Morphology and Phylogeny of Lyophylloid Mushrooms in China with Description of Four New Species.

The lyophylloid agarics are a group of ecologically highly diversified macrofungi, some of which are very popular edible mushrooms. However, we know little about lyophylloid species diversity in China. In this study, we described four new species from China: Lyophyllum atrofuscum, L. subalpinarum, L. subdecastes, and Ossicaulis sichuanensis. We conducted molecular phylogenetic analyses of Lyophyllaceae based on the nuclear ribosomal RNA gene (nLSU) and the internal transcribed spacer regions (ITS). Phylogenetic analyses by the maximum likelihood method and Bayesian inference showed that the four new species are unique monophyletic species. A key to the species of Lyophyllum from China and a key to Ossicaulis worldwide were given.

Density and seasonal dynamics of Bemisia tabaci and its predators in different agricultural landscapes in South China.

Bemisia tabaci is the main pest of agriculture in many regions of the world. The resistance of whitefly to pesticides has increased as a consequence of the continuous irrational use of wide-spectrum pesticides. Thus, pesticides are no longer always effective as a long-term control method. The agricultural landscape can affect the occurrence of an insect population. The objective of this study was to clarify the occurrence of whitefly and its predators in tomato fields in different agricultural landscapes. Different landscapes are classified into urban, flower, water, and mountain landscapes by the principal component analysis method. In 2018-2019, whitefly had the longest main activity period and the lowest density in the flower landscape. The water landscape helped to maintain the highest densities of whitefly during the main activity period. Nine species of predators were sampled, and Nesidiocoris tenuis, Chrysoperla sinica, Menochilus sexmaculata, and Harmonia axyridis were the dominant species throughout the sampling season in both years. During the main activity period, N. tenuis had the highest density in all sampled landscapes. The density of the dominant predators was the highest in the flower landscape, and each natural predator had the largest temporal niche width in the 2-year sampling period. Bemisia tabaci, N. tenuis, and M. sexmaculata were highly synchronized temporally. The flower landscape showed satisfactory results in suppressing whitefly. Increasing the proportion of flowering plants and increasing the diversity of plant crops in the agricultural landscape can effectively reduce the densities of whitefly during an outbreak.

Flowering agricultural landscapes enhance parasitoid biological control to Bemisia tabaci on tomato in south China.

Agricultural landscape pattern may enhance biocontrol services by supporting parasitoid populations, including parasitoids of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). In this study, we selected four landscape types in Yunnan province, in south China, which were characterized by flower fields, mountain, river, and urban areas as their main elements. We then carried out systematic surveys in tomato fields found within each landscape type, to determine the diversity, occurrence, and parasitism rate of parasitoids. We found that parasitoids from the genus Encarsia and Eretmocerus were the main natural enemies present, and the most abundant species were recorded in the flower and the mountain landscapes. Also, Encarsia formosa (Hymenoptera: Chalcidoidea) formed the highest relative abundance regardless of the landscape type. We also found that the population density of B. tabaci in flower landscapes was the lowest than that in other landscape types. During the main activity period of B. tabaci, the parasitism rate in the flower landscape was higher than that in other landscape types. Our findings showed that the occurrence of B. tabaci was relatively mild in the flower landscapes. The landscape type was also beneficial to parasitoids as it enhanced their parasitism rate. Therefore, agriculture environmental schemes should consider increasing the size of flower fields in the surrounding landscape to enhance the sustainable control of B. tabaci by the natural agricultural ecosystem.

Regulation of dynamics and densities of whitefly Bemisia tabaci by agricultural landscapes in south China.

Agricultural landscape patterns can affect the population dynamics of pest insects. We selected four landscapes (flower field, mountain, river and urban) based on principal components analysis in Yunnan Province, south China. Through systematic investigation carried out in tomato fields, we intended to clarify the population dynamics and densities of Bemisia tabaci under different landscape types. During the main activity period of B. tabaci, the population densities of B. tabaci nymphs in tomato fields in the river and the urban landscape types were the highest compared to the other landscape types; the population densities of female adults in tomato fields in the river landscape type were also the highest. While the population densities of B. tabaci nymphs and female adults in the flower landscape type, no more than five individuals (ind.) 100 cm-2 leaf in both years, were the lowest. The density of B. tabaci nymphs in the middle position of tomato plants was higher than those in the other positions, while the density of adults in the upper position of tomato plants was higher, regardless of landscape types. Our findings showed that the population growth of B. tabaci can be easily controlled by the flower landscape type.