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Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An investigation was conducted at Kaha Vegetable Research Farm in the Kaliobia Governorate from 2021 to 2023 with an aim to evaluate the performance of six inbred lines of summer squash and their fifteen crosses in both open field and plastic greenhouse conditions. The study spanned two successive summer seasons (2022 and 2023) and focused on assessing horticultural traits and resistance levels to the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Significant variations were observed in the mean performance of all traits among different genotypes. Analysis revealed significant differences in both general (GCA) and specific (SCA) combining abilities for all studied traits, except for the number of days to anthesis of the first female flower, indicating the presence of both additive and non-additive gene effects in traits inheritance. In the plastic greenhouse, genotype P3 exhibited the highest resistance with an average of 10.6 mites per 2 inches², while the cross P2 × P6 showed tolerance with an average of 4.4 mites per 2 inches². This study highlights the potential of new summer squash hybrids with desirable horticultural traits and resistance to the two-spotted spider mite. Additionally, parent 222/2 (P1) demonstrated the best combining ability for all traits, while parents 264 (P5) and 240/3 (P4) were the most effective combiners for total yield. Breeders may leverage these parents for genetic enhancement and the production of hybrids with superior horticultural qualities. Overall, this research provides valuable insights for researchers, breeders and farmers involved in the cultivation, breeding and utilization of summer squash in Egypt. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi and predatory mites can independently contribute to control the two-spotted spider mite Tetranychus urticae Koch. It is important to assess the risk of possible fungal infections in predators when a combination of them are being considered as a tandem control strategy for T. urticae in IPM program. The first part of this study tested 4 Beauveria bassiana isolates and 2 Metarhizium anisopliae for virulence against T. urticae, egg and adult stages. Strains B4 was found to be the most potent toward egg and adult stages, causing 88.5% mortality for the adult stage at a concentration of 108 spores/ml. and the LC50 was 6.61x 106. When applied on the egg stage the hatchability was 25.2% compared with the control which reached 99% and the LC50 was 1.14 x107. The second part evaluated the pathogenicity of the most effective isolates B4, three concentrations were applied LC25, LC50 and LC90 against the adult of the two predator mites Phytoseiulus persimilis and Neoseiulus californicus. The bioassay results indicated that the isolate B4 was harmless against P. persimilis and slightly harmful against N. californicus. No viable fungal hyphae were found on predator cadavers. Observations with scanning electron microscopy revealed that conidia were attached to the cuticle of predatory mites within 24 h after spraying with strain B4, and had germinated within 24-48 h. After 48 h, conidia had gradually been shed from the mites, after none of the conidia had penetrated the cuticular surfaces. In contrast, the germinated conidia successfully penetrated the cuticle of T. urticae, and within 72 h the fungus colonized the mite’s body. Our study demonstrated that although several B. bassiana strains displayed a high virulence in T. urticae there was no evident pathogenicity to phytoseiid mites. These findings support the potential use of entomopathogenic fungus in combination with predatory mites in T. urticae control programs. [ABSTRACT FROM AUTHOR]

Results of the present study are based on the ability of the predator mites Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) and Neoseiulus californicus that used as biological control agents to recognize if the prey Tetranychus urticae (Acari: Tetranychidae) is treated with entomopathogenic fungi, and measure their preference toward untreated and treated T. urticae with Beauveria bassiana. In the early stages of the fungus infection predators were able to consume T. urticae treated with the fungus. While after 48 and 72h. P. persimilis and N. californicus were able to determine the treated prey with the entomopathogenic fungi B. bassiana, and prefer to prey on the untreated mites. This avoidance behaviour of the predator mites permits to use them as complementary biological control agents with entomopathogenic fungi in Integrate Pest Management (IPM) program. [ABSTRACT FROM AUTHOR]