Susceptibility of Four Watermelon Cultivars to Infestation with Tetranyclws urticae Koch.

Abstract

Experiments were conducted to estimate the susceptibility of four watermelon cultivars (A swan, Daytona, Molokai and Giza-I) to infestation with Tetranychus urticae Koch and its population fluctuation during the two successive seasons. summer 2009 and early summer 20 I 0 at Qalubia Governorate. Aswan cultivar was the most highly susceptible recording average of 42.86 and 57.59 mite moving stages/leaf during the two successive seasons, respectively. followed by the moderately infested cultivars (Daytona) recording 28.10 and 39.75 mite individuals during the two seasons. respectively. The lowest infestation was recorded on Molokai and Giza-] cultivars, being 19.18 & 25.90 for the former and 18.10 & 25.94 for the latter cultivar during the two successive seasons, respectively. Susceptibility of watermelon cultivars to infestation with T urticae may be affected by plant leaf morphological structure and its chemical contents. The number of trichomes/cm 2 leaf averaged 647. 78, 744.44, 1111.11 and 1296.67 for Aswan, Daytona, Molokai and Giza-! respectively, the less number of trichomes the more mite infestation. Positive relationships occurred between mite infestation levels and total amino acids, free amino acids, nitrogen and total soluble sugars in watermelon cultivars, while negative relationship found with tannins and nearly shown with total phenolic compounds, total tlavonoids and total carotenes. Mite populations reached its peak during July and May in the first and second seasons, respectively, and infestation was lower in the first season than in the second, which might be due to early plantation.

Population Dynamics of Mite Pests and Predacious Mites on Three Tomato Cultivars at Menoufia Governorate in Egypt

“…The Tomato cultivars were variably infested with T. urticae during early summer plantation. These results were in agreement with those obtained by (Ibrahim et al, 2008;Abdallah et al, 2009, El-Saiedy et al, 2011, Afifi et al, 2013and Ali et al, 2015. Yassin et al, 2014 reported significant differences between the population of T. urticae and Tetranychus cucurbitacearum (Sayed) on Meram, supper-gekal and Rawan Tomato varieties.…”

“…The spider mite was recorded in few numbers in mid-August and gradually increased in number and reached its peak in mid-November/ late October, after that populations decrease in late November (Figure 2). These results were in agreement with those obtained by (Ibrahim et al, 2008;Abdallah et al, 2009, El-Saiedy et al, 2011, Afifi et al, 2013and Ali et al, 2015. Significant negative correlation values for maximum and minimum temperatures ranged from -0.89 to -0.96 with P-values between 0.0024 and 0.0005; whereas the significant positive correlation between T. urticae and relative humidity ranged from 0.80 to 0.88 with P-values between 0.0148 and 0.0077, during Nile season on three Tomato cultivars.…”

“…Mite population numbers may be impacted by the morphological and chemical features of leaves, which often differ from one plant type to another. Many researchers studied the host plant's resistance to T. urticae infestation (Ibrahim et al, 2008;Abdallah et al, 2009;El-Saiedy et al, 2011;Afifi et al, 2013 andAli et al, 2015).…”

Diversity of Piercing-Sucking Pests Infesting Some Plants of Solanaceae and Cucurbitaceae Families

“…On cantaloupe cultivars, comparable findings were stated by Metwally et al (2013) recording significantly in its susceptibility to B. tabaci. Similarly, El-Saiedy et al (2011) found that the watermelon, Aswan cultivar had a high susceptible depending on T. urticae moving stages/leaf, followed by Daytona cultivar which was moderately infestation and Molokai and Giza-1 cultivars had a low infestation. On pepper, Ismail and Heikal (2023) reported that susceptibility to T. urticae infestation varied under greenhouse conditions.…”

Sugar pea leaf contents and their influence on population fluctuations of Tetranychus urticae under field conditions at Ismailia governorate

“…This resistance is mostly influenced by the unique qualities of each cultivar, specifically the physical and chemical properties of their leaves, as evidenced by numerous research studies. Abdallah et al (2009) and El-Saiedy et al (2011) demonstrated that plant cultivars have a considerable impact on T. urticae population density due to variations in the chemical content of their leaves. Furthermore, Potter and Anderson (1982) revealed that the existence of various secondary metabolites, including flavonoids, phenols, and carbohydrates, may explain the varying degrees of resistance observed in response to infestation by T. urticae.…”