الفهرس 
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Abstract
The present experiments were conducted to study the population density of the tomato leafminer, Ttuta. absoluta and its predatory insects on tomato plants in three tomato planting dates; February, June and September, during two successive growing seasons 2020 and 2021. Field experiments were conducted at experimental farm belonging to Agricultural Research center in Kafr El Sheikh . The laboratory experiments were conducted at the laboratory of Biological Control Department, Plant Protection Institute,Sakha branch .The obtained results could be summarized as following:6.1. Influence of tomato planting dates on population density of the tomato leafminer, Tuta absoluta and its associated predatory insects .6.1.1. On the tomato leafminer , Tuta absoluta.6.1.1.1. February plantation The highest peak of the population abundance for the larvae in February plantation were recorded in the first week of May 2020 and in the second week of May 2021 and represented by 56 and 55 larvae / plant during the two seasons, respectively . Meanwhile , for the male moths in February plantation , the highest peaks were recorded in the fourth week of April 2020 and the third week of April 2021 and represented by 375 and 380 moths / trap respectively .6.1.1.2. June plantation The highest peaks of T. absoluta larvae in June plantation were recorded on the second week of July 2020 and on the fourth week of July 2021 and represented by 124 and 130 larvae / plant during the two seasons , respectively .While , the highest peak of T. absoluta male moths were recorded in the first week of August 2020 and 2021 during the two seasons 2020 and 2021 and represented by 770 and 780 moths / trap , respectively.6.1.1.3. September plantation The highest peaks of T. absoluta larvae in September Plantation were recorded in the first week of January 2021 and 2022 during the two seasons and represented by 32 and 22 larvae / plant , respectively . Moreover , the highest peaks of T. absoluta male moths were recorded in the first week of January 2021 and in the second week of January 2022 and represented by 65 and 59 moths / trap. respectively.6.1.1.4. The monthly and the seasonaly average number of the larvae In February plantation , May 2020 recorded the highest average number of T. absoluta larvae (47.0 ± 4.8 larvae / plant) during the first season while , April 2021 recorded the highest average number of the insect larvae( 47.3 ± 4.1 larvae / plant ( during the second season . In June plantation , July 2020 recorded the highest average number of the insect larvae ( 96.0 ± 24.7 larvae / plant ( during the first season . Also , the highest average number of the insect larvae recorded in July 2021 ( 102.0 ± 16.2 larvae / plant (during the second season . In September plantation , January 2021 and 2022 recorded the highest average number of the insect larvae and represented by ( 32.0 ± 0.0 and 22.0 ± 0.0 larvae / plant ( during the two seasons , respectively .The highest annually average number of the insect larvare recorded in June plantation during the two seasons 2020 and 2021 and represented by ( 51.4 ± 12.0 and 60.9 ± 10.8 larvae / plant ,( respectively . Statistical analysis revealed that , a highly significant differences between the the three planting dates during the two eeasons according to the annually average number of the insect larvae . 6.1.1.5. The monthly and the seasonaly average number of the male moths In February plantation , April 2020 recorded the highest number of T. absoluta male moths ( 291.2 ± 35.9 male moths/trap ) during the first season while , during the second season , the highest avrrage number recorded ( 313.8 ± 23.9 male moths/trap ) in April 2021 In June plantation , July 2020 recorded the highest average number of the insect male moths ( 350.0 ± 203.1 male moths/trap ) during the first eeason while , during the second season , the highest average number recorded ( 382.5 ± 184.9 male moths/trap ) in July 2021 In September plantation , December 2020 recorded the highest average number of T. absoluta male moths ( 30.0 ± 3.7 male moths/trap) during the first season while , November 2021 recorded the highest average number of the insect male moths ( 37.3 ± 13.1 male moths /trap ) during the second season . The highest annually average number of the insect male moths recorded in June plantation during the two successive seasons 2020 and 2021 and represented by ( 200.0 ± 80.0 and 181.5 ± 53.1 male moths /trap ), respectively .Statistical analysis recorded that, a highly significant differences between the three plantations during the two seasons according to the annually average number of the insect male moths . 6.1.2. On the associated predatory insects 6.1.2.1. The eleven-spot ladybird , Coccinella undecimpunctata L.February plantation recorded the first category . It hosted the highest annually average number of the insect predator C. Undecimpunctata and presented by 3.4 ± 0.7 and 3.0 ± 0.5 individuals in both 2020 and 2021 seasons , respectively . While , September plantation harboured the lowest annually average number and presented by 0.5 ± 0.2 and 0.6 ± 0.3 individuals in both 2020 and 2021 seasons , respectively. 6.1.2.2. The mirid bug, Macrolophus pygmaeus Rambur . June plantation recorded in the first category . It hosted the highest annually average number of the insect predator M. pygmaeus and presented by 1.6 ± 0.8 and 2.7 ± 0.6 individuals in both 2020 and 2021 seasons , respectively . While , February and September plantations did not harbour any individuals in both 2020 and 2021 seasons .6.1.2.3. The earwig , Labidura riparia )Pallas) . June plantation came in the first category . It hosted the highest annually average number of the insect predator L. riparia and presented by 8.5 ± 3.1 and 7.6 ± 2.9 individuals in both 2020 and 2021 seasons , respectively . While , February and September plantations did not harbour or attracted any individuals in both 2020 and 2021 seasons .6.1.2.4. The green laceewing , chrysoperla carnea (Stephens) February plantation came in the first category . It hosted the highest annually average number of the insect predator C. carnea and presented by 0.9 ± 0.3 and 10.5 ± 0.5 individuals in both 2020 and 2021 seasons , respectively . While , June and September plantations did not harbour or attracted any individuals in both 2020 and 2021 seasons .6.1.2..5. the tomato bug, Nesidiocoris tenuis Reuter . June plantation came in the first category . It hosted the highest annually average number of the insect predator N. tenuis and presented by 300.0 ± 70.5 and 286.0 ± 89.9 individuals in both 2020 and 2021 seasons , respectively . While , February plantation harboured the lowest annually average number and presented by 2.1 ± 0.6 and 1.4 ± 0.6 individuals in both 2020 and 2021 seasons , respectively . 6.1.2..6. The relationship between associated predatory insects and T. absoluta . The tomato bug, N. tenuis recorded the highest average number 300.0 ± 70.5 and 286.9 ± 89.9 individuals , followed by L. riparia 8.5 ± 3.1 and 7.6 ± 2.9 individuals in June plantation during the two seasons 2020 and 2021 , respectively . Meanwhile C. undecimpunctata came in the first category during February plantation and represented by 3.4 ± 0.7 and 3.0 ± 0.5 individuals during the two seasons, respectively . The simple correlation coefficient between the numbers of T. absoluta and its predators on tomato plants in three plantating dates during the two growing seasons 2020 and 2021 demonstrated that , this relation varied from date to date and from season to season particularly to the tomato predatory bug, N. tenuis. The numbers of N. tenuis significantly correlated with those of T. absoluta during February and September plantations in the first season, but were correlated during June and September plantations in the second season. In both seasons, the numbers of the eleven-spotted ladybird C. undecimpunctata significantly coincided with those of T. absoluta during February and June plantations, but not during September plantation.6.2.Seasonal activity and biological studies on the mirid zoophytophagous bug N. tenuis .6.2.1. Effect of planting dates on population denisty of N. tenuis . In February plantation , the tomsto bug N. tenuis recorded the highest population density (160 and 133 individuals / plant ) in the fourth week of May 2020 and 2021 during the two seasons , respectively . In June plantation , the tomato bug N. tenuis recorded the highest population density (680 and 450 individuals / plant ) in the fourth week of September 2020 and 2021 during the two seasons , respectively .In September plantation , the tomato bug N. tenuis recorded the highest population density( 5 individuals /plant) in the second week of October 2020 during the first season and ( 8 individuals /plant) in the first week of January 2022 during the second season The highest average number of T. absoluta was estimated in June plantation in the first and second seasons (51.4 ± 12.0 and 60.8 ± 10.9 larvae / plant , respectively). In addition, the highest average number of N. tenuis was estimated also in June plantation of both seasons (285.9 ± 96.1 and 263.4 ± 88.1 individuals, respectively). The numbers of N. tenuis positively coincided with those of T. absoluta, in a significant way, during February and June plantations, but not during September plantation during the two seasons6.2.2. Effect of food type on some biological aspects of the tomato bug N. tenuis.No difference found between the incubation period of the tomato bug eggs of those fed on tomato plants only or on larvae of T. absoluta only presented by ( 7.0 ± 0.49 days) while the incubation period of the tomato bug eggs of those fed on tomato plants with larvae of T. absoluta was shorter presented by ( 6.4 ± 0.21 days (The total developmental stage of the tomato bug N. tenuis recorded the shortest duration when fed on the larvae of T. absoluta or tomato plants with larvae of T. absoluta and presented by ( 13.0 ± 0.33 and 12.4 ± 0.33 days) with no significant differences ,while the longest duration nymphal stage was recorded when tomato bugs fed on tomato plants only and presented by ( 15.8 ± 0.49 days). In case of feeding on tomato plant only, the longevity of N. tenuis adults was shorter than that when predator fed on the other two feeding types and presented by (18.8 ± 0.95 days). The fecundity of N. tenuis female was higher when fed on tomato plants infested with T. absoluta larvae or on T. absoluta larvae presented by (91.6 ± 4.25 egg / female) than those fed on tomato plants only that presented by (43.2 ± 5.5 egg / female).6.2.3 The relationship between the insect pest , T.absoluta and the tomato bug ,N.tenuis . The relationship between , N.tenuis and T.absolta , ( predator – prey ratio ) on tomato plants in different plantating dates , during the two seasons , 2020 and 2021. The very narrowed predator - prey ratio was recorded in June plantation in both yesrs ;2020 and 2021 represented by ( 1 : 0.18) and (1 : 0.23) , respectively. Moreover September plantation in both yesrs ;2020 and 2021 were also narrowed and represented by ( 1 : 2.8 ) and ( 1 : 1.5 ) ,respectively .Meanwhile , February plantation came in the last category in both years and represented by (1 : 22.7) and ( 1:12.4), respectively 6.3. Effect of four solanaceous plants on developmental and population parameters of the tomato leaf miner, Tuta absoluta (Meyrick) under free and no choice feeding conditions. The mean number of the developmental stages of T. absoluta reared on different solanaceous host plants under no choice feeding conditions show that tomato plants recorded the highest average number of larvae followed by egg plants and potato plants and represented by 99.3 ± 5.6 , 52.3 ± 4.1 and 51.3 ± 4.1 larvae / cadge , respectively . No larvae were found in pepper plants . In tomato plants also the larvae developed to pupal stage and adult stage followed by egg plant and potato . Tomato plants exhibted the most preferred host plant for rearing the insect larvae followed by egg plant and potato plants .statistical analysis revealed that , a highely significant differences were recorded between the different solanaceous host plants according to the mean number of the insect developmental stages The mean number of the developmental stages of T. absoluta reared on different solanaceous host plants under free choice feeding conditions show that tomato plants recorded the highest average number of larvae followed by egg plant and potato plant and represented by 37.7±3.5 , 25.3 ± 2.7 and 24.7 ± 2.2 larvae / plant , respectively . No larvae were found in pepper plants . In tomato plants also the highest larvae developed to pupal stage and adult stage followed by egg plant and potato plants . Tomato plants attracted the female insect to egg-laying and exhibted the most preferred host plant for rearing the insect larvae followed by egg plant and potato plants . statistical analysis revealed that , a highely significant differences were recorded between the different solanaceous host plants according to the mean number of the insect developmental stages. The duration and survival rate of the developmental stages of the insect on different solanaceous host plants under no choice feeding conditions show no significant differences in the incubation period or the pupal stage for the tomato leaf miner T. absoluta on different solanaceous host plants . Meanwhile , the larval stage recorded he lowest average duration on tomato plants followed by egg plant and potato plants and presented by 9.0 ± 0.8 , 13.3 ± 0.8 and 14.2 ± 1.8 days, respectively with significant differences.Pepper plants recorded no eggs , larvae or pupae during the experiments . Tomato plants exhibted the highest survival rates for all the immature stages of the insect and recorded 99.3 % , 95.7% and 95.8 % for larval stage , pupal stages and total immature stages , respectively . Egg plant ranked the second category and recorded 94.2% for the total immature stages .while potato came in the third category and recorded 84.4 % for the immature stages The duration and survival rate of the developmenral stages of the insect on different solanaceous host plants under free choice feeding conditions show no significant differences in the incubation period or the pupal stage for the tomato leaf miner T. absoluta on different solanaceous host plants . Meanwhile , the larval stage recorded he lowest average duration on tomato plants followed by egg plant and potato plants and presented by 8.0 ± 0.1 , 9.3 ± 0.8 and 10.2 ± 1.2 days with significant differences.Pepper plants recorded no eggs , larvae or pupae during the experiments . Tomato plants exhibted the highest survival rates for all the immature stages of the insect and recorded 98.8 , 95.7 and 95.5 % for larval stage , pupal stages and total immature stages , respectively . Egg plant ranked the second category and recorded 94.0% for the immature stages .while potato came in the third category and recorded 85.0% for the immature stages Tomato plants recorded the highest female productivity under no choice feeding conditions and presented by125.0 ± 5.0 larva / female followed by egg plant and potato plants 101.3 ±3.0 and 98.8 ± 5.0 larva / female with no significant differences , respectively. The female productivity reared on different solanaceous host plants under free choice feeding conditions show that,tomato plants recorded the highest female productivity under free choice feeding conditions and presented by 63.3 ± 3.2 larva / female followed by egg plant and potato plants 39.5 ±3.8 and 32.5 ± 5.2 larva / female with no significant differences , respectively.