| The strawberry, Fragaria ananassa Duch has been one of the most favorable fruits since it has aroma volatiles, sweet taste and full of vitamine C. Especially during the annual Chinese Spring Festivals, a time gap of fresh fruit supply, strawberry fruit becomes high-grade goods for celebrations. In order to fill the strawberry market, the production of strawberry has been developing fastly recently, bringing a large number of strawberry and a lot of job opporunities. At the mean while, the high intensive production has been significantly reduced by the disease and insect pests, such as the gray mold Botrytis cinerea, green peach aphid Myzus persicae (Sulzer), whitefly Bemisia tabaci (Gennadius), Spodoptera litura (Fabricius) and so on. It will be more efficient to take measures against the disease and insect pests if we fully understood the occurrence of the dominant pest species with their dynamic communities.In this study, the sticky yellow boards together with randomly strawberry plant sampling method were used to investigate the composition and seasonal dynamics of biodiversity of arthropod community in plastic screenhouse strawberry (Fragaria ananassa Duch.). The seasonal population dynamics of the main insect herbivores, predators, parasitoids and detritivores were described. The spatial distribution patterns of some key insect pests were specially surveyed and analysed, and finally, the field sampling criterions for forecast purpose for three main insect species were proposed. The main results are summarized as follow:1. The investigation on arthropod community in plastic greenhouse strawberry showed that the arthropod biodiversity indices, the numbers of species and individuals were higher in Autumn and Spring, with main peaks around the end of October. Shannon-Wiener H' index, Evenness and Simpson index fluctuated in a small range. Most of the arthropods sampled were herbivores, accounting for 47.6 % of the total individuals, and the natural enemy the least (about 10%). The whitefly Bemisia tabaci (Gennadius), the western flower thrip Frankliniella occidentalis Pergande and the green peach aphid Myzus persicae (Sulzer) were the dominant species in the community through the whole strawberry season.2. The population dynamics of the insects could be classified as 3 patterns: mono-peak patterns in early-season aroung Autumn and in late-season around Spring, respectively, and di-peak pattern in early- and in late-season. The whitefly Bemisia tabaci (Gennadius), the green peach aphid Myzus persicae (Sulzer) had a typical mono-peak pattern in early-season, the Frankliniella occidentalis showed as a typical mono-late-peak pattern. While some of non-straberry feeders, e.g. Laodelphax striatellus, and aphid-predators, etc., showed as di-peak pattern, corresponding to the migration activitiy, and host aphid abudance in the Automn and Spring, respectively. The seasonal population dynamics of the dominant species in both northern and southern greenhouse were similar in some way, although the absolute density differed significantly. In the northern strawberry greenhouse, there were a large number of whitefly Bemisia tabaci (Gennadius) in greenhouse C and green peach aphid Myzus persicae (Sulzer) and Tetranychus kanzawai in greenhouse A.3. The common cutworm Spodoptera litura (Fabricius) has been one of the most destructive insect pests in the early stage of plastic greenhouse strawberry in Zhejiang, China. To understand the spatial distribution pattern of S. litura in the strawberry field, the densities of the small larvae, the middle-large larvae, damaged leaves were exclusively sampled in the transplanted strawberry greenhouse field. Three methods of aggregated indices, Taylor's power law and Iwao's regression analysis of M-m were used to test the distribution patterns. The results showed the small larvae, the number of damaged leaves and the percentage of damaged leaves belong to the aggregated distribution, while the middle-large larvae belong to either random distribution or even distribution.4. The spatial distribution pattern of the green peach aphid Myzus persicae (Sulzer) in the transplanted greenhouse strawberry field was investigated and the rusult showed that the nymphs together with the adult aphids performed as aggregated distribution pattern. While analysed with spatial autocorrelation analysis, there was little distinctive relationship to spatial location. In order to better understand the distribution of the green peach aphid, the spatial density map was drawn using the Kiriging input values and several high-density centers were discovered.5. On the basis of long-term seasonal sampling and investigation, the population sampling criterions for forecast of Myzus persicae (Sulzer), Tetranychus kanzawai Kishida, and Spodoptera litura (Fabricius) were proposed. The main components in the sampling criterions include the sampling plans and methodologies on densities of nymphs/larvae and adults, damage ranking, data recording forms, data-importing, analysis and auto-reporting.
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