الفهرس 
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Abstract
The potato, Solanum tuberosum L. is an important solanaceous crop in many parts of the world. During the last twenty years; the potato cultivated area has steadily increased in Egypt, rendering potato the second most important vegetable crop after tomato. Potato plants are attacked by several pests, such as aphids, whiteflies, leaf miners, potato tuber moth and two spotted red spider mite under Egyptian conditions. These pests affect directly or indirectly plant growth and subsequently, affect the yield.
These investigations were conducted at experimental Farm of the Plant Protection Research Institute, Qaha, Qalubiya governorate, during three successive seasons (2015-2016, 2016-2017 and 2017-2018). The objectives of these investigations were to
1- Survey certain insect and animal pests as well as their associated predators on potato, Solanum tuberosum L.
2- Study the population dynamics of major pests attacking some potato cultivars
3- Study the effect of some ecological factors on population dynamics of potato pests.
4- Effect of different rate of leaf chemical components on rat of infestation by potato pests.
5- Evaluate the efficiency of some untraditional pesticides against sap-sucking pests on potato plants.
To achieve these objectives, three potato cultivars; Sponta, Daiamond, Hatma , were chosen and planted at Qaha experimental Farm of the Plant Protection Research Institute; throughout two successive seasons 2015/2016 and 2016/2017. Each season divided into two plantations (spring and autumn). The spring plantation started from last of January to the end of May, while the autumn season started from mid of September till the 1st week of January. The total study area was 4 kerats cultivated with three different potato cultivars (Sponta, Daiamond and Hatma) during two successive seasons (2015/2016 and 2016/2017), each cultivar was divided into three replicates.
The main obtained results could be summarized as follows:
1. Survey of pests and natural enemies occurred on three of potato cultivars (Sponta, Daiamond and Hatma).
At the first, population of Phthorimaea operculella became rarely in the field. Survey the insect and mite pests infesting three potato cultivars; Sponta, Diamond and Hatma; indicated that, the recorded insect pests are belonging to five orders (Orthoptera, Hemiptera, Thysanoptera, Lepidoptera and Acariformes) contain about eight species (Thisoicetrus littoralis, Nezara viridula, Bemisia tabaci, Myzus persicae, Aphis gossypii, Empoasca decipiens, Thrips tabaci and Phthorimaea operculella) belonging to seven insect families (Acrididae, Pentatomidae, Alyrodidae, Aphidiae, Cicadellidae, Thripidae and Gelechidae). While only one mite pest species (Tetranychus urticae) belonging to family Tetrachychidae was recorded.
The associated neutral enemies: seven species there were (Ischnura sengalensis, Chysoperla carnea, Coccinella undecimpunctata, Coccinella septempuncata, Cydonia vicina nilotica, Aphidius ervi and Amblyseius gossypii) belong to five families (Agrionidae, chrysopidae, Coccinellidae, Braconidae and Phytoseiidae) and five orders were recorded (Odonata , Neuroptera , Coleoptera, Hymenoptera and Acari) as a result of survey of natural enemies which associated with potato pests during two seasons (2015/2016 & 2016/2017).
2. Population dynamics of certain pests infesting Sponta, Diamond and Hatma cultivars of potato plants.
The population dynamics of pests infesting the previous three cultivars of potato during two seasons (2015/2016 & 2016/2017) showed that, the seasonal abundance of the pests were higher during 2015/2016 than 22016/2017 (2806.64 & 2751.57 individual pests / 120 leaflets respectively) irrespective of plantation and verities, The statistical analysis of the total mean number of pests showed significant difference at 0.05% for two plantations and t value equal 2.44. On the other hand the population densities of the pests were higher abundant on autumn plantation than these recorded on spring plantation (2835.79 & 2722.43 individual pests/ 120 leaflets, respectively). Irrespective of varieties and seasons. Total mean number of pests on Sponta, Diamond and Hatma were 1612.75, 2159.24 and 1807.57 individual pests/ 180 leaflets, respectively. The statistical analysis of the total mean number of pests showed significant difference at 0.001% between Sponta and other two cultivars, whereas F value = 35.77 *** LSD= 34.57 pests.
2.1. Population dynamic of certain pests infesting Sponta, Diamond and Hatma cultivars of potato plants
At the first weekly mean number of these pests were higher during 2015 / 2016 than 2016/2017 (2803.64&2751.57 individual pests /120leaflets, respectively irrespective of plantation and varieties. The difference between two seasons was significant at 0.05, whereas t= 2.24.
On the other hand, the population densities were higher abundant on autumn plantation (2835.8individual pests /180 leaflet) than recorded on spring plantation (2751.57 /120 leaflet), irrespective of plantation and cultivars.
According to cultivars, there were significant difference, whereas F= 35.8 sig. at 0.001% L.S.D=34.8 individuals. Hatma cultivar harbored 2130.9/180 leaflet individual, Diamond infested with 1807.8 individual, while Sponta was the least infestation which infested with 1619.8 individuals/ 180 leaflets, irrespective of seasons and plantation.
1.1.1. Autumn plantation, cultivar Sponta:
Statistical analyses of obtained data showed significant difference between weekly mean number of pests during two seasons, whereas F= 26.7 & 27.9 and L.S.D= 42.1 & 38.3 individual for two seasons Tetranychus urticae was the most dominant. According to L.S.D values these pest could be divided into 3 groups on follows: 1st T. urticae ( 47.7%&49.1%) , 2nd group Bimisia tabaci ( 31.5%& 27%),. and 3rd groups which contains Aphis gossypii (5.1%_7.9%), Muzus persica (6.8%&6.9%), Thrips tabaci (6.7%&6.6%) and Empoasca dicipiens (2.2%&2.2%).
Bemisia tabaci
Population density in the first season was higher than that recorded in second seasons (131.6&108.5 insect/ 30 leaflet, respectively). The population density of the eggs had three peaks in 1st season while in the second season recorded 4 peaks. The population density of nymphs recorded four peaks in each season.
Myzus persica
Population formed four peaks in each seasons.
Aphis gossypii
Population density of this pest formed three peaks in each seasons during investigation period.
Empoasca dicipiens
In each seasons had three peaks for each one.
Thrips tabaci
Population of this pest formed 6.7%&6.6% from total pests during two seasons respectively and had four peaks during each seasons.
Tetranychus urtica
Population of this pest formed 47.7%&49.1% from total pests during two seasons respectively. T. urticae had three peaks for eggs & Movable stage during two seasons.