Preference monitoring of Bactrocera spp. through installation of methyl eugenol traps at different heights in Jujube orchard

Preference monitoring of Bactrocera spp. through installation of methyl eugenol traps at different heights in Jujube orchard. Pure and Abstract An experiment was conducted during the years (2016 to 2017) on preference monitoring of Bactrocera spp. through installation of methyl eugenol traps at different heights in jujube orchard. The pheromone traps baited with lure toxicant mixture (95% methyl eugenol + Thiodan insecticide) were installed at (T1) = ground surface, (T2) = 1 m height. (T3) = 2 m height and (T4) = 3 m height. The effect of different heights of methyl eugenol pheromone traps on the male-adult B. zonata and B. dorsalis catches was statistically significant (P<0.05); and the fruit fly catches in traps varied significantly during 26-12-16 to 10-04-17 (P<0.05). The highest B. zonata catches (61.38) were monitored in traps installed at 2m height; while the weekly B. zonata trap catches simultaneously decreased to (51.35), (43.03) and (38.09) at trap heights of 3 m, 1m and 0 m (surface), respectively. The average weekly trap catches of B. zonata were 83.7. The maximum weekly B. dorsalis catches (0.49) were found in traps installed at 2 m height; while the weekly B. dorsalis trap catches decreased to 0.43, 0.36 and 0.29 when the traps were installed at 3 m, 1 m and 0 m (surface) heights, respectively. The average weekly trap catches of B. dorsalis were 7.65. It was concluded that the methyl eugenol pheromone traps were most effective when installed at 2 m height; while traps installed at 3 m and 1 m height could not catch B. zonata and B. dorsalis more than the surface installed traps. The B. zonata starts its rapid development from the April with certain fluctuation.


Introduction
Jujube, Ziziphus jujuba Mill., locally called 'ber' and belongs to the family Rhamnaceae, is an indigenous fruit of China and South Asia, produced in temperate regions such as China, India, Pakistan, Syria, Australia and Malaysia. Jujube requires a hot and dry climate. It can survive temperatures of up to 50 o C and with such a tolerance for heat it is of little surprise that it does not do well when temperatures approach freezing. Jujube fruits are deciduous and can tolerate cold winters to 28 o F. They have a low chilling requirement allowing them to produce fruit in areas having mild winters. Long, hot summers are necessary to ripen good fruit crops. Pollination is done by bees and flies. In Pakistan, jujube is extensively cultivated, but thrive best under ecological conditions of Hyderabad, Khairpur, Multan, Sargodha and Lahore Divisions. Hyderabad is famous for producing quality fruit for export to Middle East. The tree is hard, drought resistant and can thrive in poor alkaline tracts without much irrigation and care, and survive on soils where other fruit trees cannot [1]. Ber or jujube, a common fruit grown in the warm subtropical regions of Pakistan, belongs to the genus Zizyphus of family Rhamnaceae [2]. In Pakistan, Ber is produced over an area of 5425 hectares with an annual production of 27950 tones [3]. Fruit [11]. Severity of damage is caused by three fruit fly species namely, Bactrocera zonata (Saunder), Carpomia vasuviana (Costa) and Bactrocera cucurbitae (Coquillett), from the time of fruit setting up to harvesting. All above mentioned fruit fly species inflict colossal losses which ultimately confine the fruit production involve deployment of large numbers of Jackson traps baited with highly attractive male-specific lures [12]. For example, methyl eugenol (ME; 4-allyl-1, 2dimethoxybenzene-carboxylate) and cuelure (C-L; 4-(p-acetoxyphenyl)-2butanone) are used for detection of oriental fruit by, Bactrocera dorsalis (Hendel) and melon by, Bactrocera cucurbitae (Coquillett), respectively. However, an important environmental concern of these trapping systems is that detection traps are currently deployed in association with toxic liquid insecticide formulations such as naled [13]. The current study was carried to determine the population dynamics of various fruit flies' species in term of identification on different varieties of beer. The importance of the present survey for fruit flies in beer orchard was exploited for managing the population densities of fruit flies through integrated pest management program. In different orchards of jujube, the study was useful in managing the population densities of fruit flies and their integrated pest management (IPM) programs.

Materials and Methods
The experiment was conducted during the year 2016-17 for the monitoring of Bactrocera spp. on an area of 10 acres of jujube orchard farm, Agriculture Research Institute (ARI) Tandojam. The male adult population of fruit flies was recorded weekly through pheromone trap baited with lure toxicant mixture (95% methyl eugenol+ 5%Thiodan insecticide). The experiment was conducted to observe the fruit fly catches by hanging fruit fly traps at different heights on jujube trees. Treatments T1 = Pheromone traps installed on ground surface T2 = Pheromone traps installed at 1-meter height T3 = Pheromone traps installed at 2 meters height T4 = Pheromone traps installed at 3 meters height The experiment was replicated five times. The pheromone traps were replenished after 15 days to keep fresh chemical for attraction of the fruit flies. Killed male flies in traps were counted and species were identified at weekly interval. The collected data was statistically analysis using statix. 8.1 version.

Results
The study was conducted during season

Pearson's correlation among B. zonata population and abiotic factors
Correlation estimates between B. zonata population and abiotic factors (temperature and relative humidity) was worked out and presented in (Table 2). There was significant and positive correlation (R2= 0.8476 * ) between B. zonata population and temperature. Whereas, negative and nonsignificant correlation (R2= -0.5343 NS ) was analyzed among the B. zonata population and relative humidity. This indicates that the B. zonata population was linearly increased by the elevation of temperature and the B. zonata population did not fluctuated by the relative humidity up down.

Pearson's correlation among B. dorsalis population and abiotic factors
Correlation estimates between B. dorsalis population and abiotic factors (temperature and relative humidity) was worked out and presented in (Table 4).
There was significant and positive correlation (R2= 0.5112 * ) between B. dorsalis population and temperature.
Whereas, negative and non-significant correlation (R2= -0.7645 NS ) was analyzed among the B. dorsalis population and relative humidity. This indicates that the B. dorsalis population was linearly increased by the elevation of temperature and the B. dorsalis population did not fluctuated by the relative humidity up down.  [16] observed to evaluate the fruit fly capture in traps at different heights by using methyl eugenol. The results showed that the maximum average male fruit flies (515) were caught at the height of 5 feet, whereas, the minimum (315) were caught at the ground level. These results suggest that for the monitoring of fruit flies, the methyl eugenol traps should be hanged at the height of 5 feet from ground level to get the maximum counts of fruit flies.

Conclusion
It could be concluded that methyl eugenol pheromone traps were most effective when installed at 2 m height; while traps installed at 3 m and 1 m height could not catch B. zonata and B. dorsalis more than the surface installed traps. The B. zonata starts its rapid development from the month of April; while B. dorsalis starts flaring up in April and then reached its peak population. The B. dorsalis is basically the mango fruit fly and its population were more associated with the mango season rather to associate its population with the abiotic factors. Generally, the B. zonata population was markedly higher than the population of B. dorsalis.