wewewe reportreport a level. - 農研機構 ... brown leafhopper idioscopus nivesparsus mmangoango...

IntroductionIntroduction

We We We We report a similar estimation of report a similar estimation of

i l d l i i l d l i economic loss due to losing economic loss due to losing pollinators at a local and national pollinators at a local and national pplevel.level.

2


Mango (Mango (MangiferaMangifera indicaindica Linnaeus) is Linnaeus) is native to southern Asianative to southern Asianative to southern Asia.native to southern Asia.

Cultivation of mango in Taiwan can Cultivation of mango in Taiwan can be traced back to as early as 1561 when be traced back to as early as 1561 when be traced back to as early as 1561 when be traced back to as early as 1561 when the Dutch introduced it from Java, the Dutch introduced it from Java, Indonesia into the island.Indonesia into the island.

3


Additional mango varieties e g Additional mango varieties e g Additional mango varieties, e.g., Additional mango varieties, e.g., Pearl, Pearl, HafoasHafoas, , OngaOnga, Java, , Java, ggApplegroomApplegroom, were introduced in , were introduced in early 20th century during the early 20th century during the early 20th century during the early 20th century during the Japanese colonial period. Japanese colonial period.

4


Five American varieties of mango, i.e., Five American varieties of mango, i.e., Haden Irwin Haden Irwin KeittKeitt Kent and Kent and ZillZill Haden, Irwin, Haden, Irwin, KeittKeitt, Kent and , Kent and ZillZill, , were introduced from Florida, United were introduced from Florida, United S b i li f h SiS b i li f h SiStates by specialists of the SinoStates by specialists of the Sino‐‐American Joint Commission of Rural American Joint Commission of Rural American Joint Commission of Rural American Joint Commission of Rural Reconstruction (Reconstruction (JCRRJCRR) in 1954 and ) in 1954 and th lti ti f th i ti th lti ti f th i ti the cultivation of these new varieties the cultivation of these new varieties in the 1960s had a revolutionary effect in the 1960s had a revolutionary effect 9 y9 yon mango production in Taiwan.on mango production in Taiwan.

5


Irwin, Irwin, Haden and Haden and ZillZill were better were better ddadaptive varieties :adaptive varieties : harvested from May to July before harvested from May to July before harvested from May to July before harvested from May to July before the typhoon seasonthe typhoon season hi h i ldhi h i ld high yieldhigh yield high qualityhigh qualityg q yg q y no long strands of fiber no long strands of fiber attractive peel colorattractive peel color attractive peel colorattractive peel color high market valuehigh market value

6


JCRR launched a Tropical Fruit JCRR launched a Tropical Fruit JCRR launched a Tropical Fruit JCRR launched a Tropical Fruit Development Program in Development Program in 19601960 to to help farmers grow new varieties of help farmers grow new varieties of mango. The extension work was a mango. The extension work was a mango. The extension work was a mango. The extension work was a tremendous success and mango tremendous success and mango l i i d d i ll l i i d d i ll plantation increased dramatically, plantation increased dramatically,

especially in especially in YujingYujing township of township of p yp y j gj g ppTainan County, in the 1960s.Tainan County, in the 1960s.

7


h f l l b d f h f l l b d f The first local breed of mango, JinThe first local breed of mango, Jin‐‐Hwang appeared in 1976. Up to now, Hwang appeared in 1976. Up to now, Hwang appeared in 1976. Up to now, Hwang appeared in 1976. Up to now, 6 locally bred quality varieties (e.g., 6 locally bred quality varieties (e.g., T iT i N YN Y Wi N 6) tl Wi N 6) tl TainongTainong No. 1, YuNo. 1, Yu‐‐Win No.6), mostly Win No.6), mostly hybrids of the American varieties, are hybrids of the American varieties, are y ,y ,now being grown by farmers and sold now being grown by farmers and sold in the market in the market in the market. in the market.

8


All these new breeds are not only juicy All these new breeds are not only juicy All these new breeds are not only juicy All these new breeds are not only juicy and tasty, but also readily acceptable in and tasty, but also readily acceptable in both domestic and export markets.both domestic and export markets.

Mango yield and value increased by Mango yield and value increased by two orders of magnitude within a 55two orders of magnitude within a 55‐‐year period year period year period. year period.

9


Th l i ld f 6 Th l i ld f 6 The annual yield of mango was 2,016 The annual yield of mango was 2,016 m.tm.t. in 1946, 152,062 . in 1946, 152,062 m.tm.t. in 1981, and . in 1981, and 94 , 5 ,94 , 5 , 9 ,9 ,212,875 212,875 m.tm.t. in 2001. . in 2001.

The value of mango produced was The value of mango produced was ggNTD16 million in 1946, NTD1,530 NTD16 million in 1946, NTD1,530 million in 1981 and NTD4 600 million million in 1981 and NTD4 600 million million in 1981 and NTD4,600 million million in 1981 and NTD4,600 million in 2001.in 2001.

10


Mango became the third most important Mango became the third most important f it i T i t th t f th t f it i T i t th t f th t fruit crop in Taiwan at the turn of the 21st fruit crop in Taiwan at the turn of the 21st century. Recently, the popular Irwin mango century. Recently, the popular Irwin mango y y p p gy y p p ghas been selected as one of the country's has been selected as one of the country's four four ““flagship export productsflagship export products ”” It is It is four four flagship export products.flagship export products. It is It is evident that Taiwan has benefited greatly evident that Taiwan has benefited greatly from the genetic diversity of mango.from the genetic diversity of mango.

11


While enjoying the economic benefit While enjoying the economic benefit due to an increase in the genetic due to an increase in the genetic due to an increase in the genetic due to an increase in the genetic diversity and diverse produce of mango, diversity and diverse produce of mango, T i i l l T i i l l Y jiY ji hh Taiwan, particularly Taiwan, particularly YujingYujing,, thethe most most important mango production area in important mango production area in p g pp g pTaiwan, suffered great economic as well Taiwan, suffered great economic as well i l d i t l l d t i l d i t l l d t as social and environmental loss due to as social and environmental loss due to

unfruitfulness and shy cropping of unfruitfulness and shy cropping of y pp gy pp gmango during the period from 1975 to mango during the period from 1975 to 199019901990.1990.

12


The purpose of this study is to The purpose of this study is to d t d l th d t d l th document and analyze the document and analyze the impact and the underlying impact and the underlying p y gp y gcauses of this crop failure, and causes of this crop failure, and their relationship with pollinator their relationship with pollinator their relationship with pollinator their relationship with pollinator diversity.diversity.

13

Materials and MethodsMaterials and Methods

Collect and analyze data on mango Collect and analyze data on mango plantation and yield between 1945 plantation and yield between 1945 and 2009 from Taiwan Agricultural and 2009 from Taiwan Agricultural and 2009 from Taiwan Agricultural and 2009 from Taiwan Agricultural Yearbook.Yearbook.

Interview mango growers in Interview mango growers in YujingYujingg gg g j gj gto understand the historical to understand the historical b k d f f il b k d f f il background of mango crop failure background of mango crop failure and how this problem was solved.and how this problem was solved.pp

14

Materials and MethodsMaterials and Methods

Literature review to demonstrate Literature review to demonstrate the loss of pollinator diversity might the loss of pollinator diversity might have played a significant role in have played a significant role in have played a significant role in have played a significant role in mango crop failure. mango crop failure.

Analyze the cost and benefit of Analyze the cost and benefit of Analyze the cost and benefit of Analyze the cost and benefit of relying on a single alternative relying on a single alternative

lli i d i lli i d i pollinator in mango production. pollinator in mango production.

15

Results: Four stages of mango productionResults: Four stages of mango production

Based on (1) mean annual yield per Based on (1) mean annual yield per hectare; (2) sizes of planted and hectare; (2) sizes of planted and harvested area; and (3) annual harvested area; and (3) annual harvested area; and (3) annual harvested area; and (3) annual yield of mango from 1945 to 2009: yield of mango from 1945 to 2009:

Stage 1 (Stage 1 (19451945‐‐1964)1964)g (g ( 945945 9 4)9 4) Stage 2 Stage 2 (1965(1965‐‐1974)1974) St St (( )) Stage 3 Stage 3 (1975(1975‐‐1992)1992) Stage 4 Stage 4 (1993(1993‐‐2009)2009)g 4g 4 ( 993( 993 9)9)

16

Table 1. Mean annual mango yield per hectare in Taiwan and Table 1. Mean annual mango yield per hectare in Taiwan and ggTainan County and their coefficient of variation (CV) at 4 Tainan County and their coefficient of variation (CV) at 4 different stages. different stages.

StageMean annual yield per ha in CV

Mean annual yield per ha in T i C t CVg y p

Taiwan (kg/ha) Tainan County (kg/ha)

( 6 ) ± % ± %1 (1945‐1964) 7737.9 ± 1802.1 23.3% 8085.7 ± 2410.0 29.8%

2 (1965‐1974) 13585.1 ± 3492.5 25.7% 15812.2 ± 4217.2 26.7%

3 (1975‐1992) 7326.5 ± 2354.5 32.1% 5715 ± 2795.4 48.9%

17174 (1993‐2009) 10632.4 ± 1066.0 10.0% 11811.8 ± 1613.3 13.7%


At Stage 1, the mango harvested area At Stage 1, the mango harvested area never exceeded 700ha. Beginning in never exceeded 700ha. Beginning in 1963 two statistics appeared in 1963 two statistics appeared in 1963, two statistics appeared in 1963, two statistics appeared in Taiwan Agricultural yearbook, Taiwan Agricultural yearbook, g y ,g y ,namely the planted area and the namely the planted area and the h d i di i i h d i di i i harvested area, indicating an increase harvested area, indicating an increase of young mango plantations. of young mango plantations. of young mango plantations. of young mango plantations.

18


The planted area increased The planted area increased The planted area increased The planted area increased dramatically in stage 2. dramatically in stage 2.

The difference between planted area The difference between planted area ppand harvested area reached its peak, and harvested area reached its peak, 4600ha in 1974 and narrowed down 4600ha in 1974 and narrowed down 4600ha, in 1974 and narrowed down 4600ha, in 1974 and narrowed down at stage 4.at stage 4.gg

19


Annual yield of mango was not high Annual yield of mango was not high Annual yield of mango was not high Annual yield of mango was not high at Stage 1. However, annual yield at at Stage 1. However, annual yield at the end of Stage 2 was more than 10 the end of Stage 2 was more than 10 times of that of Stage 1. Annual yield times of that of Stage 1. Annual yield times of that of Stage 1. Annual yield times of that of Stage 1. Annual yield of mango doubled at stage 3 and of mango doubled at stage 3 and

i i again at stage 4.again at stage 4.

20


The mean annual yield of mango per The mean annual yield of mango per h i T i C t i hi hl h i T i C t i hi hl ha in Tainan County is highly ha in Tainan County is highly correlated to that of Taiwan. In most correlated to that of Taiwan. In most of the past 65 years, mean annual of the past 65 years, mean annual

ld hld hyield per hectare in Tainan County yield per hectare in Tainan County was higher than that of Taiwan but it was higher than that of Taiwan but it was higher than that of Taiwan, but it was higher than that of Taiwan, but it happened only in one of the 17 years happened only in one of the 17 years at Stage 3, indicating serious crop at Stage 3, indicating serious crop failures during this stagefailures during this stagefailures during this stage.failures during this stage.

21

Table 2. Mean annual mango yield per hectare in Taiwan and Table 2. Mean annual mango yield per hectare in Taiwan and ggTainan County and their coefficient of variation (CV) at 4 Tainan County and their coefficient of variation (CV) at 4 different stages. different stages.

StageMean annual yield per ha in CV

Mean annual yield per ha in Tainan County CV

Taiwan (kg/ha) Tainan County (kg/ha)

1 (1945 1964) 7737 9 ± 1802 1 23 3% 8085 7 ± 2410 0 29 8%1 (1945‐1964) 7737.9 ± 1802.1 23.3% 8085.7 ± 2410.0 29.8%

( 6 ) 8 ± % 8 ± 6 %2 (1965‐1974) 13585.1 ± 3492.5 25.7% 15812.2 ± 4217.2 26.7%

( ) ± % ± %3 (1975‐1992) 7326.5 ± 2354.5 32.1% 5715 ± 2795.4 48.9%

22224 (1993‐2009) 10632.4 ± 1066.0 10.0% 11811.8 ± 1613.3 13.7%


In addition, the CV of mean annual In addition, the CV of mean annual yield per hectare in Tainan County yield per hectare in Tainan County was always higher than that of was always higher than that of was always higher than that of was always higher than that of Taiwan, especially at Stage 3, Taiwan, especially at Stage 3, i di i bi fl i f i di i bi fl i f indicating a bigger fluctuation of indicating a bigger fluctuation of mango production in Tainan County mango production in Tainan County g p yg p yat this stage.at this stage.

23


The correlation between the annual The correlation between the annual yield of mango in Tainan County and yield of mango in Tainan County and yield of mango in Tainan County and yield of mango in Tainan County and that of Taiwan is even higher (rthat of Taiwan is even higher (r22 = = 0.97). However, the annual yield of 0.97). However, the annual yield of mango in Tainan County is only 41% mango in Tainan County is only 41% mango in Tainan County is only 41% mango in Tainan County is only 41% of that of Taiwan at Stage 3, of that of Taiwan at Stage 3,

f l l h h f l l h h significantly lower than the significantly lower than the percentages of other stages, reflecting percentages of other stages, reflecting percentages of other stages, reflecting percentages of other stages, reflecting production problems during this production problems during this ttstage.stage.

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Results: Results: unfruitfulness and shy cropping unfruitfulness and shy cropping at Stage 3at Stage 3

In 1974, when annual yield of mango In 1974, when annual yield of mango reached a record high of 59,898 reached a record high of 59,898 m.tm.t., ., reached a record high of 59,898 reached a record high of 59,898 m.tm.t., ., the government set the government set YujingYujing area of area of T i C h l h T i C h l h Tainan County where nearly three Tainan County where nearly three quarters of mango in Taiwan were quarters of mango in Taiwan were q gq gharvested as the Mango Special Crop harvested as the Mango Special Crop Region in hope to contributing Region in hope to contributing Region, in hope to contributing Region, in hope to contributing significantly to local economy and significantly to local economy and g y yg y yraising the income of the farming raising the income of the farming community community community. community.

25


Ironically, in 1975, mango yield of Ironically, in 1975, mango yield of Taiwan dropped 27 8% to 43 293 Taiwan dropped 27 8% to 43 293 Taiwan dropped 27.8% to 43,293 Taiwan dropped 27.8% to 43,293 m.tm.t. though the sizes of planted . though the sizes of planted and harvest area kept increasing. and harvest area kept increasing. Mango yield reduction in Tainan Mango yield reduction in Tainan Mango yield reduction in Tainan Mango yield reduction in Tainan County, particularly in County, particularly in YujingYujing area, area, was astonishing: dropped almost was astonishing: dropped almost 50% from 44,537 50% from 44,537 m.tm.t. in the . in the 50% from 44,537 50% from 44,537 m.tm.t. in the . in the previous year to 29,243 previous year to 29,243 m.tm.t. in 1975. . in 1975.

26


Mango growers in Mango growers in YujingYujing area put area put pressure on government to find out the pressure on government to find out the pressure on government to find out the pressure on government to find out the underlying cause of mango underlying cause of mango

f f l d hf f l d hunfruitfulness and shy cropping iunfruitfulness and shy cropping in 1975.n 1975.

The government spent more than 10 The government spent more than 10 illi NT d ll t b ild d b id illi NT d ll t b ild d b id million NT dollars to build roads, bridges, million NT dollars to build roads, bridges,

mechanical pesticide spraying facilities mechanical pesticide spraying facilities p p y gp p y gand water supply facilities, etc., in a total and water supply facilities, etc., in a total area of 1 100 ha around area of 1 100 ha around YujingYujing townshiptownshiparea of 1,100 ha around area of 1,100 ha around YujingYujing township.township.

27

Th I P l d f Th I P l d f


The Improvement Programs lasted for The Improvement Programs lasted for more than a decade and facilitated more than a decade and facilitated more than a decade and facilitated more than a decade and facilitated many research projects from various many research projects from various di i li h h ti lt l t di i li h h ti lt l t disciplines such as horticulture, plant disciplines such as horticulture, plant physiology, plant pathology and physiology, plant pathology and p y gy, p p gyp y gy, p p gyentomology. Despite extensive entomology. Despite extensive research on factors related to mango research on factors related to mango research on factors related to mango research on factors related to mango fruit set, few advances were made fruit set, few advances were made towards finding the resolution of towards finding the resolution of reliable and increasing crop production reliable and increasing crop production reliable and increasing crop production. reliable and increasing crop production.

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The annual mango yield continued to The annual mango yield continued to fl id l il fl id l il fluctuate widely until 1992. fluctuate widely until 1992. Consecutive bumper harvests were Consecutive bumper harvests were ppoften followed by consecutive lean often followed by consecutive lean h t Th l i ld h d h t Th l i ld h d harvests. The annual yield reached a harvests. The annual yield reached a new record high of 152,062 new record high of 152,062 m.tm.t. in . in g 5g 51982 but sharply dropped to a record 1982 but sharply dropped to a record low of 28 618 low of 28 618 m tm t the following year the following year low of 28,618 low of 28,618 m.tm.t. the following year. . the following year.

29


The annual mango yield of Tainan The annual mango yield of Tainan County in 1983, 1984, 1985, and 1986 County in 1983, 1984, 1985, and 1986 was only 18 7% 30 4% 18 2% and was only 18 7% 30 4% 18 2% and was only 18.7%, 30.4%, 18.2% and was only 18.7%, 30.4%, 18.2% and 25.4% of that of Taiwan, respectively.25.4% of that of Taiwan, respectively.

30

P ibl f f i f l d h P ibl f f i f l d h


Possible cause of unfruitfulness and shy Possible cause of unfruitfulness and shy croppingcroppingpp gpp g

Abnormal climate (lower temperature Abnormal climate (lower temperature Abnormal climate (lower temperature, Abnormal climate (lower temperature, higher rainfall, and therefore less pollinator)higher rainfall, and therefore less pollinator)d i th fl i d i th fl i during the flowering season.during the flowering season.

Biennial bearing for certain varieties Biennial bearing for certain varieties Percentage of perfect (hermaphrodite) Percentage of perfect (hermaphrodite)

flowers was too low to set fruits for most flowers was too low to set fruits for most mango varietiesmango varieties

Water stressWater stress Water stressWater stress31


Anthracnose in flowersAnthracnose in flowers Poor site conditionPoor site condition Poor nutrition of treesPoor nutrition of trees TTrees were inadequately fertilizedrees were inadequately fertilized TTrees were inadequately fertilizedrees were inadequately fertilized PPoor tree management (i.e. too high a oor tree management (i.e. too high a

density of mango trees overdensity of mango trees over crowded crowded density of mango trees, overdensity of mango trees, over‐‐crowded crowded crown without pruning and thinning, crown without pruning and thinning, ll f l f )ll f l f )allowing fruit setting in early age of trees)allowing fruit setting in early age of trees)

Overuse and/or misuse of pesticidesOveruse and/or misuse of pesticidesppdamaging mango foliage and flowersdamaging mango foliage and flowers

32

Results: Results: Overuse and/or misuse of pesticidesOveruse and/or misuse of pesticides

Lin (1989) hypothesized that overuse Lin (1989) hypothesized that overuse f ti id i ht h li i t d f ti id i ht h li i t d of pesticides might have eliminated of pesticides might have eliminated

nonnon‐‐target insects, particularly target insects, particularly g p yg p ypollinators of mango, thus hindered pollinators of mango, thus hindered mango fruit setting He called for mango fruit setting He called for mango fruit setting. He called for mango fruit setting. He called for cautious application of pesticides, cautious application of pesticides, especially during the flowering especially during the flowering season without further testing his season without further testing his season, without further testing his season, without further testing his hypothesis.hypothesis.

33


Insect pests of mango in Taiwan:Insect pests of mango in Taiwan:p gp gMMango shoot bores ango shoot bores ChlumetiaChlumetia transversatransversa California California scale insect scale insect AonidiellaAonidiella aurantiiaurantii California California scale insect scale insect AonidiellaAonidiella aurantiiaurantii MMango brown leafhopper ango brown leafhopper IdioscopusIdioscopus

iinivesparsusnivesparsusMMango green leafhopperango green leafhopper I. I. clypealisclypealisMango Mango psyllidpsyllid MicroceropsyllaMicroceropsylla nigranigra Small yellow Small yellow thripsthrips ScirtothripsScirtothrips dorsalisdorsalisyy pp pp Oriental fruit fly Oriental fruit fly BactroceraBactrocera dorsalisdorsalis

34


The two species of mThe two species of mango leafhopper ango leafhopper The two species of mThe two species of mango leafhopper ango leafhopper are the are the most destructive pests during most destructive pests during

fl i fl i mango flowering stagemango flowering stage

Mango red spider miteMango red spider mite ((OligonychusOligonychusmangiferusmangiferus) has become a serious ) has become a serious mangiferusmangiferus) has become a serious ) has become a serious foliage pest in recent years.foliage pest in recent years.g p yg p y

35


Pest (Number of pesticides and Pest (Number of pesticides and formulations year) formulations year) formulations, year) formulations, year) MMango shoot bores (4) ango shoot bores (4) California red scale (California red scale (22) ) Mango Mango psyllidpsyllid ((22‐‐3)3)Mango Mango psyllidpsyllid ((22 3)3) Small yellow Small yellow thripsthrips (1)(1) OO i l f i fl (i l f i fl ( ) ) OOriental fruit fly (riental fruit fly (2) 2) MMango leafhoppers (ango leafhoppers (55, 1982), (6, 1986), , 1982), (6, 1986), g pp (g pp (55, 9 ), ( , 9 ),, 9 ), ( , 9 ),(12, 1994), (18, 2000), (23, 2002), (27, (12, 1994), (18, 2000), (23, 2002), (27,

) ( ) ) ( ) 2004), (30, 2007) 2004), (30, 2007) 36

Th f i id d i Th f i id d i


The amount of pesticides sprayed in The amount of pesticides sprayed in YujingYujing area is not traceable now, butarea is not traceable now, butYujingYujing area is not traceable now, butarea is not traceable now, but

“F t lli di d i t t “F t lli di d i t t For controlling disease and insect pests, For controlling disease and insect pests, fungicides and insecticides were usually fungicides and insecticides were usually mixed in solutions for spraying at the same mixed in solutions for spraying at the same time and the concentrations of individual time and the concentrations of individual ffagent were usually much higher than the agent were usually much higher than the regulation permitted Spraying of such regulation permitted Spraying of such regulation permitted. Spraying of such regulation permitted. Spraying of such mixed solution resulted in the damage of mixed solution resulted in the damage of foliage flower and fruit settingfoliage flower and fruit setting ” (1975” (1975 1976)1976)foliage, flower and fruit setting.foliage, flower and fruit setting. (1975 (1975‐‐1976)1976)

37


Chang Chang et alet al. (1979) considered the . (1979) considered the gg ( 979)( 979)spraying of fungicides and pesticides spraying of fungicides and pesticides i j d t h i l i ll i j d t h i l i ll injured mango trees physiologically injured mango trees physiologically and caused unfruitfulness and shy and caused unfruitfulness and shy yycropping of mango in cropping of mango in YujingYujing. However, . However, the overuse and/or misuse of the overuse and/or misuse of the overuse and/or misuse of the overuse and/or misuse of pesticides also likely caused local pesticides also likely caused local extinction of pollinators.extinction of pollinators.

38


Target pests were killed by pesticides Target pests were killed by pesticides and farmers enjoyed a bumper harvest and farmers enjoyed a bumper harvest and farmers enjoyed a bumper harvest. and farmers enjoyed a bumper harvest. As nonAs non‐‐target pollinators were also target pollinators were also killed by pesticides to a point that killed by pesticides to a point that pollination become impossible, farmers pollination become impossible, farmers pollination become impossible, farmers pollination become impossible, farmers then suffered a collapse of yield. then suffered a collapse of yield.

The yield would not recover before the The yield would not recover before the yyfunctional diversity of pollinators was functional diversity of pollinators was rebuilt from surrounding forestrebuilt from surrounding forestrebuilt from surrounding forest.rebuilt from surrounding forest.

39


The fluctuation of annual yield The fluctuation of annual yield The fluctuation of annual yield The fluctuation of annual yield apparently was related to an unstable apparently was related to an unstable population or local extinction of population or local extinction of nonnon‐‐target pollinators target pollinators nonnon‐‐target pollinators. target pollinators.

40

Results: Pollinator disappearanceResults: Pollinator disappearance

Unaware that the misuse of pesticides Unaware that the misuse of pesticides was the cause of shy cropping of was the cause of shy cropping of was the cause of shy cropping of was the cause of shy cropping of mango in 1975, the government went mango in 1975, the government went on to subsidize more mechanical on to subsidize more mechanical pesticide spraying facilities to mango pesticide spraying facilities to mango pesticide spraying facilities to mango pesticide spraying facilities to mango growers in growers in YujingYujing from 1976 and on and from 1976 and on and this was not helpful to rebuild the this was not helpful to rebuild the functional diversity of pollinators and functional diversity of pollinators and functional diversity of pollinators and functional diversity of pollinators and consequently the improvement of crop consequently the improvement of crop i ldi ldyield.yield.

41

Results: Discovering an alternative pollinator

While decline in fruit set was getting While decline in fruit set was getting more pronounced year after year, more pronounced year after year, mango trees around the garbage dump mango trees around the garbage dump mango trees around the garbage dump mango trees around the garbage dump site continued to have high fruit set.site continued to have high fruit set.

Abundance of oriental latrine fly Abundance of oriental latrine fly yy((ChrysomyaChrysomya megacephalamegacephala) at the ) at the

b d it b l t d t th b d it b l t d t th garbage dump site may be related to the garbage dump site may be related to the success of mango fruit set.success of mango fruit set.gg

42

Results: Discovering an alternative pollinatorResults: Discovering an alternative pollinator

Visceral of chicken and/or hog was Visceral of chicken and/or hog was k h d i h f l k h d i h f l taken to the dump site so that female taken to the dump site so that female

flies laid eggs on the visceral. Days flies laid eggs on the visceral. Days flies laid eggs on the visceral. Days flies laid eggs on the visceral. Days later, the visceral filled with maggots later, the visceral filled with maggots

b ht t th h d b ht t th h d was brought to the mango orchards. was brought to the mango orchards. The newly emerged flies then stayed The newly emerged flies then stayed y g yy g yin the mango orchards and in the mango orchards and reproduced more offspring on site reproduced more offspring on site reproduced more offspring on site. reproduced more offspring on site.

43


To cost down, the mango growers To cost down, the mango growers , g g, g glater replaced the visceral with fish, later replaced the visceral with fish, which was much cheaper in price which was much cheaper in price which was much cheaper in price, which was much cheaper in price, to attract the oriental latrine fly to attract the oriental latrine fly during mango flowering season. during mango flowering season.

44


The abundant oriental latrine fly The abundant oriental latrine fly l h l d ll dl h l d ll dapparently helped pollination and apparently helped pollination and

mango fruit set, and brought the crop mango fruit set, and brought the crop mango fruit set, and brought the crop mango fruit set, and brought the crop production back to normal. This production back to normal. This fi di d fi di d finding encouraged more mango finding encouraged more mango growers to leave decayed visceral of growers to leave decayed visceral of g yg ydomestic animals in their orchards to domestic animals in their orchards to maintain a high population of oriental maintain a high population of oriental maintain a high population of oriental maintain a high population of oriental latrine flies.latrine flies.

45


Field experiment showed that the Field experiment showed that the pporiental latrine fly was indeed an oriental latrine fly was indeed an effective pollinator In1991 the effective pollinator In1991 the effective pollinator. In1991, the effective pollinator. In1991, the mango yield of Tainan County mango yield of Tainan County reached 42.5% of that of Taiwan and reached 42.5% of that of Taiwan and this ratio remained to be around 50% this ratio remained to be around 50% this ratio remained to be around 50% this ratio remained to be around 50% till now. till now.

46


Prior to Stages 3, the value of mango Prior to Stages 3, the value of mango d d i T i C t % d d i T i C t % produced in Tainan County was 77% produced in Tainan County was 77%

(1968), 73% (1970) and 79% (1972) of (1968), 73% (1970) and 79% (1972) of 9 73 97 79 979 73 97 79 97that of Taiwan, but dropped to 68% at that of Taiwan, but dropped to 68% at the beginning of Stage 3 in 1975 and the beginning of Stage 3 in 1975 and the beginning of Stage 3 in 1975 and the beginning of Stage 3 in 1975 and further dropped to 60% (1976), 53% further dropped to 60% (1976), 53% (1980) and 41% (1981). Statistics on (1980) and 41% (1981). Statistics on annual mango value became annual mango value became annual mango value became annual mango value became unavailable after 1981. unavailable after 1981.

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Results:Results: Cost of losing pollinator diversityCost of losing pollinator diversity

T k 8 l th T k 8 l th Take year 1980 as an example, the Take year 1980 as an example, the total value of mango production in total value of mango production in g pg pTaiwan was NTD1,067 million. If Taiwan was NTD1,067 million. If value of mango production in value of mango production in value of mango production in value of mango production in Tainan County remained to be 70% Tainan County remained to be 70% of that of Taiwan, the value would of that of Taiwan, the value would have been NTD747 million have been NTD747 million have been NTD747 million. have been NTD747 million.

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Results: Cost of losing pollinator diversityResults: Cost of losing pollinator diversity

The real value of mango produced in The real value of mango produced in Tainan County that year was only Tainan County that year was only Tainan County that year was only Tainan County that year was only NTD569 million. The difference NTD569 million. The difference between the expected value and the between the expected value and the true value was NTD178 million true value was NTD178 million true value was NTD178 million. true value was NTD178 million.

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The mango crop reduction in Tainan The mango crop reduction in Tainan County due to loss of functional County due to loss of functional County due to loss of functional County due to loss of functional diversity of pollinators in diversity of pollinators in YujingYujing area area

ll l fll l fwas NTD178 million in 1980 alone. If was NTD178 million in 1980 alone. If we take a conservative estimate that we take a conservative estimate that we take a conservative estimate that we take a conservative estimate that Tainan County lost NTD100 million Tainan County lost NTD100 million

d i St th th t t l d i St th th t t l per year during Stage 3, then the total per year during Stage 3, then the total monetary loss due to loss of pollinator monetary loss due to loss of pollinator y py pdiversity would have been NTD1.8 diversity would have been NTD1.8 billionbillionbillion.billion.

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The finding of oriental latrine fly The finding of oriental latrine fly solved the problem of mango solved the problem of mango solved the problem of mango solved the problem of mango pollination and subsequent fruit pollination and subsequent fruit setting and fruit production. However, setting and fruit production. However, YujingYujing was filled with stinky smell of was filled with stinky smell of YujingYujing was filled with stinky smell of was filled with stinky smell of dead fish during the mango flowering dead fish during the mango flowering season. season. YujingYujing people had to tolerate people had to tolerate numerous oriental latrine flies flying numerous oriental latrine flies flying numerous oriental latrine flies flying numerous oriental latrine flies flying around as well as to live with the smell around as well as to live with the smell f h f h for months. for months.

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In addition, the oriental latrine fly is In addition, the oriental latrine fly is , y, yknown for producing known for producing myiasismyiasis in in humans and other animals and humans and other animals and humans and other animals and humans and other animals and transmitting pathogens. It was transmitting pathogens. It was reported as the most dangerous reported as the most dangerous dipterandipteran vectors of enteric pathogens vectors of enteric pathogens dipterandipteran vectors of enteric pathogens vectors of enteric pathogens and the dominant vector of and the dominant vector of helminthhelminthparasite eggs. parasite eggs.

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To avoid the stinky odor, several To avoid the stinky odor, several formula of artificial diet for massformula of artificial diet for mass‐‐formula of artificial diet for massformula of artificial diet for massrearing oriental latrine flies were rearing oriental latrine flies were d l d I di f h ifi i l d l d I di f h ifi i l developed. Ingredients of the artificial developed. Ingredients of the artificial diet for fly larva included bean powder, diet for fly larva included bean powder, y p ,y p ,fish meal and chicken feed. The fish meal and chicken feed. The ad antage of using this artificial diet ad antage of using this artificial diet advantage of using this artificial diet advantage of using this artificial diet was economic, convenient, clean, was economic, convenient, clean, odorless, and satisfactory nutritional odorless, and satisfactory nutritional content for normal development of fly content for normal development of fly content for normal development of fly. content for normal development of fly.

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Mango growers in Mango growers in YujingYujing accepted the accepted the odorless artificial diet to massodorless artificial diet to mass‐‐rearing rearing odorless artificial diet to massodorless artificial diet to mass rearing rearing flies for pollination and the dead fish flies for pollination and the dead fish

ll l lll l lsmell was no longer an environmental smell was no longer an environmental problem after 1990s. However, the problem after 1990s. However, the problem after 1990s. However, the problem after 1990s. However, the potential risk of the oriental latrine potential risk of the oriental latrine fli i di it fli i di it flies carrying diseases or parasites as flies carrying diseases or parasites as vectors, and the nuisance problems vectors, and the nuisance problems , p, pcaused by flies to caused by flies to YujingYujing communities communities remain to be assessed and managed remain to be assessed and managed remain to be assessed and managed. remain to be assessed and managed.

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Relying on a single artificially reared Relying on a single artificially reared pollinator for pollination, like hand pollinator for pollination, like hand pollinator for pollination, like hand pollinator for pollination, like hand pollination, is unnatural and may not pollination, is unnatural and may not b i bl I i f b i bl I i f be sustainable. Interview of mango be sustainable. Interview of mango growers indicated that not all mango growers indicated that not all mango g gg gvarieties rely solely on oriental latrine varieties rely solely on oriental latrine fli f lli ti A fli f lli ti A flies for pollination. As more mango flies for pollination. As more mango varieties are introduced or developed, varieties are introduced or developed, ppmore diverse pollinators may be more diverse pollinators may be needed for successful fruit production needed for successful fruit production needed for successful fruit production. needed for successful fruit production.

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Low pollinator diversity may limit the Low pollinator diversity may limit the Low pollinator diversity may limit the Low pollinator diversity may limit the chances of producing new fruit chances of producing new fruit varieties. Furthermore, high varieties. Furthermore, high population of flies may continue to population of flies may continue to population of flies may continue to population of flies may continue to compete out other potential pollinators compete out other potential pollinators

d k h b l f ld k h b l f land make rehabilitation of natural and make rehabilitation of natural pollinators difficult. pollinators difficult. pollinators difficult. pollinators difficult.

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The impact of losing the original The impact of losing the original pollinator diversity on natural pollinator diversity on natural pollinator diversity on natural pollinator diversity on natural vegetation within and around mango vegetation within and around mango orchard, thus the loss of ecosystem orchard, thus the loss of ecosystem function, such as nutrient cycling, function, such as nutrient cycling, function, such as nutrient cycling, function, such as nutrient cycling, water and soil conservation, water and soil conservation,

i f bili i f bili maintenance of ecosystem stability, maintenance of ecosystem stability, etc., that may affect mango orchard etc., that may affect mango orchard , y g, y gmanagement in the long run may management in the long run may

b k b knever be known.never be known.57

Results: Recent development of mango productionResults: Recent development of mango production

As the mango cultivation practice As the mango cultivation practice mature, mango production stabilized mature, mango production stabilized and the demand for better quality and the demand for better quality and the demand for better quality and the demand for better quality and safer fruit product increased, and safer fruit product increased, more mango growers began to bag more mango growers began to bag their fruits from the damage of insect their fruits from the damage of insect their fruits from the damage of insect their fruits from the damage of insect pests. pests.

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The bagging technique is labor intensive The bagging technique is labor intensive and the labor cost can only be covered if the and the labor cost can only be covered if the produce is exported or sold in organic produce is exported or sold in organic produce is exported or sold in organic produce is exported or sold in organic market. market. 59


In fact, the recent opening of foreign In fact, the recent opening of foreign , p g g, p g gmarket such as Japan, Europe, and market such as Japan, Europe, and Chi d Chi d China, encouraged more mango China, encouraged more mango growers to follow the strict export growers to follow the strict export g pg pregulation and reduce the use of regulation and reduce the use of pesticides This bagging method is pesticides This bagging method is pesticides. This bagging method is pesticides. This bagging method is an environmentally friendly act an environmentally friendly act toward recovering pollinator diversity.toward recovering pollinator diversity.

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Reducing the use of pesticides alone Reducing the use of pesticides alone is not enough. We recommend a more is not enough. We recommend a more is not enough. We recommend a more is not enough. We recommend a more proactive approach to restore proactive approach to restore

lli di i i lli di i i pollinator diversity in mango pollinator diversity in mango production system, which may production system, which may p y , yp y , yinclude protection of remaining include protection of remaining ildness set refuge for pollinators in ildness set refuge for pollinators in wildness, set refuge for pollinators in wildness, set refuge for pollinators in

or around the mango production or around the mango production g pg psystem, and reintroducing or system, and reintroducing or restocking local pollinatorsrestocking local pollinatorsrestocking local pollinators.restocking local pollinators.

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llConclusionConclusionIn the past 6 decades, the society and In the past 6 decades, the society and In the past 6 decades, the society and In the past 6 decades, the society and economy of Taiwan benefited greatly economy of Taiwan benefited greatly f ti di it f f ti di it f from genetic diversity of mango. from genetic diversity of mango. However, overuse and/or misuse of However, overuse and/or misuse of , /, /pesticide probably caused decline or pesticide probably caused decline or loss of pollinator diversity and the loss of pollinator diversity and the loss of pollinator diversity and the loss of pollinator diversity and the failure of pollination in turn reduced failure of pollination in turn reduced mango production in mango production in YujingYujing, a key , a key mango producing area in Taiwan mango producing area in Taiwan mango producing area in Taiwan. mango producing area in Taiwan.

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ConclusionConclusionConclusionConclusionMango growers suffered a great Mango growers suffered a great economic loss due to loss of economic loss due to loss of functional diversity of mango functional diversity of mango functional diversity of mango functional diversity of mango pollinators during the period from pollinators during the period from 1975 to 1992. The finding and mass1975 to 1992. The finding and mass‐‐rearing of an alternative pollinator rearing of an alternative pollinator rearing of an alternative pollinator, rearing of an alternative pollinator, the oriental latrine fly the oriental latrine fly C. C.

h lh l h d h h d h megacephalamegacephala, have ensured a rather , have ensured a rather stable mango harvest since 1990s. stable mango harvest since 1990s. g 99g 99

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C l iC l iConclusionConclusionIn order to maintain satisfactory fruit In order to maintain satisfactory fruit yyproduction, production, YujingYujing suffered from the suffered from the stinky smell of dead fish and the stinky smell of dead fish and the stinky smell of dead fish, and the stinky smell of dead fish, and the nuisance and potential health risk nuisance and potential health risk caused by flies. The problem of smell caused by flies. The problem of smell was fortunately solved though the was fortunately solved though the was fortunately solved, though the was fortunately solved, though the nuisance problem and the health nuisance problem and the health issue remain to be assessed and issue remain to be assessed and managed managed managed. managed.

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ConclusionConclusionThe increasing dependency on single The increasing dependency on single The increasing dependency on single The increasing dependency on single pollinator increases the risk of stable pollinator increases the risk of stable harvest and limits the potential of harvest and limits the potential of growing new varieties To manage the growing new varieties To manage the growing new varieties. To manage the growing new varieties. To manage the risk, a restoration program on risk, a restoration program on

ll d d dll d d dpollinator diversity is recommended pollinator diversity is recommended so to maintain a functional diversity so to maintain a functional diversity so to maintain a functional diversity so to maintain a functional diversity of pollinators in mango orchard.of pollinators in mango orchard.

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AcknowledgementAcknowledgement

We would like to thank Dr. Ku TeWe would like to thank Dr. Ku Te‐‐YehYehof FFTC for his inspiration to link of FFTC for his inspiration to link pollinator diversity with mango pollinator diversity with mango pollinator diversity with mango pollinator diversity with mango production in this paper. Thanks are production in this paper. Thanks are also extended to Ms. Wu also extended to Ms. Wu WenWen‐‐HsinHsinfor her help in data analysis and graph for her help in data analysis and graph for her help in data analysis and graph for her help in data analysis and graph preparation.preparation.

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[email protected]@tfri.gov.tw

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wewewe reportreport a level. - 農研機構 ... brown leafhopper idioscopus nivesparsus mmangoango...

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