Phellinus noxius (P. noxius) is an important pathogen that causes brown root rot of trees in tropical and sub-tropical areas and has led to severe damage to trees. A quick and accurate diagnostic technique is essential to the timely confirmation of the pathogen and possible treatment. In this study, a fast, sensitive and accurate approach of molecular technique was used to diagnose the brown root rot pathogen on trees and in soils of subtropical Hong Kong. Two pairs of specific PCR primers were used to amplify the target rDNA internal transcribed spacer (ITS) region through polymerase chain reaction (PCR) for both tree tissues and soil samples. The amplified ITS fragments were then sequenced and analyzed phylogenetically for the diagnostic identification of the pathogen P. noxius. The results showed that 13 of 38 suspected trees in Hong Kong were infected with P. noxius through molecular detection. The pathogen showed no specific preference to any particular tree species. Quantitative PCR was applied to soils grown with trees identified both positive and negative for P. noxius, but the soils with healthy trees were also found positive for P. noxius. For the first time, P. noxius was reported to infect a wide range of tree species in Hong Kong and widely presented in soils, probably serving as a reservoir for the pathogen. Through this study, it is proposed that P. noxius is a soil-borne pathogen, which increases its infectivity when trees start to grow in the soil as a means in addition to the previously proposed root-to-root contact.

Apolygus lucorum is currently a major pest of tea plantations, affecting the normal growth of tea shoots and reducing yield and quality. This study measured the effect of damage by A. lucorum alongside mechanical damage using UV spectrophotometry and high performance liquid chromatography. We found that the nutritional characteristics of tea varied with the level of bug damage, which influenced levels of caffeine, theanine, and tea polyphenols. As damage increased, caffeine content gradually increased. In contrast, theanine levels in highly damaged leaves were reduced compared to other levels of damage. The polyphenol level, like caffeine, increased with increasing damage. The levels of five other substances-Epigallocatechin, Catechin, Epigallocatechin gallate, Epicatechin, and Epicatechin gallate were all higher in tea with higher damage. Damage from A. lucorum changed the chemical profile of the tea, caused tea water turbidity, taste bitterness and decreased freshness, leading to the tea quality decline.