and Defoliation Degree of Marssonina Blotch on Fruit Quality and Shoot Growth of 'Fuji'/M.9 Apple Tree

Abstract

Abstract. This study investigated the influence of seasonal incidence and defoliation degree caused by Marssonina blotch (Diplocarpon mali Harada et Sawamura) on shoot growth and fruit quality of 'Fuji'/M.9 apple tree. The occurrence of marssonina blotch in Gunwi region was observed from the mid of July 2009, and percentage of defoliation was about 10% in the end of October. In 2010, that started in the early of June. By the end of September, percentage of defoliation was 20% and it reached 50% in late October. Secondary growth of terminal shoot in 2010 was three times as much as that in 2009. In 2009, the soluble solid contents and the red color (hunter a value) during fruit maturation increased to 13.8 °Brix and 16.2, respectively. In 2010, the soluble solid content during fruit maturation remained in the 12.1-12.6 °Brix range after early October, and the red color began to increase after the end of September when the percentage of defoliation was 20%. As for fruit quality by defoliation degree, the red color decreased when defoliation percentage of bourse shoot at the end of October was more than 30%. Fruit weight and soluble solids also decreased when defoliation percentage was more than 50%. Fruit length and diameter of over 30% defoliation treatments begun to decrease after the middle of August, compared with those of under 30% defoliation treatment. Photosynthetic rate of the leaves that was located at the secondary growth of bourse shoot was similar to that of leaves which was located at the middle of bourse shoot. However, the size and the soluble solid content of fruit were not affected by photosynthesis activities of bourse shoot leaves which was develop in the secondary shoot growth.

Vegetative Growth, Productivity, and Fruit Quality in Tall Spindle of ‘Fuji’/M.9 Apple Trees

“…1A) 으로 해석된다 (Park et al, 2013;Sagong et al, 2011). 반면 재식 8년차에는 세장방추형의 낙엽률이 키큰방추형보다 높 았음에도 불구하고 (Fig.…”

“…반면 재식 8년차에는 세장방추형의 낙엽률이 키큰방추형보다 높 았음에도 불구하고 (Fig. 1B), 과중 및 과실품질의 차이가 없 었던 것 (Tables 3 and 4)은 세장방추형의 과실수가 키큰방추 형보다 10개 정도 적으면서 신초생장은 더 왕성하였던 결과 (Tables 2 and 3)를 미루어보아, 과실수 및 신초생장에 따른 과실품질 증감현상 (Choi et al, 2009;Marini et al, 2002;Yoon et al, 2005)이 낙엽에 따른 과실품질 감소현상 (Park et al, 2013;Sagong et al, 2011) Table 5).…”

An Empirical Assessment of the Economic Damage Caused by Apple Marssonina Blotch and Pear Scab Outbreaks in Korea

“…The damage function parameters for each disease were identified by using regional data derived from the Rural Development Administration (RDA) for the period of 2010 to 2012. Marssonina blotch causes early defoliation in apple trees; thus, the resultant damages to the fruit are associated with quality and weight reduction [28][29][30]. By contrast, pear scab not only affects the leaves and flowers of pear trees but also damages the fruit [31,32].…”

State of Knowledge of Apple Marssonina Blotch (AMB) Disease among Gunwi Farmers

“…Favorable conditions for infections include 23.5°C and 20 mm of rain; for disease development a daily temperature of 25°C and 20 mm of rain are required (Park et al, 2013). Fuji and Golden Delicious apples are highly susceptible to AMB (Yin et al, 2013).…”

“…The quality of the apple fruit is also affected by the decrease in starch content instigated by the decreased photosynthetic rates of the diseased leaves (Sagong et al, 2011). The weight of an apple from an infected tree also has a 22.6-30% decrease (Park et al, 2013). Even though the leaf has fallen from the tree, the fungus continues to sporulate on the surface of the leaf, and the spores can spread by the wind and infect healthy trees (Jacobi, 2013 …”