Nondetrimental impact of two concomitant entomopathogenic fungi on life history parameters of a generalist predator, Coccinella septempunctata (Coleoptera: Coccinellidae).

The non-persistent impact of biocontrol agents can be revealed for pest control when associated entomopathogenic fungi (EPFs) negatively affect the natural enemies. In this assay, impacts of Beauvaria bassiana (Balsamo) Vuillemin, and Metarhizium anisopliae (Metschnikoff) Sorokin were studied for their compatibility or side effects on life table parameters of an important generalist predator, Coccinella septempunctata L. The results indicated non-significant impacts of both EPFs on life table parameters of C. septempunctata. The development time (egg-adult) was not significantly different in control (69.79 days) and EPFs treated C. septempunctata (69.35-80.07 days). Both fungi did not induce any significant changes in the fecundity, adult pre-oviposition period (APOP), total preoviposition period (TPOP), and mean generation time (T) as compared to control treatment. Similarly, no difference in fecundity rate of C. septempunctata was observed after EPFs treatment (287.7-288.5) compared to control (290.0). The highest net reproductive rate (R0) occurred in control (87.05 offspring individual-1) and M. anisopliae (86.31 offspring individual-1) as compared to B. bassiana treated beetles (76.97 offspring individual-1). The age-specific fecundity curves indicated that the C. septempunctata had a similar fecundity rate in both EPFs treatments and control. This study demonstrates no significant side effects of B. bassiana and M. anispoliae on the performance and biology of C. septempunctata. Considering the compatibility of both EPFs with C. septempunctata, their combinations can be recommended in various integrated pest management programs.

Molecular characterization and expression patterns of heat shock proteins in Spodoptera littoralis, heat shock or immune response?

The Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.), is a major agricultural lepidopterous pest causing extensive damage in a variety of crops including vegetable, cotton, fodder, and fiber crops. Heat shock protein (HSP) family members play important roles in protecting insects against environmental stressors. In this study, we characterized three putative heat shock proteins (SpliHsp70, SpliHsp90, and SpliHSF) from S. littoralis and analyzed their expression levels in response to heat, cold, ultraviolet irradiation, Bacillus thuringiensis, and Spodoptera littoralis nucleopolyhedrovirus treatments. Significant upregulation of SpliHsp70 was observed in female pupae, while the highest expression levels of SpliHsp90 and SpliHSF were found in female adults. Heat shock triggered increases in SpliHsp levels compared to cold treatment. SpliHsp90 exhibited the highest expression levels during the first 30 min of UV treatment. Both bacterial and viral pathogenic agents effected the regulation of Hsps in S. littoralis. These findings suggest that SpliHsp genes might play significant roles in the response to biotic and abiotic stress, as well as in the regulation of developmental stages.

High Prevalence of Pantoea in Diaphorina citri (Hemiptera: Liviidae): Vector of Citrus Huanglongbing Disease.

As an important insect vector, Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae) transmits the pathogen 'Candidatus Liberibacter asiaticus' (CLas) that is associated with citrus greening also known as Huanglongbing (HLB) disease. The bacterial endosymbionts have a potential role in shaping the host range of insect herbivores and their performance on different host plants, which might affect the endosymbiont distribution in insect populations. Here, we detected and characterized Pantoea endosymbiont in nymph and adult ACP specimens collected from Citrus reticulata Blanco and Cordia myxa L. plants. The phylogenetic tree constructed using endosymbiotic bacteria 16S ribosomal RNA sequences indicated that Pantoea sp. was closely related to Mixta calida, sharing about 98% identity and was grouped with other Mixta and Pantoea endosymbionts. Our findings showed 100% and 92.3% infection of Pantoea in adults while 61.5% and 90% infection of Pantoea in nymphs collected from C. reticulata and C. myxa plants, respectively. Understanding the interaction of endosymbiotic bacteria with ACP associated with host plants could be useful for developing an effective management strategy for both ACP and HLB disease.

Detection of Wolbachia (Rickettsiales: Anaplasmataceae) and Candidatus Liberibacter asiaticus (Rhizobiales: Rhizobiaceae) Associated With Diaphorina citri (Hemiptera: Liviidae) Collected From Citrus reticulata (Sapindales: Rutaceae) and Alternate Host, Cordia myxa (Boraginales: Boraginaceae).

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important insect pest of the citrus crop worldwide. It vectors the pathogen 'Candidatus Liberibacter asiaticus' (CLas) that causes a serious disease known as citrus greening. Here, we tested the infection frequency of Wolbachia and CLas from 100 D. citri individuals collected from two host plants belonging to families Rutaceae (Citrus reticulata Blanco) and Boraginaceae (Cordia myxa L.) using molecular methods. The following trend of endosymbionts infection in adult D. citri was found; 85.4% (35/41) by Wolbachia, and 19.5% (8/41) by CLas collected from C. reticulata plants and 65.4% (17/26) by Wolbachia, and 15.4% (4/26) by CLas in case of C. myxa plant. However, 61.5% (8/13) nymphs collected from C. reticulata and 20.0% (4/20) collected from C. myxa plants were infected by Wolbachia, while no nymph was infected by CLas collected from either host plants. Findings from this work represent the first report of CLas presence in D. citri feeding on C. myxa plants. By studying the presence of CLas with other endosymbiotic bacteria, future basic and applied research to develop control strategies can be prioritized.

Identification of a putative antifreeze protein gene that is highly expressed during preparation for winter in the sunn pest, Eurygaster maura.

A cDNA library generated from the fat body of field-collected, diapausing adults of the sunn pest, Eurygaster maura revealed the presence of a transcript that encodes a protein that shares the distinct physiochemical and structural features of an insect antifreeze protein. The transcript, which is most abundant in the midgut, accumulates in adults as they leave the fields in late summer and migrate to surrounding mountainous areas to overwinter. Transcript abundance again declines when adults return to the fields the following spring. This winter pattern of abundance suggests that this protein may be critical for winter survival in the cold regions where the bug enters its obligatory diapause.