M.Sc. Thesis entitled:"Ecological studies on the important insect pests on apple trees at El-Beheira Governorate"
SUMMARY
Apple, Malus domesticus, is one of the important fruit in Egypt. Available statistics refer that apple orchards in Nobaria district occupy 70 % from the total area of apple orchard in Egypt. These orchards are infested by the many of insect pests. Some of these pests may cause serious economic damage to apple trees.
1-Survey of the insect pests on apple trees at El-Beheira Governorate:
The aim of this study was to make a survey of insect pests infesting apple trees at two districts in El-Beheira Governorate during the two successive seasons 2004/05 and 2005/06:
Twenty six insect species belonging to sixteen families and five orders were recorded as follow; Seven species appeared to be important pests (Major Insect Pests), Fig scale insect, Russelaspis postulants, Apple wooly aphids,Eriosoma lanigerum, Leopard moth, Zeuzera pyrina, Pubescent rose chafer, Tropinota squalida, Shot hole bark beetle, Scolytus amygdali, Peach fruit fly, Bactrocera zonata, and Mediterranean fruit fly, Ceratitis capitata. Secondary insect Pests, Oyster shell scale, Lepidosaphes ulmi, San Jose scale, Quadraspidiotus perniciosus, Cotton aphids,Aphis gosspyii, Apple clear wing moth, Synathedon myopaeformis, and California red scale,Aonidiela aurantii. Occasional Pests, Retithrips syiacus, Parltoria olea, Hemiberlesia latania, Ceroplastes floridensis, Dysaphes plantaginea,Iceria purchasi, Iceria seychellarum, Pseudococcus citri, Leyonetia clerkella,Anarsia lineatella, Pachnoda fasciata, Pentodon disbar, Carpophilus hemipterus, and Drosophila melanogaster.
B) Abou El-Matamir district (Old delta land):
Sixteen insects belonging to 13 families and four orders were recorded; Hemiptera (eight species,Aonidiela aurantii,Quadraspidiotus perniciosus, Iceria aegyptiaca, Eriosoma lanigerum, Emposca faba, Nezara viridula, Iceria seychellarum, and Aphis gossypii), Lepidoptera (Synathedon myopaeformis, and Zeuzera pyrina) Coleoptera (Carpophilus hemipterus, Tropinota squalida, and Scolytus amygdali) and Diptera (Bactrocera zonata, Ceratitis capitata, and Drosophila melanogaster).
2- Population studies on main economic insect pests on apple trees:
2.1. Fig Scale Insect Russelaspis postulans,
Seasonal abundance of R. pustulans total population:
Four peaks of the total population recorded in the two seasons; November 11th, May 5th, July 14th and August 25th throughout the first season from October 21st 2004 till October 20th 2005. In the consecutive season (2005/06), the four peaks were recorded in November 17th, April 6th, July 13th and October 19th.
Population dynamic of immature:
The first nymphal instar (Crawlers), three peaks of infestation with the first nymphal instar of R. pustulans were recorded in November 18th, June 30th and October 6th in the 1st season, in the 2nd season, three peaks with this instar were recorded in November 17th, June 29th and October 19th.
The second nymphal instar, there are two peaks of infestation for the 2nd nymphal stage at the two seasons, recorded in the first season in January 13th and July 17th respectively, in the 2nd season in December 15th and July 13th respectively.
Population dynamics of adult stage:
Non-gravid female, the non gravid female of R. pustulans had two peaks in the 1st season, in January 13th and August 11th. This instar recorded three peaks in the 2nd season 2005/06, in December 1st, March 23rd and September 21st, the variation in number of peaks in the two seasons was due to the influence of the environmental factor, Similar trend were noticed in the 2nd season.
The gravid female stage, maximum occurrence of the gravid female (deposited eggs) was recorded in October 21st, May 5th and August 11th. Only two peaks for the gravid female were recorded in the 2nd season (2005/06) in March 23rd and July 27th. There wasn’t any individuals of this instar during the period from December 16th till February 24th in the 1st year, in the 2nd season the period from November 17th till January 26th the sample were free of this instar, these results mean that the insect overwinter as a gravid female.
The fig scale insect has two annual generations on apple trees at El-Beheira Governorate, the first begin at September until May of the following year (Overwintering generation) and the second generation begin at May and continues until August (summer generation). The period of the summer generation was very low than the period of the Overwintering generation in the two years.
2.2. Woolly apple aphid, Eriosoma lanigerum Hausman,
Population fluctuation:
In the first year 2005, two peaks of infestation, the first occurred at May 5th, the second peak was occurred at August 4th. In the second year 2006, the first peak was recorded in May 11th, the second peak occurred in mid August.
Infestation rate "IR":
The infestation rate "IR" increased gradually to reach 52% in the latest week of July (the peak of "IR") in the first year 2004/05. In 2005/06 year the "IR" increased gradually to reach 62% in the latest week of May and early of June (the peak of "IR").
2.3. Leopard moth,Zeuzera pyrina,
Two methods were used to estimate the population fluctuation of the adult stage.
A) The empty pupal skins protruding from the apple trees:
The pupal skins protruding from the tunnels of the wood indicate that the moth emergence and determine the periods of the occurrence of Z. pyrina.
At Nobaria district, in 2005 season, the emergence of the first moth started to appear late in April, the highest abundance was reached early in July, while the lowest count was obtained in October 6th. There wasn’t any sign of pupal exuivae during the period from the first week of November 2004 to the third week of April 2005. In 2006, there wasn’t any pupal exuivae during the period from the second week of October 2005 to the second week of April 2006. Emergence of the first moth started in the third week of April, and then increased gradually throughout the season to reach a peak in late July, the number of the emerged adults decreased gradually until the latest week of September, and the last empty pupal exuivae was collected in September 28th.
Abou El-Matamir district, there wasn’t any pupal exuivae during the period from the first week of November 2004 to the first week of May 2005, emergence the first moth started in May 13th, then this numbers increased gradually and fluctuated throughout the season to reach a peak in July 8th, the last empty pupal exuivae was collected on mid September. In 2006 season, during the period from the first week of November 2005 to the first week of May there was not any sign of pupal exuivae. Emergence the first moth started in May 19th, the collected pupal exuivae was increased gradually throughout the season to reach a peak in mid July, and the last empty pupal exuivae was collected on September 22nd.
B) Pheromone traps:
Nobaria district, weekly caught moths bypheromone traps during 2005 year indicate that April 21st was the time of the earliest flight of Z. pyrina in Nobaria district and October 20th was the latest, during the season activity the number of trapped moths increased gradually to reach maximum by June 30th and July 21st. In 2006 year three peaks of the trapped moths were observed where the earliest peak was in June 15th, the second peak in July 13th and August 3rd was the latest peak, the season activity in 2006 year extended from the third week of April to the latest week of September.
Abou El-Matamir district, in another hand in Abou El-Matamir district the weekly trapped moths by pheromone traps during 2005 indicated that the season activity extended from May 13th to September 16th with two peaks throughout the season activity in July 8th and August 5th. In 2006 year this result becomes confirmed, where the season activity extended from May 13th to September 16th, the number of moths increased gradually to reach the peak in July 14th.
2.4. Pubescent rose chafer Tropinota squalida Scop.
A) Abundance and population fluctuation of T. squalida:-
Weekly caught insects by blue water traps during 2005 year indicate that February 3rd was the time of the earliest flight of T. squalida adults in Nobaria district and April 7th was the latest traps, during the flowering time the number of trapped beetle increased gradually to reach maximum by March 17th. Almost this trend was repeated in 2006 year with a little difference where the earliest flight was in January 26th, the number of the trapped insect increased gradually to reach maximum by March 9th and April 20th was the latest.
In another hand in Abou El-Matamir district, the weekly trapped insects by blue water traps during 2005 season indicate that, February 11th was the time of the earliest appearance of this insect. The maximum number of trapped beetles was found on March 25th, the number of beetles decreased gradually and the latest flight was in mid April; This trend was repeated in 2006 where February 3rd was the earliest appearance, March 17th the maximum of beetles were trapped and April 14th was the latest appearance.
B) Population density of T. squalida,
The mean numbers of T. squalida catched by the two methods (for estimating the density of Tropinota squalida), was 2.1 and 0.33 beetles catched by the hand picking per tree per day and one blue water trap per day respectively.
At Abou El-Matamir district, this means was 1.24 and 0.223 catched by the hand picking and blue water trap respectively.
This trend also could be seen in the case of 2006, the recorded mean number of adults per tree (Hand picking technique) and per blue water trap in Nobaria district was 2.27 and 0.413 beetles respectively, and meanwhile this means was 1.01 and 0.176 at Abou El-Matamir district respectively.
2.5. Shot hole bark beetles, Scolytus amygdali Guér,
The present work was conducted to study the population fluctuation, population density and the number of generations of the shot hole bark beetles Scolytus amygdali on apple trees in the two districts (Nobaria and Abou El-Matamir) at El-Beheira Governorate under the laboratory condition.
A) In Nobaria district, the weekly numbers of S. amygdali beetles emerged from apple branches at Nobaria district indicated that,in the first season (2004/05), the population of Scolytus amygdali recorded five activity periods. The first activity period extended from the first week of November to the 3rd week of January, with a peak in the latest week of November. The 2nd activity period extended from the 2nd week of March to the latest week of May with a peak observed during 2nd week of May. Followed by the 3rd activity period, that extended from the 1st week of June to the latest week of the same month. The 4th peak was recorded at the 2nd week of July during the 4th period of activity that extended from the latest week of June to the latest week of July. Thereafter, the population fluctuated slightly during the latest activity period that covered the period from the 1st week of August to the latest week of October with a peak in the 3rd week of October.
In the 2nd season (2005/06), five peaks of 78, 85, 100, 110 and 92 beetles/5 cutting branches. These peaks observed at the third week of November, the first week of May, mid June, the third week of July and the third week of September, respectively.
B) In Abou El-Matamir district, the population ofS. amygdali was subjected to variable fluctuations during the period of study to record five periods of activity, the first period extended from first week of November to the first week of December. The 2nd activity period extended from the 2nd week of April to the latest week of May with a peak recorded on the first week of May. The third activity period was extended from the 4th week of May to 17th June with a peak at the 2nd week of June. The 4th period of activity covered the period from the 3rd week of June to the latest week of July with a peak recorded on mid July, followed by the latest period of activity from the latest week of July to the 4th week of October with a peak at mid of October.
Similar trend were noticed in the second season 2005/06, the population curve showed five peaks of abundance. The five peaks were 46, 60, 52, 46 and 49 beetles/5 cutting branches at mid November, May 18th, July 6th, August 10th and October 19th respectively.
The obtained results on the adult population of the shot hole bark beetles Scolytus amygdali during 2005 and 2006 in two locations at El-Beheira Governorate demonstrated that this species having five overlapping generations annually.
2.6. Peach fruit fly, Bactrocera zonata,
Population fluctuation of male flies, Bactrocera zonata through two successive season, from November 4th 2004 to November 3rd 2005 (the first season) and continued until October 26th 2006 (the second season). Jackson traps baited with Methyl eugenol were distributed in the orchard to record the weekly number of males through the mentioned periods.
A) Nobaria district, the 1st period of activity of B. zonata extended from November 11th until January 13th with two peaks in November 25th and December 16th. The 2nd appearance of males of B. zonata were extended from March 31st to May 19th, with a peak on April 28th, the 3rd main activity period extended from June 2nd to July 14th, with a peak on June 23rd. During the periods from January 27th to March 24th and from July 21st to September 22nd the insect were completely disappeared.
The population activity in the second season 2005/06 was similar with the first season, where the longest period of activity extended from the latest week of September in the preceding year 2005 to January 26th 2006 with a peak in December 8th. The second period of activity was extended from March 23rd to May, with a peak on April 20th and 27th, followed by the third period activity that extended from May 25th to July 20th, with a peak on June 25th. The fourth period of activity extended from September 14th to October 26th with a peak on October 19th. As well as the first year, the insect were completely hidden during the periods from February 2nd to March 16th, from May 11th to May 18th and from July 27th to September 7th.
B) Abou El-Matamir district, the 1st activity period of B. zonata extended from November 12th to December 17th, and then completely disappeared until April 22nd. The 2nd period of activity was extended from April 29th to July 22nd with a peak on June 10th.
The population activity in the second season (2005/06) was similar with the 1st season, where the longest period of activity extended from September 16th in the preceding year 2005 to December 23rd, then completely disappeared until the 1st week of April. The 2nd activity period that extended from April 14th to June 30th with a peak on June 2nd, the latest activity period was extended from August 25th to October 27th, with a peak on September 22nd.
2.7. Mediterranean fruit fly, Ceratitis capitata,
Three Jackson traps baited with Trimedlure were distributed in the orchard to record the weekly number of male through the mentioned period.
A) In Nobaria district, the 1st period of activity ofC. capitata extended from November 11th until January 27th with a peak in December 16th. The 2nd activity period of males of C. capitata were extended from February 10th to March 24th, with a peak on March 3rd. The 3rd main activity period (the longest period of activity), extended from June 2nd to September 15th, with the highest peak on July 14th. During the periods from March 31st to May 19th and from September 22nd to October 13th the insect were completely disappeared.
The population dynamics in the second season 2005/06 was similar with the first season, where the 1st period of activity extended from October 20th in the preceding year 2005 to January 26th 2006 with a peak in December 15th and 22nd. The 2nd period of activity was extended from February 23 to April 6th, with a peak on March 16th, followed by the longest period of activity that extended from June 1st to September 14th, with the highest peak on July 20th. As well as the first year, the insect males were completely hidden during the February month, during the period from April 13th to May 25th and from September 21st to October 12th.
B) In Abou El-Matamir district, the first activity period extended from November 12th to December 10th, and then completely disappeared until January 28th. The 2nd period of activity was extended from February 4th to March 25th with a peak on February 18th. The 3rd period of activity was extended from April 29th to August 19th with the highest peak on July 22nd , the latest activity period extended from September to October 28th with a peak on October 7th and 14th .
In the same time, the population activity in the 2nd season (2005/06), was similar with the 1st season, where the 1st period of activity extended from November 4th to December 16th, with a peak on November 18th. The insect completely disappeared until the latest week of January, followed by the 2nd activity period that extended from February 3rd to March 10th with a peak on March 10th, the insect males were completely hidden during the period from March 17th to May 5th. The 3rd activity period was extended from May 12th to August 11th, with a peak on July 7th. The latest activity period that extended from September 22nd to October 27th, with a peak on October 20th.
This results indicated that the population of C. capitata was dominant on B. zonata population through the two seasons 2004/05 and 2005/06 In contrast to the earlier occurrence toB. zonata (ripening stage for apple fruits), the C. capitata occurrence was high in June and July (maturity stage for apple fruits).
Ph.D. Thesis entitled:"Monitoring the changes in population density of insect pests inhabiting fruit orchard fields"
1- Survey of the insect pests on navel orange and peach trees at El-Behaira Governorate:
The insect pests attacking navel orange and peach trees were surveyed throughout two successive seasons, 2009/10 and 2010/2011 at Nobaria district, El-Behaira Governorate.
A) The navel orange trees:
Twenty six insect pests belonging to fifteen families from orders Thysanoptera, Hemiptera, Lepidoptera, Diptera and Coleoptera were recorded. The most dominant and economically important pests were the scale insects (Lepidosaphes beckii and Ceroplastes floridensis), the citrus leaf minor, Phyllocnistis citrella, the pubescent rose chafer, Tropinota squalida and the fruit flies (Ceratitis capitata and Bactrocera zonata). The less economically important pests were the scale insects (Chrysomophalus ficus, Aonidiella aurantii, Ceroplastes rusci, Coccus hesperidum andMycetaspis personata), the leaf hopper, Empoasca lybica, the mealybugs (Pseudococcus citri, Iceria aegyptiaca, Iceria purchasi and Iceria seychellarum, aphids Toxoptera aurantii, Myzus persicae andAphis gossypii), citrus flower moth,Prays citri, green stink bug, Nezara viridula, whiteflies, (Aleurotrachilus citri and Bemisia tabaci), the drosophila flies, Drosophila melanogaster and Carpophilus hemipterus.
Scale insect and mealy bugs:
During the 1st season, the percentages of infestation of navel orange leaves by the scale insects and mealy bugs indicated that the most dominant scale insect was the purple scale, Lepidosaphes beckii (49.2 %), followed by the Florida wax scale, Ceroplastes floridensis (31.03%), then California red scale, Aonidiella aurantii (8.07%), Chrysomophalus ficus (3.07%), Icerya aegyptiaca (2.6%), Icerya purchasi (2.38%), Chrysomophalus personatus (1.7%), Icerya seychelarum (0.88%), Ceroplastes rusci (0.59%), and finally Coccus hespiridium (0.47%). During the 2nd season 2010/11, almost similar results were obtained, since the purple scale, L.beckii was the common scale insects 58.72 % followed by C. floridensis 25.11 %, A. aurantii 5.74 %, I. aegyptiaca 3.53 %, I. seychelarum 2.7 %, C. ficus2.1 %, C. personatus 1.25 %, I. purchasi0.59, C. rusci 0.25 %.
B) The peach trees:
Twenty-one insect belonging to fifteen families and5 orders; Hemiptera (eleven species were recorded,Aphis gossypii,Myzus persicae, Aonidiela aurantii,Nezara viridula, Lepidosaphes ulmi, Chrysomphalus ficus, Icerya aegyptiaca, Pseudulacaspis pentagona, Icerya purchasi, Bemicia tabaci andEmpoasca lybica), Lepidoptera (Anarsia lineatella andSynathedon myopaeformis), Coleoptera (Carpophilus hemipterus, Tropinota squalida, Scolytus amygdaleand Pachnoda fasciata), Hymenoptera (Vespa orientalis) and Diptera (Bactrocera zonata, Ceratitis capitata andDrosophila melanogaster).
2- Survey and seasonal abundance of predators inhabiting navel orange trees at El-Behiera Governorate:
The most abundant predator was Chrysoperla carnea; which represented 28.43% and 30.35% from the total swept predators. The 2nd rank was occupied by Syrphus corollae; (22.32% and 24.62% from the total swept predators during the 1st and 2nd season, respectively).The eleven spot beetle, Coccinella undecimpunctatawas in the third rank of the total swept predators (15.53% and 14.98). Then the seven spot beetle,Coccinella septempunctata(12.9% and 11.85%), then Cydonia vicina var isis(9.6% and 9.12%). However the lowest occurring predatory species were Cydonia vicina var nilotica(5.36% & 2.67), Rodalia cardinalis(4.9% & 5.02%) and Paederus alffierii(1.6% & and 1.37%).
3- Population studies on the main economic insect pests on navel orange and peach trees:
3.1. The purple scale insect,Lepidosaphes beckiiNewman:
Field studies were carried out on the purple scale,Lepidosaphes beckii throughout two successive years extended from February 2009 to February 2011. Three peaks of overlapping generations were recorded per year.In the 1st year three peaks of infestation were recorded in May 1st, September 4th and November 13th. While in 2nd year of investigation, these peaks were recorded during April 30th, mid October and November 26th.The highest rate of population densities were recorded at March, April, decreased up to August then raised up again in September, October and November.
The insect distributes on the whole navel orange tree with special preference to the southern and western cardinal sides. The population of L. beckii prefers the middle stratum of navel orange where considerable density of insect population usually occurs.
The relationships between the population density of inspected insect stages and prevailing weather factors -degree of temperature and relative humidity- were studied and statistically analyzed through both the years of study. Positive strong correlations were detected between daily minimum and daily mean of temperature and total counts of insect population.
Parasitoids of L. beckii:
One species of Aphytis was recorded parasitizing on L. beckii. In 1st season this species parasitized L. beckii from March to November. Four peaks of parasitism were recorded, in April 17th, July 10th, August 21st and October 30th. In 2010/11 season, Aphytis lepidosaphes was detected on its host, L. beckii throughout the year. Five peaks of parasitism were detected in March 19th, June 11th, September 3rd, October 1st and December 24th. Highly significant correlations were found between numbers of L. beckii and numbers of A. Lepidosaphes (r = 0.552 and 0.738 in 2009/10 and 2010/11, respectively).
3.2. The Florida wax scale, Ceroplastes floridensis:
These studies also aimed to obtain some ecological information about the Florida wax scale insects, Ceroplastes floridensis. Three peaks of overlapping generations were recorded per year.In the 1st year three peaks of infestation were recorded in June 12th, September 4th and the highest peak was recorded in December 11th. While in 2nd year of investigation, these peaks were recorded during July 9th, September 3rd and December 24th.The favorable periods and population increase for this insect were at May, August, and November.
The insect distributes on the whole navel orange tree with special preference to the northern cardinal sides. The population of C. floridensis prefers the middle stratum of navel orange where considerable density of insect population usually occurs.
The relationships between the population density of inspected insect stages and prevailing weather factors -degree of temperature and relative humidity- were studied and statistically analyzed through both the years of study. Positive correlations were detected between daily minimum, daily mean and daily maximum of relative humidity and total counts of insect population.
3.3. Citrus leaf miner Phyllocnistis citrella:
The citrus leaf miner infestation start to appear in the first orchard (old citrus trees) on March 27th 2009, in the second season 2010 the infestation first occurred during the first week of April. The number of larvae was increased gradually to record the first peak of abundance during the first week of May in the two seasons 2009 & 2010. The population density shapely fluctuated throughout the following months. Then the citrus leaf miner disappeared from the 2nd week of January in the first season and from the 3rd weak of January in the 2nd season, 2011.
The citrus leaf miner completed seven distinct peaks during the main period of activity that extended from March 27th to January 8th, in the 1st season 2009. In the 2nd season (2010/11) the insect completed only five peaks these peaks represented the number of CLM field generations. These peaks were recorded during the activity period that extended between the 1st week of April to the 3rd week of January.
In the 2nd orchard which represented the young trees which tended to produce many new numbers of flushes during the growth cycle, the infestation was first detected much earlier than the elder trees. Where the first appearance of CLM was detected at the 3rd week of March in the 1st season and the 2nd season. In the 1st season 2009/10, the CLM completed eight peaks of infestation. The average number of larvae per leaf throughout the year was 2.004. In the 2nd season, similar trend was obtained. The average number of larvae per leaf throughout the year was higher as compared with the 1st season, because it recorded 2.322 larvae per leaf.
Branches located on west direction harboured the maximum of population larvae. In the other orchard (12 years old trees), the total number of larvae located in west and south directions were significantly surpassed those recorded on east and west directions. While the lowest number of larval population were recorded in north direction in the young trees during the 1st and 2nd season respectively. In 2nd orchard (12 years old trees), the lowest number of insect population were recorded in the north direction in the 1st season and in east direction in the 2nd season.
The relationships between daily minimum, mean and maximum temperature and the means of P. citrella population was statistically highly significant in both orchards during 2009/10 and 2010/11 seasons. These results indicated thatthe activity of insect population positively correlated with maximum, mean and minimum temperature prevailing during the season of insect activity. The "r" values also indicate that the relationships between the maximum and mean of relative humidity and the means of P. citrella population was highly positive significant in the two orchards during the two seasons.
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Efficacy of three different insecticides against citrus leaf miners:
The efficiency of the treatments on citrus leaf miner population was evaluated by two different methods, the number of living larvae and the percent of infestation which calculated based on the number of infested leaves in relation to the total number of leaves in the sample.
The three insecticides namely Acetamiprid, Abamectin and Spinosad. After the 1st spray, the general means of the reduction percentage throughout the whole inspection period showed that acetamiprid exhibited the highest mean (88.08%) followed by abamectin (73.03%) and spinosad (57.13%). After the 2nd spray, the general mean of the reduction percentage hroughout the whole inspection period showed that acetamiprid exhibited the highest mean (88.33%) followed by abamectin (84.66%) and spinosad (69.06%). Similar results were obtained in the case of percentage of infestation by leaf miner.
3.4. Pubescent rose chafer, Tropinota squalida:
To study the population fluctuation and population density of T. squalida in the peach and navel orange orchards at Nobaria district, two methods were used during the insect activity. The 1st method is that hand picking method was used for counting the number of T. squalida adults. The 2nd method is that the water pan traps (blue - white - yellow - green) were distributed under the trees in four cardinal directions and examined weekly in the two tested fields.
The adults attacked the trees during flowering stage and synchronized with the appearance and disappearance of peach and navel orange flowers. The highest value of population density of T. squalida adults in peach orchard recorded at February 20th and February 19th. While in navel orange trees, the highest value of population density recorded at March 27th and April 2nd.
Concerning the water pan traps,the results indicated that the blue traps were more attractive to the adult beetles in peach and navel orange trees than the other traps. All the coloured traps were captured the adult beetles of T. squalida. Highly significant differences (P = 0.01) were obtained between the blue and other traps whereas the blue traps were more attractive for T. squalida than the other traps. These results were obtained in both navel orange and peach orchards during the two seasons.
Counting of T. squalida began with fewer numbers of adult/trap and then the number increased gradually to reach the top in March 27th and March 13th, in navel orange and peach orchard, respectively during the 1st season, 2009. On the other side, these numbers were relatively fewer during 2010 than the 1st year those of 2009
In peach orchards, the seasonal activity of T. squalida began two week earlier than those obtained at navel orange orchard for the two seasons 2009 and 2010. The activity season extended to April 24th and April 23rd for both seasons 2009 and 2010, respectively.
The highest infestation percentage and beetles number was recorded in March followed by February for both peach and navel orange orchards during the two tested seasons 2009 and 2010.
3.5. Fruit flies, Ceratitis capitata and Bactrocera zonata:
The population densities for each of the Mediterranean fruit fly C. capitata and peach fruit fly B. zonata, were estimated using two types of sex lure attractants. These sex lure are Trimedlure and Methyleugenol for capturing males of Ceratitis capitata and Bactrocera zonata respectively. Another type of attractants is food baits (buminal), which attracts both sexes (males and females) for both species. This study was carried out in two orchards of fruit, Navel orange and peach orchards for a period of two seasons where extended from February 2009 to February 2011. Both types of traps received the highest numbers of flies in navel orange orchard than peach orchard. Three peaks of both species of flies were recorded yearly; the highest peak was corresponded with the ripening of fruits in October for both species while the other peaks were happened for 1st season in April and June or July in both of Navel orange and peach orchards by using Jackson traps baited with designated lure
Buminal baits caught highest number of females than males for both species of flies. As it is in the case of the sexual attractants, the food attractant were recorded highest number of MFF than PFF. Buminal bait was used in McPhil traps and placed at 1.5-2 meter up to the soil surface.
Effect of partial bait spray and completely cover spray on the reduction of Ceratitis capitata (wiedemann) and Bactrocera zonata (Saundders) in navel orange orchard:
Partial bait spray and completely cover spray were applicated to control both species of fruit flies, Ceratitis capitata (wiedemann) and Bactrocera zonata (Saundders), in navel orange orchard under field conditions. The obtained data showed that the numbers of fruit flies were relatively lower in treated plots with completely cover spray than partial bait spray, while untreated plots (control) were relatively higher. The complete cover spray was more efficient in control male than female of fruit flies. The rate of fruit infestations was influenced by weekly capture flies for each treatment. Cover sprays didn't stop the female of fruit flies from stinging navel orange fruits.
Use of plant growth regulators to reduce navel orange fruits susceptibility to fruit flies:
The navel orange fruits treated by GA3 were significantly different from control plots. The lowest percentages of infestation were noticed in case of treatment by GA3 (15 ppm) followed by the concentration of 10 ppm and 5 ppm.
The mean number of fruits attacking by the fruits flies were lower than control but not significant by using of NAA with 5 ppm concentration. While there were no significant differences among 10 ppm and 15 ppm. Those treatment were significant differences than control.
The highest mean number of infected fruit was noticed in case of 1.5 % followed by 1 % then 0.5 %. There were no significant differences among these treatments and control.