Systematic & Applied Acarology Special Publications (2000) 4, 9-17 9 An overview of occurrence, development and damage of bamboo mites and their integrated management in Fujian, China*
YANXUAN ZHANG1, ZHI-QIANG ZHANG2, QIAOYUN LIU3, JIANZHEN LIN1 & JIE JI1
1 Institute of Plant Protection, Fujian Academy of Agriculture Science, Fuzhou 350013,
China; e-mail zyxlj@https://www.doczj.com/doc/199274184.html,
2Landcare Research, Private Bag 92-170, Auckland, New Zealand
3 Laboratory of Forest Protection, Fujian Forestry Bureau, Fuzhou 350002, China
Abstract
This paper gives an overview of the occurrence of mite pests (Schizotetrany-chus nanjingensis Ma & Yuan, Aponychus corpuzae Rimando and Aculus bam-busae Kuang) and their damage to the moso bamboo (Phyllostachys pubescens) in Fujian province, China. The effects of mites on the physiology of the plants and their yield are briefly discussed. Possible causes of their out-breaks in bamboo forests are outlined. A schematic model for the integrated management of bamboo mites is proposed.
Key words: Bamboo (Phyllostachy pubescens), mites, outbreak, integrated management
Introduction
Fujian province is located in the southeast coast of China. It covers an areas of 123,000 km2, 95% of which are mountains and hills.
* This paper is based on an invited talk given by the senior author at the “4th International Symposium on Population Dynamics of Plant-Inhabiting Mites” held in Kyoto, Japan in May 1999.
10 Systematic & Applied Acarology Special Publications (2000) 4
Fujian has some 680,000 acres of the moso bamboo (Phyllostachys pubescens). This is one quarter of the moso bamboo in the world. The economic development in coastal areas of China since the mid-1980s has resulted in a great number of buildings being constructed, and these have caused a great demand for the moso bamboo, the culm of which is used for scaffolding. Other increased demands also stimulated the growth of bamboo forestry in Fujian: the use of bamboo in bed sheets and furniture, floors in houses, and bamboo shoots as food.
Since the late 1980s, the bamboo forestry has become one of the five main supporting business in Fujian. Bamboo forestry has become a major income for local governments and farmers in mountainous areas. The annual revenue from the bamboo forestry in Fujian reached 1.2 billion yuan or 140 million US dollars in recent years.
In 1990, our surveys revealed that spider mites (Schizotetranychus nanjingensis Ma & Yuan and Aponychus corpuzae Rimando) and a rust mite (Aculus bambusae Kuang) were causing damage to the moso bamboo in Fujian. In 1994, outbreaks of mites occurred in some major bamboo production areas. By 1998, these mites were found in sixty-three counties/cities/districts. In some areas only one species was present, but in most areas, mixed populations of mites were common (Zhang et al. 1998a). The mite problems in Fujian were more severe than earlier reports of damage to bamboo plants by Schizotetranychus mites in Zhejiang (Yu & Shi 1990) and Shandong (Sun et al. 1997).
Our survey of bamboo forests in 63 counties/cities/districts in 1998 showed that 5% of them were heavily damaged, 30% of them were moderately damaged, 40% of them were lightly damaged and 25% of them were not infested (most of these forests were natural mixed forests at high altitudes with a single mite species).
Mite feeding reduced the chlorophyll content in bamboo leaves. Schizotetranychus nanjingensis feeding reduced it by 11% with light damage (1-3 nests per leaf), 24% with moderate damage (4-10 nests per leaf), and 57% with heavy damage (11-20 nests per leaf or more) (Zhang et al. 1998b). Aponychus corpuzae feeding reduced it by 11% with light damage (5-10 mites per leaf), 58% with moderate damage
ZHANG et al.:Overview 11 (33.4-48.5 mites per leaf) and 63% with heavy damage (65.8-80.0 mites per leaf) (Zhang et al. 1998c).
Mite feeding also reduced the sugar content in bamboo leaves. Schizotetranychus nanjingensis reduced it by 2% with light damage, 13% with moderate damage, and 55% with heavy damage (Zhang et al. 1998b). Aponychus corpuzae reduced it by 5% with light damage, 12% with moderate damage, and 51% with heavy damage (Zhang et al. 1998c). Likewise, mite feeding also reduced the total sugar content in bamboo leaves. Schizotetranychus nanjingensis reduced it by 12% with light damage, 19% with moderate damage, and 57% with heavy damage (Zhang et al. 1998b). Aponychus corpuzae reduced it by 3% with light damage, 39% with moderate damage, and 67% with heavy damage (Zhang et al. 1998c).
The contents of 18 amino acids and water were also noticeably reduced by mite feeding (Zhang et al. 1998b,c).
Damaged plants have abnormal physiology and metabolism. Bam-boo plants normally change leaves every other year. Damaged plants might change leaf every year, or even twice each year.
Mite damage significantly reduced the leaf areas of bamboo plants by 30% with light damage and by 58% with heavy damage (Zhang et al. 1998b,c). A noticeable result was that new culm became thinner and longer. Our investigation showed that an acre of lightly damaged forest lost 20-30% new culm (300-450) with a loss of 3750 kilograms of shoots, moderately damaged forest lost 30-40% new culm (450-600) and heavily damaged forests looked burnt from a distance.
Mite damage to bamboo forests has affected the economy, ecology and biodiversity of Fujian province.
Fujian government and many scientists have paid great attention to the occurrence, development and damage of bamboo mites. The project “Studies on biology of phytophagous mites and their integrated management” became a key project of Fujian Science Council during the 1996-1999 period, and “Using predatory mites to control pest mites of bamboo forests” became another key project of Fujian Science Council during the 1999-2001 period.
12 Systematic & Applied Acarology Special Publications (2000) 4Mite occurrence, development and damage
Before 1985, the bamboo plants were mixed with other trees in poly-culture natural forests. There were only 750 bamboo plants in a hect-are. After 1986, most natural bamboo forests were changed into artificial monoculture forests to increase production. The number of bamboo plants was increased to over 2000 in a hectare in some areas.Over-harvesting caused diseases and pest outbreaks in some forests.The use of some pesticides for chemical control killed natural enemies.We observed 30 natural and 30 artificial bamboo forests. The results showed that natural polyculture forests had 5-10 times as many natural enemies (especially predatory mites of the Phytoseiidae) as artificial monoculture ones, where the underfloor lower plants were cut, soils were turned and plant growth hormones were used. These cultural practices resulted in monoculture, ecologically unstable and weakened forests which are more susceptible to pest outbreaks (Fig. 1).
FIGURE 1. Schematic analysis of occurrence, development and damage of bamboo mites in Fujian.Monoculture
Overharvesting Misuse of pesticides Reduced plant diversity
Increased pest density
Reduced soil nutrient Monoculture & Weeding Reduced density of
Natural enemies
Reduced plant diversity Increased pest density Reduced soil nutrient Change of forest climate and soil nutrient content Reduced forest coverage
Reduced numbers of natural enemy unable to check pest
growth in early season Monoculture
facilitate pest growth
and dispersal Pest occurrence in 63 counties/cities/districts in Fujian
Pest damage reduced some farmer’s income and affected the forest environment
ZHANG et al.:Overview 13 Integrated forest and pest management
Since 1996 we have conducted investigations at main bamboo growing areas in Fujian and analyzed the occurrence and development of pest mites. We proposed the following management practices to restore for-est health and reduce/prevent pest damage in the long term: (1) chang-ing monoculture bamboo forests into polyculture ones, (2) promoting healthy bamboo culture, and (3) increasing natural enemies of pest mites.
In seriously damaged areas, we advised farmers to cut diseased/ damaged bamboo plants, burn them and re-introduce other trees to increase plant diversity in the forests. In moderately damaged areas, we reduced pest mite densities efficiently by 94-98% in 30 days with selective injections of solutions of systemic pesticides (50% methami-dophos, 40% omethoate, 20% fenvalerate, 20% methomyl, or 50% chlorfluazuron diluted by 10-30 times) into joints on the culm.
To establish sustainable and ecological pest management system in bamboo forests, we first interplanted broad leaf trees with the moso bamboo at about 2:8 or 3:7 ratios to resume the biodiversity of bamboo forests. Secondly, we established healthy culture in bamboo forests to increase their natural resistance to pests and diseases, and the compen-satory ability of bamboo plants. Since 1997 we have made a great deal of efforts in using “organic” fertilizers (fermented sugar-cane byprod-ucts) mixed with N, P, K, Mn, Zn and Si elements to boost the growth of bamboo plants. We mixed these fertilizers with “imitate compound biopesticides” and applied them to root systems of bamboo plants dur-ing late April to early June, 40-60 days after releasing predatory mites (Amblyseius longispinosus Evans). In IMP forests, pest mites were 1.4-1.6/leaf but in untreated forests there were as many as 160 per leaf. Yield was increased by 98-467% and the number of culm by 840-975 per acre after one year of integrated management. The diameter of the new culm in treated area was increased by 2.0-4.0cm and height by 2.0-4.2cm compared to untreated areas. We have established a sustain-able forest and pest management model (Fig. 2).
14 Systematic & Applied Acarology Special Publications (2000) 4
FIGURE 2. A schematic model of sustainable forest and pest management for the moso bamboo in Fujian.
Discussion
Changes in the cultivation of bamboo (monoculture, crowding of bam-boo plants and removal of underfloor plants) may be major causes of mite outbreaks. Monoculture and removal of underfloor plants reduces alternative habitats/food for predatory mites which otherwise might Integrated Management of Bamboo Mites
Augmentation of
integrated
nutrient manage-
ment (INM)
Plant Nutrition Implementation of integrated pest management (IPM)Plant Protection Modification of monoculture into polyculture Plant Ecology Establishment of farmer school Social Regulation Establishment of pest/predator sampling plans Conservation of predators Release of mass-reared predators Training workshops using video tapes Field demonstration Reduction of cutting of underfloor plants Intercroping Increase of forest diversity Plant nutrient
input to increase
bamboo’s
tolerance to
pests and its
compensatory
capacity Establishment of sustainable forest and pest management models
Restoration of bamboo forest diversity and repair of damaged forests
ZHANG et al.:Overview 15 prevent spider mites from reaching damaging levels. Monoculture and crowding facilitate the dispersal of spider mites from plants to plants. These also deplete the nutrients in the soil and malnutrition plants thus become more susceptible to mites. Successful control of spider mites may therefore be achieved through modification of cultivation practice to restore the natural balance, which will in turn augment the natural enemies of phytophagous mites to keep them under control.
Pest mites (S. nanjingensis, Ap. corpuzae and Ac. bambusae) have caused economical, ecological and sociological problems in Fujian Province. Research on the systematics, biology and control of mites on the moso bamboo is progressing and some of the results are summa-rized in the following papers in this book.
Acknowledgments
This paper resulted from a “Key Project of the Nine-Five Period” spon-sored by Fujian Science Council. Dr Z.-Q. Zhang's visits to Fujian in July 1997 and September-October 1998 were funded by Fujian Ying-zhiban, a provincial office for promoting exchange and collaboration between scientist in China and elsewhere.The senior author thanks Professor Yutaka Saito for his valuable suggestions and financial sup-port for her attending The 4th International Symposium on Population Dynamics of Plant-Inhabiting Mites and visiting Hokkaido University in May 1999. We also thank Dr Ting-Kui Qin (Australian Quarantine and Inspection Services, Canberra) for a critical review of the manu-script.
References
Sun, X.-Y., Zhou, C.-G., Liu, Y.-M., You, C.-X. & Yu, B. (1997) Preliminary studies on the biology of Schizotetranychus bambusae. Scientia Silvae Sin-icae, 33, 274-277[in Chinese].
16 Systematic & Applied Acarology Special Publications (2000) 4
Yu, H.-X. & Shi, J.-M. (1991) Studies on Schizotetranychus nanjingensis.
Journal of Bamboo Research, 10(2), 61-67 [in Chinese with English abstract].
Zhang, Y.-X., Liu, Q.-Y., Lin, J.-Z., Song, M.-G., Cai, Q.-J. & He, X.-Y.
(1998a) Studies on species distribution and damage by spider mites in bamboo trees in Fujian Province. Journal of Fujian Academy of Agricul-tural Sciences, 12(3), 11-15 [in Chinese with English abstract].
Zhang, Y.-X., Liu, Q.-Y., Lin, J.-Z., Song, M.-G. & He, X.-Y. (1998b) Influ-ence on the physiology and biochemistry of bamboo damage by the Schizotetranychus nanjingensis Ma et Y uan. Entomological Journal of East China, 7, 65-70 [in Chinese with English abstract].
Zhang, Y.-X., Tong, R.-X., Liu, Q.-Y., Wu, J.-Q. & He, X.-Y. (1998c) Prelimi-nary studies on the influence of the Aponychus corpuzae harm on the phys-iology and biochemistry of Phyllostachys pubescens. Journal of Fujian Forestry Science & Technology, 25(4), 13-16 [in Chinese].
ZHANG et al.:Overview 17
Abstract in Chinese
Accepted: 10 February 2000
Copyright 2000 Systematic & Applied Acarology Society
第二章进程管理 2. 试画出下面4条语句的前趋图: S2: b:=z+1; S3: c:=a-b; S4: w:=c+1; 3. 程序在并发执行时，由于它们共享系统资源，以及为完成同一项任务而相互合作， 致使在这些并发执行的进程之间，形成了相互制约的关系，从而也就使得进程在执行期间出现间断性。 4. 程序并发执行时为什么会失去封闭性和可再现性？ 因为程序并发执行时，是多个程序共享系统中的各种资源，因而这些资源的状态是 由多个程序来改变，致使程序的运行失去了封闭性。而程序一旦失去了封闭性也会导致其再失去可再现性。 5. 在操作系统中为什么要引入进程概念？它会产生什么样的影响? 为了使程序在多道程序环境下能并发执行，并能对并发执行的程序加以控制和描述，从而在操作系统中引入了进程概念。 影响: 使程序的并发执行得以实行。 6. 试从动态性，并发性和独立性上比较进程和程序? a. 动态性是进程最基本的特性，可表现为由创建而产生，由调度而执行，因得不到资源 而暂停执行，以及由撤销而消亡，因而进程由一定的生命期；而程序只是一组有序指令的集合，是静态实体。 b. 并发性是进程的重要特征，同时也是OS的重要特征。引入进程的目的正是为了使其 程序能和其它建立了进程的程序并发执行，而程序本身是不能并发执行的。 c. 独立性是指进程实体是一个能独立运行的基本单位，同时也是系统中独立获得资源和 独立调度的基本单位。而对于未建立任何进程的程序，都不能作为一个独立的单位来运行。 7. 试说明PCB的作用?为什么说PCB是进程存在的唯一标志? a. PCB是进程实体的一部分，是操作系统中最重要的记录型数据结构。PCB中记录了操 作系统所需的用于描述进程情况及控制进程运行所需的全部信息。因而它的作用是使一个在多道程序环境下不能独立运行的程序(含数据)，成为一个能独立运行的基本单位，一个能和其它进程并发执行的进程。 b. 在进程的整个生命周期中，系统总是通过其PCB对进程进行控制，系统是根据进程 的PCB而不是任何别的什么而感知到该进程的存在的，所以说，PCB是进程存在的唯一标志。 8. 试说明进程在三个基本状态之间转换的典型原因. a. 处于就绪状态的进程，当进程调度程序为之分配了处理机后，该进程便由就绪状态变 为执行状态。 b. 当前进程因发生某事件而无法执行，如访问已被占用的临界资源，就会使进程由执行 状态转变为阻塞状态。 c. 当前进程因时间片用完而被暂停执行，该进程便由执行状态转变为就绪状态。 9. 为什么要引入挂起状态？该状态有哪些性质？ a. 引入挂起状态主要是出于4种需要（即引起挂起的原因）: 终端用户的请求，父进程 请求，负荷调节的需要，操作系统的需要。