الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 113 |  |  |
| | | from | 113 | | |
Abstract
Field experiments were done at the Experimental Farm of Sakha Agricultural Research Station during 2020/2021 and 2021/2022 seasons. The obtained results couldbe summarized as follows: 1. Survey and populations fluctuations of major insect pests: Survey revealed the occurrence of 13 insect species, belonging to 9 families and 7 orders. Coleoptera constitute (7.69%)out of total Surveyed . Diptera (7.69%), Hemiptera (7.69%), Homoptera (30.76); Lepidoptera (30.76%), Orthoptera (7.69%) and Thysanoptera (7.69%). The major insect species are; C. vittata, Pegomyia mixta, Nezara viridula , Bemisia tabaci , Aphis gossypii, Myzus persicae, Empoasca spp., Agrotis ipsilon , Spodoptera exigua, Spodoptera littoralis , Scrobipalpa ocellatella, Gyllotalpa gyllotalpa and Thrips tabaci These insects cause high reductions in sugar and roots yield, especially, Cassida vittata, Scrobipalpa ocellatella and Spodoptera littoralis+ Spodoptera exigua Concerning the population fluctuations Cassida vittata were not detected on the plants till and November. The population density progressively increased towards the end of the season. Scrobipalpa ocellatella was not detetected on the plants till 5 October. The population density progressively increased towards the end of the Season. Spodoptera exigua +Spodoptera littoralis were noticed on 5th October and the population density progressively decreased towards the end of the season during the two seasons. 2. Survey and population fluctuation of insect predators: The survey showed the incidence of of 16 predatory insects species belonging to 9 families and 7 orders.The major insect predators are C. carred, Coccinelladie, 65 Formicidae, Carabidae, Staphylinidae, Syrphus corolla , Orius livigtos , Labidura riparia and Sphodromantis bioculata . Insect predators occurring sugar beet plants were collected for two seasons. The survey was done using bag and cut method , The survey showed the incidence of 16 predatory insects, species, belonging to 9 families 7 orders (Table 5).Coleoptera constitute (50.00%) out of total surveyed species, Hymenoptera (18.75%), Each of Diptera, Hemiptera, Neuroptera,Dermaptera and Dictyoptera were (6.25%) (Fig 1 ).The numbers of these major insect predators in two seasons increased towards the end of the Season. This, mean insect predators we’re synchronized with insect pests. 3. Survey and population fluctuation of insect parasitoids Results darify the occurrence of 12 insect parasitoids species belonging to 8 families (order : Hymenoptera). Species of parasitoids on Scrobipalpa ocellatella constitute (25. 00%) out of total surveyed species. Each of Cassida vittata and Spodoptera spp. were 16.66%.Also, Bemisia tabaci, Nezara viridula, aphids, Pegomyia mixta and Cicadellidae were 8.33% The major insect parasiloids are; Monorthocheata nigra, Diadegma spp., Cotesia ruficrus , Opius nitidulator , Anagrus atomus , Diaeretiella rapae , Encarsia Formosa and Trissolcus basalis. The peaks of parasitoids Coincided with major insect pests (hosts). 4. Survey and population fluctuations of spiders (order : Araneae). The survey indicate that the incidence of 13 spider species, belonging to 9 families (Order: Araneae).The greatest population density was that of linyphid species being 32 indiv. /70 plants, followed by Araneidae (29) , Lycosidae (27), Salticidae (26),Philodromidae (26), Gnaphoside (21), Tetragnsthidae (21), Theridiidae (20) and Thomisidae(20) /70 plants.The numbers of spider species increase towards the end of the two seasons. 66 5. Correlation coefficient waves between major sugarbeet insects and their associated insect predators + parasitoids and Spiders : The highly significant positive correlations were recorded between sugar beet insects and their associated insect predators + parasitoids a nd spiders.These results show that the importance role of natural enemies in controlling these insects.The values of correlation between insects × predators ranging between 0.501**to 0.656** , while the values between insects × parasitoids ranging between 0.633** to 0.761**.On the other hand , the corresponding values of corretation between insect × spiders ranging between 0.601**to 0.721**. 6. Efficiency of certain Insecticides (different groups) on insect pests and their side effect on arthropod predators: Data indicate that ecdysone agonists are efficient in managing sugarbeet insects. At the Same time,these insecticides are safe to predators in comparison with conventional ones during the two seasons.Overall mean of reduction ranging between (72.16 to 86.78%). against insects. Also, (21.40 to 28.38%) against predators due to ecdysone agonists.while, overall mean of reduction in predators populations due to conventional insecticides ranging (97.57-100%). 7. Effect of ecdysone agonists and conventional on root and sugar yield : The results demonstrated that the importance of insecticides in raising sugar and root yield during the two seasons.Highly differences among the plots sprayed with Insecticides and untreated plots ( control) in root and sugar yield during the two seasons.Also, the data showed that no differences among plots Sprayed with conventional and the plots treated with ecdysone agonists in root and sugar yield during the two seasons. These results show that ecdysone agonists play a vital role in reducing insect pests, consequently in raising the productivity of sugar beet 67 crop. At the same time, these insecticides are very safe against predators in comparison with conventional ones. Tables (23, 24 and 25) show that highly differences among the plots sprayed with ecdysone agonists and conventional insecticides and untreated plots ( control) in Root and sugar yield during the two seasons.Concerning, spodoptera spp. root and sugar yield were 9.976 and 1.407, respectively in control plots. Whereas the values were 22.047, 22.023, 22.047, 22.00, 22.047, 22.071, 22.047, 22.00, 22.047 and 22.095 for root yield in plots treated with insecticides.While, sugar yield were 3.750, 3.790, 3.820, 3.790, 3.858, 3.752, 3.926, 3.742, 3.822 and 3.890 for plots treated with insecticides.The same results were recorded in Scrobipalpa ocellatella and Cassida vittata The same results were attaned during the second season.These results demonstrated that the importance of insecticides in protecting sugar and root yield. Also, the results show that no differences among plots sprayed with conventional and plots treated with ecdysome agonists in root and Sugar yield.