Occurrence and Seasonal Abundance of Fruit Fly, Bactrocera zonata Saunders (Diptera: Tephritidae) in Relation to Meteorological Factors

Rashid Ahmed Khan* and Muhammed Naveed

Plant Protection Division (PPD), Nuclear Institute for Agriculture and Biology, P.O. Box 128, Jhang Road, Faisalabad, Pakistan

ABSTRACT

Fruit flies belonging to the genus, Bactrocera are among the major pests of fruits worldwide. Among the many species of fruit flies, Bacterocera zonata is a serious pest of fruits causing severe losses to the fruit production and quality, in Pakistan. In the present experiment the population of B. zonata was monitored using methyl eugenol traps during the year, 2015. Occurrence and population dynamics of the fruit fly were compared with meteorological factors, such as temperature, relative humidity and sunshine. The highest mean population of fruit fly remained at 499 in the month of August. It started to decline afterwards and remained at 348 in the month of September. The lowest population was recorded at 26, 3, 2 and 1 for November, December, January and February, respectively. The optimum monthly average temperature and relative humidity ranged from 26 to 35 °C and 60%, respectively. The population of the fruit fly was positively correlated with the temperature and slightly negative correlation was seen for relative humidity.

Article Information

Received 21 June 2016

Revised 22 August 2016

Accepted 16 January 2017

Available online 10 May 2017

Authors’ Contribution

RAK conceived and designed the study, performed analysis and wrote the article. MN performed experimental work and helped in data collection.

Key words

Bactrocera zonata, Methyl eugenol, Population dynamics, Meteorological factors.

DOI: http://dx.doi.org/10.17582/journal.pjz/2017.49.3.999.1003

* Corresponding author: rashidpp2004@yahoo.co.uk

0030-9923/2017/0003-0999 $ 9.00/0

Introduction

True fruit flies (Diptera: Tephritidae) comprising of approximately 4,500 species distributed globally are considered serious pests of soft fruits (White and Elson-Harris, 1992; Tan and Nishida, 1998). Out of these about 40 species of the genus, Bactrocera are considered to be important pests.

Among the fruit fly, the peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) is the most abundant and serious pest of fruit orchards in the world. It attacks fruit like guava, peach, mango, citrus, apricot, fig and apple etc. Besides fruits, it may infest some vegetables like tomato, pepper and eggplants as secondary hosts (Kapoor and Agarwal, 1982; Liquido et al., 1990; White and Elson-Harris, 1992; El-Minshawy et al., 1999; Hashem et al., 2004; Ghanim, 2009; El-Gendy, 2012).

According to an estimate losses in fruits without management have been recorded at upto 24% to cucurbits in Pakistan (Stonehouse et al., 1998). Two species of fruit flies established in different regions of Pakistan include, peach fruit fly, Bactrocera zonata and cucurbit fruit fly Bactrocera cucurbitae (Coquillett). Incidence and abundance of B. zonata has been recorded in coastal and sub-coastal areas of Baluchistan and Sindh, as well as semi-desert areas and northern plains of Punjab. Its presence has also been recorded as a rare pest from the foothills of Islamabad, Peshawar valley (Marwat et al., 1992).

The aim of the present study was to monitor fruit fly, B. zonata population throughout the year and to determine the influence of meteorological factors such as temperature, relative humidity and sunshine on the population dynamics of the peach fruit fly, B. zonata.

Materials and Methods

Study area

The experiment was conducted at the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad from January to December, 2015. The area in question mainly consists of mango, guava and citrus.

Design of the fruit fly trap and installation

The fruit fly trap was constructed from transparent plastic bottles of approximately 1 liter capacity. Two holes were cut, one in the lid and the other exactly the opposite to facilitate the entry of fruit flies. The holes were fitted with a PVC pipe of about 1/2 inch diameter with a length of 3 inches (Fig. 1). The lure was suspended exactly in the center. Ten traps were suspended with the branches of the fruit trees randomly about 2 meters above the soil surface. All the traps were randomly distributed among mango, guava and citrus plants.

Attractant used in the study

Commercial formulation of methyl eugenol, a sex pheromone used specifically for capturing of B. zonata was used. Using a syringe 1 ml of methyl eugenol was applied to cotton and then suspended in the middle of the bottle. The cotton swab was replaced every month with fresh ones.

Data analysis

Data of the ten traps were pooled for a single week and expressed as the number of fruit fly captured/month. Analysis of Variance (ANOVA) was performed using statix 8.1 and means were compared by Least Square Design (LSD). The differences among means were considered significant at P≤0.05 level. All the plots were drawn using software MS-EXCEL 2007.

Results and Discussion

The fruit fly population showed a trend of fluctuation throughout the year. The highest mean numbers of fruit fly catch, 499 was recorded in August and the lowest fruit fly catch, 2/trap/month was recorded in February. The highly active months of fruit fly were from May to September, whereas the highly inactive months were December to March. Moderate population was recorded in the month of November and April (Table I). The optimum minimum and maximum temperatures correspond to the peak level of the weekly fruit fly catch were recorded at 25-40 °C, whereas temperature above 40 °C and below 20 °C were critical for fruit fly as very low or no fruit fly was recorded (Fig. 2A). The most favorable relative humidity range for the fruit fly was recorded between 40-60 % (Fig. 2B). Rain fall had no impact on the fruit fly population (Fig. 2C). The peak in the fruit fly population also coincided with the ripening of fruits.

This kind of trend has also been shown in the mango orchards during the fruiting season (Mwatawala et al., 2006). In fact the presence of fruit trees and the fruiting duration can have significant effects on the peach fruit fly (Ye, 2001). The maximum population of peach fruit fly, Bactrocera zonata, was reported during the third week of June (357.0 flies/trap) in India. The peak population, 170.66 males/week, of the oriental fruit fly, Bactrocera spp. was also recorded in July in India (Agarwal and Kumar, 1999; Makhmoor and Singh, 1998). Abdel Galil et al. (2010) recorded a population peak of fruit flies in September that coincided with the ripening season of citrus, guava and mango. The present findings are more or less in line with the reports of the previous investigators.

Table I.- Fluctuation in the fruit fly population in relation to metrological data.

Months	Mean populationa	Average temperature °C		Relative humidity (%)	Sun- shine (h)
Months	Mean populationa	Max	Min	Relative humidity (%)	Sun- shine (h)
January	2.00H	16.48	6.89	75.32	4.99
February	1.67H	21.95	11.13	66.03	5.57
March	4.33H	24.50	13.64	64.03	6.99
April	51.00F	33.21	20.71	43.86	9.10
May	129.33C	36.69	24.87	27.54	10.61
June	70.67DE	38.12	25.57	38.96	9.5
July	79.33D	34.90	27	61.00	5.12
August	499.33A	35.90	26.70	60.00	6.97
September	348.67B	35.38	24.35	52.00	8.18
October	57.33EF	32.13	19.09	52.87	8.29
November	26.33G	27.10	12.06	61.50	6.58
December	3.67H	21.75	7.21	62.60	7

a Means within the same column followed by the different letters are significantly different at P≤0.05 level according to ANOVA LSD test.

The fruit fly population started to decline after August, reaching to significantly lower number in October (Table I). Win et al. (2014) also reported the lower population in the month of October and November. In another study, Mahmood and Mishkatullah (2007) recorded lower population of fruit fly from November to February, whereas an increase was recorded from March to August. They also recorded peak population of trapped fly adults in July and August, whereas the maximum decline was recorded in October, depending upon the availability of mature fruits and temperature.

The population again started to build up from April to July and attaining peak level in August. In an earlier investigation, the author claimed that the maximum population of Bactrocera species was recorded in August (Mahmood and Mishkatullah, 2007). In line with the previous investigation Dacus dorsalis appeared in the field in April and reached the maximum population in August (Gillani et al., 2002). These high fruit fly catches coincided with the guava fruiting season. The population dynamics of the fruit fly population are strongly influenced by the abiotic factors such as temperature and rainfall (Amice and Sales, 1997). The significant effect of the weather factors on population of the fruit fly and among them, rainfall have been reported as the most important factor. (Khan et al., 2003).

The lowest numbers of catches were recorded from December to March showing no significant differences in population. This may be due to the low availability of fruit and low temperature. The population of fruit fly started to build up at the end of March. The main factor affecting population build-up of fruit flies in the tropics is fruit abundance and availability (Papadopoulos, 1999). The availability of hosts and abundance of cultivated fruits such as, mangos and guavas are important factors which contribute to the population fluctuations of Bactrocera species (Drew and Hooper, 1983).

The weak positive correlation between fruit fly population and temperature was observed (Fig. 3A, B). No correlation was seen for sunshine hours, and relative humidity to the number of insects trapped (Fig. 4A, B). Amice and Sales (1997) observed influence of abiotic factors, such as temperature on the population dynamics of fruit flies. Win et al. (2014) reported a positive correlation (r=0.33) of minimum temperature with insect count. Similarly, positive correlation of the fruit fly with temperature was reported by Kannan and Venugopala (2006). Sarada et al. (2001) reported a population of Bactrocera sp. showed positive correlation with minimum temperature and weak positive correlation with maximum temperature. Our results are in agreement with these previous researchers.

Conclusion

Based on the results of our current studies, although the population of fruit fly is strongly influenced by the minimum and maximum temperatures, availability of the ripened fruits, especially mango and guava is a major limiting factor for the population build-up of B. zonata.

Acknowledgements

We sincerely thank Mr. Mureed Hussain Shah, PSA, Plant Protection Division, NIAB for maintenance of the fruit fly traps.

Statement of conflict of interest

We declare that we have no conflict of interest

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