1993 Vol. 6, No. 4
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1993, 6(4): 351-357.
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Abstract:
The algorithms of estimating competition index was divided into two groups according to its competition tree searching regimen, and one of them was improved. Then, two new searching algorithms were created, which operate well for stand with various spatial patterns. Introducing an independent index system makes a computer model restructured easily. With new and improved algorithm, a system can get a stand growth simulation done in a dramatically shorter time than it used to. One of the staggering problems, unendurable of implementing time, which had been an obstacle to the application of individual tree model, was overcome. The equations were provided to access extra RAM demand and calculate the implementing time.
The algorithms of estimating competition index was divided into two groups according to its competition tree searching regimen, and one of them was improved. Then, two new searching algorithms were created, which operate well for stand with various spatial patterns. Introducing an independent index system makes a computer model restructured easily. With new and improved algorithm, a system can get a stand growth simulation done in a dramatically shorter time than it used to. One of the staggering problems, unendurable of implementing time, which had been an obstacle to the application of individual tree model, was overcome. The equations were provided to access extra RAM demand and calculate the implementing time.
1993, 6(4): 358-367.
Abstract:
Through measurements of above-ground biomass production and 10 nutrition elements' accumulation in four types of man-made treerrattan mixed plantations (the age of trees and rattan are 18-year-old and 5-year-old respectively) and a pure plantation of Calamus tetradactylus Hance. The results showed that the total above-ground biomass yield is 164.849,164.844,170.195, 98.864 and 16.234 t/ha respectively for the type I to V; and the biomass of the trees accounts for over 92%,rattan for 2%~4%, and litter for 2%~5% in the tree-rattan plantations. The contents of nutrition elements in different organs of tree, rattan and litter vary in different species for specific element. The total amount of the tested 10 elements are 1 977.78, 2 142.54, 1778.21 and 989.36 kg/ha respectively for the types I to IV, among them, 82%~90% distributed in the tree layer, 4%~6.5% in rattan, and 5%~12% in litter compared with the distribution of biomass, rattan and litter have higher percentages in nutrition contents. The amount of nutrition elements required for an unit dry matter production and the ratio of nutrition returning back to the soil vary in different types of stands. In type I to V, the total amount of the 10 nutrition elements required for producing a ton of dry matter is 11.999,12.999,10.449,10.008 and 23.974 kg/ha respectively. The ratio of nutrition elements returning to the soil is 30.3%, 39.3%,30.3%, 54.4% and 92.1% respectively.
Through measurements of above-ground biomass production and 10 nutrition elements' accumulation in four types of man-made treerrattan mixed plantations (the age of trees and rattan are 18-year-old and 5-year-old respectively) and a pure plantation of Calamus tetradactylus Hance. The results showed that the total above-ground biomass yield is 164.849,164.844,170.195, 98.864 and 16.234 t/ha respectively for the type I to V; and the biomass of the trees accounts for over 92%,rattan for 2%~4%, and litter for 2%~5% in the tree-rattan plantations. The contents of nutrition elements in different organs of tree, rattan and litter vary in different species for specific element. The total amount of the tested 10 elements are 1 977.78, 2 142.54, 1778.21 and 989.36 kg/ha respectively for the types I to IV, among them, 82%~90% distributed in the tree layer, 4%~6.5% in rattan, and 5%~12% in litter compared with the distribution of biomass, rattan and litter have higher percentages in nutrition contents. The amount of nutrition elements required for an unit dry matter production and the ratio of nutrition returning back to the soil vary in different types of stands. In type I to V, the total amount of the 10 nutrition elements required for producing a ton of dry matter is 11.999,12.999,10.449,10.008 and 23.974 kg/ha respectively. The ratio of nutrition elements returning to the soil is 30.3%, 39.3%,30.3%, 54.4% and 92.1% respectively.
1993, 6(4): 368-372.
Abstract:
The dynamics of sap flow in space and time in stem was studied by heat pulse technique in 2- and 6-year-old poplar plantation (Populus deltoides Bartr. cv. "Lux" ex. I-69/55) in Yinan County,Shandong Province in 1991. The research has revealed that the sap flow occurred in the sapwood of the stem. The sap flow velocity of the same annual ring is similar, but it varied obviously along the diameter direction. The sap flow velocity of the outer ring is higher than that of inner ring in daytime. The sap flow changes with meteorological factors and forms a curve with a widen peak. The quantity of sap flow in stem per hour is 3~6 L/h in 2-year-old tree and 20~35 L/h in 6-year-old tree. The sap flow volume in the stem per day is 13.6~22.8 L/d in 2-year-old tree and 89.2~152.6 L/d in 6-year -old poplar.
The dynamics of sap flow in space and time in stem was studied by heat pulse technique in 2- and 6-year-old poplar plantation (Populus deltoides Bartr. cv. "Lux" ex. I-69/55) in Yinan County,Shandong Province in 1991. The research has revealed that the sap flow occurred in the sapwood of the stem. The sap flow velocity of the same annual ring is similar, but it varied obviously along the diameter direction. The sap flow velocity of the outer ring is higher than that of inner ring in daytime. The sap flow changes with meteorological factors and forms a curve with a widen peak. The quantity of sap flow in stem per hour is 3~6 L/h in 2-year-old tree and 20~35 L/h in 6-year-old tree. The sap flow volume in the stem per day is 13.6~22.8 L/d in 2-year-old tree and 89.2~152.6 L/d in 6-year -old poplar.
1993, 6(4): 373-379.
Abstract:
The water cycling of hydrological processes of Phyllostachys pubescens Mazel ex H. de Lehaie plantation is analyzed in this paper. Precipitation and its allotting amount in the system and its seasonal changes are studied. The results show that: throughfall and stemflow in P. pubescens plantations increased with the increase of precipitation. There is an index relation between the canopy interception and precipitation. The annual canopy interception ratio of P. pubescens plantation is 11.1%, stemflow latio is 4.4%. The root system of P. pubescens has a greater effect on soil physical properties. As for the soil layer of o~60cm, the total porosity is 71.7%, final infiltration ratio 8.28mm/min. The yearly runoff ratio in the researched watershed 54.8%,surface runoff only 0.8%,interflow ratio 15.0% and underflow 39.0%, it demonstrates that there is a fairly good effect of water consevation in P. pubescens plantations.
The water cycling of hydrological processes of Phyllostachys pubescens Mazel ex H. de Lehaie plantation is analyzed in this paper. Precipitation and its allotting amount in the system and its seasonal changes are studied. The results show that: throughfall and stemflow in P. pubescens plantations increased with the increase of precipitation. There is an index relation between the canopy interception and precipitation. The annual canopy interception ratio of P. pubescens plantation is 11.1%, stemflow latio is 4.4%. The root system of P. pubescens has a greater effect on soil physical properties. As for the soil layer of o~60cm, the total porosity is 71.7%, final infiltration ratio 8.28mm/min. The yearly runoff ratio in the researched watershed 54.8%,surface runoff only 0.8%,interflow ratio 15.0% and underflow 39.0%, it demonstrates that there is a fairly good effect of water consevation in P. pubescens plantations.
1993, 6(4): 380-389.
Abstract:
This paper presents the results of a resource inventory of rattan species in China from 1985 to 1990. It is recognized that in China there are 40 species and 21 varieties belonging to 3 genera, 4 species of Plectocomia Mart; 36 species and 21 varieties of Calamus Linn, and 1 species of Daemonorops Blume, which are distributed over southern China from south-east coast to southwest mountainous areas and Taiwan, Hainan and some islands. This paper not only deals with the geographic distribution of the species and their numbers and characteristics of the plant flora but also briefly discusses the status of the resources and utilization of commercial rattan species in China.
This paper presents the results of a resource inventory of rattan species in China from 1985 to 1990. It is recognized that in China there are 40 species and 21 varieties belonging to 3 genera, 4 species of Plectocomia Mart; 36 species and 21 varieties of Calamus Linn, and 1 species of Daemonorops Blume, which are distributed over southern China from south-east coast to southwest mountainous areas and Taiwan, Hainan and some islands. This paper not only deals with the geographic distribution of the species and their numbers and characteristics of the plant flora but also briefly discusses the status of the resources and utilization of commercial rattan species in China.
1993, 6(4): 390-396.
Abstract:
A field trial on fertilization of thinned middle-aged plantation of Chinese fir on hilly red-yellow soil in subtropical area was conducted from 1987~1990. Tree increment of the first year didn't show any difference among treatments, bat the 2nd- and 3rd-year increment after fertilization indicated that N fertilizer increased tree growth the most significantly, P fertilizer significantly, and K unsignificantly; while the growth response to fertilizer was higher in volume and DBH than in height, and the growth response to P or K fertilizer was smaller than that to N, NP or NPK fertilizer. The net DBH and volume increment, resulting from the repeated application of 263 kg urea per ha or 263 kg urea plus 503 kg calcium magnesium per ha in 1987 and 1989, were promoted by 36%~48% and 32%~48%,and the value of input/output was 1:3.75~3.78,respectively. The effect of background diameter on the late growth responre to fertilization was also evaluated, the larger the background DBH before fertilization, the more remarkable the fertilization efficiency. Since the second thinning in winter of 1989, only N fertilizer could significantly increase the DBH growth of the trees, whose DBH was equal to or above the average background diameter. Since the background diameter of the trees had an influence on the late growth and fertilization efficiency, it should be regulated to a similar level by thinning from below before fertilization, which is helpful to the comparison and promotion of fertilization efficiency.
A field trial on fertilization of thinned middle-aged plantation of Chinese fir on hilly red-yellow soil in subtropical area was conducted from 1987~1990. Tree increment of the first year didn't show any difference among treatments, bat the 2nd- and 3rd-year increment after fertilization indicated that N fertilizer increased tree growth the most significantly, P fertilizer significantly, and K unsignificantly; while the growth response to fertilizer was higher in volume and DBH than in height, and the growth response to P or K fertilizer was smaller than that to N, NP or NPK fertilizer. The net DBH and volume increment, resulting from the repeated application of 263 kg urea per ha or 263 kg urea plus 503 kg calcium magnesium per ha in 1987 and 1989, were promoted by 36%~48% and 32%~48%,and the value of input/output was 1:3.75~3.78,respectively. The effect of background diameter on the late growth responre to fertilization was also evaluated, the larger the background DBH before fertilization, the more remarkable the fertilization efficiency. Since the second thinning in winter of 1989, only N fertilizer could significantly increase the DBH growth of the trees, whose DBH was equal to or above the average background diameter. Since the background diameter of the trees had an influence on the late growth and fertilization efficiency, it should be regulated to a similar level by thinning from below before fertilization, which is helpful to the comparison and promotion of fertilization efficiency.
1993, 6(4): 397-402.
Abstract:
Wood basic density and fiber length of 232 5-year-old plants of Eucalyptus (including 45 provenances of Eucalyptus grandis, E. saligna, E. camadulensis and E. urophylla) were tested and analyzed,which were collected from the Eucalyptus Provenance Trial Forest in Changtai County, Fujiaa Province. The results showed that: the variation range of wood basic density of the 4 species of Eucalyptus (E. grandis, E. saligna, E. camadulensis and E. urcphylla) were 0.407~0.462 g/cm3,0.427~0.475 g/cm3,0.498~0.541 g/cm3 and 0.471~0.588 g/cm3 respectively, while that of the fiber length 880.6~994.5 um,859.0~937.8 um, 841.4~924.8 um and 847.9~945.5 um respectively. E. urophylla has the fastest growth speed, the biggest wood basic density and longer fiber length. Among the various provenances, Queensland 14431, Brazil 14860 and South Africa 13365 of E. grandis; New Wales 14527, 13029, 13015 of E. saligna; Queensland 14106, 15052 of E. camadulensis; and Indonesia 12895, 12898 of E. urophylla were the better ones, which had the faster growth speed, better wood basic density and fiber length.
Wood basic density and fiber length of 232 5-year-old plants of Eucalyptus (including 45 provenances of Eucalyptus grandis, E. saligna, E. camadulensis and E. urophylla) were tested and analyzed,which were collected from the Eucalyptus Provenance Trial Forest in Changtai County, Fujiaa Province. The results showed that: the variation range of wood basic density of the 4 species of Eucalyptus (E. grandis, E. saligna, E. camadulensis and E. urcphylla) were 0.407~0.462 g/cm3,0.427~0.475 g/cm3,0.498~0.541 g/cm3 and 0.471~0.588 g/cm3 respectively, while that of the fiber length 880.6~994.5 um,859.0~937.8 um, 841.4~924.8 um and 847.9~945.5 um respectively. E. urophylla has the fastest growth speed, the biggest wood basic density and longer fiber length. Among the various provenances, Queensland 14431, Brazil 14860 and South Africa 13365 of E. grandis; New Wales 14527, 13029, 13015 of E. saligna; Queensland 14106, 15052 of E. camadulensis; and Indonesia 12895, 12898 of E. urophylla were the better ones, which had the faster growth speed, better wood basic density and fiber length.
1993, 6(4): 403-408.
Abstract:
The growth and propagation of Bursapkelenchus xylophilus (Steiner & Buhrer) Nickle and B. mucronatus Mamiya & Enda on the wood segments of 4 tree species was tested. The results showed that both of the nematodes could grow and propagate well on and in the pine wood segments for over 8 months; on the wood segments of hemlock, spruce, and douglas fir the nematodes could not propagate well and hardly entered the wood. Among the 29 fungal species tested, 3 were very suitable for the nematodes propagation, which were Aleurodiscus canadensis Skolko, Cytospora pint Desm. and Tyromycfs kravtzevianus Bondarzew & Parmasto in Parmasto. The nematodes did not propagate in the other 11 fungal species, and the rest 15 fungi as food sources for the nematodes varied greatly. The results showed that the nematodes growth and propagation on fungi were not relevant to the original hosts and the taxonomic category of the fungi.
The growth and propagation of Bursapkelenchus xylophilus (Steiner & Buhrer) Nickle and B. mucronatus Mamiya & Enda on the wood segments of 4 tree species was tested. The results showed that both of the nematodes could grow and propagate well on and in the pine wood segments for over 8 months; on the wood segments of hemlock, spruce, and douglas fir the nematodes could not propagate well and hardly entered the wood. Among the 29 fungal species tested, 3 were very suitable for the nematodes propagation, which were Aleurodiscus canadensis Skolko, Cytospora pint Desm. and Tyromycfs kravtzevianus Bondarzew & Parmasto in Parmasto. The nematodes did not propagate in the other 11 fungal species, and the rest 15 fungi as food sources for the nematodes varied greatly. The results showed that the nematodes growth and propagation on fungi were not relevant to the original hosts and the taxonomic category of the fungi.
1993, 6(4): 409-413.
Abstract:
Spraying an 0.2% aqueous solution of boric acid upon the crown of pines during developing shoots in order to prevent necrosis of buds achieved good results. Employing a smoking sprayer in spraying 6.5% chlorothalonil during the initial stage of developing shoots also achieved fairly good results. If a combined operation with both chemical compounds mentioned above to make a mixed emulsion are in progress, the result will become even more effective. Under the economic standard today,the abovementioned control measures for die-back of pines are readily accepted by forest productive units and open up prospects for popularization and application.
Spraying an 0.2% aqueous solution of boric acid upon the crown of pines during developing shoots in order to prevent necrosis of buds achieved good results. Employing a smoking sprayer in spraying 6.5% chlorothalonil during the initial stage of developing shoots also achieved fairly good results. If a combined operation with both chemical compounds mentioned above to make a mixed emulsion are in progress, the result will become even more effective. Under the economic standard today,the abovementioned control measures for die-back of pines are readily accepted by forest productive units and open up prospects for popularization and application.
1993, 6(4): 414-422.
Abstract:
This paper deals with growth models of clump of Daemondrops margaritae. The growth models of mother stem, total length of stems and number of surviving clumps are in accordance with the exponential equation: Y=aXb, and the coefficients are all bigger than 0.98. On the basis of these models, the structure of distribution of stem length and number of clumps are analyzed, and the dynamic models of length structure and structure of clumps are proposed in this paper, which are Nap=(a+b·InA)L'+cL'(InL'/A) and Lap=(a+b/A)L'2+(c+d/A)L'2·InL'.
This paper deals with growth models of clump of Daemondrops margaritae. The growth models of mother stem, total length of stems and number of surviving clumps are in accordance with the exponential equation: Y=aXb, and the coefficients are all bigger than 0.98. On the basis of these models, the structure of distribution of stem length and number of clumps are analyzed, and the dynamic models of length structure and structure of clumps are proposed in this paper, which are Nap=(a+b·InA)L'+cL'(InL'/A) and Lap=(a+b/A)L'2+(c+d/A)L'2·InL'.
1993, 6(4): 423-430.
Abstract:
Four methods of estimating the three-parameter Weibull distribution were evaluated by computer simulation and field data comparison. Through computer simulation, regression Estimator is the best method. However, The simulation result of Chinese fir plot data is not so good. Other three methods, maximum likelihood estimator, moments estimator and percentile estimator almost give the same results as estimate parameter b and c of Weibull distribution by the field data. Considering that computer calculation will take a lot of time, the percentile estimator is the best one.
Four methods of estimating the three-parameter Weibull distribution were evaluated by computer simulation and field data comparison. Through computer simulation, regression Estimator is the best method. However, The simulation result of Chinese fir plot data is not so good. Other three methods, maximum likelihood estimator, moments estimator and percentile estimator almost give the same results as estimate parameter b and c of Weibull distribution by the field data. Considering that computer calculation will take a lot of time, the percentile estimator is the best one.
1993, 6(4): 431-436.
Abstract:
Oligcchroa atriqumella Hampson is one of the moot serious pest of Acacia mearnsii in Fujian Province. This paper reports the results of the studies on the bionomics and control of this pest from 1988 to 1991. It has 6 generations a year in Huaan, Fujian Province. In the field, there is an overlapping, generation. The larvae over winter within thin cocoons in the twigs and leaves or in the thick growth of grass or the fallen leaves. The overwintering larvae pupate in late-March next year. There are five instars for the larvae and they do harm by curling leaves of the plant. The overwintering larvae last 117-148 days and the others last 16~24 days; The pupae last 8-15 days. The adults fly to light at night. The eggs are laid individually on the tender twigs and tender leaves or insects nest and the average number of eggs laid per female is 103.Control methods include hand-collection of the larvae. Spraying insecticides such as diluted 40% Omethoate 800~1 000 times, 50% Methamidophos 800~1 000 times, 20% Fenvalerate 2000 times and 2.5% Decis 4000 times, respectively, upon 3~5 th larvae in laboratory were found to be very effective with a mortality of 90%.
Oligcchroa atriqumella Hampson is one of the moot serious pest of Acacia mearnsii in Fujian Province. This paper reports the results of the studies on the bionomics and control of this pest from 1988 to 1991. It has 6 generations a year in Huaan, Fujian Province. In the field, there is an overlapping, generation. The larvae over winter within thin cocoons in the twigs and leaves or in the thick growth of grass or the fallen leaves. The overwintering larvae pupate in late-March next year. There are five instars for the larvae and they do harm by curling leaves of the plant. The overwintering larvae last 117-148 days and the others last 16~24 days; The pupae last 8-15 days. The adults fly to light at night. The eggs are laid individually on the tender twigs and tender leaves or insects nest and the average number of eggs laid per female is 103.Control methods include hand-collection of the larvae. Spraying insecticides such as diluted 40% Omethoate 800~1 000 times, 50% Methamidophos 800~1 000 times, 20% Fenvalerate 2000 times and 2.5% Decis 4000 times, respectively, upon 3~5 th larvae in laboratory were found to be very effective with a mortality of 90%.
1993, 6(4): 437-443.
Abstract:
Our survey in the lac-producing areas in Yunnan has demonstrated that these areas are characteristic of longitude-oriented distribution with remarkable vertical zonal variations. Based on the survey, they are divided into three regions and three zones of different altitudes. The three regions are western Wuliang mountain, Wuliang-Ailao mountains and eastern Ailao mountain. The altitudes of the three zones are 600~800 meters, 800~1 300 meters and 1 300~1 500 meters respectively. Our division exactly reflects the conditions in the lac-producing areas and is of great value for the understanding of the distribution of lac resources and the arrangement of lac production.
Our survey in the lac-producing areas in Yunnan has demonstrated that these areas are characteristic of longitude-oriented distribution with remarkable vertical zonal variations. Based on the survey, they are divided into three regions and three zones of different altitudes. The three regions are western Wuliang mountain, Wuliang-Ailao mountains and eastern Ailao mountain. The altitudes of the three zones are 600~800 meters, 800~1 300 meters and 1 300~1 500 meters respectively. Our division exactly reflects the conditions in the lac-producing areas and is of great value for the understanding of the distribution of lac resources and the arrangement of lac production.
1993, 6(4): 444-449.
Abstract:
Technology on how to use herbicides, such as 41% Roundup and 25% Velpar to eliminate weeds on forest land was studied through low and ultra-low volume spray. The size of spray-plate is 0.7mm and 1.0mm. This kind of technology can be used in regenerated forest after logging, tending in young stands, reform of bamboo groves and preservation of fire-preventing lines and it can save the cost for 70%, save the manual labour for 80%. The extension area in over 40 production units in Guangdong Province has reached over 1 333 ha.
Technology on how to use herbicides, such as 41% Roundup and 25% Velpar to eliminate weeds on forest land was studied through low and ultra-low volume spray. The size of spray-plate is 0.7mm and 1.0mm. This kind of technology can be used in regenerated forest after logging, tending in young stands, reform of bamboo groves and preservation of fire-preventing lines and it can save the cost for 70%, save the manual labour for 80%. The extension area in over 40 production units in Guangdong Province has reached over 1 333 ha.
1993, 6(4): 450-455.
Abstract:
This paper deals with the changes of tannin, soluble sugar and starch of two non-astrigent type fruits of persimmon during their development. Results showed that the fruit growth and sugar accumulation had two peak periods, following blooming and companying matureness respectively. The soluble sugar mainly consisted of glucose, fructose and sucrose, among which fructose had the largest proportion both in the inital and mature stages of fruit development in all cultivars. PCNA had higher content of sucrose than that of PVNA in almost the whole process. Main . deasringency of the PCNA occurred at the pre-period of fruit development, while that of the PVNA occurred at the near mature time. So some PCNA cultivars which matured later than PVNA was deastringent earlier.
This paper deals with the changes of tannin, soluble sugar and starch of two non-astrigent type fruits of persimmon during their development. Results showed that the fruit growth and sugar accumulation had two peak periods, following blooming and companying matureness respectively. The soluble sugar mainly consisted of glucose, fructose and sucrose, among which fructose had the largest proportion both in the inital and mature stages of fruit development in all cultivars. PCNA had higher content of sucrose than that of PVNA in almost the whole process. Main . deasringency of the PCNA occurred at the pre-period of fruit development, while that of the PVNA occurred at the near mature time. So some PCNA cultivars which matured later than PVNA was deastringent earlier.
1993, 6(4): 456-461.
Abstract:
A great quantity of germanium was abounded in wild Panax ginseng during its growing period for decades, and its medical effects were very strong. The content of germanium absorbed and accumulated in Panax ginseng cultured cells was about 8~17 ppm. Chemical vector compounds VA, VB, and VC of free toxicity for cells were prepared, and germanium was introduced into Panax ginseng cultured cells through using these vectors. During a growth period of 28 days, the quantity of germanium introduced via VA, VB, or VC attained upto 2978, 286, and 483 ppm respectively. Abound of germanium in Panax ginseng was a function of mature cells. Superaddition of germanium via vectors was reasonable at the end of logarithm period. Superaddition of germanium in culture had no influence on biosynthesis and accumulation of Panax ginseng saponin.
A great quantity of germanium was abounded in wild Panax ginseng during its growing period for decades, and its medical effects were very strong. The content of germanium absorbed and accumulated in Panax ginseng cultured cells was about 8~17 ppm. Chemical vector compounds VA, VB, and VC of free toxicity for cells were prepared, and germanium was introduced into Panax ginseng cultured cells through using these vectors. During a growth period of 28 days, the quantity of germanium introduced via VA, VB, or VC attained upto 2978, 286, and 483 ppm respectively. Abound of germanium in Panax ginseng was a function of mature cells. Superaddition of germanium via vectors was reasonable at the end of logarithm period. Superaddition of germanium in culture had no influence on biosynthesis and accumulation of Panax ginseng saponin.
1993, 6(4): 462-465.
Abstract:
The population density and secretion of lac insect (Kerria chinensis Mahdihassan) in winter and summer generations have been studied in this paper. The research results have shown that the secretion of female adult is about 95% of total secretion, the secretion of larvae is very little, the population density of female adult in late period of winter and summer generations, 20~30 bodies/cm2, is favourable for secretion. In winter generation, the highest secretion of lac insect parasitizing Dalbergia balansae Prain is about 10.60mg/♀, and its population density is 25 bodies/cm2; in summer generation, the highest secretion is 15.64mg/♀, and its population density is 27 bodies/cm2. Lac insect smoothly secrete in winter generation and flourishingly secrete in summer generation. In summer generation, there is a high secreting period in pregnant female 3~4 stages, population density is 35~40 bodies/cm2. Other biological characters of lac insect have also been discussed in this paper.
The population density and secretion of lac insect (Kerria chinensis Mahdihassan) in winter and summer generations have been studied in this paper. The research results have shown that the secretion of female adult is about 95% of total secretion, the secretion of larvae is very little, the population density of female adult in late period of winter and summer generations, 20~30 bodies/cm2, is favourable for secretion. In winter generation, the highest secretion of lac insect parasitizing Dalbergia balansae Prain is about 10.60mg/♀, and its population density is 25 bodies/cm2; in summer generation, the highest secretion is 15.64mg/♀, and its population density is 27 bodies/cm2. Lac insect smoothly secrete in winter generation and flourishingly secrete in summer generation. In summer generation, there is a high secreting period in pregnant female 3~4 stages, population density is 35~40 bodies/cm2. Other biological characters of lac insect have also been discussed in this paper.
1993, 6(4): 466-469.
Abstract:
The natural enemy complex of oriental moth, Cnidocampa flavescens (Walker), was reported in this paper. There are 9 species of natural enemies in its population in Jilin Province, which forms a natural enemy net of the moth. Each one of the complex has its own biological characteristics and specified nich. They compete with each other in space and food, among them, Chlorocryptus coreanus Szeligeti is the dominant one, whose parasitic rate is 33.96%~60.51%. The second one is Trichcgramma dendrolimi Mats, whose parasitic rate is 10%~37%. The total parasitic rate of the above-mentioned ones is higher in the forest, where the moth had occurred for many years than the newly occurred area.
The natural enemy complex of oriental moth, Cnidocampa flavescens (Walker), was reported in this paper. There are 9 species of natural enemies in its population in Jilin Province, which forms a natural enemy net of the moth. Each one of the complex has its own biological characteristics and specified nich. They compete with each other in space and food, among them, Chlorocryptus coreanus Szeligeti is the dominant one, whose parasitic rate is 33.96%~60.51%. The second one is Trichcgramma dendrolimi Mats, whose parasitic rate is 10%~37%. The total parasitic rate of the above-mentioned ones is higher in the forest, where the moth had occurred for many years than the newly occurred area.
1993, 6(4): 470-472.
Abstract:
In this paper the light microscopy, electron microscopy and orientation ultrathin sectioning techniques are used for the detection of MLO, and the MLO in the infected sieve elements can be directly and reliably observed with an electron microscope. The convincing detection is furnished for the study in the elimination of MLO of paulownia saplings and this technique can also be used universally in the detection of MLO in other plants.
In this paper the light microscopy, electron microscopy and orientation ultrathin sectioning techniques are used for the detection of MLO, and the MLO in the infected sieve elements can be directly and reliably observed with an electron microscope. The convincing detection is furnished for the study in the elimination of MLO of paulownia saplings and this technique can also be used universally in the detection of MLO in other plants.
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