الفهرس 
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Abstract
C. melo L. is one of the most important cucurbitaceous vegetable crop cultivated in Egypt and many countries worldwide. The cantaloupe cultivated area was increased during the last years especially in new reclaimed areas to accommodate local consumption and for exportation. The current investigation was conducted over 2015, 2016 and 2017 summer plantation season and 2015 2016 Nili plantation season at Plant Protection Research Institute (Qaha region, southeast of Qalyubiya Governorate) to assess of an Integrated Pest Management program for the control of B. tabaci infesting cantaloupe cultivars in the field.
6.1. Assessement performance of cantaloupe cultivars under B. tabaci attack
The four cantaloupe cultivars, within growth stages, under B. tabaci attack were assessed. Moreover, certain morphological and physiological traits of the cultivars and B. tabaci infestation were summarized in the following:
6.1.1. Effect of different cultivars on infestation rate by B. tabaci
The mean numbers of deposited eggs or nymphs/leaf on the four cantaloupe cultivars (Arava, Majus, Darvina and Royal 481) over summer plantation seasons of 2015, 2016 and 2017 were summarized as follows:6.1.1.1. Preference of cultivars for oviposition
Darvina and Royal 481 were the most preferred cultivar for egg oviposition. Arava and Majus were least oviposited cultivars.
6.1.1.2. Preference of cultivars for nymphal infestation
The highest mean counts of B. tabaci nymphs were recorded on leaves of Darvina followed by Royal 481. However, Arava and Majus cultivars harbored lower nymphal infestation .
6.1.1.3. Effect of infestation rates on the resultant yield
The highest yield of cantaloupe fruits was by Majus 15.7 kg/plot and Royal 481 yielded weight of 14.73 kg/plot. However, the susceptible cultivar Darvina gave moderate weight as 11.9 kg / plot. Arava although with lower rates of infestation gave 6.55 kg / plot, the lowest yield.
6.1.2. Effect of cantaloupe growth stages on the whitefly; B. tabaci preference
B. tabaci eggs or nymphs on the four tested cultivars varied in numbers over the early stage (younger leaves) and late stage (older leaves ).6.1.2.1. Difference between the four cultivars in early and late stages in relation to oviposition preference and nymphal infestation
Royal 481 proved to be the most preferred cultivar for B. tabaci egg oviposition followed by Darvina in early stage. In the late stage Darvina was the most deposited eggs , followed by Royal 481.
Darvina was the most infested with nymphs followed by Royal 481 over early and late stages. Arava and and Majus had the lower numbers of eggs and nymphs in early and late stages.
6.1.2.2. Preference of cantaloupe stages for egg oviposition and nymphal infestation
Generally, eggs were oviposited on high numbers on the younger leaves for 2015, 2016 and 2017. However, the nymph population was low in early stage and was high in the late stage nymphs/leaf in 2015, 2016 and 2017, respectively.
6.1.3 . Morphological characters as shown by SEM
6.1.3.1. Effect of leaf trichome density and length on B. tabaci
egg oviposition in the early stage
Majus cultivar showed high density of trichomes (47.7 trichome /1 mm2) and moderate hair length (209.8 μm). Royal 481 had the lowest mean number of trichomes (20.5 trichome/1 mm2) and longest trichomes (377.7 μm). Darvina had moderate of leaf trichome density and shortest trichome lenght (31.1 trichome/1mm2) and shortest hair (115.1 μm). Arava had moderate trichome density and length (26.2 trichome /1 mm2 and 272.5 μm, respectively).
6.1.3.2. Effect of leaf trichome density and length on B. tabaci eggs deposition in the late stage
As in early stage the highest mean number of trichomes was recorded in Majus (79.5 trichome/1mm2) and longest trichome length of (266 μm). However, the moderate number of trichomes was recorded in Royal 481 and Darvina 43.6 and 38.5 trichome /1 mm2, respectively as the trichome measure 277 and 173.1 μm in lenght, respectively. The lowest mean number of trichomes 27.7 trichome /1 mm2 was recorded in Arava with the shortest trichome length (164.3 μm).
6.1.3.3. Oviposition preference in relation to trichomes in cantaloupe early and late stages
The mean number of eggs in early and late stages were 10.97 and 6 eggs/leaf, respectively. The mean number of trichomes in early and late stages was 31.4 and 37.3 trichome/1 mm2, respectively. The mean length of leaf didn’t significantly differ in early and late stages.
6.1.4. Leaf stomata in cantaloupe cultivars
Darvina and Royal 481 cultivars hosted high numbers of deposited eggs 40.83 and 60.8 eggs/leaf, respectively . They had more closed stomata percentages as 54.3 and 76.2%, respectively.However, Arava and Majus with low numbers of eggs had high percentages of opened stomata 66.65 and 78.6%, respectively.
6.1.5. Role of biochemical element, moisture and enzymes in the tested cultivars in B. tabaci infestation
Biochemical elements and moisture content in leaves dry weight and enzymes activity in leaves fresh weight of cantaloupe cultivars in relation to nymph infestation were summarized as follows:
6.1.5.1. Biochemical elements, moisture content and enzyme activity in the tested cultivars
”Majus ” was found to have lower levels of carbohydrate, highest levels of reducing sugars, lower levels of non -reduced sugar, lower level of total sugars, highest level of potassium, lower level of moisture content, higher level of phenoloxidase and peroxidase enzymes in early and late stages. However, the susceptible cultivar ” Darvina ” had higher levels of carbohydrate, non reducing,total sugars, moisture content. Lowest levels of phenoloxidase and peroxidase. Royal 481 contained high levels of carbohydrates, non-reducing, potassium, phosphorous, and low activity of phenoloxidae and peroxidas enzymes.6.1.5.2. Correlation between biochemical elements, moisture content, enzymes activity and nymphal infestaion in cantaloupe early and late stages
The level of total protein, carbohydrates, reducing, non-reducing and total sugars, potassium and alpha esterases were high in the late stage than the early stage. However, phenols, moisture content, activities of phenoloxidase and peroxidase enzymes were high in the early stage than in the late one. The statistical analysis revealed that, total protein, reducing sugars, potassium and phenols content had insignificant negative response on the insect infestation, however, carbohydrate, non-reducing and total sugars content had positive significant response in the early stage. In the late stage, all tested biochemical elements had insignificant positive response on the infestation, however, enzymes activities decreased by increasing infestation but without significance except with alpha esterases.
6.1.5.3. Correlation between biochemical elements, moisture content and enzymes activity and nymphs infesting the four cantaloupe cultivars
Reduced sugar, total protein, phosphorous and alpha esterases expressed highly significant negative correlation with nymphs infesting all tested cultivars. Moreover, non- reduced and total sugars had strong positive correlation with infestation in all tested cultivars except in Arava. Potassium had positive significant response except in Royal 481.Total phenols had strong negative impact on nymphs infesting cultivars except Darvina. The activities of phenoloxidase and peroxidase were significantly decreased by heavy infestation.
Alpha esterses had highly positive correlation with nymphal
infestation.
6.1.5.4. The role of tannin content in relative resistance of
cantaloupe cultivars against B. tabaci infestation
The highest level of tannins was found in the lowest infested cultivar Majus (423 µg/gm). And, the
lowest content was estimated in Arava (144 µg/gm) followed by Royal 481 (228 µg/ gm).
6.2. Interaction effect of cantaloupe cultivars and sowing date on
B. tabaci infestation and yield parameters
The obtained results over the three years of study indicated that there were highly significant
differences among the three tested sowing dates and among the tested cultivars.
6.2.1. Effect of different sowing dates and cantaloupe cultivars on oviposition preference of B.
tabaci
The lowest mean number of eggs was recorded on leaves of Arava and Majus cultivars over 2015, 2016
and 2017. Darvina and Royal
481 cultivars recorded higher numbers of eggs.
Concerning the effect of sowing dates, the second sowing date (Apr. 2) harbored the highest
infestation over 2015, 2016 and 2017. Third sowing date ( Apr.16 ) showed the lowest mean of
deposited eggs. The first sowing date (Mar.16) had moderate infestation in the
three tested seasons.
6.2.2. Effect of different sowing dates and cantaloupe cultivars on the nymphal infestation of B. tabaci
Arava and Majus hosted lower nymphal infestation in 2015, 2016 and 2017. On the other hand, Darvina and Royal 481 had the highest levels of infestation in 2015, 2016 and 2017. Nymph population in the second sowing date (Apr.2) was the highest in terms of number of nymphs/leaf. The third sowing date ( Apr. 16) recorded the lowest nymphal infestaion. The first sowing date (Mar. 16) showed moderate infestation.
6.2.3. Interaction between cantaloupe cultivars and sowing dates on the resultant yield
No significance differences existed among the yield from dates. Arava, Majus, Darvina and Royal 481 yielded 30.52, 27.48, 17.44 and 14.65 kg/plot, respectively. The first sowing date yielded the highest weight of cantaloupe fruits as 12.22 kg/plot. The second sowing date (Apr. 2) yielded the lowest mean of weight (4.25 kg/plot). The third sowing date gave modertae weight of cantaloupe yield (6.05 kg/plot).
6.3. Interaction between certain weather factors and plant age on the level of infestation with B. tabaci
The interaction between three tested sowing dates and Max.T, MinT and RH and cantaloupe plant age (as third degree of polynomial) on means of deposited B. tabaci eggs and nymphal activity over summer plantation seasons ; 2015 , 2016 and 2017 was summarized as follows:
6.3.1. Effect of weather factors and plant age on deposited B. tabaci egg and nymphal infestation in different sowing dates
Plant age had significant effect on egg laying and nymphal activity in the three sowing daes over three years in most instances. The statistical analysis of the combined data indicated that the egg laying and nymphal infestation were highly influenced by the plant age than the weather factors in most instances.
6.4. B. tabaci infestation and yield production in relation to inorganic fertilization (NK)
The effect of inorganic fertilizers on B. tabaci nymphal infestation over 2015 and 2017. Ammonium sulphate (20.6 % N2) and potassium sulphate (48% K2O) were used in combinations at three rates (40, 50 and 60 units/fed.) as soil treatment .
6.4.1. Effect of the combination of inorganic fertilizers on nymphal infestation over 2015 and 2017
Nymphs decreased as K2O increased as follow 40 N2 + 40 K2O, 40 N2 + 50 K2O and 40 N2 + 60 K2O units with nymph population as 3.95, 3.46 and 2.8 nymphs/leaf, respectively. 6.4.2. Effect of the combination of inorganic fertilizers rates on the resultant yield
Application of N2 at lower rate (40 units) mixed with higher levels of K2O (60 units) gave higher cantaloupe weight as 4.01 kg /plot.
6.5. Reducing B. tabaci infestation using intercropping with non-host aromatic plants
Cantaloupe was intercropped with three non-host aromatic plants garlic, dill or coriander in the open field to study their effects on B. tabaci infestation.
6.5.1.Effect of intercropping cantaloupe on B. tabaci oviposition preference
Cantaloupe intercropped with garlic, dill or coriander received lower infestation compared to monoculture cantaloupe (over 2015).
In the second season of study (2016) cantaloupe intercropped with garlic, dill or coriander had less numbers of B. tabaci eggs.
6.5.2. Effect of intercropping cantaloupe on B. tabaci nymphal infestation
Cantaloupe intercropped with garlic, dill or coriander received lower numbers of nymphs compared to cantaloupe monoculture over 2015 and 2016.