Introduction

Per capita consumption of fruits in Pakistan repre-sents their greater demand, particularly apple, ber,guava and mango. However, like other agriculturalcrops these are attacked by a number of insect peststhat ultimately reduce the yield and affect the mar-ketable quality of these most perishable ones. The useof pesticides, a possible threat to our environment, hasnot only created problems like development of resis-tance but has also increased the production costs tomany folds. There is thus a need to develop strate-gies, which are environmental friendly besides beingeconomical. The use of all control practices in com-patible manner perhaps provides answer to such a sit-uation at present. This means that use of cultural andbehaviour modifying tactics as major components andpesticides only as synergists can help to combat this

dilemma.Fruit flies are amongst the most commonly fruit

damaging insects in Pakistan. In certain cases, fruitsrot out at the punctured sites. In one of the studies, theoriental fruit fly Bactrocera dorsalis (Bezzi) caused5-100 percent loss to various fruits in Pakistan (Syedet al., 1970). Losses up to 80 percent have been repor-ted in guava fruits (Kafi, 1986). Similarly, Jalaludin etal. (1999) reported 60-80 percent losses in guavafruits by B. dorsalis. Meanwhile, Kapoor (1993)reported that ber fruit fly could cause 90-100 percentdamage to ber fruit.

Many conventional and modern techniques of pestcontrol have been tested to avoid the losses caused byfruit flies in the world. These pests control techniquesinclude orchard sanitation, physical, chemical, biolo-gical control and sterile male technique (Vijaysergaran,1991). However, in Pakistan, the sole reliance has beenmade on pesticides for the control of fruit flies, whichhas created environmental contamination, residuesproblem, killing of nontarget species, and development

ENTOMOLOGICAL RESEARCHVol. 35, No. 2, pp. 79-84, June 2005

Management of Fruit Flies (Diptera: Tephritidae) of the Most Perishable Fruits

KHAN, Muhammad Ahsan1, Muhammad ASHFAQ1, Waseem AKRAM* and Jong-Jin LEE

College of Agriculture and Life Science, Chonbuk National University, Korea;1Department of Agri-Entomology, University of Agriculture, Faisalabad, Pakistan

ABSTRACT We investigated to minimize the dependency on the use of chemicals and thusdevelop safe and environmental friendly control program for the most perishable fruits i.e., apple,‘ber’, guava and mango. Our findings on the composition of fruit fly species reveal that Bactroceradorsalis was dominant on apple (33.96% existence), Corpomya incompleta on ‘ber’ (51.91%existence) and Bactrocera zonata on guava (49.62% existence) and mango (74.66% existence).The correlation between population and infestation percentage was non-significant in appleorchards, whereas positive and highly significant in between population and infestation, as well ason the cumulative basis in ‘ber’, guava and mango orchards during 1998-1999. Hoeing, baitingand methyl eugenol were statistically equal resulting about 77% decrease in infestation. Themaximum control of 91.68% was observed where all four-control operations including Dipterex�

were integrated together. Weather factors, when computed together, had maximum effect onpopulation fluctuation and infestation with rainfall contributing the major role. For guava fruits,the months of August (14.06A individuals/trap/day) and September (13.81A individuals/trap/day)were important, resulting in maximum infestation percentage of 10.76 to 14.74%, respectively.

Key words : Fruit flies, Management, Non-chemical, Perishable fruits

*Corresponding authorE-mail: apwaseem18@yahoo.com, Tel: 82-63-270-2528

Research Paper

Entomol. Res., 35(2), June 200580

of resistance in insects. Presently, the use of malelures and protein baits is being fostered for the controlof fruit flies. These measures are not practiced in inte-grated manner (Khan, 1997). Therefore, there is a direneed to develop a long lasting pest control strategy.

The present project has thus been developed on lowcost basis to manage fruit flies through combinationof various control strategies that minimize the indis-criminate use of insecticides.

Materials and Methods

Studies were carried out on the management of fruitflies during the year 1998-2001 on four most com-monly consumed fruits viz. apple, ber, guava andmango at four selected localities. The data on popu-lation dynamics by installing methyl eugenol and cuelure traps, and infestation percentage by ring methodwere recorded for two years from 1998 to 1999 ineach selected fruit of its respective locality. Fruit fliescollected from each fruit plant were identified. Thepest was managed through integrated approachincluding hoeing, baiting and using insecticideindividually and in all-possible combinations on thefruit showing maximum infestation. Role of abioticfactors on population fluctuation per trap and infes-tation percentage of fruit flies were determined byprocessing the data into simple correlation, multipleregression models and principal components analysis(PCA).

Eight gardens with at least 30 trees in each wereselected. Sex attractants methyl eugenol and cue lure@ 5-6 mL each were used in traps for monitoring thepopulation. Four gardens were treated with methyleugenol and four with cue lure. Six traps per hectarewere installed at fortnightly interval with trap-to-trapdistance of 30±5 m for 24 hours. Each garden rep-resented one replication, thus there were four repli-cations for each trap and for each fruit at their respec-tive localities. The data were recorded from fruitformation to fruit maturity for two consecutive seasonsfor each fruit to the time when the trapped populationreached zero.

Infestation percentage was recorded at fortnightlyinterval from four randomly selected trees with thehelp of one square meter iron ring as follows.

No. of infested fruitsFruit infestation (%) =_________×100

Total number of fruits

The ring was placed at four sides of each selected

fruit tree. The total number of fruits and number ofinfested fruits in the ring were counted.

Meteorological observation on ambient temperature(X1 maximum, X2 minimum), relative humidity (X3),and rainfall (X4) were recorded for each locality toassess the effect of weather on the fruit fly population(Y1) and infestation percentage (Y2) on different fruitplants at their respective localities. The data weresubjected to square root transformation before statisti-cal correlation.

Study was conducted on guava orchard (showingmaximum infestation of fruits by fruit flies during thesummer fruiting season of the year 2001). Four con-trol practices viz. hoeing (T1), baiting (T2), sex attrac-tant pheromone (methyl eugenol) (T3) and Dipterex�

80 SP (T4) were applied singly and in their possiblecombinations as: Hoeing±Baiting (T5); Hoeing±Sexpheromone (T6); Hoeing±Dipterex� 80 SP (T7);Baiting±Methyl eugenol (T8); Baiting±Dipterex� 80SP (T9); Methyl eugenol±Dipterex� 80 SP (T10);Hoeing±Baiting±Methyl eugenol (T11); Hoeing±Baiting±Dipterex� 80 SP (T12); Hoeing±Methyleugenol±Dipterex� 80 SP (T13); Baiting±Methyleugenol±Dipterex� 80 SP (T14); Hoeing±Baiting±Methyl eugenol±Dipterex� 80 SP (T15); and Control(T16), thus making a total of 16 treatments including acontrol. There were three replications for each treat-ment. One garden represented one replication with 30trees, thus a total of 48 gardens were selected. Thegarden-to-garden distance was approximately onekilometer. Hoeing was done under the canopy of eachtree at 15 days interval throughout the fruiting season.

Six-methyl eugenol traps per hectare with trap-to-trap distance 30 meters were used for mass capturingof fruit flies in guava orchards because these showedmaximum catches compared with cue lure. The trapscontaining the baits affixed on 15×30 cm woodensheet were installed 1.5 meter above ground level onbranches of the tree. The cotton wicks soaked withmethyl eugenol were placed in traps and changed after15 days interval, while the baits were changed after 30days interval. The data on trapped adult population offruit flies were recorded fortnightly throughout thefruiting season.

The data so collected was subjected to statisticalanalysis using RCB design. The means were com-pared by DMR test at p = 0.05. The impact of weatherfactors on population fluctuation and infestation offruit flies for each fruit was calculated by processingthe data into simple correlation. The data was alsoprovided for multivariate regression models among

abiotic factors, population fluctuation and infestationwith the objective to see the actual role of weatherfactor on population fluctuation and infestation offruit flies. Principal component analysis (PCA) wasalso performed to determine the influence of weatherfactors on infestation and population of fruit flies.

Results and Discussion

Relatively small mean population of fruit flies wasrecorded on apple at Murree Hills during the twoyears, ranging from a maximum of 1.31 individu-als/trap/day to a minimum of 0.56 individuals/trap/dayon August 1 and October 1, respectively. Maximuminfestation by fruit flies in apple orchards was record-ed (4.61%A) on October 1 being statistically at parwith 4.53%A and 4.51%A recorded on September 15and October 15, respectively (Fig. 1).

The entire month of March was crucial for ‘ber’fruits with maximum catches of fruit flies during first(14.18A individuals/trap/day) and second (10.68Bindividuals/trap/day) fortnight (Fig. 2). Infestationpercentage was maximum (14.72%A) on March 1followed by February 15 and March 15 (11.33%A and10.26%A, respectively).

For guava fruits, the months of August (14.06Aindividuals/trap/day) and September (13.81A indi-viduals/trap/day) were important, present findings arein agreement with those of Bascan et al. (1989) andVargas et al. (1989) who observed population peaks onguava in autumn (Fig. 3). As far as the infestationpercentage values are concerned, population of fruitflies remained throughout the fruiting season fromflowering to maturity, resulting in maximum infes-tation during the second fortnight of August (13.87%B)and 1st fortnight of September (15.85%B).

The months of July (10.56AB individuals/trap/day)

Khan et al. : Management of Fruit Flies 81

0

3

6

Jul. Aug. Sep. Oct. Nov.

Pop

ulat

ion

trap

ped

vs in

fest

atio

n %

Pop. Trap

Infest.%

Fig. 1. Average population trapped and infestation % of fruitflies in apple fruits 1998-1999 (15 days data collection inter-val Jul.-Nov.).

0

10

20

May Jun. Jul. Aug. Sep. Oct.

Pop

ulat

ion

trap

ped

vs in

fest

atio

n % Pop. Trap

Infest.%

Fig. 3. Average population trapped and infestation % of fruitflies in guava fruits 1998-1999 (15 days data collection inter-val May-Oct.).

Dec. Jan. Feb. Mar. Apr.

Pop

ulat

ion

trap

ped

vs in

fest

atio

n %

0

10

20

Pop. Trap

Infest.%

Fig. 2. Average population trapped and infestation % of fruitflies in ber fruits 1998-1999 (15 days data collection intervalDec.-Apr.).

0

5

10

15

Mar. Apr. May Jun. Jul. Aug. Sep. Oct.Pop

ulat

ion

trap

ped

vs in

fest

atio

n %

Pop. Trap

Infest.%

Fig. 4. Average population trapped and infestation % of fruitflies in mango fruits 1998-1999 (15 days data collection in-terval Mar.-Oct.).

and August (11.18A individuals/trap/day) showedmaximum adult catches of fruit flies in mango or-chards (Fig. 4). These results are in direct conformitywith those of Mann (1996). Maximum infestation(10.25%A) was recorded on September 15 and theinfestation percentage did not differ significantly fromthose recorded on October 1 (9.68%A).

The percent values of existence versus infestationagainst total catches have reportedly been higher forguava fruit showing existence (%) versus infestation(%) as 29.70 : 7.56% (524) followed by 20.75 : 5.66%(366), 46.54 : 5.32% (821) and 3.00 : 2.39% (53) on‘ber’ mango and apple, respectively.

Methyl eugenol traps showed maximum percentexistence of fruit flies in all the fruit orchards duringthe two fruiting years (1998-1999). B. dorsalis wasdominant on apple (33.96% existence), Corpomyaincompleta on ‘ber’ (51.91% existence) and B. zonataon guava (49.62% existence) and mango (74.66%existence). B. dorsalis was also very serious on guavawith 46.37% existence. Similarly B. zonata, C.vesuviana and B. cucurbitae were at second place andfound serious for apple (28.30% existence), ‘ber’(36.34% existence) and mango (21.80% existence),respectively. It was also found that maximum species(six) of fruit flies were recorded on apple followed byguava (five).

The correlation between population and infestationpercentage of fruit flies was non-significant (-0.136)in apple orchards (Table 1). A positive and highly

significant correlation was recorded between popula-tion and infestation in ‘ber’ (0.942*, 0.804*, 0.868*)and guava (0.902*, 0.938*, 0.919*). However, thecorrelation in mango fruits was non-significant dur-ing 1998, while in 1999 and on cumulative basis thecorrelation was highly significant with positive res-ponse (0.453NS, 0.605*, 0.525*, respectively).

Weather factors played significant contributiontowards population fluctuation and infestation percen-tage of fruit flies in apple, guava and mango orchards,whereas in orchards of ‘ber’ these factors remainednon-significant towards population fluctuation andinfestation. All other factors, when computed togethercontributed maximum towards population fluctuationand infestation. Principal component analysis (PCA)reveals that rainfall exerted positive influence onpopulation fluctuation and infestation with 92.87,68.13, 87.90 and 69.21 percent variance for apple, ber,guava and mango fruits, respectively.

On an average of two year’s studies weather factorsdid not play a significant role towards fluctuationwhereas, temperature and relative humidity with posi-tive responses affected percentage significantly. The r2

values were 0.174 and 0.209 for population and infes-

Entomol. Res., 35(2), June 200582

Table 1. Correlation coefficient values between populationper trap per day and infestation (%) in various selected fruitsat different localities during various study years

Name Numberof Years r-Values of cases

fruit computed

1998 -0.269NS 7Apple 1999 -0.167NS 7

Cumulative -0.136NS 14

1998-1999 0.942* 8Ber 1999-2000 0.804* 8

Cumulative 0.868* 16

1998-1999 0.902* 11Guava 1999-2000 0.938* 11

Cumulative 0.919* 22

1998-1999 0.453NS 15Mango 1999-2000 0.605* 15

Cumulative 0.525* 30Overall 0.642* 82cumulative

*Significant at p⁄0.05, NS = Non-significant

0

10

20

30

Treatments

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10

T11

T12

T13

T14

T15

Con

trol

Infe

stat

ion

perc

enta

ge

Fig. 5. Management of fruit flies based on infestation per-centage in guava fruits during 2001.

0

50

100

T1 T2 T3 T4 T5 T6 T7 T8 T9T10 T11 T12 T13 T14 T15

% in

fest

atio

n de

crea

sed

Treatments

Fig. 6. Management of fruit flies based on percentage in-festation decrease of guava fruits during 2001.

tation when weather factors were computed together,the regression equation so calculated was Y1= -1.1442±0.3765X1±0.1059X2±0.1294X3-0.0503X4 and Y2

= -2.0531-0.2732X1±0.6249X2±0.3751X3-0.0159X4, respectively. Rainfall proved to be the mostimportant factor with positive response in combina-tion with contrasting behaviour of temperature show-ing 85.96 percent variance.

All the control measures viz., hoeing, baiting, phe-romone traps and use of chemical (Dipterex� 80 SP@1 gm/liter water) showed lowest infestation of fruitflies i.e., 2.44% (T15) in guava orchards followed by2.86% (T13) in combination of hoeing±pheromone±use of chemical (Fig. 5), reducing the infestation upto 91.68 and 90.25%, respectively (Fig. 6). Theinfestation level of 5.39% (T11) was recorded in com-bination of hoeing, baiting and use of pheromones asagainst 29.34% infestation in control with infestationbeing reduced up to 81.63% in the absence of insec-ticidal application. More over, it is also clear that mi-nimum catches of fruit flies were recorded in applefruit, resulting in lowest infestation percentage.

Keeping in view the results, significant differenceswere recorded amongst dates of observations andtreatments. All the control methods gave significantcontrol of fruit flies as compared to control treatment(Singh et al., 2000). Hoeing, baiting and methyleugenol were statistically equal resulting in 76.52(T1), 76.58 (T2) and 76.76% (T3) decrease in infes-tation, respectively. These findings are not in confir-mation with those of Marwat et al. (1992) who report-ed that the larval infestation was reduced up to24.14% by mass trapping of males. In present studies,maximum control was observed where all the controloperations were integrated together showing 91.68%(T15) reduction in infestation followed by 90.25%(T13) reduction in infestation when hoeing, methyleugenol and the insecticide were applied together. Thedecrease in the infestation was 81.63% (T11) wherechemical control was excluded. Use of Dipterex� 80sp @1 gm/one liter water alone resulted in 71.09%(T4) decrease in infestation. Present findings are inpartial agreement with those of Abbasi et al. (1992)who reported Dipterex was the most effective in reduc-ing larval infestation. Similarly, Chughtai and Baloch(1998) reported Dipterex� gave best results amongstvarious insecticides. Cultural practices as suggestedby Schmid et al. (1998) are supportable with the pre-sent studies to some extent as it was found that thecombined application of pheromones, hoeing andbaiting resulted in significant control of fruit flies in

guava orchards.The present findings however, cannot be compared

with Makhmoor and Singh (1998) due to the differ-ences in their materials and methods. We are partiallyin agreement with the results of Mahmood et al.(1995) who recorded better control with Dipterex� incombination with methyl eugenol baited traps. Ourstudies are also in line with the achievements ofEnkerlin and Mumfore (1997) and Jaiswal et al.(1997).

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(Received 5 January 2005; Accepted 24 January 2005)