• The Plant Pathology Journal
• /
• v.37 no.1
• /
• pp.24-35
• /
• 2021

Blue mold caused by Penicillium expansum is one of the most significant postharvest diseases of apples. Some microorganisms associated with the surface of ripening apples possess the ability to inhibit the growth of P. expansum. However, the existing literature about their colonization in the stages before ripening is not explored in depth. This study aims to characterize the antagonistic capacity of bacterial populations from five fruit development stages of 'Royal Gala' apples. The results have shown that the density of the bacterial populations decreases throughout the ripening stages of fruit (from 1.0 × 105 to 1.1 × 101 cfu/㎠). A total of 25 bacterial morphotypes (corresponding to five genera identified by 16S RNA) were differentiated in which Bacillus stood out as a predominant genus. In the in vitro antagonism tests, 10 Bacillus strains (40%) inhibited the mycelial growth of P. expansum from 30.1% to 60.1%, while in fruit bioassays, the same strains reduced the fruit rot ranging from 12% to 66%. Moreover, the bacterial strains with antagonistic activity increased in the ripening fruit stage. B. subtilis subsp. spiziennii M24 obtained the highest antagonistic activity (66.9% of rot reduction). The matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis revealed that bacteria with antagonistic activity produce anti-fungal lipopeptides from iturin and fengycin families.

• Journal of the Korea Society for Simulation
• /
• v.30 no.2
• /
• pp.41-48
• /
• 2021

As the rural population continues to decline and aging, the improvement of agricultural productivity is becoming more important. Early prediction of crop quality can play an important role in improving agricultural productivity and profitability. Although many researches have been conducted recently to classify diseases and predict crop yield using CNN based deep learning and transfer learning technology, there are few studies which predict postharvest crop quality early in the planting stage. In this study, a early quality prediction model is proposed for sprout ginseng, which is drawing attention as a healthy functional foods. For this end, we took pictures of ginseng seedlings in the planting stage and cultivated them through hydroponic cultivation. After harvest, quality data were labeled by classifying the quality of ginseng sprout. With this data, we build early quality prediction models using several pre-trained CNN models through transfer learning technology. And we compare the prediction performance such as learning period and accuracy between each model. The results show more than 80% prediction accuracy in all proposed models, especially ResNet152V2 based model shows the highest accuracy. Through this study, it is expected that it will be able to contribute to production and profitability by automating the existing seedling screening works, which primarily rely on manpower.

• Research in Plant Disease
• /
• v.29 no.4
• /
• pp.390-398
• /
• 2023

Apple white rot, caused by Botryosphaeria dothidea, is one of the important diseases in Korea. B. dothidea can cause pre- and postharvest decay on apple fruit as well as canker and dieback of apple trees. In this study, we isolated bacteria from the trunk of apple trees and tested their antagonistic activity against B. dothidea. Five bacterial isolates (23-168, 23-169, 23-170, 23-172, and 23-173) were selected that were most effective at inhibiting the mycelial growth of the pathogens. The isolate 23-172 was identified as Bacillus amyloliquefaciens and four isolates 23-168, 23-169, 23-170, and 23-173 were identified as Bacillus velezensis by RNA polymerase beta subunit (rpoB) and DNA gyraseA subunit (gyrA) gene sequencing. All isolates showed strong antagonistic activity against B. dothidiea as well as Colletotrichum fructicola and Diaporthe eres. All isolates exhibited cellulolytic, proteolytic and phosphate solubilizing activities. In particular, two isolates 23-168, 23-169 were shown to significantly reduce the size of white rot lesions in pretreated apple fruits. These results will provide the basis for the development of a fungicide alternative for the control of white rot of apple.

• The Korean Journal of Pesticide Science
• /
• v.13 no.3
• /
• pp.148-158
• /
• 2009

We tested and selected some agrochemicals reducing the occurrence of major pests and diseases during garlic storage. Tebuconazole, diphenylamine and prochloraz as fungicides and dimethate as a insecticide were sprayed or drenched before harvest. And the harvested garlic was dipped in each of the agrochemicals. The residues of pesticides in garlic bulbs treated were analyzed every month from harvesting time for 6 months. In case of Danyang garlic, which was treated with pesticides before and after harvesting, the residues of diphenylamine, tebuconazole, prochloraz, and dimethoate ranged from 0.008 to 0.28, from 0.03 to 0.32, from 0.02 to 0.12, and from 0.02 to 0.25 mg/kg, respectively. In case of Uiseong garlic, the residues of diphenylamine, tebuconazole, prochloraz and dimethoate ranged from 0.008 to 0.09, from 0.08 to 0.45, from 0.02 to 0.57, and from 0.04 to 0.38 mg/kg, respectively. And, in case of Namdo garlic, the residues of diphenylamine, tebuconazole, prochloraz, and dimethoate ranged from 0.008 to 0.52, from 0.07 to 1.67, from 0.02 to 0.17, and from 0.03 to 0.73 mg/kg, respectively. Some of the garlic samples treated with tebuconazole exceeded its maximum residue limits (MRLs) of 0.1 mg/kg set by Korea Food Drug Administration (KFDA), but dimethoate was detected below its MRL of 1.0 mg/kg. In case of diphenylamine and prochloraz, their MRLs for garlic were not set. Adapting their MRLs, 5.0 mg/kg of diphenylamine for apple and pear and 0.5 mg/kg of prochloraz for strawberry and grape, residue levels of diphenylamine and procloraz were below than their MRLs, with the exception of samples two times treated with procloraz in Namdo garlic. These results indicate that dimethoate can be used as an agrochemical to control the postharvest disease in garlic in only MRL aspect.