[Investigation of infestation of Carpoglyphus lactis in stored jujube from Anhui Province].

OBJECTIVE: To investigate the breeding of Carpoglyphus lactis in stored jujube from Anhui Province, so as to provide the evidence for preventing the harm of C. lactis to stored jujube. METHODS: The jujube samples stored for more than 6 months were collected from dried fruit shops and/or Chinese herbal medicine warehouses, which were chosen as survey sites in Anhui Province. The mites were isolated and identified under a microscope. RESULTS: Totally 19 samples infested with C. lactis were obtained from 300 samples in 17 cities of Anhui Province, the breeding rate and breeding density of C. lactis were 6.33% and 6.52 per gram respectively. The constituent ratios of different developmental stages were adult 85.72%, larva 12.27%, dormancy body 0.56%, and egg 1.45%, respectively. CONCLUSIONS: The breeding density of C. lactis in the stored jujube is high and the species diversity is rich, so the control of C. lactis and the prevention of human acariasis should be strengthened.

Use of CLSA and SPME-headspace techniques followed by GC-MS analysis to extract and identify the floral odorants.

Flowers of Ziziphus spina christi are known to be attractive for parasitoids and predators. In Y-tube olfactometer experiments, the dried flowers attracted significantly (p < 0.001) the female parasitoids Aphelinus abdominalis. The flower volatile compounds were analyzed to understand which compounds could be specifically responsible for this attractiveness. The volatile compounds of Ziziphus flowers were extracted by closed-loop-stripping-analysis (CLSA) and also by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis. The main chemical classes of the volatile compounds are aldehydes, monoterpene-alcohols, ketones and hydrocarbons. Flower extract and some specific compounds will be further tested for their responsiveness to predators and parasitoids in behavioural and electrophysiological experiments.

[Population structure and niche of main scale insects in jujube orchards intercropped with wheat].

To effectively control the scale insects in jujube orchards, a field study was made on the population structure and niche of Pseudococcus comstock Kuwane, Ceroplastes japonicus Green and Quadraspidiotus perniciosus Comstock in the jujube orchards intercropped with wheat in Taigu area of Shanxi Province. The results showed that at the early development stage of jujube trees, these three kinds of scale insects mainly distributed on the southeast direction of the lower and central parts of the tree crown, and P. comstock was the dominant species, with a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects. At the mid-stage of jujube trees development, these scale insects mainly distributed on the northwest direction of the upper part of the tree crown, C. japonicus had a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects, and the niche proportional similarity and interspecific competition of the three kinds of scale insects were not obvious. At the later stage of jujube trees development, there was no significant difference (P > 0.05) in the population structure of the three kinds of scale insects on the different parts and directions of tree crown, but the density of Q. perniciosus was bigger, and C. japonicus had a wider breadth of two-dimensional temporal-spatial niche. The average values of niche proportional similarity and interspecific competition of the three kinds of scale insects were smaller (P < 0.05) at the later development stage of jujube trees. Therefore, P. comstock should be controlled at the early development stage of jujube trees, all the three kinds of scale insects should be controlled selectively at the mid-stage of jujube trees development, and their overwinterings should be decreased by all means at the later development stage of jujube trees.

[Functional groups of natural enemies and their temporal-spatial dynamics in jujube orchard intercropped with herbage].

In this paper, an investigation was made on the temporal-spatial dynamics of the functional groups of natural enemies in the jujube orchard 2.5 km west of Taigu (112 degrees 8'E, 38 degrees 9'N, 780 m elevation), Shanxi Province in 2002, aimed to work out an effective strategy to control the pests there. In this orchard, four management modes were applied, i. e., intercropping herbage combined with integrated pest management (IPM), intercropping combined with conventional pest management (CM), intercropping with no pest management (NM), and non- intercropping (CK). The results indicated that the total number of natural enemies in IPM, CM and NM was 187.99%, 151.82% and 210.03% higher than CK, respectively, and the recovery and reconstruction rates as well as the average breadth and overlap indices of two dimensional temporal-spatial niches of the functional groups were higher in intercropping modes than in CK. The average diversity index of the functional groups in intercropping modes was significantly bigger than that in CK, but the fluctuation of the diversity standard error of the functional groups was significantly smaller (P < 0.05). The fluctuation trends of the dominance, diversity, and evenness of functional groups had a significant correlation (P< 0.01) with those of species. These results showed that intercropping herbage in jujube orchard was favorable to the conservation, proliferation, and making use of natural enemies. The natural enemy's community in jujube orchard intercropped with herbage was more stable than that without intercropping, and the numbers and functions of the functional groups were differed with different management modes and different stages. Among the functional groups of natural enemies, ladybirds had a stronger ability of recovery, while spiders and parasitoids were weaker. It was feasible to use functional groups instead of species to study the natural enemy's community in jujube orchard.

Community structure and its dynamics of pest, predatory and neutral insects in a jujube ecosystem.

An investigation on the insects in the jujube ecosystem in Taigu District of Shanxi Province, Northern China showed that more species and individual numbers of pest, predatory and neutral insects were found on the tree than on the ground. The ratio of the species and individual numbers of predatory and neutral insects to those of pest insects fluctuated from year to year. Homoptera, Coleoptera and Lepidoptera were the dominant groups of pest insects, while those of predatory insects were Coleopteran, Hemiptera, Diptera and Hymenoptera. The vertical distribution of the community structure of the same or different subcommunity was different in different seasons, as was the case of the same or different subcommunity in the same season. The diversity indexes of pest, predatory and neutral insects fluctuated with seasons, and the populations of predatory and neutral insects had a significant correlation (r = 0.9833, P <0.05) with the fluctuation of pest insects. There was also a significant correlation between the pest, predatory and neutral insects in different stratums of tree canopy, especially in the middle stratum of tree canopy (r = 0.9887, P <0.01).

[Insect community and its relationship with Ceroplastes japonicus occurrence in jujube orchards].

Employing community character indices and canonical correlation analysis, this paper studied the insect communi structure and its relationship with the occurrence degree of Ceroplastes japonicus in jujube orchards. The results showed that based on the community discrepancy coefficient of 0.20, the insect community in various sampling fields could be categorized into two groups, i. e. , plain and hill. The occurrence of C. japonicus in plain region was heavier, with lower insect community diversity, smaller species number, and higher dominance of phytophagous insects, while that in hill region was lighter, with higher insect community diversity, more abundant species, and higher dominance of natural enemy insects. Canonical correlation analysis indicated that at the significant level of 0.05, the first and second pairs of canonical correlation coefficients of C. japonicus occurrence characters and insect community characters were 0. 9904 and 0.8538, respectively, suggesting that the occurrence of C.japonicus was significantly correlated with the characters of insect community. Community diversity (with the coefficient of 3. 4893), species number (with the coefficient of 5.8060), and dominance (with the coefficient of 6.9353) had most important effects on the occurrence of C. japonicus.

[Community structure and its dynamics of predatory arthropod in jujube orchards intercropped with different herbage species].

By using community structural characteristic indices and principal component analysis, this paper studied the community structure and its dynamics of predatory arthropod in the jujube orchards intercropped with Astrugalus complanatus, Trifolium repen, Lotus comiculotus, and Medicago sativa. The results showed that in all test jujube orchards, spider and predatory insects were the predominant components of the predatory arthropod community, and their relative abundances were 48.3% - 52.7% and 38.8% - 44.4% , respectively. There were significant differences (P < 0.05) in the mean density, diversity, and evenness of the most common predatory arthropod groups in the jujube orchards intercropped with different herbage species, with the sequence of intercropped with Lotus comiculotus > Medicago sativa > Astrugalus complanatu > Trifolium repens, but for dominant concentration index, the sequence was intercropped with Trifolium repens > Astrugalus complanatu > Medicago sativa > Lotus comiculotus. The average density of predatory spiders was significant higher (P < 0.05) than that of predatory insects in all test jujube orchards. The individuals of Coccinellidae, Pentatomidae, inoccllidae, Chrysopidae, Thomisidae, Araneidae and Phytoseiidae played the dominant role in the community.

[Spatial distribution pattern and space dependence of Contarinia sp. and Erigonidium graminicola in jujube orchard].

With the principles and methodologies of geostatistics, this paper studied the spatial structure and space dependence of Contarinia sp. and its natural enemy Erigonidium graminicola in a jujube orchard at different date. The results indicated that the semivariogram of Contarinia sp. on 8 June, 27 August and 19 October could be described by spherical model, showing an aggregated spatial distribution with the ranges of spatial dependence being 26.3, 7.8 and 22.0 m, and the degrees of spatial dependence being 88.05%, 85.77% and 87.58%, respectively. The semivariogram of Erigonidium graminicola could be also described by spherical model, showing an aggregated distribution with the ranges of spatial dependence being 28.3, 22.5 and 22.2 m, and the degrees of spatial dependence being 90.09%, 87.96% and 85.72%, respectively. It is suggested that Erigonidium graminicola is the dominant natural enemy against Contarinia sp. population in the examined jujube orchard.

[Community succession patterns of pests and natural enemies in jujube orchard ecosystem].

Through investigation and by the methods of optimal partitioning, principal component analysis, and one-or two-dimensional ordination, this paper analyzed the main groups and succession trends of the pest and natural enemy communities at a jujube orchard of Taigu area. The results showed that the communities had more obvious dominant factors and temporal succession pattern. The first three principal components of the communities had a bigger variation, with an obvious follow effects. The community succession was temporally divided into four stages, i. e., in the periods of pre-budding, leaf expanding and blooming, fruiting, and maturing. The dominant species of pests and their natural enemies were demonstrated.

[Arthropod community structure and its fuzzy clustering analysis in jujube orchard].

Based on the principles of community ecology and by the method of fuzzy clustering, this paper studied the temporal and quantitative dynamics of the arthropod community and sub-community in jujube orchard (Feidong 2003), aimed to utilize natural enemy resources for pest control. There were 52 species of arthropod belonging to 47 families in the orchard. Arachnida and Cecidomyidae had a higher relative abundance than other families being 0.3465 and 0.2309, respectively. The individuals of the arthropod community were the highest on 8 June and 21 September. The total community and pests-neutral insect sub-community could be clustered into 4 clusters, respectively. For total community, the clusters (T = 0.92) were those on 22 March, 6 April, 22 November, and on other dates, and for pests-neutral insect sub-community, they (T = 0.94) were those on 22 March, 6 April, 8 June, and on other dates. The natural enemy sub-community could be clustered into 3 clusters (T = 0.94), i. e., those on 22 March, on 6 April, and on other dates. The results of cluster analysis partly reflected the seasonal differences of total community and sub-community, while the temporal overlaps of cluster results reflected the complexity of community structure.