الفهرس 
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Abstract
The peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) is considered one of the most serious polyphagous insect pests which spread in several regions of the world. It severely attack of many fruit species such as; guava, peach, mango, citrus, apricot, fig and apple. In addition fruit fly also attacks some vegetables such as tomato, pepper and egg-plants as secondary hosts and inflicts damage to the fruits directly (through oviposition punctures and subsequent larval feeding on pulp) or by causing blemished fruits, which limit marketing possibilities (especially export of fruits). The infestation may reach up to 50% in summer crop of guava in Pakistan. The fruit attacked by this pest are malformed, mis-shaped, under sized and rotted inside.
In Egypt, in last decade, B. zonata became a serious pest owing to the suitability of climate and their significant damage to Egyptian agriculture is increasing year after year. Because of newly fields which have been added to the orchards, over cropping operations. Also, because of the difficulties for choosing a suitable method of control in view of the awareness of problems associated with the use of insecticides as cover spray. It is also recorded in several governorates in Egypt where it caused an estimated 190€ million damage a year. In Pakistan, this pest caused from 25 to 50% losses in guava fruits at the farm level of an estimated $200 million annually, with added losses to traders, retailers and exporters.
Therefore, to face this serious pest and to prevent its spread; the present work threw a light to study the following aspects which play an important role in controlling this harmful pest:
1- Ecological studies including Survey of Bactrocera zonata on different hosts and study the population fluctuation of the adult male round the year through the use of Cue lure and influence of some abiotic parameters such as temperature (minimum, maximum) and mean relative humidity. It is necessary to have basic information on the incidence of the pest in relation to weather parameters which help in determining appropriate time of action and suitable method of control. Monitoring pest population round the year is one of the most important basic information in formulating IPM concept for sustainable agriculture.
2- Some biological aspects in order to detect the different stages of the pest and duration times.
3- Morphological & the ultra structural studies, using SEM, the light has been focused on the ultra structure of sensilla on the different parts of the peach fly. Hopefully this discrimination could help researchers to get-rid of this serious pest throughout its sensory system which can play an important role in the insect control (biological or chemical) by using recent insecticides which block the function of this system.
4- Evaluation of fruit flies control methods (Male annihilation technique (MAT) and bait application technique (BAT) to minimize the effect of hazards of pesticides utilization, environmental pollution and also to avoid the damage caused by this pest.
The obtained results were summarized as follows:
A- Ecological studies:
*Survey of hosts:
A qualitative survey of peach fruit fly, B. zonata hosts was carried out at Assuit Governorate by collecting infested fruit either on the trees or DROPping to the ground and identification the obtained flies. Apparently, B. zonata attack a wide range of fruits that differ in their ripening time stage all over the year. Mango, guava, apple, apricot, orange, mandarin, fig, peach and squash were seemed to be the main hosts of the peach fruit fly in the surveyed area.
*Seasonal abundance of the fly round the year
The seasonal abundance of peach fruit fly, B. zonata was studied for two successive seasons 2008/2009 and 2009/2010 located at three districts in Assiut Governorate (Upper Egypt) “EL-badary, Manfalout and Assuit ” cultivated with peach, guava, mango and citrus (orange& mandarin). The study was carried out using Jackson sticky traps baited with methyl eugenol (ME) as a specific Para-pheromone lure of males. The annual totals of B. zonata males for two years of study 2008/2009 and 2009/2010 were 11076 and 6421 flies, respectively.
The results indicated that the population of peach fruit fly adults were active all over the year except in short periods, during cold winter because of the reduction of temperature which obligates the immature stages interring a state of over- wintering, subsequently prolonging of the immature stage durations and reducing the number of the adults. Also, during hot summer, when the climatic factors (especially extremes of temperature) were not favorable for insect activity (This temperature might cause a high mortality in the flies) and in the absence of suitable host fruit or during harvesting stage. The pest population increased either gradually or suddenly with the progressive weeks of study affecting by availability of host fruits and weather factors changes.
Influence of host fruit availability on fruit fly population fluctuations
The present result mentioned that host fruits are essential for the existence of B. zonata in the tested area. During the harvesting stage or absence of suitable host fruit, a remarkable decrease occurred in the population density. Collection and destruction of fallen, damaged, over-ripe, and excess ripe fruits are strongly recommended to reduce resident populations of fruit flies in all kind of fruit host.
Statistical analysis by using simple correlation of the two mentioned years 2008/2009 and 2009/2010 indicated a positive and significant correlation (r= 0.3927 and 0.3798 respectively) between the fly population and availability of host fruits. The availability of host fruit was found to be an important factor influencing fruit fly numbers in the tested area.
Effect of certain weather factors on the activity of B. zonata
The relationships between the populations of B. zonata adult (estimated as weekly catch) and the prevailed weather factors (weekly means of maximum, minimum temperature, and relative humidity) were studied. Data obtained was subjected to multiple regression analysis programme. Statistical analysis by using simple correlation of the first mentioned year indicated a highly significant correlation between the fly population and both maximum and minimum temperatures. While insignificant correlation is shown between the relative humidity and the pest population.
For the second year, the simple correlation was significant for only minimum temperature, while the insignificant coefficient were those of maximum temperature and relative humidity.
The numerical values of correlation co-efficient of the two mentioned years indicated a positive correlation between the fly population and both of maximum, minimum temperature showed (r= 0.395 and 0.413 respectively) and (r= 0.243 and 0.280 respectively). However, the relative humidity negatively correlated on two years (r= -0.218 and -0.182 respectively) with the fly catch.
Depending upon multi-factor regression analysis, the climatic factors were responsible for 19.11 % of the population changes of peach fly for the first season 2008/09. The minimum temperature played the most important role in population change, where it was responsible for 10.92%. For the second season 2009/10, the three climatic factors were responsible for 36.3 % in the annual population changes. The relative humidity played the most important role on the population change, where it was responsible for the main change of 18.60 %.
It may be concluded that from the two season of the study the weekly catch of peach fly was mainly influenced by the availability of host fruits and minimum temperature all over the investigated years. The relative humidity and maximum temperature came next.
B- Biological studies:
The biological experimental treatments were carried out under laboratory conditions (25 ± 2˚C and 60- 65 % R.H.).
1-The life cycle study of B. zonata
* The egg stage
The egg of B. zonata is similar to that of C. capitata, is very slender, curved in shape, has a shiny white color turns gradually into the creamy yellow with time of hatching. The incubation period ranged between 2-5 days with a mean of 3.3 ± 0.24 days and the percentage of hatchability was 70.0%.
* The larval stage
The larvae of B. zonata were successfully reared on the artificial diet based on wheat bran. The duration of the larval stage (3 instars), was ranged between 6-10 days with a mean 8.28 ± 0.26 days and the percentage of pupation was 78.57%.
* The pupal stage
The pupal stage duration was ranged between 9-12 days with a mean 10.27 ± 0.22 days. The emergence percent was 87.27%.
* The adult stage
Adult emergence starts morning with sunshine, most of them emerged between 5.35 a.m. and 12 at noon but the maximum number of emerged adults took place between 9 a.m. and 11 a.m. during the 1st and 2nd day while on the 3rd day most of emergence took place between 6 and 9.30 a.m. Sex ratio was observed to be about 1: 1. Mating was occurred after 19 days of adult emergence. A limited numbers of flies start to mate in the 16th and 18th day after emergence, flies moved around very activity in the cages until they got their mates. Mating usually occurs in the evening timing with sunset at the dusk. The females started to lay eggs in 2-4 days after mating; the pre-oviposition period was about 21-23 days after emergence. The oviposition period lasted about 2-7 days. Longevity of adults was determined for both female and male; the female had an average of 43.55±3.46 days with a range of 38-49 days. While, the longevity of male lasted about 38.5±3.67days of average with a range of 33-44 days.
C- Morphological and Ultra-structural studies
The light has been focused on the morphology & ultrastructure of the sensilla on the different parts of the male and female peach fly, B. zonata according to different host fruit species (mango, guava, peach, orange) using scanning electron microscope.
The present results noticed the head is strongly sclerotised capsule jointed to the thorax by a flexible membranous neck. The main sense organs on the head are a pair of compound eyes, three ocelli and a pair of antennae. In the male, the whole head is greater than in the female in most of the tested host (mango, guava and orange). In contrast with peach fruit, the male considered the smallest head.
Antennae
The antennae of B. zonata were very similar in terms of their general structure to those of other fruit flies studied. Both sexes of all tested hosts had three distinct types of the sensilla on the scape: trichoid (dense in male), basiconic II, and cheatica (varying in number according to different hosts). The pedicel had two types of trichoid sensilla in both sexes of all hosts, trichoid sharp found only in male and female of peach fruit, basiconic II found in both sexes of all hosts, except in female peach were absent. Also, cheatica sensilla on both sexes and compainform (dome-like structure) are found only in male mango but absent in the rest of hosts. On funiculus there were four morphologically distinct types of the sensilla: trichoid (I, II), basiconic (I) (significantly larger in female), clavate (Absent or may be slightly found in mango and guava of both sexes, but the number increased in the other host of peach and orange) and coeloloconic (I) found in female of all hosts but varied in length and also in male of orange and peach. While, the male in mango & guava, contain coeloconica sensilla (II) curved.
Mouthparts
The mouthparts of B. zonata are similar in general structure to those of another Tephritid genus, Bactrocera have specific structural modifications that determine what adult flies can ingest and thus the type of food they feed on in nature (fed on dry, semi-solid substrate and a dilute solution). The proboscis as in other cyclorraphous Diptera consists of three main parts, a basal rostrum, a median haustellum, and a terminal pair of fleshy oral or labellar lobes (labellum). The labellum has a series of fine tube-like structures, called pseudo tracheae, on its inner surface. It is reinforced by some bristles and sensilla such as cheatica (I, II), trichoid (I, II) found on both sexes of all hosts and Basiconica (BsII) found on female guava only.
The maxillary palp
The maxillary palp of B. zonata in different host fruits composed of one segment ending in a club-shaped free end. In all hosts, a significant sex difference found in length and width. Maxillary palp of male tended to be larger than those of females. Many types of sensillae were recorded covering its surface. Those are trichoid sensilla (I, II) considered the most conspicuous type, found on both sexes of all hosts. Trichoid sharp found only on the female mango and orange host. Basiconica (BsI) could consider the most common type found in both sexes of all hosts but densely distributed in guava and peach (Finger-like structure). Basiconica (BsII) found in female orange only. Basiconica (BsIII) found only in male orange. Clavate sensilla, found in both sexes of guava and peach hosts, but in mango and orange may be absent or found with slightly number. Coeloconica sensilla (CoI) found only on males of guava and peach with a dense number. Cheatica sensilla (ch), these sensillae are usually found over the dorsal surface of the palp. Found on both sexes of all hosts.
The wing
As in all fruit flies and dipterous insects, B. zonata have only one pair of wing articulating with the thorax and consisting of flattened lobes supported by hollow veins. The hind wing becomes wholly modified to form the halters, which concerned with the maintenance of stability in flight. According to different host fruits, guava and orange female wing tended to be larger than those of males. In mango, no significant difference found between both sexes. In peach, wing male larger than that of female. Different types of sensilla located on the wing of adult male and female, those are cheatica sensilla found on the costal margin of the wing on both sexes of all hosts, but with different number of rows according to different host fruit. Trichoid (Tr I, II) scattered all over the wing of both sexes on orange and also male guava but become absent in the other tested host; trichoid sharp (Trs) found only in both sexes of mango and trichoid blunt (Tb) found on female guava, male and female peach.
Tarsus
As in all dipterous insects, it is composed of five-segments. The first, which is next to tibia, is much longer than the others and called basitarsus or metatarsus. The fifth tarsal segments or pretarsus bears a pair of curved claws, which are used to climbing rough surface. On the ventral side of the base of each claw, a membranous pulvillus was covered with tent hairs on its ventral surface. These hairs could present the sensory types of sensillae of this area (trichoid sensillae with glandular process). Tarsus of male in guava, peach and orange has a dense and larger microtrichia than that found of female. While in mango, female become larger and dense than male. Tarsomere implanted with microtrichia (M) in the floor, lateral margin guarded with trichodea sensillae on both sexes of all hosts.
Adult genitalia
The male genitalia ”aedeagus” found on the sternite 5 of the abdomen consisting of 2-pair of lobes, the inner lob forming median penis and the outer one forming parameres. On the other hand, female genitalia ” ovipositor’, found on the last abdominal segment, consists of 3-segmented: Oviscape (ovsc); Eversible ovipositor sheath (ev ovp sh) and Aculus (acul). Because, the ovipositor is telescopic it may not always extended to show the aculus apex.
D- Control studies
Because of the concealed feeding behavior of fruit fly maggots, the actual damage is virtually safe from the insecticide applications. Also, of the pollution of the environment through toxic residues left in the atmosphere and on the fruits (insecticidal residual toxicity in fruits). Control measures are to be directed at the adult flies, these studies aim to evaluate the effect of pheromonic control (MAT) and bait application techniques (BAT) on suppression the population of this pest and reducing the infestation percents. Both of the mentioned techniques minimize the environmental pollution.
Techniques evaluation was estimated according to the population fluctuation by randomly distribution of wooden plywood blocks and Jackson trap baited with methyl eugenol. These studies were carried out in orchards in Assuit Governorate on season 2011.
Methods of techniques application:
1. Male Annihilation Technique (MAT):
MAT technique was carried out using wooden plywood blocks (5cm x 5cm x 1cm) impregnated with a mixture of male lure/toxicant (8:2). The lure used is Methyl Eugenol, which attracts B. zonata male flies. Malathion 57% (EC) is the insecticide used. This killer blocks were hanged on the trees by metallic wire on regular distance at height of about 1-2 meters in shady and airy place and randomly distributed in the tested orchards. The effectiveness of blocks was assessed by daily counts of dead flies found in MAT- catchers that placed under lure blocks; these are a plastic container attached at the neck level. The lured and killed B. zonata males in the containers were counted and recorded weekly without renewal the treatments.
The present results reported that MAT by soaked wooden blocks attracted and killed about two times more flies than the traps, is cheaper, simpler, lasted considerably longer, require no recharging and replacement, and is less likely to be blown down or stolen, so the traps are used to attract fruit flies as a part of monitoring and for predicting the infestation level. Trapping alone has not been sufficiently effective to obtain adequate suppression.
It is evident from the results obtained that the population of B. zonata showed a significant reduction after applying the MAT control method as compared to un-treated area. There was a remarkable difference in the catches of flies in both the treated and untreated regions. Therefore, Male Annihilation Technique (MAT) considers the only effective to control the male adult of fruit fly in the fields. MAT is a sustainable agricultural practice which can reduce the cost of production without damaging and disturbing the flora and fauna.
2. Bait Application Technique (BAT):
BAT technique was carried out using powered hand sprayer (20 L. capacity) containing a mixture of 0.5 L. Malatox 57% (insecticide); 1L. Buminal 37.5% (food attractant) in 18.5 L. of water as a carrier applied to one side of each tree trunks. Three applications at least were made at the tested orchard. Efficacy of this method in controlling peach fruit fly was evaluated based on captures of flies (male only) in Jackson trap baited with sex-lure attractants methyl eugenol. Bait sprays applied on regular 7-10 day rounds. This method is relatively safe to non-target insects and is also less polluting to the environment than cover sprays, as it produces very little spray drift and very little chemical residue.
The present result mentioned that the population of B. zonata was already high in Al-Azhar university farm at the start of treatment. The results revealed that after the implementation of the control method, the captures of the adult flies (male only) decreased significantly within two weeks of application; there was difference in the trap catches in both the treated and untreated zones. However, despite a reduction in fruit infestation levels in the treated areas, peach fruit fly attack was still persistent throughout the period of treatments and also through the year.
Hence, the control measures were not effective enough to further lower down the B. zonata populations. Fallen fruits in backyards act as a reservoir of the pest. In most cases, fallen fruits are left on the ground and hence contribute in continuously flooding the population of the pest. Therefore, Fruit sanitation is an essential component of the control method. For an effective control, fruit sanitation has a significant contribution to reducing fruit fly population beside the implementation of the control method. This is a technique that either prevents fruit fly larvae from developing or removes young emerging flies so they cannot return to the crop to breed. There are a number of methods that can be employed such as: destroying infested fruit on the tree or the fallen fruit collected before and during harvest; bagging or deep-burying infested fruit; mulching or mowing the fallen fruit and even drowning larvae in the fruit. Intensive irrigation directly after harvest of the fruit can also be employed to kill pupae in the soil. Removing fruit before it ripens also reduces the larvae entering the soil to pupate. Also no fruit should be left on the tree after harvest.